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Ecosystem Service
Assessment of Wetland
Water Purification for the
Shepard Slough Study Area
A Report Prepared for Alberta Environment and Sustainable Resource
Development for the Ecosystem Services Pilot Project
Report Prepared by: Irena F. Creed Consulting
September 6, 2011
FINAL REPORT
Ecosystem Service Assessment of
Wetland Water Purification for the
Shepard Slough Study Area
WOR ht. UREA:
He | FRONT
eee. :
A REPORT PREPARED FOR THE
ECOSYSTEM SERVICES PILOT PROJECT
Irena F. Creed Consulting
September 6, 2011
FINAL REPORT
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ISBN Number 978-1-4601-0280-0 (Printed Version)
ISBN Number 97 8-1-4601-0281-7 (Online Version)
Web Site: http/www. environment. alberta ca
Any comments, questions or suggestions regarding the content of this document may be
directed to
Policy and Legislation Integration Branch
10" Floor, Oxbridge Place
9820 — 106 Street
Edmonton, Alberta T5K 2J6
Fax: (780) 422-4192
Additional copies of this document may be obtained by contacting
Information Centre
Alberta Environment and Sustainable Resource Development
4" Floor, Twin Atria Building
4999 — 98 Avenue
Edmonton, Alberta T6B 2X3
Telephone: (780) 427-2700
Fax: (780) 422-4086
E-mail: [email protected]
PREFACE
Parable of the Catskills watershed that provides drinking water to New York City
“Over time, this watershed ecosystem became overwhelmed by sewage, industnal and
agricultural runoff to the point that the water quality in the city fell below EPA drinking water
standards. An economic analysis provided costs of two alternatives for restoring water
quality. The cost of purchasing and restoring the watershed so that it could continue to
provide the service of punfication and filtration was calculated to be $1 billion. The cost of
building and maintaining a water punfication and filtration plant was $6-8 billion in capital
costs, plus annual operating expenses of $300 million. The City has opted to buy and restore
the watershed, i.e., to let nature work for people
National Science Board, Task Force on the Environment, Environmental Science and
Engineering for the 21st Century: The Role of the National Science Foundation
<http://www.nsf.gov/cgi-bin/getpub?nsb0022> and
<http:/Awww.nsf.gov/nsb/tfe/nsb99133/box1.htm
ACKNOWLEDGEMENTS
| would like to acknowledge Ms. Gillian Kerr, Project Manager of the Ecosystem Services
Pilot Project for her leadership in bringing the discussion of Ecosystem Services as a
mechanism for wetland conservation to the forefront in the Province of Alberta
| thank Dr. Paul Adamus, principal of Adamus Resource Assessment, Inc., Corvallis, Oregon
and Adjunct Professor at Oregon State University for leading the workshop that inspired the
design of the regional assessments presented in this report and for providing insights and
resources during the execution of the regional-basic assessment
| thank Geneva Claessen who oversaw the activities of the consultants hired to conduct the
ecosystem assessments, and members of the Biophysical Working Group and the Socio-
economic Working Group, who provided advice to the consultants during the initial workshop
and who asked many questions about the work which improved the final report. It has been
wonderful to work with such an engaged ground of scientists and managers
| thank Justin Wilkes, Senior GIS Analyst, Geographic Information Office, Alberta
Environment and Sustainable Resource Development who provided data
Finally, | acknowledge David Aldred and Adam Spargo, for their contributions to the work
activities, and to Nicholas Lantz, Samson Girma Mengistu, Christopher Quick, Gabor Sass
and Chuiging Zeng who provided an extra pair of hands to ensure that we met the ambitious
deadline for this contract
TABLE OF CONTENTS
Preface
Acknowledgements
Table of Contents
List of Tables
List of Figures
Executive Summary
1.0
2.0
3.0
40
5.0
Introduction
The Shepard Slough Case Study
Water Purification: An Essential Ecosystem Service
Water Purification: A Comparison of Assessment Approaches
Water Purification: A Demonstration of the “Regional-Basic” Assessment Approach
5.1 Wetland Assets
5.2 Wetland Assessment - Trends
5.2.1 Natural Drivers
5.2.2 Human Drivers
5.2.3 Selection of Trend Period
Wetland Assessment - Conditions
5.3.1 Wetland Functions
5.3.1.1 Wetland Purification Metric 1 (VVP1), Wetland Area
5.3.1.2 Wetland Purification Metric 2 (VVP2), Pollutant Sources
5.3.1.3 Wetland Purification Metric 3 (WP3), Pollutant Removal Potential
5.3.1.4 Wetland Purification Metric 4 (VVP4), Pollutant Transport Potential
5.3.1.5 Wetland Purification Metric 5 (WP5), Potential Significance
5.3.1.6 Wetland Purification Metric 6 (WP6), Recharge Potential
5.3.1.7 Wetland Purification Function Score
5.4 Wetland Water Purification Benefits
Conclusions.
References Cited
Bibliography
Appendices .. sacl ater eats sacebibmaane i bite
A1:COMPARISON OF METHODS FOR WETLAND INVENTORIES .....
A2:COMPARISON OF METHODS FOR LAND USE/ LAND COVER MAPS................
A3:MAPS OF WATER PURIFICATION METRICS 1 TO 6 AND THE INTEGRATED
WATER PURIFICATION SCORE.............. eee Psrteshem
A4:DATA FOR WATER PURIFICATION METRICS 1 TO 6 AND THE
INTEGRATED WATER PURIFICATION SCORE EF eee ns Re eee
A5: RESPONSES TO QUESTIONS FROM THE BIOPHYSICAL AND
SOCIOECONOMIC TEAM LEADERS ON THE REPORT PREPARED FOR
THE ECOSYSTEMS SERVICES PILOT PROJECT ENTITLED ECOSYSTEM
SERVICE ASSESSMENT OF WETLAND WATER PURIFICATION FOR THE
SHEPARD SLOUGH STUDY AREA, dated SEPTEMBER 3, 2011
TABLE 1
TABLE 2
TABLE 3
TABLE 4
TABLE 5
TABLE 6
TABLE 7
TABLE 8
LIST OF TABLES
A wetland assessment framework for water purification services (adapted
from personal communications from Ciara Raudsepp-Hearne, June 24
2011 and Paul Adamus, June 27, 2011)
Definition of ecosystem system terms used in this report (adapted from
Glossary generated by the ESPP on Wetlands Core Team, provided by
Yihong Wang, June 27, 2011)
Hydrological principles for sustainable ecosystem management (after
Creed et al. 2011)
A comparison of two regional wetland assessment approaches (advanced
vs. basic) developed in this study to the WESPUS site wetland
assessment approach (Adamus 2011)
Preliminary list of data resources available to support a Regional-
Advanced wetland assessment approach [with metric codes from Table 4
data quality (Low, Medium, High) reflecting range of data options that are
currently available, and data description providing examples of data that
can be used for derivation of metrics]
Relationship of P-PET (mm/yr) as a function of global climate oscillations
(yearly average. based on water year, June to May) ..
Description of GIS and remote sensing data products and the method of
derivation that were used to estimate water purification metrics (after
Strahler 1957)
Wetland derived water purification benefits .....
IN THE APPENDICES
TABLE A1.1.Comparison of different methods for wetland inventories available for
ecosystem service assessments of the Shepard Slough
TABLE A2.1.Comparison of Land Use/Land Cover (LU/LC) maps available for
ecosystem service assessments of the Shepard Slough.
TABLE A4.1.Metric and water purification scores (WPS) for all wetland complexes
present in 1990, 2000 and 2010 ..
FIGURE 1
FIGURE 2
FIGURE 3.
FIGURE 4
FIGURE 5.
FIGURE 6.
FIGURE 7.
FIGURE 8.
FIGURE 9.
FIGURE 10.
LIST OF FIGURES
The Ecosystem Services Pilot Project's study area —- Shepard Slough
Time series of water quality at government water quality monitoring
stations at an upstream (Bow River at Cochrane - ABO5BHO010) and
downstream (Bow River below Carseland Dam - ABO5BM0010) location
to the study area. Data points reflect annual median of approximately 12
water quality measurements taken at monthly intervals. Downstream TP
and TN median values are approximately 7x the upstream value, whereas
downstream Chiorophyll-a and turbidity median values are approximately
2x the upstream value..........
Size class frequency distribution of “historical” wetland area defined by
three different techniques: (a) aerial photography based “static” approach
(Ducks Unlimited 1965 wetland inventory); (b) GIS (LIDAR) based “static”
approach: (c) satellite (LANDSAT TM imagery) based “dynamic” approach
Size class frequency distribution of “current” wetland area defined by 2005
Ducks Unlimited Canada wetland inventory (based on “growing season”
aerial photography) and 2005 LANDSAT TM imagery (based on August
27" satellite image, influenced by 30 mm storm event that occurred 3
days before image capture)
Fifty-year time series (1960-2010, water years from June to May) of
natural (climatic) drivers of potential change in a wetland’s water
purification service: (a) precipitation minus potential evapotranspiration (P-
PET): and (b) global climatic oscillations that influence P-PET, including
the Multi-decadal El Nifo/Southern Oscillation Index (MEI), the Northern
Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), Pacific
Decadal Oscillation (PDO), and the Southern Oscillation Anomaly Index
Change in urban land use from 1990 to 2000 and to 2010
Fifty-year time series (1960-2010, water years from June to May) of
natural (climatic) drivers of potential change in a wetland’s water
purification service: (a) precipitation minus potential evapotranspiration (P-
PET): and (b) change in wetland area (ha) derived by LANDSAT TM
imagery, with water years selected for trend analysis highlighted
Relationship of P-PET (mm/water yr) versus wetland area (ha), revealing
alternative steady states, with wetlands showing a dry state when P<PET
and a wet state when P>PET
Trends in frequency distribution of water purification scores for wetland
assessment unit: WP1, wetland area
Trends in frequency distribution of water purification scores for wetland
assessment unit: WP2, pollutants within the wetland’s contributing area
FIGURE 11. Trends in frequency distribution of water purification scores for wetland
assessment unit: WP3, purification potential of wetland
FIGURE 12. Trends in frequency distribution of water purification scores for wetland
assessment unit: WP4, purification demands on wetland............................0.......
FIGURE 13. Trends in frequency distribution of water purification scores for wetland
assessment unit: WP5, proximity of wetland to stream or river................
FIGURE 14. Trends in frequency distribution of water purification scores for wetland
assessment unit: WP6, position within wetland’s stream watershed ...................
FIGURE 15. Trends in frequency distribution of aggregated water purification scores ..
FIGURE 16. Change in wetland purification potential from current condition (2010) to
historic condition (1990) .
FIGURE 17. Year 2000 $USD frequency distribution of published studies estimating
economic benefit of wetlands for purification of water supplies
(Kazmierczak 2001) .....
IN THE APPENDICES
FIGURE A3.1 WP1 metric scores for wetlands in Shepard Slough.........
FIGURE A3.2 WP2 metric scores for wetlands in Shepard Slough.........................00ccccecee eee
FIGURE A3.3 WP3 metric scores for wetlands in Shepard Slough
FIGURE A3.4 WP4 metric scores for wetlands in Shepard Slough................
FIGURE A3.5 WP5 metric scores for wetlands in Shepard Slough
FIGURE A3.6 WP6 metric scores for wetlands in Shepard Slough
FIGURE A3.7 Water purification scores (WPS) wetlands in Shepard Slough
EXECUTIVE SUMMARY
There is a critical need for regional scale assessments of wetlands for ecosystem services.
This study reports on a regional scale assessment using Geographical Information Systems
(GIS) and remote sensing (RS) technologies for water purification services provided by
wetlands in Shepard Slough, the study area for the Ecosystem Services Pilot Project (ESPP).
Prototypes were developed for both a basic (readily available GIS and RS data, most of it freely
downloadable from the Internet) and advanced (higher quality datasets with higher spatial
resolution) approach. Due to the severe time constraints of the contract (during which we were
unable to gain access to the required data for the advanced approach), only the “Regional-
Basic” approach was implemented. Based on this Regional-Basic approach, we found
monetary benefits to increase from 1990 to 2010 for water purification, with the monetary
increase due mainly to an increase in wetland area defined by inundated water. We expect the
“Regional-Advanced” approach to provide a more precise analysis, as the basic approach is
based largely on the area of wetlands for water purification and ignores many of the other
wetland features important for water purification
The following recommendations are made:
1. Ecosystem services selected for the ESPP are based on different wetland inventories,
wetland areas, and functional attributes, as a result of work completed by three different
consulting groups in a timeframe too short to allow for effective coordination of activities.
Each ecosystem service assessment should be based on common ground rules
including common wetland assessment units and common time periods for assessment
of trends to enable realistic comparison among the ecosystem services and to enable
fair trade-offs to be made between various services. For future ecosystem service
assessments, it is recommended that a consensus be reached as to the (scientific
and technical) definition of wetland assessment units and the period of time over
which the change in condition of wetland assessment units will be considered;
and/or that one individual/group be tasked to provide these foundational data
layers for the purpose of ecosystem service assessments.
Ecosystem service assessments should be designed that (a) capture the dominant
ecological and hydrological processes, and (b) reflect the availability of data to develop
and test the ecosystem service assessments. For future ecosystem service
assessments related to water quantity and/or quality, it is recommended that the
selected areas be based on a hydrological system, e.g., sub-watershed or
watershed, with consideration of Government of Alberta water quantity/quality
monitoring sites for ecosystem service assessment validation.
The recommended methodology (the “Regional-Advanced approach) was not
completed, not because it was too labour intensive, but rather because of delays in
receiving specific data. There is a need for more effective and efficient data
management to support ecosystem service assessments. For future ecosystem
service assessments, it is recommended that all data providers be brought
together to compile, coordinate and evaluate what data are available for the
assessment.
Until site and regional assessments are directly compared, it will be difficult to precisely
assess the overall utility in estimating ecosystem services at various scales of planning
For future ecosystem service assessments, it is recommended that site
approaches (WESPUS) are benchmarked to regional approaches, including the
Regional-Basic (sensu Cobbaert) and Regional-Advanced (sensu Creed)
approaches. Recent initiatives both by the ESPP project activities (led by Kerr)
and AWRI-Wetland Health project activities (led by Bayley) provide site based
assessments of about 100 wetlands throughout southern Alberta that can now be
used to benchmark regional wetland assessment approaches.
Current inventories do not factor in the temporal dynamics of wetlands including
inundated and saturated areas. For future ecosystem service assessments, it is
recommended that a combination of LIDAR, Landsat/SPOT, and SAR imagery are
used to map wetlands (both inundated (open water) and saturated areas), and
determine their spatial and temporal dynamics over changing climatic conditions
and response to human activities. It is also possible to determine wetland type
(i.e., bog, fen, marsh, swamp) which may result in different influences on water
purification potential.
Regional climate is defined by two steady states (wet and dry). These different states
strongly influence the presence of inundated (open) water on the landscape. Identifying
and understanding the presence of climate regimes and drivers is important to allow
quantification of human driven impacts on wetlands. Understanding the link between
Climate and surface water dynamics allows the incorporation of this natural driver into
human drivers of wetland function. For future ecosystem service assessments, it is
recommended that the range of natural variation in wetland function (area) due to
natural drivers (climate) should be defined using a combination of historic
meteorological and remote sensing data.
Natural drivers cause substantial variation in wetland structure and function, and it is
important to understand this natural variation so that accurate estimates of ecosystem
services can be achieved. One could monitor this natural variation on an annual basis.
Alternatively, one could use the maximum extent of wetlands based on climate normal
(past 30 years) or some other reasonable climate period to estimate the maximum
potential for ecosystem services related to water purification. For future ecosystem
service assessments, it is recommended that regional wetland assessments be
designed to consider both spatial and temporal dynamics of wetland function.
For the ESPP, regional assessments for the ecosystem services provided by wetlands
were done independently, considering one service at a time. For future ecosystem
service assessments, consideration of the potential for interaction effects of
ecosystem services is needed so that trade-offs among ecosystem services may
be considered.
1.0 INTRODUCTION
The Ecosystem Services Pilot Project (ESPP) is intended to demonstrate a rigorous quantitative
approach to ecosystem service assessments that will empower decision makers in the Province
of Alberta. Decision makers have identified gaps in current policy tools, including insufficient
evidence to support avoidance, mitigation and compensation decisions on wetlands; insufficient
consideration of cumulative effects and long-term consequences of decision making; and limited
ability to communicate the values of wetlands to developers and decision makers. To fill these
gaps, the ESPP hired consultants to conduct a biophysical assessment of wetland ecosystem
services that would advise the social and economic assessments that are occurring
concurrently.
Specifically, the consultants were asked to:
e Develop documented tools and techniques for ecosystem service assessments of
wetlands that are user friendly and based on existing data;
e Apply these tools to the ESPP to provide ecosystem service assessments of the past,
present and future condition and trends (e.g., past 20 years, future 10 years); and
e Apply these tools to the ESPP to determine the magnitude and distribution of ecosystem
services that wetlands provide or contribute to at regional and site-specific scales.
The ESPP Steering Committee selected the following ecosystem services as initial focal points:
(1) flood control/water supply/storage; (2) water purification/quality; and (3) carbon storage
Three consultants were selected to pursue the three selected ecosystem services, including O2
Planning + Design Inc. (led by George Roman) for water supply/storage and flood control, Irena
F. Creed Consulting (led by Irena Creed) for water purification/quality, and Ducks Unlimited
Canada (Pascal Badiou) for carbon storage. Each consultant was asked to produce a report
that describes: the metrics, functions, values, services being measured and/or mapped; the
approach taken, including potential metrics and units of measurement; the data assumptions
and limitations (e.g. spatial and temporal availability and resolution); description of how the
information produced is relevant to answering the wetland approval gaps identified previously;
list of elements of the ecosystem services that are important and need to be highlighted for
decision makers; and identification of elements of the ecosystem services which are
approaching a threshold that places human well-being at risk.
The contract started June 27, 2011, with a draft report submitted August 6, 2011, and a final
report submitted September 6, 2011. During the month between submitting the draft and final
reports, questions were received from members of both the Biophysical and Socioeconomic
working groups, and these questions were not only answered (See Appendix 6) but were the
basis for the revisions made to the final report. It is important to note that our wetland
assessment approach for water quality was not selected based on data available for the
Shepard Slough, but rather on data for which data sharing agreements were established and
data were received by July 25, 2011.
RECOMMENDATION #1:
Ecosystem services selected for the ESPP are based on different wetland inventones, wetland areas, and
functional attributes, as a result of work completed by three different consulting groups in a timeframe too
short to allow for effective coordination of activities. Each ecosystem service assessment should be
based on common ground rules including common wetland assessment units and common time pernods
for assessment of trends to enable realistic comparison among the ecosystem services and to enable fair
trade-offs to be made between various services. For future ecosystem service assessments, it is
recommended that a consensus be reached as to the (scientific and technical) definition of
wetland assessment units and the period of time over which the change in condition of wetland
assessment units will be considered; and/or that one individual/group be tasked to provide these
foundational data layers for the purpose of ecosystem service assessments.
2.0 THE SHEPARD SLOUGH CASE STUDY AREA
The Shepard Slough straddles the eastern boundary of the City of Calgary, and reaches into
Rocky View County and the Town of Chestermere (Figure 1). This endorheic flatiand at the
eastern flanks of the foothills to the Rocky Mountains was chosen by the ESPP Steering
Committee because it was hydrologically isolated from major water courses (G. Kerr, personal
communication, June 21, 2011); a fact that has since been debated. As such, these lands are
seen as an ideal location for ecologically “green” infrastructure that will satisfy multiple functions
and services such as revitalized wetland habitat for biodiversity, water storage, water
purification, flood control and carbon sequestration
The Shepard Slough study area comprises 267 km* of rolling prairie landscape, which contains
( y C
thousands of depressions. Given that the depressions are underlain by low permeability
surficial geological materials, meltwater, as well as groundwater, discharging from deeper
flowpaths, collects in these features and transforms many of them into marshy or reedy pools
termed sloughs. The relatively low annual precipitation and high evaporative demand during the
summer makes most of these wetlands ephemeral in nature, although larger ones can be
described as permanent water bodies. The sloughs range in size from small pools to large
shallow lakes that have provided wetland habitat for waterfowl and waterbirds for millennia. Ina
recent survey, several bird and amphibian species, as well as two grassland communities and
species, were found that are listed either as provincially rare or species of concern (AECOM
2011)
Urban and agricultural development has led to the disappearance of many of the wetlands over
recent years, a result of draining for either land conversion or the construction of irrigation
ditches and canals (City of Calgary 2004). Despite this, due to legacy effects of increasingly
wet years, an increase in inundated water on the landscape has been observed in Landsat
imagery. The two main built water conveyances are the Western Headworks canal and the
Shepard Ditch. Western Headworks transports water from the Bow River and stormwater from
subdivisions lying to the north and feeds the artificial Chestermere Lake. Shepard Ditch was
built early in the 20th century in order to alleviate flooding problems surrounding the Canadian
Pacific railway line
All of these changes to the drainage of this area have raised concern regarding water quality
impacts to the Bow River, which now receives water through the Shepard Ditch. In addition
increased stormwater flows into Chestermere Lake have decreased the water quality of the
lake, raising concerns of local residents. Apart from a water quality measurement station at
Chestermere Lake, there are no other monitoring stations that can provide useful water quality
indicators regarding the impact of development within the study area. The closest upstream
and downstream water quality stations on the Bow River are so far removed from the study site
(Figure 1 - inset) that it is impossible to determine the impact of development within the study
area on the Bow River. As expected, downstream measurements indicate that the City of
Calgary and abutting lands have a significant negative impact on the water quality of the Bow
River, leading to seven fold increases in total phosphorus and total nitrogen and doubling of
chlorophyll —a and turbidity levels (Figure 2). Government of Alberta personnel (Karen Raven
pers. Comm.) indicated that the pollutant of primary concern in the Calgary region, is
phosphorus, although nitrogen should be a concern as well, with the greatest risk for
phosphorus and nitrogen pollution from untreated sewage effluent and agricultural run-off
Carrying fertilizers. It is not known if the Shepard Slough lands are improving or deteriorating
water quality within the Bow River
Recently, the City of Calgary, along with the Government of Alberta, have recognized the
potential value of this area in terms of habitat for wildlife, as well as the provision of services for
humans in terms of water purification and flood control. In 2003, under the Shepard Stormwater
Diversion Project, stormwater from parts of the City of Calgary has been diverted from
Chestermere Lake into a constructed wetland complex (Shepard Constructed Wetland), 240 ha
in size which eventually drains into a widened Shepard Ditch. It is planned that these
constructed wetlands will ultimately treat more than 50 per cent of the stormwater from
Calgary's east industrial parks and subdivisions to the north. Studies are required to determine
the effects on water quality in the large receiving bodies of water such as the Bow River and
Chestermere Lake, as well as the smaller wetlands dotting this area
RECOMMENDATION #2:
Ecosystem service assessments should be designed that (a) capture the dominant ecological and
hydrological processes and (b) reflect the availability of data to develop and test the ecosystem service
assessments. For future ecosystem service assessments related to water quantity and/or quality,
it is recommended that the selected areas be based on a hydrological system, e.g., sub-watershed
or watershed, with consideration of Government of Alberta water quantity/quality monitoring sites
for ecosystem service assessment validation.
Ee es. ae ee
ee Kilometers
er
——
Cochrane
*
Carseland
*
Lakes and Reservoirs
Natural Conveyances
Study Area Boundary
| | | City of Calgary Boundary C
i
Canals
Ditches |
Roads i
*% Water Quality Stations
FIGURE 1: The Ecosystem Services Pilot Project’s study area — Shepard Slough
UPSTREAM DOWNSTREAM
—
Total Phosphorus (mg/L)
Total Nitrogen (mg/L)
1990 1995
UPSTREAM DOWNSITR
Chi-a (ug/L)
Turbidity (NTU)
1985 1990 1995 y : 1990 1995
FIGURE 2: Time series of water quality at government water quality monitoring stations at an
upstream (Bow River at Cochrane - ABO5BHO0010) and downstream (Bow River below
Carseland Dam - ABO5BM0010) location to the study area. Data points reflect annual median
of approximately 12 water quality measurements taken at monthly intervals. Downstream TP
and TN median values are approximately 7x the upstream value, whereas downstream
Chlorophyll-a and turbidity median values are approximately 2x the upstream value
3.0 WATER PURIFICATION: AN ESSENTIAL ECOSYSTEM SERVICE
Water quality refers to the physical, chemical and biological properties of a water supply. Water
purification is the improvement of water quality by the removal of contaminants from a water supply.
In this report, we focus on sediments and nutrients (nitrogen and phosphorus) as contaminants
Wetlands provide natural water purification through biophysical processes whereby natural
assets such as plants, fungi, bacteria, and animals remove harmful contaminants, pathogens
(bacteria/viruses), metals, persistent organic pollutants, excess nutrients, and sediments as
water moves through the wetlands and their associated contributing areas. Water purification
depends on water infiltrating soils and removal of pollutants by adsorption to soil particles and/or
absorption by living organisms in the soil or water. These “natural” purification processes
provide clean drinking water and water suitable for human (recreation, industrial, agricultural)
and non-human (biodiversity) uses
Natural water purification is a function of the rate of water movement through the system and
the integrity of purification processes related to the affinity of substrates to adsorb or absorb
(metabolize) contaminants in the water.
Human activities can degrade the purification potential of wetlands by: (1) altering water flow
pathways such that water by-passes (flows above or below) the natural purification system of
the riparian buffers; (2) increasing sediment and nutrient loads beyond the purification potential;
and/or (3) damaging the riparian buffers and thus its purification functions. The consequences
of these degradations to the purification potential of wetlands are that sediments and nutrients
may enter the water supply un-attenuated.
For example, human activities can decrease purification capacity of wetlands due to different
alterations to the hydrological system. Perhaps most importantly, soil compaction significantly
reduces the infiltration capacity of soils resulting in decreased infiltration where by polluted
water is then delivered directly to surface waters. In the extreme case of impervious surfaces
(e.g., roads, parking lots, highways, and buildings) all of the water is conveyed quickly into
receiving waters or city drains. Altering water flow (rate and direction) within a hydrological
system can also result in large changes to purification processes. Changing water flow
processes and/or pathways can result in changes to the oxygen content of soils that may have
differential effects on the fate of nutrients (e.g., N removal depends on transformation to N2O/N>
that requires oxygen poor soils whilst P removal depends on adsorption to soil particles that
requires oxygen rich soils).
Furthermore, human activities can increase pollutant loading to water through urbanization and
industrialization in the form of point source (e.g., factories) or non-point sources (e.g., fertilizer
applications to agricultural fields).
Finally, human activities can change the composition of organisms within or adjacent to
wetlands by introducing species with different nutrient fixation, transformation, and/or uptake
potentials that may fundamentally alter the nutrient cycling potential of a wetland. The three
zones that provide an important function in water purification are: emergent zone, wet meadow
zone, and riparian upland zone. The species composition within these zones plays an important
role in the sediment and nutrient retention potential of the wetland.
For example, an emergent zone dominated by Typha spp. would result in the accumulation of
nitrogen in the biomass (Zedler 2000), as could Alder trees with symbiotic N2 fixing bacteria
(Hurd et al 2001). Picard et al (2005) found that monocrop microcosms of three plant species
(Scirpus validus, Phalarisarundinacea and Typha latifolid) removed nutrients under
experimental conditions. An additional treatment combining these three species with another
(Carex lacustris) also removed nutrients, suggesting that biodiversity can be maintained when
planning for nutrient removal.
The most important part of a wetland’s contributing area is the riparian area located directly
adjacent to it. In many landscapes a riparian area of adequate width can be very effective at
reducing sediment and nutrient loads before they reach the wetland proper. As a result removal
or alteration of riparian areas (e.g. wet meadow zone, riparian shrub, and forest zones) reduces
the ability of wetlands, streams and rivers to cleanse themselves.
Provincial guidelines have been developed that define riparian buffers for streams (30m), rivers
(60m) and lakes (100m) (Alberta Environmental Protection 1994). Municipal guidelines are
more liberal, requiring a 6m riparian buffer from water sources for development approvals
(Municipal Government Act 2010). However, adaptive rather than standard, riparian buffer
widths are advised, as the conditions required for effective purification function may vary greatly
among wetlands. For example, in the boreal plains, Creed et al. (2008) found that hydrological
flow pathways influence the formation of surface or near surface saturated areas (i.e., wet
areas), and that riparian buffers should be defined by the extent of these wet areas to reduce
sediment and nutrient (e.g., N) loads as they are transported to surface waters.
In general, the economic valuation of ecosystem services is very difficult. However, with
respect to water purification it is perhaps easier to quantify. The classic example of putting a
price tag on water purification comes from New York City, where the state opted to spend $1
billion to restore the Catskills watershed that provided New York City’s drinking water rather
than to spend $8 billion on building a new treatment facility and paying annual operating
expenses of $300 million.
Using this example, the US National Research Council (NRC) developed four recommendations
in terms of a watershed management strategy for a potable water supply in New York City (NRC
2000 Watershed Management for Potable Water Supply: Assessing the New York City
Strategy).
NRC (2000) Watershed Management for Potable Water Supply:
Assessing the New York City Strategy
The watershed management program should be prioritized to place importance first on microbial
pathogens, second on organic precursors of disinfection by-products, third on phosphorus, and fourth
on sediment and turbidity.
The concept of balancing watershed rules and regulations with targeted support of watershed
community development is a reasonable strategy for NYC and possibly other water supplies.
Water supplies should be receptive to the possibility of additional treatment options.
Efforts to quantify the contribution of watershed management to overall reduction of risk from
waterborne pollutants.
In this report, we focus on the last point of the NRC document: “Efforts to quantify the
contribution of watershed management to overall reduction of risk from waterborne pollutants”
The framework we adopted is shown in Table 1, with terms defined in Table 2. We identify four
steps, three of which are completed, in this wetland assessment for water purification services:
(1) establish wetland assets; (2) estimate water purification service, which is related to both
function and value; and (3) convert ecosystem service scores to dollars. This framework was
defined for the ESPP by the Biophysical Team working group during the Calgary meeting (June
24, 2011).
In this report, we illustrate how Steps 1-3 could be approached, including a basic economic
valuation that was developed in consultation with Paul Adamus, an advisor to the ESPP. In no
way is this basic economic valuation intended to replace the socioeconomic teams assessment;
rather, it is to showcase one way of doing an economic valuation from which the socioeconomic
team may benefit. We were advised not to complete a scenario analysis (Step 4), as this would
be the focus of future ESPP activities.
TABLE 1: A wetland assessment framework for water purification services (adapted from
personal communications from Ciara Raudsepp-Hearne, June 24, 2011 and Paul Adamus,
June 27, 2011).
ee Pera ar
he ES
Se
“ESTABLISH wetiand assets
x
Wetland area (ha)
Change in indicators related to
functional effectiveness of a specific
wetland, the opportunity to remove
pollutants of that wetland, the
potential significance of the wetland
to upstream and downstream water
users, and the cumulative effect of
the wetland on regional water
supplies (see Section 4: Table4)
| FUNCTIONS relating to water
infiltration; nutrient cycling; water
purification by soils and vegetation;
regulation of runoff, removal of
sediment, nitrogen and phosphorus
from runoff, removal of sediment,
nitrogen and phosphorus from surface
and/or ground water
VALUES related to context of wetland
processes with respect to upstream
supply of pollutants and downstream
demand for purified water
ESTIMATE water purification
service, which reflects both
functions and values
BENEFITS from water purification by
wetlands on the landscape, including
improved quality of water for drinking
recreation, aesthetic appreciation, and
reduced risk of health complications
Change (% or $) in water treatment
costs (related to increase in
magnitude of pollutants due to
removal of wetlands and/or
reduction of wetland capacity to
remove pollutants due to
development pressures)
CONVERT ecosystem service
scores to dollars (To be done
by the Socioeconomic Working
Group)
Change in health care costs (% or
)
Change (% or $) in water treatment
CONDUCT a scenario SCENARIOS generated using regional-
analysis for decision makers
(To be done in future phase of
ESPP)
scale models (e.g., MARXAN) to
establish wetland management targets
that best minimize adverse impacts to
water quality from wetland loss
costs
Change in health care costs (% or
$)
IDENTIFY policy indicators for
decision makers
POLICIES developed to meet wetland
management targets
Avoided cost of water treatment
TABLE 2: Definition of ecosystem system terms used in this report (adapted from
Glossary generated by the ESPP on Wetlands Core Team, provided by Yihong Wang,
June 27, 2011).
Fr Bi Sy TS
‘Natural Asset
The quantity or store of a natural resource from which ecosystem services are
provided
Ecological Integrity
The ability of an ecosystem to maintain its principal characteristics, within historical
ranges of variability, over a long time period
Ecological Condition
The relative ability of a wetland to support and maintain its complexity with respect
to ecological processes as compared to wetlands of a similar class without human
alterations
Ecological Process
A characteristic physical, chemical and/or biological activity that influences the
flow, storage and/or transformation of materials and energy within and through
ecosystems
Ecological Function
A process that is necessary for the self-maintenance of an ecosystem and its
integrity
Ecological Metric
An easily measured quantity that serves as a proxy or surrogate for more difficult to
measure characteristics of ecosystem condition
Ecological Indicator
A composite of metrics used to represent a particular characteristic of a system
Ecological Value
A value that is provided by the function, that is defined both by its upstream
demand for the ecosystem service (e.g., upstream areas contain pollutant sources
that need purification) and its downstream supply of the ecosystem service (e.g
downstream water users rely on a pure water supply provided by the wetland)
Ecosystem Service
A combination of the process and its value
Driver
Any natural or human-induced factor that directly or indirectly causes a change in
an ecosystem
Cumulative Effects
The combined effects of all past, present, and reasonably foreseeable future
human activities on an ecosystem
Cumulative Benefits
The combined benefit that all wetlands are providing to ecosystem services
Cumulative Effects
The combined effects of all past, present, and reasonably foreseeable future
human activities on an ecosystem
Threshold
A change in driver that results in a problem condition in an ecological, economic, or
other system
Scenario
A plausible and often simplified description of how the future may develop based
on a coherent and internally consistent set of assumptions about key driving forces
and relationships. Scenarios are neither predictions nor projections and sometimes
may be based on a “narrative storyline”
Policy Indicator
A quantitative measure that provides a means to communicate effectively with
policy-makers regarding conditions and trends in ecosystem services
Water Purification
The removal of contaminants from a water supply for human use. In this report,
contaminants refer to sediment and nutrients (nitrogen and phosphorous)
Water Quality
The physical, chemical and biological properties of a water supply. In this report,
water quality focuses on sediment and nutrient (nitrogen and phosphorous)
concentrations in the water supply
4.0 WATER PURIFICATION ASSESSMENT APPROACHES
There is a critical need for the development of a tool for remote and rapid assessments of
wetland ecosystem services, which would use only remote sensing (RS) data and existing GIS
layers. Such a tool would be extremely useful for wetland avoidance, assessing cumulative
effects to wetlands from development across large regions, and assessing the cumulative
benefits of wetlands. For these reasons, it would form an important planning tool (P. Adamus,
Pers. Comm., July 25, 2011).
In order for a wetland purification assessment approach to be scientifically rigorous it needs to
be rooted in principles that are statements of fundamental truth about the biophysical form and
function of a hydrological system. The principles that guide our assessment approach are listed
in Table 3. These hydrological principles espouse a system’s approach which considers the
proper spatial and temporal context of a hydrological system under consideration, either for
study or management. Other key considerations within these principles are hydrological
connectivity, redundancy and diversity. They all need to be properly accounted for in order to
manage ecosystems on a sustainable basis.
In developing this remote and rapid assessment tool, we recognized the need for data that were
accessible and/or affordable and for which there was complete coverage for the Province of
Alberta. Currently, most Government of Alberta (GOA) data are “static” - one map based on
one snapshot. Wetland assessments for ecosystem services require not just a synoptic (one-
time) assessment of wetland conditions, but rather a trend in wetland condition ideally over a
generation (30 years). Some Government of Alberta datasets are “dynamic’(e.g. Landsat and
SPOT coverage) but often have a trade-off. The trade-off is spatial resolution: the datasets with
the highest temporal frequency of observation have decreased spatial resolutions. The data
selected for this report reflect these tradeoffs, with the Government of Alberta of having the best
spatial and temporal coverage for each of the data layers used to define the water purification
functions and values.
In selecting the remote and rapid assessment toolkit, we hold the benchmark for comparison as
the Wetland Ecosystem Service Protocol (WESP) that was developed for the United States
(WESPUS) by Dr. Paul Adamus and presented at an ESPP workshop attended by the
consultants(June 24-26, 2011). We need to emphasize that our understanding of WESPUS is
that it focuses on water purification issues related to sediment, nitrogen and phosphorus
removal and not other pollutants or contaminants (including metals, persistent organic
pollutants, bacteria, and viruses).
1. Site Assessment
(after WESP, Wetland Ecosystem Services Protocol, after Adamus 2011)
e Assessments are based on a large number of metrics. While there are assumptions and
associated errors with each metric, if averaged, the uncertainty associated with each
metric appears to cancel out, leaving more intuitively correct results;
Assessments are conducted on individual wetlands;
It is field-based and uses expert and local knowledge, making it customized to each site;
and
It is wetland-specific, with metrics that define functions and values specific to individual
wetlands.
WESP conducts an in-depth, process-based analysis of a small area, providing a stronger
ranking of wetlands, but it does not enable all wetlands to be ranked in the near future,
prolonging avoidance decisions.
TABLE 3: Hydrological principles for sustainable ecosystem management (after Creed et
al. 2011).
Delineate hydrological system Delineate hydrological system boundary based on knowledge of
boundaries | dominant hydrological flowpaths (many hydrological systems will
Consider the entirety of the coincide with topographic boundaries but in some places other factors
hydrological system within which control hydrological response units)
management actions take place
identify critical hydrological A) Minimize disturbance to soils, especially within or near source areas
features that focus the recharge of water into subsurface pathways
Lippe me eee -e okueselee (e- ma B) Minimize disturbance in filter areas around streams, wetlands and
Le UE mele Be lice mic sem lakes, and other sensitive sites (required buffer width will depend on
and storage functions dominant hydrological processes in given locale to maintain water
quality of receiving water bodies)
C) Minimize disturbance to storage areas (such as permanent and
ephemeral wetlands)
Maintain hydrological A) Consider the interconnectedness and interdependence of water
pathways through watersheds when developing management plans (i.e
Minimize disruptions to water, look beyond the wetland proper and consider where the wetland occurs
sediment, nutrient flows within with respect to the watershed and water flows)
terrestrial system B) Locate roads, bridges, culverts, and areas of impact to ensure
surface and subsurface hydrological connectivity is maintained and flow
is neither impeded nor enhanced
Respect temporal variability A) Recognize there is natural variability in hydrological processes at
Acknowledge temporal (historic) multiple scales from daily to multi-decadal
factors that influefice hydrological B) Recognize there is human induced variability in hydrological
processes — Hees processes of different severity (from past management practices to
= climate change)
C) Recognize the timing, frequency, and magnitude of extreme events
may be changing because of the interplay between natural and
anthropogenic factors that are hard to separate
Respect spatial heterogeneity A) Consider how scale influences dominance of hydrological processes
Acknowledge spatial (geographic (moving from headwaters to regional basins)
and scale) factors that influence B) Consider how geographic context influences dominance of
hydrological processes hydrological processes, including climate, bedrock geology, surficial
geology, soil type and depth, topography and its influence on the
, . drainage network, and vegetation type and age
Maintain redundancy and A) Consider watershed functions that might be most impacted by future
diversity extreme events and plan to protect features that perform those functions
Manage with the ethos that B) Consider multiple ecosystem services when assessing “trade-offs” in
redundancy and diversity of making development choices (optimization for one ecosystem service
hydrological form and function may occur at the cost of another)
contributes to an ecosystem that C) Consider the interactive nature of the hydrological system with
can absorb outside disturbances climatic, geomorphic, ecologic, and socio-economic systems
In our pursuit of regional assessments, it must be emphasized that regional assessments do not
replace site assessments altogether. Perhaps at the regional planning stage they do, however,
even for regional approaches there will always be a need for ground calibrations of the remotely
derived products especially when working in new areas.
For individual permit decisions, regional assessments should not be a substitute for a field-
based tool, like WESPUS, except in instances where wetlands are physically inaccessible (as in
large areas of Alberta) or property access cannot be obtained. That is because there are
important metrics of some wetland ecosystem services that are assessed much more accurately
during a site visit (and the converse is true also). A fruitful way forward will be the clear
articulation of the complementary nature of site and regional approaches at different parts of the
planning process.
2. Regional-Basic Assessment
(after US Rapid Assessment Methodology (RAM), customized for Alberta by Cobbaert
et al. 2010)
e Assessments are based on a small number of metrics, providing transparency, though
this does not necessarily lead to intuitive results;
Assessments are conducted on many wetlands concurrently;
It is GIS based (static maps), once calibrated with field data; and
It is wetland-general, with metrics that define functions and values to many wetlands
within the region. This would allow all wetlands to be ranked easily, helping to inform
avoidance decisions sooner. However, the product is a potentially weak ranking of
wetlands.
3. Regional-Advanced Assessment
(after WESP, customized and regionalized for Alberta by Creed, this project)
e Assessments are based on many metrics;
e Assessments are conducted on many wetlands concurrently, enabling both region- and
site-based assessments (reflecting a systems-based approach);
It is a GIS and RS based approach, using datasets that are generally available but not
currently used by the GOA. This approach will enable consideration of both spatial and
temporal dynamics (an improvement of even the site assessment); and
It has reduced reliance on local experts, enabling it to be usable at broad scales, but
with a richer understanding/data inclusion than is currently possible with the REGIONAL-
BASIC approach.
The merits of each approach were discussed and debated at meetings with the Biophysical
Team held during the week of the Paul Adamus WESPUS workshop (June 24-26, 2011), with
concerns related to the trade-offs of selecting one over the other identified.
We opted to proceed with the Regional-Advanced approach, as it was more consistent with the
assessments currently being developed by the Alberta Water Research Institute (AWRI),
Wetland Policy project (Bayley, Creed, Foote, and Krogman). We proceeded to develop the
metrics, functions and values for this Regional-Advanced approach (Table 4). However, due to
challenges in licensing and delivery of data within the brief (4 week) period of the contract, the
wetland assessment approach for water quality was selected based on data received by July
25, 2011 (see Table 5): the required data were not received and therefore we used a modified
Regional-Basic approach supported by data downloaded from the Internet.
We want to emphasize that our analysis does not tap into the full potential of what GOA data
can provide for these types of analyses. A major step forward for the ESPP, as it transitions
from pilot to implementation, will be the development of knowledge management systems that
support the ecosystem service frameworks.
RECOMMENDATION #3:
The recommended methodology (the “Regional-Advanced approach) was not completed, not because it
was too labour intensive, but rather because of delays in receiving specific data. There is a need for
more effective and efficient data management to support ecosystem service assessments. For future
ecosystem service assessments, it is recommended that all data providers be brought together to
compile, coordinate and evaluate what data are available for the assessment.
RECOMMENDATION #4:
Until site and regional assessments are directly compared it will be difficult to precisely assess the overall
utility in estimating ecosystem services at various scales of planning. For future ecosystem service
assessments, it is recommended that site approaches (WESPUS) are benchmarked to regional
approaches, including the Regional-Basic (sensu Cobbaert) and Regional-Advanced (sensu
Creed) approaches. Recent initiatives both by the ESPP project activities (led by Kerr) and AWRI-
Wetland Health project activities (led by Bayley) provide site based assessments of about 100
wetlands throughout southern Alberta that can now be used to benchmark regional wetland
assessment approaches.
TABLE 4: A comparison of two regional wetland assessment approaches (advanced vs. basic) developed in this study to
the WESPUS site wetland assessment approach (Adamus 2011) (continued on following two pages)
SITE ~ WESP
Metric Description
‘Total number of metrics= 42
FUNCTIONS
Number of metrics = 17
Historical change in wetland size
oer ay eaga, area to wetiand’s contributing
interupted nyroprid (wetand general
with surface water but goes mostly dry
poston dope versus wetland generally
not covered with surface water but goes wet at
least once a year)
wetland (no part of the wetland is
inundated for more than 14 consecutive days of
the year)
inundated wetiand (a significant percentage of
the wetland is inundated more than 14days but
less than 9 months)
Inundated wetland (a significant percentage of
wetland is inundated even during the driest
period of the year)
Annual fluctuation in water depth
Average annual or predominant depth of water
Presence of groundwater discharge within the
wetland
Relative width of the wet meadow zone
(vegetated zone)
Absolute width of the wet meadow zone
(vegetated zone)
Presence of undercut banks visible above the
Upland inclusions occur within the wetland
Soil composition within the wet meadow zone
Ground irregularity defined by presence of
burrows, fallen trees, boulders, mounds, etc.
Devegetation of the wet meadow zone through
grazing or mowing
REGIONAL — ADVANCED
REGIONAL — BASIC
Metric Description
Total number of metrics = 39
Historical change in wetland size
Metric Description
Wetland size
Ratio of wetland area to wetland's
contributing area
Ratio of wetland to contributing area
Interrupted hydroperiod (wetiand generally
covered with surface water but goes mostly
dry at least once a year, versus wetland
generally not covered with surface water
but goes wet at least once a year)
Saturated-only wetland (no part of the
wetland is inundated for more than 14
consecutive days of the year)
inundated wetland (a significant percentage
of the wetland is inundated more than
14days but less than 9 months)
Inundated wetland (a significant percentage
of wetland is inundated even during the
driest period of the year)
Presence of groundwater discharge within
the wetland
Relative width of the wet meadow zone
(vegetated zone)
Absolute width of the wet meadow zone
(vegetated zone)
Complexity of the upland open water edge
(tortuosity)
Soil composition within the wet meadow
zone
VALUES: Pollution source:
Number of metrics = 6
Upsiope soil erodibility risk defined by soil maps
Unvegetated (disturbed - roads, rail, buildings,
impervious surfaces) surface in the contributing
area
Presence of water quality limited rivers and
Bare ground and accumulated plant litter in the
wet meadow zone
Natural land cover in 100 ft upsiope buffer
VALUES: Transport potential of pollutants
Number of metrics = §
Ratio of upsiope inundated wetlands to the
wetland
Transport from upsiope (defined by presence of
disturbed land, ditches, channels, soils with high
runoff coefficients in the contributing area)
Throughfiow complexity (defined by direct or
indirect flow of surface water through the
contributing area and presence of woody
vegetation in flow path)
Slope of the contributing area
Connection with drainage ditches, culverts and
pipes
VALUES: Loading potential of pollutants
sources occur within the contributing area (i.e.,
irrigation, fertiliser treatment)
is there excessive sediment loading from
disturbances within the contributing area {i.e.,
construction, gravel roads)
Has soil or sediment alteration occurred within
the wetland (i.e., compaction, excavation, etc.)
fumed of metrics = 6
Upslope soil erodibility nsk defined by soil
Number of metrics = 1
Unvegetated (disturbed roads, rail, buildings,
impervious surfaces) surface in the contnbuting
area
Presence of water quality limited rivers and
streams upslope and hydrologically connected
wetland
Presence of disturbed land within
the contributing area
Open water interspersion with emergent
vegetation
Presence of saline soils within the contributing
area
Number of metrics = 6
Ratio of upslope inundated wetlands to the
wetland
Number of metrics = 3
% upslope wetlands to total
wetlands within the stream
catchment
Transport from upslope (defined by presence of
disturbed land, ditches, channels, soils with
high runoff coefficients in the contributing area)
Throughflow complexity (defined by direct or
indirect flow of surface water through the
contributing area and presence of woody
vegetation in flow path)
Percent non forested/shrubland
class within the CA
Slope of the contributing area e
Slope of the contributing area
Connection with drainage ditches, culverts and
pipes
Number of metrics = 4
Dner water regime resulting from disturbances
within the wetland (i.e., drainage ditches, deep
ripping, widening of outflows)
Do accelerated inputs of nutnents,
contaminants, and/or salts from external
sources occur within the contnbuting area (Le
irrigation, fertiliser treatment)
‘Is there excessive sediment loading from
disturbances within the contnbuting area (i.e
construction, gravel roads)
Has soil or sediment alteration occurred within
the wetland (i.e., compaction, excavation, etc )
Relative elevation of wetland in watershed
Presence of downstream drinking water sources
Annual duration of wetland outflow connection
with surface water
Outflow from wetland is confined by water
control infrastructure (e.g., pipes, culverts, etc.)
Presence of downstream domestic drinking
water supply wells
Presence of known water quality issues below
the wetland
Presence of connection to known water quality
issues below the wetland
Wetiand lies within a designated groundwater at
risk aquifer
Wet season connection of wetland open water
to offsite surface water
Is wetland’s inundated water maintained by an
existing dyke or berm or if removed will current
hydrology be sustained
Relative elevation of wetland in watershed
Riparian wetland, defined by
distance of wetland to nearest
stream or river
Relative elevation of wetland in
watershed
RB8/WP6
Presence of downstream drinking water
sources
Annual duration of wetland outflow connection
with surface water
Outflow from wetland is confined by water
control infrastructure (e.g., pipes, culverts, etc.)
Presence of downstream domestic drinking
water supply wells
Aquatic diversity rating of each wetland defined
by the Aquatic Environmentally Significant
Areas database
Presence of known water quality issues below
the wetland
Presence of connection to known water quality
issues below the wetland
Wetland lies within a designated groundwater
at risk aquifer
Wet season connection of wetland open water
to offsite surface water
Is wetland’s inundated water maintained by an
existing dyke or berm or if removed will current
hydrology be sustained
Change in turbidity of major water sources in
the area of interest
Connectivity of wetlands to the watershed
outflow
TABLE 5: Preliminary list of data resources available to support a Regional-Advanced wetland
assessment approach [with metric codes from Table 4, data quality (Low, Medium, High) reflecting
range of data options that are currently available, and data description providing examples of data
that can be used for derivation of metrics] (continued on following page).
Historical change in wetland
size
LIDAR DEM to provide potential wetland area, and
combination of optical (aerial photography, LANDSAT
TM, or SPOT) and microwave (ERS/RADARSAT)
satellite imagery to provide inundated and saturated area
dynamics
Ratio of wetland to contributing
area
LIDAR DEM required to map contributing area of
wetlands in this relatively flat landscape
Interrupted hydroperiod
Optical (aerial photography, LANDSAT or SPOT) to map
within year time series of inundated soils
Saturated-only wetland
Optical (aerial photography, LANDSAT or SPOT) and/or
microwave (ERS/RADARSAT) to map within year time
series of inundated (or saturated) soils
inundated wetland
Optical (aerial photography, LANDSAT or SPOT) to map
within year time series of inundated soils
inundated wetiand
Optical (aerial photography, LANDSAT or SPOT) to map
within year time series of inundated soils
Presence of groundwater
discharge within the wetland
Thermal (LANDSAT) to map discharge areas within
watershed
Relative width of the wet
meadow zone
Optical (aerial photography) for wet meadow vegetation
or microwave (ERS/RADARSAT) for saturated soils
Absolute width of the wet
meadow zone
SNE NEN SE ES
Optical (aerial photography) for wet meadow vegetation
or microwave (ERS/RADARSAT) for saturated soils
“4
Complexity of the upland open
water edge
LIDAR DEM with optical (aerial photography, LANDSAT
or SPOT) to map within year time series of inundated
soils
Soil composition within the wet
meadow zone
AGRASID soil map for soil types and optical data (aerial
photography) for wet meadow vegetation or microwave
data (ERS/RADARSAT) for saturated soils
Upsiope soil erodibility risk
defined by soil maps
AGRASID soil map for soil erodibility risk
Unvegetated (disturbed - roads
rail, buildings, impervious
surfaces) surface in the
contributing area
LiDAR DEM combined with LULC derived from optical
data (LANDSAT or SPOT)
Presence of water quality
limited rivers and streams
upslope and hydrologically
connected wetland
GOA water quality monitoring data and LIDAR DEM
combined with microwave (ERS/RADARSAT) imagery to
map probability of connections to water quality limited
rivers
Open water interspersion with
emergent vegetation
Optical (aerial photography) to define emergent
vegetation within open water
Natural land cover in 100 ft
upslope buffer
LIDAR DEM combined with LULC derived from optical
data (LANDSAT or SPOT)
Presence of saline soils within
the contributing area
AGRASID soil map for soil salinity
Ratio of upslope inundated
wetlands to the wetland
LiDAR DEM combined with high resolution optical (aerial
photography or SPOT)
Transport from upslope (defined
by presence of disturbed land,
ditches, channels, soils with
high runoff coefficients in the
contributing area)
LiDAR DEM combined with LULC plans for municipalities
and/or optical data (LANDSAT, SPOT, and/or aerial
photography)
Throughfiow complexity
(defined by direct or indirect
flow of surface water through
the contributing area and
presence of woody vegetation
in flow path)
Time series of LULC change focused on human
modification of drainage network from SPOT or
LANDSAT imagery
Slope of the contributing area
LIDAR DEM
Connection with drainage
ditches, culverts and pipes
LiDAR DEM combined with high resolution optical data
(aerial photography or SPOT)
Drier water regime resulting
from disturbances within the
wetland (i.e., drainage ditches,
deep ripping, widening of
outflows)
Municipality infrastructure and disturbance history, or
optical data (aerial photography)
Do accelerated inputs of
nutrients, contaminants, and/or
salts from external sources
occur within the contributing
area (i.e., irrigation, fertiliser
treatment)
Optical data (LANDSAT) time series to define chl-a of
open water
Is there excessive sediment
loading from disturbances within
the contributing area (i-e.,
construction, gravel roads)
Optical data (LANDSAT) time series to define turbidity of
open water
Has soil or sediment alteration
occurred within the wetiand
(i.e., compaction, excavation,
etc.)
Optical data (LANDSAT) time series to define turbidity of
open water
Relative elevation of wetland in
watershed
LIDAR DEM
Presence of downstream
drinking water sources
GOA water quality monitoring stations
Annual duration of wetland
outfiow connection with surface
water
LiDAR DEM combined with microwave
(ERS/RADARSAT) imagery to map probability of
connections both within and among years
Outfiow from wetland is
confined by water control
infrastructure (€.g., pipes
culverts, etc.)
Municipality infrastructure data or optical data aerial
photography )
Presence of downstream
domestic drinking water supply
wells
Municipalities or GOA groundwater well location data
Aquatic diversity rating of each
wetland defined by the Aquatic
Environmentally Significant
Areas database
GOA AESA map and/or site based assessments for
aquatic diversity (e.g., NAWAMP, DUC)
Presence of known water
quality issues below the wetland
GOA water quality monitoring stations
Presence of connection to
known water quality issues
below the wetland
LiDAR DEM, natural and human modifications to
drainage networks, GOA water quality monitoring
stations
Wetland lies within a designated
groundwater at risk aquifer
GOA groundwater vulnerability maps
Wet season connection of
wetiand open water to offsite
surface water
LiDAR DEM combined with microwave
(ERS/RADARSAT) imagery to map probability of
connections both within and among years
Is wetland’s inundated water
maintained by an existing dyke
or berm or if removed will
current hydrology be sustained
Municipalities or GOA infrastructure data or optical data
(aerial photography)
Change in turbidity of major
water sources in the area of
interest
Optical data (L:ANDSAT) time series to define turbidity of
open water
Connectivity of wetlands to the
watershed outflow
LiDAR DEM combined with microwave
(ERS/RADARSAT) imagery to map probability of
connections both within and among years
Many of the metrics listed in Table 5 are derived from LIDAR data. LIDAR is becoming the
standard data for generation of digital elevation models. While LIDAR acquisition continues
to be a priority for many government agencies, it will take time to obtain complete coverage
for many provinces and states. For example, the Government of Alberta’s license for LIDAR
currently excludes much of the white (inhabited) zone and some portions of the green
(forested) zone. This should not be viewed as a deterrent for site-specific wetland
ecosystem service assessments.
In Table 5, we were strategic in identifying low, medium and high quality data options for
defining the water purification metrics. A few of the metrics require high quality data (i.e.,
LIDAR) data, as they are currently defined (e.g., the metric for ratio of wetland to
contributing area requires LIDAR to capture the subtle changes in topography that define
these contributing areas). There are at least two options for dealing with such metrics when
no LIDAR data are available: (1) remove that metric from the calculation of the wetland
function score; and (2) develop proxies for the metric (e.g., in the absence of high quality
data needed for definition of contributing areas, one could use lower quality data to define a
fixed buffer width (such as 100m from water’s edge instead of the contributing area)). It is
clear that wetland ecosystem service assessments are an evolutionary and adaptive
process — as finer datasets come on line then better metrics can be defined — and that we
must start the process with whatever data are readily available with the promise that we will
review and refine the process as better data become available.
5.0 WATER PURIFICATION: A DEMONSTRATION OF THE REGIONAL-
BASIC ASSESSMENT APPROACH
5.1 WETLAND ASSETS
Wetlands can be defined as areas where the water table is at, near, or above the ground
surface long enough to enable the accumulation of organic matter (Tarnocai 1980). Water
storage is particularly important in terms of hydrological response (rapid water delivery to a
stream or lake) as well as biogeochemical behaviour (e.g., storage, transformation or export
of nutrients). In order to define and map wetland assets there are a number of ground and
remote sensing (RS) based approaches available (cf. Creed and Sass 2011). RS
approaches include airborne and satellite based platforms with both optical and microwave
sensors (Appendix 1).
Wetland Inventory - Basic
A number of wetland inventory options exist that provide full coverage of wetlands within the
Shepard Slough study area (see Appendix 1, Table A1.1). In particular, three inventory
options were explored. The Ducks Unlimited (DU) wetland inventory provides coverage of
Shepard Slough in 1965 and 2005. This inventory was developed using digitization of
wetlands from aerial photography. The second inventory option uses digital terrain analysis
techniques (Creed and Sass 2011) to define the potential of wetlands to occur on the
landscape. The inventory is developed from a LIDAR DEM. The third inventory utilises RS
optical and microwave image analysis techniques to identify open water that is then
assumed to be the location of wetlands. Each technique generates a different wetland
inventory for the area. Figure 3 compares the size distribution of wetlands derived from
aerial photography (DU 1965 wetland inventory [static]), digital terrain analysis (LIDAR
approach [static]) and satellite RS (LANDSAT TM imagery [dynamic]). Figure 4 compares
the size distribution of the DU 2005 and Landsat 2005 mapping static maps.
The following criteria were used to guide the selection of the appropriate wetland inventory
option:
(1) Spatial consistency: To provide consistency the option selected must provide full
coverage over the entire Shepard Slough study area. Mosaicking wetland inventories
with partial coverage will lead to biases in the ecosystem service assessments (i.e.
better quality inventories for certain areas of Shepard Slough will result in the incorrect
conclusion that those wetlands have a higher water purification function and value
when it may simply be the result of improved delineation of the wetlands).
(2) Temporal dynamics: To allow assessment of changing human development
pressures on ecosystem services provided by wetlands the option selected must
provide wetland coverage throughout Shepard Slough for multiple time periods,
particularly over the past 10 years when urban development has increased
significantly in Shepard Slough.
Based on these criteria satellite based optical mapping of open water was chosen to
develop the wetland inventory. Landsat images from 1984 to present were ordered from the
United States Geological Survey (USGS) (http://glovis.usgs.gov). Wetland areas were
derived by applying a threshold to each 30m resolution atmospherically corrected Landsat
Band 5 image (Sass and Creed 2011).
The DU inventory is developed from manual digitization of wetland boundaries from fine
resolution aerial photography and includes both the inundated (open water) and saturated
zones. In contrast, the Landsat inventory is development from coarser resolution satellite
imagery and includes the inundated zone only. We did not attempt to explicitly estimate
inundated areas. Depending on the Stewart and Kantrud (1979) classification of wetlands,
inundated areas may constitute a minor (Class 1, 2) to major (Class 3, 4, 5) portion of
wetland surface. For this reason, we were not comfortable using a variable ratio between
inundated and saturated areas to approximate saturated areas. Second, the inundated
versus saturated areas serve distinct functions in terms of removal of contaminants. For
example, inundated areas are important for P removal, but saturated areas are important for
N removal. This complementary role of inundated and saturated areas in water purification
processes is precisely why we advocate the Regional-Advanced wetland assessment
approach, as the Regional-Basic wetland assessment approach does not represent these
processes that are so important for water purification. For this reason, we believe this report
showcases the theory of considering ecosystem services, but better data are needed before
the theory is put into practice.
Our use of the Landsat inventory for wetlands results in a highly conservative estimate of
the water purification potential of wetlands, because the saturated areas, which are
important in the water purification function of wetlands, are not included. It must be
emphasized that we are not endorsing the use of inundated areas alone as a basis for
wetland water purification assessments. We fully recognize the importance of saturated
areas, and in particular, Class 1, 2 and 3 wetlands, for water purification and other
ecosystem services and these wetlands must not be excluded from policy decisions.
Wetland Inventory - Advanced
The wetland definition includes both inundated (open water) and saturated soils as part of a
wetland. Both areas of a wetland play a role in water purification. It is therefore important to
capture the spatial and temporal dynamics of both open water and saturated soils.
Cost effective emerging technologies enable us to do this (Sass and Creed 2011). Existing
wetland inventories can be improved by adopting GIS and RS methods using readily
available imagery (LIDAR, Landsat, SPOT and SAR) that can efficiently create a time series
of wetland occurrence, their probability of being wet (showing range of natural variability)
and permanent loss of wetlands (due to drainage).
RECOMMENDATION #5:
Current inventories do not factor in the temporal dynamics of wetlands including inundated and
saturated areas. For future ecosystem service assessments, it is recommended that a
combination of LIDAR, Landsat/SPOT, and SAR imagery be used to map wetlands (both
inundated (open water) and saturated areas), and determine their spatial and temporal
dynamics over changing climatic conditions and response to human activities. It is also
possible to determine wetland type (i.e., bog, fen, marsh, swamp), which may result in
different influences on water purification potential.
DU Historic Inventory
(1965)
Landsat Satellite Inventory
(Maximum Wetlands 1984-
2010)
GiS-based Wet Area
Potential
Number of Wetlands
an a ar an
of is
“ A) WY A
Area (ha)
FIGURE 3: Size class frequency distribution of “historical” wetland area defined by three
different techniques: (a) aerial photography based “static” approach (Ducks Unlimited 1965
wetland inventory); (b) GIS (LIDAR) based “static” approach; (c) satellite (LANDSAT TM
imagery) based ‘dynamic’ approach.
100000 DU Current Inventory
(2005 Growing Season)
= Landsat Satellite
Inventory (August 27
2005)
”
pie
Oo
=
=
pa
=
>
ra]
>
S
—
—
o
2
=
=
= |
Area (ha)
FIGURE 4: Size class frequency distribution of “current” wetland area defined by 2005
Ducks Unlimited Canada wetland inventory (based on “growing season” aerial photography)
and 2005 LANDSAT TM imagery (based on August 27" satellite image, influenced by 30
mm storm event that occurred 3 days before image capture).
5.2 WETLAND ASSESSMENT — TREND
To tease out the effect of natural vs. human drivers, one has to establish a “reference
condition” that is representative of the range of natural variability in climatic conditions in the
region, and then compare the effects of human activity against this reference condition. A
challenge occurs when the range of natural variability in climatic conditions translates into a
broad range in wetland areas, causing the impacts of human activities to be “lost”. In other
words, the “signal” from human drivers cannot be distinguished from the “noise” from natural
drivers. We attempted to establish a “reference condition” by exploring the relationship
between climatic conditions and wetland areas.
5.2.1 NATURAL DRIVERS
The change in the amount of water stored on the land is influenced by climatic conditions
(e.g., wetting versus drying trends). Within Shepard Slough, we examined these natural
drivers of changing water storage by estimating the water budget. The water budget is
defined as the water inputs [precipitation (P)] to the system versus the water outputs
[evapotranspiration (ET) and discharge (Q)] from the system and is represented by the
formula P = ET + Q. This formula assumes that the change in water stored in the wetland is
negligible. This water budget was used to estimate the water surplus of the system.
We calculated a simple measure of effective precipitation, or how much water is available to
enter the surface water or groundwater flow systems after accounting for evapotranspiration
(the process by which water is transferred from the land to the atmosphere by evaporation
from land surfaces and by transpiration from plants). The effective precipitation is computed
using precipitation (P) minus potential evapotranspiration (PET, a measure of how much
water would be lost to the atmosphere if an unlimited source of water were available). If the
annual P-PET is positive, a water surplus exists and it is considered a wet year (i.e., energy
limited). In contrast, if the annual P-PET is negative, a water deficit exists and it is
considered a dry year (i.e., water limited).
The transient nature of evapotranspiration renders it a difficult parameter to measure, but an
attentive assessment can be implemented using PET. In this report, PET was estimated
using the technique by Hamon (1963), because it is simple and requires readily available
data (temperature data only)
(Equation 1):
He 2.1xH,e
5 a Ban cide Pa’ ® Equation 1
cuaeeten «eg
where PET amon is in mm-month", H; is number of monthly average daylight hours per day,
Tz (°C) is the mean monthly temperature, and e, is the saturated water vapor density term
(Equation 2):
{ .77' \
e. = 0.6108 exp) le
37.347) |
| Equation 2
In this report, the annual time series data for P-PET was derived based on water year
defined as June 1 to May 31 of the following year. The 50-year annual P-PET average for
Calgary International Airport was -37 mm (reflecting a moderately dry region), based on
measurements from 1960 to 2010.
A time series of P-PET over the past 50 years is presented in Figure 5. It shows that P-PET
at Calgary airport (about 10 km from the Shepard Slough centre) demonstrates strong
cyclical variations over time, from a high of 185 mm in 1966, to a low of negative 252 mm in
1968. To assess the influence of global climatic oscillations on the Calgary regional climate,
annual P-PET values were regressed on annual average indices of five major climatic
oscillations (Table 6). Multivariate El Nino/Southern Oscillation Index (MEI), Northern
Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) were found to
influence the region’s P-PET. While MEI was found to explain over 30% of the regional
temporal variability in P-PET, NAO and AMO explained 28% and 26% of the P-PET
fluctuation in the region respectively. The relationships between P-PET and the five climatic
oscillations considered in this assessment were summarized as indicated below (Table 6).
Table 6 provides the explanation of variance in P-PET caused by individual oscillations only:
other work shows that when considering the interacting influences of multiple oscillations,
more than 50% of the variance can be explained (S. Girma, Pers. Comm.). It is important to
discriminate the relative importance of these natural drivers in future ecosystem service
assessments because they have a predictable periodicity that can help in estimating near
future hydro-climatic conditions.
FIGURE 5: Fifty-year time series (1960-2010, water years from June to May) of natural
(climatic) drivers of potential change in a wetland’s water purification service: (a)
precipitation minus potential evapotranspiration (P-PET); and (b) global climatic oscillations
that influence P-PET, including the El Nifo/Southern Oscillation (ENSO), the Northern
Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), Pacific Decadal
Oscillation (PDO), and the Southern Oscillation Anomaly (SOA).
TABLE 6: Relationship of P-PET (mm/yr) as a function of global climate oscillations
ane average. based on water year, June to May).
ne 2, NERS CED TT PE AEE CRG en A ae oie MoM SMS 2
Multivariate El Nifio/Southern 2a MEI
Oscillation Index >= PET 40.72 + 75.72.sin¢ aoe + 4.93)
Northern Atlantic Oscillation 2a.NAO
25.61 + 58.71 .sint 7 1.79)
) d
Atlantic Multi-decadal “ ? os 22.AMO .
Oscillation 41.99 + 60.56. sint 0001 + 5.78)
Pacific Decadal Oscillation 2 22 PDO
: 26.68 + 58.48. sing = 3.83)
0.025
Southern Oscillation Index InSO :
Anomaly : : 28.78 + 62.06. sin(————. — 2.57)
0.128
5.2.2 HUMAN DRIVERS
In addition to climatic drivers, changes in land use/land cover (LULC) have resulted in
changes in size and magnitude of wetlands on the landscape, as well as water flows to
sustain wetlands, and pollutant loadings that are to be purified by the wetlands. To examine
the extent of LULC change over the selected 20 year trend period, a LULC based on
LANDSAT TM imagery was developed (Figure 6).
Several options are available to provide complete LULC coverage of the Shepard Slough
AOI (see Appendix 2, Table A2.1). The following criteria guided selection of the LULC
option:
(1) Spatial consistency: To assess spatial patterns, it is important that each class (i.e.,
Forest, agriculture, urban) of the LULC map be derived from a single data source for
the entire Shepard Slough. Where difference resolutions of LULC options exist,
inherent biases can occur when combining these difference sources for the same
class. For example, if a portion of Shepard Slough is based on a LULC map with
greater assessment of forested areas, lower water purification scores will be estimated
for this area over other potions using lower quality LULC.
(2) Temporal dynamics: To assess temporal patterns, it is important to have a time
series of LULC to examine expanding development pressures on ecosystem services.
Given that there was a quality assured LULC map from AGCAN for 2009, we used it to
define our 2010 LULC image. For 1990 and 2000 Landsat images were ordered from the
United States Geological Survey (USGS) and atmospherically corrected. A supervised
Classification was developed for these two images using training polygons defined using the
AGCAN LULC map and LANDSAT TM images. The three main classes chosen for the
Classification were agriculture (grassland, pastures and croplands), urban (commercial, and
industrial land use along with road and rail infrastructure), and open water.
Due to the resolution of the Landsat imagery (30m), the Landsat LULC was unable to define
the features of forests or shrubland (which occur only in small clusters throughout Shepard
Slough but which could be important from a water quality perspective if they occur as
riparian rings around wetlands). .A time series based in finer resolution data, such as SPOT
(5m resolution), should enabled us to capture these natural land covers. Unfortunately, the
SPOT data available contained panchromatic but not optical data, which precluded the
ability to do this analysis.
This issue also highlights the need to consider what the study sites LULC baseline is. The
major LULC in Shepard Slough over the timer series (1990 — 2010) is agriculture; so to
assess the change in land use from natural to agricultural land use and its effect on water
purification scores an historic LULC as a baseline would need to be established, which was
beyond the scope of the study. Given the LULC reality of the Shepard Slough since
the1990 baseline has been agricultural, with urbanization being the contemporary
development pressure, agriculture was removed from the disturbed land use (used to
determine WP2 metric scores, see section 5.3.1.2) to improve the signal from urbanization,
which is expected to increase remarkably over the next few decades.
i i 4 6 8 10
Kilometers
Study Area Boundary
City of Calgary Boundary
Water
BE 1090
© 2000
2010
Roads
FIGURE 6: Change in urban land use from 1990, to 2000 and to 2010.
5.2.3 SELECTION OF TREND PERIOD
To examine trends in wetland water purification service, a 20 year time period from 1990 to
2010 was selected. The Millennium Ecosystem Assessment (2005) recommends a period
of one generation (generally considered to be 30 years, during which children grow up and
have children of their own) (Ciara Raudsepp-Hearne pers. comm., June 24, 2011). A 30
year time period was not achievable for two reasons: First, the satellite that provided the
core data was launched in 1984, providing a maximum possible period of 26 years; and
second, the climatic oscillations shown in Figure 5 play an immense roll in temporal variation
of wetlands, that trend analyses becomes extremely difficult by creating relative dry and wet
conditions during the 26 years
To reduce the signal caused by natural drivers related to climatic conditions and to increase
the signal caused by human drivers related to development, three “snap shots” of time,
1990, 2000, and 2009 (hereafter referred to as 2010) were selected (Figure 7). The
rationale for selecting these years includes the following. A complex relationship was
observed between climatic conditions and wetland area, where wetland areas appeared to
fall within one of two steady states — a relatively dry state (small wetland area) and a
relatively wet state (large wetland area). The selected years all fell on one of the two steady
states (i.e., the relatively dry state). The relatively dry state was selected because the
median of this dry state was closest to the long term average annual P-PET (-37 mm), and
therefore were deemed “representative” of the region based on analyses for each year
However, even these years appeared to be influenced by the legacy effects of previous
years (i.e., a relatively wet year could have long lasting effects on wetland area, Figure 7),
and showed substantial variability among the years (e.g., total inundated areas of wetlands
ranges from about 200 to 500 ha, Figure 8). Clearly, more scientific research is needed in
this area to resolve the processes leading to these two steady states, and to develop a
reference condition where the system can naturally oscillate between wet and dry
conditions
However, from the perspective of developing wetland ecosystem service assessment
approaches that can be implemented in the current atmosphere of streamlining the
development approval process, a more practical approach can be taken. We have shown
that wetland areas defined by open water show high variation due to climatic variability, and
that the associated wetland function can be significantly reduced in drier years, which would
lead to significant underestimates of the economic benefits of these wetlands during these
years. Rather than monitor this natural variation on an annual basis, one could use the
maximum extent of wetlands to estimate the maximum potential for ecosystem services
related to water purification. However, this maximum must be based on historical data
available for the region
RECOMMENDATION #6:
Regional climate is defined by two steady states (wet and dry). These difference states strongly
influence the presence of inundated (open) water on the landscape. Identifying and understanding
the presence of climate regimes and drivers is important to allow quantification of human driven
impacts on wetlands. Understanding the link between climate and surface water dynamics allows the
incorporation of this natural driver into human drivers of wetland function. For future ecosystem
service assessments, it is recommended that the range of natural variation in wetland function
(area) due to natural drivers (climate) should be defined using a combination of historic
meteorological and remote sensing data.
FIGURE 7: Fifty-year time series (1960-2010, water years from June to May) of natural
(climatic) drivers of potential change in a wetland’s water purification service: (a)
precipitation minus potential evapotranspiration (P-PET); and (b) change in wetland area
(ha) derived by LANDSAT TM imagery, with water years selected for trend analysis
highlighted
1000
800
Total Open Water Area (ha)
50 0
P-PET (mm)
FIGURE 8: Relationship of P-PET (mm/wyr) versus wetland area (ha), revealing alternative
steady states, with wetlands showing a dry state when P<PET and a wet state when
P>PET
5.3 WETLAND ASSESSMENT — CONDITION
5.3.1 WETLAND FUNCTIONS
Wetland water purification function and value was determined using the six metrics
described in Table 7. Each metric was determined using GIS and/or RS techniques. For
each metric, the wetland complex was used as the wetland assessment unit (defined in
Table 7).
TABLE 7: Description of GIS and remote sensing data products and the method of derivation that
were used to estimate water purification metrics (after Strahler 1957).
Wetland
WP1
Land saturated with water long enough to promote wetland or aquatic processes as indicated by poorly drained
soils, hydrophytic vegetation, and various kinds of biological activity that area adapted to a wet environment
Ephemeral wetlands are only periodically covered by standing or slow moving water. Manual, probabilistic and
object-based methods using air photos or LIDAR DEMs map wetlands by this definition. Methods using satellite-
based radar images define wetlands as inundated areas and surrounding areas of soil saturation. Data used for
trend analysis in this report was limited to satellite-based optical images — this limitation constrained the methods
used here to a definition of wetland as the presence of open water determined as areas of low reflectance in 30-
meter Landsat Band 5 (1.55 - 1.75ym)
Wetland complex
WP 1
Two or more separated wetlands related by biological or hydrological functions. Wetland complexes are generally
determined through distance and surface area thresholds. Wetland complexes are determined in this report by
joining wetlands within a 50-meter (< 2 Landsat 30m pixels) buffer. Methods using satellite-based radar images
would permit wetland complexes to be determined by hydrological connections between wetlands defined by soil
saturation probability
Land use/land
cover for 1990
2000, 2010
WP2, WP3
1990 and 2000 LULC developed using a supervised classification of LANDSAT TM optical bands. The
Classification is not ground-truthed and training areas were selected based on the respective LANDSAT images
and the 2010 LULC developed from the crop type mapping in the Prairies 2009 and the Grassland Vegetation
Inventory LULC
Y Wetland’s
contributing area
WP2, WP3, WP4
Area in which water drains into a water body. Contributing areas are determined from LiDAR DEMs resampled to
5-meter grid resolution using wetland complexes as the target water bodies
Sub-watershed
WP5
Area in which water drains into a stream outlet. Sub-watersheds are determined from LIDAR DEMs resampled to
S-meter grid resolution using 1st, 2nd and 3rd order stream intersections as the target points
Watershed
WP3, WP6
Area in which water drains into a river outlet. Watersheds are determined from Canadian Digital Elevation Data
DEMs using outlets of streams or ditches flowing out of study area at Bow River and Red Deer River
Stream drainage
network
WP5
Total streams contributing to a watershed outlet. Stream drainage networks are determined by applying a
threshold to flow accumulation layers derived from LIDAR DEMs resampled to 5-meter grid resolution so that
accumulation grid values greater than the threshold are considered as stream grid cells. Thresholds are
determined to include main, secondary and tertiary branches to the watershed outlet
i Stream order
WP5
Number assigned to a stream as a measure of its branching complexity where headwater streams near
contributing area divides are designated as 1st order and stream order increases downstream as links of equal
order join (Strahler, 1957)
Human modified
stream drainage
network
Stream drainage networks modified by artificial water structures including canals, drainage ditches and
stormwater infrastructure. Stream drainage network delineation using LIDAR DEMs captures open (uncovered)
human modifications. Locations of bridges and culverts that connect water features but are covered from
airborne LIDAR sensors are required to “burn” stream flows into LIDAR elevation values to avoid disconnection of
automatically derived streams and drainage areas
5.3.1.1 WETLAND PURIFICATION METRIC 1 (WP1), WETLAND AREA
What is the metric? Wetland size was defined as the total area of open water within a
wetland complex. Although the definition of a wetland includes saturated soils surrounding
the open water, the data constraints of the project prevented the identification of this zone
(see Section 5.1).
How is it being measured? \Vet area was determined for each period from LANDSAT
Band 5 using a threshold value of 20. Wetland size was defined as the total area of wet
areas within a wetland complex.
What is the condition? |n 2010 the highest frequency of wetlands falls within the 0.05 to
0.5ha range. Also, the majority of wetlands in 2010 are smaller than 4ha (Figure 9). Based
on the metric score most of the wetlands within Shepard Slough have medium to low value
(metric score < 0.5) in terms of wetland size
What is the trend? Wetland size generally increased throughout the time period with the
maximum total wetland area occurring in 2000 (Figure 9). As discussed in Section 5.2.1 wet
area is strongly influenced by climatic variation in the region. Across all three time periods
the highest frequency of wetlands falls within the 0.05 to 0.5 ha range with a large increase
in the number of wetlands in the 1 to 4 ha range occurring in 2000 and 2010. The increase
in the number and area of wetlands is largely due to the legacy effect of previous wet years
resulting in larger amounts of water on the landscape. Wetlands smaller than 0.05ha were
not identified as the resolution of Landsat (30m) is too coarse to identify these features.
eeky ty oak
5
JARS oe —Sto<t
RE at ME RAs Me Mec
7
15
FIGURE 9: Trends in frequency distribution of water purification scores for wetland
assessment unit: VWP1, wetland area
In the Regional-Basic wetland assessment approach used in the report, wetland area is the
single wetland-specific feature that determines the natural purification potential of wetlands.
The assumption is that wetland area is directly correlated with other wetland features that
contribute to the purification potential of wetlands (e.g., wet meadow and emergent
vegetation areas). No assessment has been undertaken to determine the validity of this
assumption. In the Cobbaert et al. (2010) report, there is supporting literature to suggest
that wetland area is a simple proxy for many purification functions. However, in the
Regional-Advanced wetland assessment approach based on the Adamus (2010) method,
many features of the wetland contribute to the purification potential of wetlands. Data and
time constraints prevented adoption of further metrics of purification potential of wetlands
from being assessed.
5.3.1.2 WETLAND PURIFICATION METRIC 2 (WP2), POLLUTANT SOURCES
What is the metric? The potential for a wetland to treat contaminated surface water is
dependent on the presence of disturbed land use within the wetlands contributing area.
Urban runoff water is a source of nutrients (nitrogen and phosphorus) and sediment loads to
surface waters. Wetlands intercepting this runoff water have a higher value to downstream
water users in terms of water purification than wetlands intercepting runoff from undisturbed
or natural land cover such as forest and shrub land.
The WP2 metric addresses the potential pollutant sources to a wetland. The WP2 metric is
the percentage area of the wetlands contributing area that is considered urban land use,
where urban land use is defined as residential, commercial and industrial areas along with
roads and rail infrastructure. This is a deviation from how the WP2 metric was calculated in
the original Cobbaert et al. (2010) report.
The reason for this deviation is twofold. First, WWP2 scores were not influenced by natural
land cover, as less than 1per cent of the Shepard Slough land cover is classified as natural
or undisturbed. Second, WP2 scores were strongly influenced by agricultural land cover.
VWP2 scores for all wetlands were 1.0 throughout the time series when agriculture was
included in the calculation. To try and capture temporal variation in WP2, agriculture was
removed when determining the metric scores. The assumption made was that runoff from
urban areas has higher sediment and nutrient loads than runoff from agricultural areas. This
is not a hard and fast rule and is dependent on a range of variables including urban land use
(industrial compared to residential), fertiliser application rates and tilling practices.
Removing agriculture from the WP2 metric results in a lower overall WPS for wetlands in
Shepard Slough. If the technique is to be used across Alberta, we advise that agriculture in
WP2 be included to maintain consistency across the province.
How is it being measured? Using zonal statistics in ArcGIS the total area of each land use
within the wetland complex contributing area was determined from the LULC maps
described in Section 5.2.2. Percentage urban land use was then determined by summing
the areas of urban, roads and rail together and dividing by the total area of the contributing
area.
What is the condition? |n 2010, 30 per cent of wetland complexes have greater than 50
per cent of their contributing area occupied by urban land use (Figure 10). The distribution
of wetland complexes amongst metric scores is fairly even although there is a higher
concentration of wetlands in 2010 with low urban influences (greater agricultural influences).
What is the trend? As expected for all years land use within wetland contributing areas is
dominated by agriculture. This has resulted in the largest distribution of wetland complexes
in the <20 per cent urban land use category. There has however been a significant
expansion of urban areas within Shepard Slough over the 20 year time period. Figure 10
shows an increase in wetland complexes dominated by urban land use (1.0 metric score)
over the trend period. This has resulted in an increase in the water purification value of
wetlands as they are forced to treat poorer quality water.
ge of Wetland
omplexes
_wetland’s contributine
1990 (Number, Percent)
2000 (Number, Percent)
2010 (Number, Percent)
FIGURE 10: Trends in frequency distribution of water purification scores for wetland
assessment unit: WP2, pollutants within the wetland’s contributing area.
5.3.1.3 WETLAND PURIFICATION METRIC 3 (WP3), POLLUTANT REMOVAL
OPPORTUNITY
What is the metric? VVP3 metric attempts to identify three key factors that affect the
potential of a wetland to improve water quality. These are: (A) The majority (80%) of the
wetland’s contributing area is not forested or shrubland. The rationale is that contributing
areas that are not dominated by dense forest or shrubland are likely to have increased
sediment loads in runoff water. (B) Wetland is less than five per cent of its contributing area.
It is understood that increased sediment and nutrient loads to wetlands increase with a
decrease in the ratio of wetland area to wetland contributing area. (C) Wetlands upslope of
the wetland comprise less than five per cent of the stream catchment. Vhere wetlands
occur upslope of the wetland, runoff reaching the wetland will likely have already been
treated by those wetlands upslope.
How is it being measured? The three elements of the metric were measured as follows:
(A) the percent disturbed (urban and agriculture) land use within each wetland complex
contributing area was determined from the LULC maps described in Section 5.2.2. All
wetland complexes with a total percent disturbed area within the contributing area greater
than 80 per cent were assigned a value of 1. All other wetland complexes were assigned a
value of 0. (B) The wetland complex size defined for the WP1 metric was divided by the
area of the wetland complex contributing area. All wetland complexes with a wetland area
to contributing area ratio of less than 0.05 were assigned a value of 1. All other wetland
complexes were assigned a value of 0. (C) The two major watersheds within Shepard
Slough were defined by creating a specific contributing area from the Canadian Digital
Elevation DEM. Two drainage outlets were identified (one in the north and one in the
south), from the DEM and using Terrain Analysis Software (TAS), and the contributing areas
for those drainage outlets were defined. Wetland complexes were then assigned to each
major watershed based on their location. The elevation of each wetland complex was
determined from the LIDAR DEM. For each wetland complex all wetlands with a higher
elevation were determined and the area of those wetlands summed. This total area of
wetlands upslope of each wetland complex was divided by the total area of wetlands within
each wetland complexes respective major watershed.
All wetland complexes with less than five per cent of the total area of wetland supslope were
given a value of 1. All other wetland complexes were assigned a value of 0. The metric
score for each wetland complex was determined by summing the scores for (A), (B) and (C).
What is the condition? The majority (80 per cent) of wetland complexes in Shepard
Slough in 2010 satisfy two of the elements of this metric (Figure 11). For WP3, the condition
for the majority of wetland complexes is defined by the lack of natural cover and upslope
wetlands within the contributing areas of the wetlands.
What is the trend? The long-term trend shows an increase in wetlands satisfying two of
the elements of this metric. The percentage of wetlands for each year within each metric
score does not change significantly throughout the period (Figure 11). This indicates that
although wetlands defined by open water have increased, the distribution of those wetlands
among the WP3 metric scores has not changed significantly. The trend shows no change in
the pollutant removal opportunity of each wetland, although the number of wetlands
performing that function increases.
c) :
1990 (number, percent)
2000 (number, percent)
2010 (number, percent)
FIGURE 11: Trends in frequency distribution of water purification scores for
wetland assessment unit: WP3, purification potential of wetland.
5.3.1.4 WETLAND PURIFICATION METRIC 4 (WP4), POLLUTANT TRANSPORT
POTENTIAL
What is the metric? The metric is the mean slope of a wetland’s contributing area. Steep
slopes can lead to increased export of nutrients and sediment in runoff water. Wetland
complexes with a higher mean slope within their contributing area will have a higher
potential for receiving contaminated water and thus their value is higher.
How is it being measured? A slope layer is created in ArcGIS from the LIDAR DEM.
Mean slope is calculated using zonal statistics based on the contributing areas of each
wetland complex.
What is the condition? The majority (80 per cent) of wetland complexes have a low to
moderate mean slope (2° to 4°) within the contributing area (Figure 12). Very few
contributing areas are flat (<1°) or have steep (>10°) slopes within Shepard Slough.
What is the trend? As slope is a static metric there is no trend analysis.
Bg ORAS IS on whois 9 hy oleh 2s
_ the wetland s contr
All wetland complexes
FIGURE 12: Trends in frequency distribution of water purification scores for wetland
assessment unit: WP4,purification demands on wetland.
5.3.1.5 WETLAND PURIFICATION METRIC 5 (WP5), POTENTIAL SIGNIFICANCE
What is the metric? Riparian wetlands are defined by their distance from the nearest river
or stream. Riparian wetlands have the opportunity to directly treat water before it flows into
a river or stream that will convey water to downstream users. As a result riparian wetlands
have a greater value to water purification than wetlands a long distance from streams and
rivers.
How is it being measured? Distance is measured as the Euclidean distance from the
boundary of a wetland complex to the nearest river or stream. Distance to the stream
network based on flow distance as opposed to Euclidean distance would provide a better
determination of the distance from the connection to a river or stream; however, time
constraints prevented this further analysis.
What is the condition? This metric shows that there is a wide variation in the presence of
riparian wetlands (Figure 13). In 2010, 28 per cent of wetland complexes are situated
greater than 600m from the stream network whilst 25 per cent are within 50m. This
suggests that Shepard Slough still maintains a high portion of riparian wetlands on the
landscape.
What is the trend? Since 1990 there has been an increase in both the number and
percentage of non-riparian wetlands (>600m from a stream or river) (Figure 13). This
suggests that during wetter years (2000 and 2010) wetlands are becoming inundated in the
upper reaches of the catchment further from the stream network whilst those closer to the
stream network maintain open water and ultimately improved function during dryer periods.
1990 (number, percent) eo é S 2 ae , 5% 15, 41%
2000 (number, percent) ; ‘ * ; ; 35, 35%
2010 (number, percent) 23, 28% ; ; ; ‘ 21, 25%
FIGURE 13: Trends in frequency distribution of water purification scores for wetland
assessment unit: WP5, proximity of wetland to stream or river.
5.3.1.6 WETLAND PURIFICATION METRIC 6 (WP6), RECHARGE POTENTIAL
What is the metric? The position of a wetland based on elevation in the watershed.
Wetlands situated in the upper third of the catchment (headwater wetlands) treat
precipitation and runoff dominated water supply to first order streams. These wetlands can
desynchronise flow and prevent the accumulation of nutrient and sediment inputs in
overland flow. Higher elevation wetlands also have the potential to provide recharge water
to the local groundwater system.
How is it being measured? Shepard Slough was divided into two major watersheds (north
and south). The LIDAR DEM was clipped using the watershed boundaries. The watersheds
were then divided into three regions (lower, middie and upper) based on area weighted
elevation. Each clipped DEM was then reclassified into three groups using a 3 group
quantile function in ArcGIS. This function creates three equal area (pixel) groups with
increasing elevation ranges. Wetland complexes were classified into the three regions
based on their maximum elevation.
What is the condition? \n terms of area weighted elevation, wetland complexes are
currently evenly distributed throughout Shepard Slough (Figure 14).
What is the trend? \|n 1990 during the driest year of the three years studied there is a
greater percentage of wetlands in the lower regions of Shepard Slough. In comparison
during 2000, the wettest year of the three, there are a greater percentage of wetlands in the
upper regions of Shepard Slough (Figure 14). This indicates that natural (climatic) drivers
have a strong influence on the elevation position of wetlands in Shepard Slough. Under
drier climate scenarios resulting from climate change, the higher value (metric score = 1)
headwater wetlands will be preferentially lost. Understanding the effects of climate variation
on wetland position will be important for informing future decisions on wetland conservation.
NVetiand
Percentage of V
ory
n «
Uo
WP6 - Metric Sco
watershed | £5; :
1990 (number, percent) 15, 41% 10, 27% 12, 32%
2000 (number, percent) 29, 29% 28, 28% 42, 42%
2010 (number, percent) 28, 34% 28, 34% 27, 33%
FIGURE 14: Trends in frequency distribution of water purification scores for
wetland assessment unit: WP6, position within wetland’s stream watershed.
5.3.1.7 WETLAND PURIFICATION FUNCTION SCORE
The wetland Water Purification Score (WPS) was determined using the following formula:
(UPL } WE2 + WPS > WP > WPS } WPS)
6
The wetland purification score ranges from 0 to 1.0 (it is the average of the wetland
purification metrics WP 1 to 6). Equal weight was given to each water quality metric as no
field-based assessment was available to develop and validate a model-based approach to
integrate individual metric scores.
WPS =
Figure 15 presents the percentage of wetland complexes within each WPS score. The
majority (87 per cent) of wetland complexes within Shepard Slough have a medium wetland
purification score (0.4 to 0.7) (Figure 15). No wetland falls in the lowest category (VWWPS =
0.1, 0.2) or the highest category (WPS = 1.0).
Figure 16 shows the absolute change in water purification scores for wetland complexes
throughout the trend period. Where there are negative changes, i.e., where the wetland
water purification has declined from 1990 to 2010, there has been a loss of wetland function
related to water purification. This could be due to loss of wetland area. Where there are
positive changes, i.e., where the wetland water purification has inclined from 1990 to 2010,
there has been a gain of wetland function related to water purification. This could be either
due to (1) gain of wetland area and/or (2) increase in the water purification function or
increase in its importance.
Figure 16 shows a general increase in WPS from 1990 to 2010. This is primarily the result
of incorporating wetlands that were not included in the 1990 wetland inventory. Those
wetlands that show a reduction in WPS are the result of removal of the wetland following
urbanization.
As wetlands are lost or degraded on the landscape, the remaining ones will have higher
value with respect to purification potential. This should not be interpreted as an incentive to
disturb wetlands, but rather a disincentive. With the loss of each wetland, it becomes more
critical to protect the remaining ones. Of course, some wetlands will have higher value than
others, and it is important to identify these before further development occurs to ensure they
are protected.
In the future, the wetland purification scores could be improved in at least two ways. First,
we could improve our understanding of the relationship between Stewart and Kantrud’s
(1979) wetland classes and water purification function. Given that we used a Landsat
wetland inventory, we were not able to explore the relationship between wetland classes 1
to 5 and their relative water purification function. This is, however, an important question,
that could be pursued using a combination of the City of Calgary’s class 1 to 5 wetland
inventory, and the application of either the Remote-Basic or Remote-Advanced wetland
assessment approaches for water purification, with verification using the WESPUS site
based wetland assessments completed on behalf of the Ecosystem Services Pilot Project.
Second, we could calibrate the relative wetland purification scores to actual wetland
purification quantities, as sediment and nutrient removal data become available.
= O% So <4 + —— + +
JI4& 05 O€ 07 O€£ os 0 01 02 03 04 05 O€ 07 08 os
Water Purification Score Water Purffication Score
‘
oz u ’
0% | 1,3% 6, 16% 11, 30% 14, 38% 4,11% 1,3% | 0,0%
1990 (number, percent) | 0,0% | O,
2000 (number, percent) | 0,0% | 0,0% | 1,1% | 15,16% | 33,33% | 31,31% | 13,13% | 3,3% | 3,3%
2010 (number, percent) | 0,0% | 0,0% | 2,2% | 11,13% | 22,27% | 20, 24% | 19, 23% | 8 10% | 1,1%
FIGURE 15: Trends in frequency distribution of aggregated water purification scores.
RECOMMENDATION #7:
Natural drivers cause substantial variation in wetland structure and function, and it is important
to understand this natural variation so that accurate estimates of ecosystem services can be
achieved. One could monitor this natural variation on an annual basis. Alternatively, one could
use the maximum extent of wetlands based on climate normal (past 30 years) or some other
reasonable climate period to estimate the maximum potential for ecosystem services related to
water purification. For future ecosystem service assessments, it is recommended that
regional wetland assessments be designed to consider both spatial and temporal
dynamics of wetland function.
0 4-2 4 6 8 10
a Kilometers
Water Purification Score
Change from 1990 to 2010
—
0.01 Orange = Negative
0.05 Green = Positive
0.1
0.25
0.5
1
eae City of Calgary Boundary
Study Area Boundary
Water
Roads
FIGURE 16: Change in wetland purification potential from historic condition (1990) to
current condition (2010).
5.4 WETLAND WATER PURIFICATION BENEFITS
To determine the monetary worth of wetland water purification benefits a literature search of
wetland ecosystem service assessments was undertaken. Kazmierczak (2001) provides a
synthesis of wetland water purification valuations throughout the United States that were
reported in published studies. The methods for determining wetland valuations varied, but
were predominately based on cost savings from traditional water treatment options.
Wetland type also varied and ranged from coastal marshes to forested swamps.
Figure 17 presents the distribution of 22 wetland water purification benefit figures that are
synthesized by Kazmierczak (2001). To understand the full range of monetary wetland
benefits three values were selected: $50/ha, $500/ha, and $5,000/ha. The total benefit of
wetlands for 1990, 2000 and 2010 is presented in Table 8. It is important to note that the
figures used to determine the monetary worth of wetland benefit in this section are not
intended to be a comprehensive assessment of the dollar value of wetlands within Shepard
Slough. Rather, it is intended to complete the story of wetland water purification. Also, it is
critical to understand the individual case studies that provide the benefit monetary worth in
Figure 17. The upper limit is likely the most representative figure for wetland benefit
evaluation as case studies in the literature are unlikely to be conducted on the best case
wetland (WPS = 1.0). An appropriate benefit monetary worth would be one determined from
actual water purification determined from field monitoring of nutrient and sediment retention
in wetlands based on each individual WPS class (0.1 to 1.0).
o
uv
Zz
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zg
”
=
o
_
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2
=
~
a
9 5
8 4
74
6 4
5 4
4-
4 4
2
1
0
4
4
+
$10 $100 $500 $1,000 $5,000 $10,000 $15,000
Benefit Monteray Worth ($/ha)
FIGURE 17: Year 2000 $USD frequency distribution of published studies estimating
economic benefit of wetlands for purification of water supplies (Kazmierczak 2001).
Current Benefits (2010) of Wetlands to water puniffication within Shepard Slough:
Depending on the unit benefit worth of wetland water purification the current total benefit of
the 404 ha of wetlands in the Shepard Slough towards water purification ranges from
$13,396 ($50/ha) to $1,339,560 ($5,000/ha), with an estimate based on the median worth
($500/ha) of $133,936.
Change in Benefits (difference between 1990, 2000, and 2010) of Wetlands within Shepard
Slough:
There has been an overall increase of 21 per cent in wetland benefit to water purification of
all wetlands within Shepard Slough from 1990 to 2010. There are two main drivers for this
increase. The first and largest driver is the natural climate driver. This has resulted in an
increase in wetland area from 1990 to 2010. The second driver is the human influence
driver defined as an increase in urban areas within Shepard Slough from 1990 to 2010.
The increase in urban areas results in higher metric scores, which define the opportunity of
a wetland to treat contaminated water (VVP2, WP3)
The metric scores indicate that the benefit of wetlands for water purification is increasing in
Shepard Slough. This is the result of both natural (wet years leading to increased open
water area) and human (increase in urban areas leads to more pollutants) drivers
However, there is a cautionary note when the increase in inundated areas is the dominant
driver in the increase of wetland benefits within Shepard Slough. As the wetland inventory
is based on inundated areas only (and does not include saturated areas), there appears to
be a climatically- driven increase in wetlands on the landscape which results in an inflation
of wetland monetary benefits. In reality, this climatically-driven increase in wetlands would
become much less (if not disappear altogether) if the saturated areas were included, and we
would be able to focus on changes in wetland area caused by human activities. There is a
need to develop a comprehensive time series of wetlands that reflect the true wetland
boundary by including both inundated (current study) and saturated soils
Recommendation #8:
For the Ecosystem Services Pilot Project, regional assessments for the ecosystem services
provided by wetlands were done independently, considering one service at a time, and by
different consultants. For future ecosystem service assessments, consideration of the
potential for interaction effects of ecosystem services is needed so that trade-offs
among ecosystem services may be considered.
TABLE 8: Wetland derived water purification benefits. To achieve the range of $/ha for the range of WPS values,
the WPS value is multiplied by $50/ha, $500/ha, or $5,000/ha (from literature). This results in a lower $/ha cost for
lower WPS values. For example, for a wetland with a WPS of 0.1 the $/ha cost is determined by multiplying the
$500/ha by the WPS, 0.1 x $500 = $50/ha. This is then multiplied by the area of the wetland (ha) to determine the
overall $ benefit of that wetland
Y $15,984
$86,814
_ $0
$0
$7,920 |
So 1 ie fo
$0 |
$1,350
$1,620
$79,200 |
$159,840
$868,140
$0
$0 |
$0] -
_ $3,855
$9,065
$75
$0
$1,32 0 |
$72
= eS
“$13,207 |
$38,556
| $90,657
$756
$729
~ $132,075
$0 z
[$1,080 |
$49,320
$385,560
~ $906,570 | $9.87
$7,560.
$135
“| $3,420 7
| $6,840 |
) | $18,009 |
_| $98,784
| $180,090
~ $987,840
_$68,400 |
$61,200 |
__ $6,480
$0 |
39.
6.0 CONCLUSIONS
Based on our implementation of the Regional-Basic wetland assessment approach at
Shepard Slough in southern Alberta, for which metrics could be easily derived from GIS and
remote sensing (RS) that were accessible at no cost, we make the following conclusions:
1. Wetlands provide monetary benefits (via avoided water treatment costs). An
increase in monetary benefits of 21 per cent from 1990 to 2010 of 21% was
observed. Specifically, depending on the published rate of natural purification benefit
used, the dollar value increase ranged from $2,294 (based on $50/ha) to $229,410
($5,000/ha). Lack of data on purification rates from water treatment facilities in the
Shepard Slough precluded deriving estimates specific for the region; as these data
become available, the monetary benefits could be easily calibrated to the region.
Surprisingly, a major factor in the rise in wetland monetary benefits was
natural drivers, with climatic conditions over the 20 year period that formed the
basis of evaluation leading to an increase in wetlands on the Shepard Slough
landscape (although it is possible that human modifications to the drainage
system may have also led to an increase in wetlands). Specifically, the average
water purification score increased from 0.51 to 0.54, suggesting minor change in
purification function of wetlands. However, the total wetland area changed from 335
ha to 404 ha, suggesting major change in the size of wetlands performing that
purification function. Natural drivers of the number and area of wetlands on the
landscape underscore the need to use a “proper” wetland inventory, that
(1) considers inundated and saturated conditions (as the inundated areas used in
this study fluctuate widely in response to climatic conditions); and (2) establishes a
reference condition that reflects the natural range of variation in wetlands on the
landscape. Once these natural drivers are better considered in wetland
assessments, more reasonable estimates of monetary benefits will be achieved.
Plans reveal that future development within Shepard Slough reveal substantial
changes in land use/land cover that will lead to more substantial changes in
water purification scores. If plans result in no net loss of wetlands, than wetland
purification scores will increase, and their ability to naturally purify water increases
(increased pollutant loads = increased opportunity to purify water, assuming the
wetland purification capacity has not been exceeded). Alternatively, if plans result in
a net loss of wetlands, depending on where the wetland is lost (e.g., upslope
wetlands vs. downslope wetlands), an individual wetland’s purification score may
increase or decrease, but the regional wetland purification score will decrease
The Regional-Basic wetland assessment approach served the needs of a demonstration of
how to estimate water purification services provided by wetlands required over the time
constraints of the ESPP project. However, the decision to use it as a demonstration is in no
way an endorsement of this approach — scientific concerns include the fact that it does not
represent some of the ecological processes that determine wetland purification functions
(e.g., the sole metric for determining wetland-specific function is wetland area), it does not
adequately represent water flow paths or processes, and it does not consider both spatial
and temporal dynamics. Practical concerns include that it does not embrace emerging
technologies that could result in more comprehensive assessments.
The Regional-Advanced wetland assessment approach is recommended for future
considerations. Its conceptual underpinnings is based on the site-based wetland
assessment for ecosystem services approach called WESPUS (Adamus 2011), thus
benefitting from decades of science and practice in wetland assessments in the United
States led by Dr. Paul Adamus. It benefits from a strong foundation of scientifically peer-
reviewed studies specific to the prairie pothole regions typical of southern Alberta (i.e., it
captures processes that dominate in the White Zone). However, it needs further
investigation (and possible modification or adaptation of metrics) prior to its application to
northern Alberta (i.e., it may not capture processes that dominate in the Green Zone). To
adopt this approach the following (real or perceived) barriers need to be overcome:
1. Implement effective knowledge management strategies. There is a need to
compile and coordinate the disparate data needed for ecosystem service
assessments province-wide. A starting point is to expand the provincial GIS web
portal (AltaL!S) to bring together all of the relevant datasets (WSC and research
gauging stations, MSC meteorological data, field-based measurements, GIS and RS
data) into a single, publicly accessible venue. Such a centralized database would
encourage value-added cross-site comparisons and meta-experiments, greatly
expanding knowledge generation, and increasing the incorporation of these
resources into land management planning and operations. This centralized web
portal should also be linked to federal datasets for ease of upscaling or downscaling
of relevant data.
Embrace emerging technologies. There are terabytes of data being processed
every day by many sensors; however, much of them are being discarded because
there is no mandate or resources to archive all imagery. The Province of Alberta
needs to support federal and international RS programs that are creating multi-
decadal image datasets which will be vital for ecosystem service assessments now
and in the future and needs to encourage government agencies to embrace these
technologies and incorporate them into government activities.
Continue and expand monitoring programs. Even in this digital age of satellite
sensors and distributed sensor networks, field based measurements are still crucial.
For example, Alberta like all other areas of Canada has lost many meteorological
and water survey stations since the golden age of hydrometric data collection in the
1970s. This trend of closures, however, needs to be stopped and reversed. Existing
water monitoring stations need to be maintained because many of the critical
questions, especially those related to climate change, that can only be addressed by
analyzing long-term datasets. Furthermore, monitoring network needs to be
expanded to stations targeting meso-scale watersheds (like that of Shepard Slough),
whose size is more compatible with management activities. The Province of Alberta
should take the lead in developing a provincially coordinated ecohydrology
monitoring network, and build partnerships with universities, industries, municipal
governments, and other stakeholders including the public, to increase monitoring the
environment.
Transfer of technologies and techniques to end users. Even if the best of data,
tools and models are available, they will languish if there are not qualified people to
use them. In an era of increasing water insecurity, it is essential to promote and
enhance interdisciplinary training in the water resource sciences and applications.
We need enhanced knowledge transfer from product developers in digital terrain
analysis, remote sensing, and distributed simulation modeling, to ecosystem
scientists and managers. It is important that managers and scientists work together
to better understand the complexity of the management questions as well as the
potential solutions. The best way for this learning to occur is through the use of Web
2.0 technologies where information flows both ways and “end-users” become
“engaged-users” of GIS and RS techniques.
This was a valuable exercise, even if the sole benefit was to get people to start thinking of
wetlands as valuable natural assets for the ecosystem services that they provide.
7.0 REFERENCES CITED
Adamus, P. (2011). Manual for the Wetland Ecosystem Services Protocol for the United
States (WESPUS) (Draft Version). Adamus Resource Assessment, Inc.
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Bailey, S., Creed, |. F., Foote, A.L., & Krogman, N. (2008). Wetland Health: challenges and
opportunities in implementing Alberta’s Wetland Policy (Proposal).
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8.0 BIBLIOGRAPHY
Adamus, P. (1983). Criteria for created or restored wetlands. pp.369-372 in Hook, D.D.,
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Adamus, P. (1983). The FHWA/Adamus (WET) method for wetland functional assessment.,
in Hook, D.D., McKee, W.H., Jr., Smith, H.K., and others, eds., The ecology and
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Adamus, P. (1992). Conceptual Process Model for Basin-type Wetlands of the Prairie
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Bohlen, P. J., Lynch, S., Shabman, L., Clark, M., Shukla, S., & Swain, H. (2009). Paying for
environmental services from agricultural lands: an example from the northern
Everglades. Frontiers in Ecology and the Environment, 7(1):46-55.
Bow River Basin: State of the Watershed Summary. (2010). . Bow River Basin Council.
Brinson, M. M., & Eckles, S. D. (2011). US. Department of Agriculture conservation
program and practice effects on wetland ecosystem services: a synthesis. Ecological
Applications, 21(sp1):S116-S127.
Cedfeldt, P. T. (2000). Using GIS to Identify Functionally Significant Wetlands in the
Northeastern United States. Environmental Management, 26(1):13-24.
CES - Ecosystem Services Fact Sheets: Water Purification. (n.d.). Ecosystem Services Fact
Sheets: Water Purification. Union of Concerned Scientists and the Ecological Society
of America, . Retrieved July 27, 2011, from
http://esa.org/ecoservices/comm/body.comm.fact.wate.html
Chan, K. M. A., Shaw, M. R., Cameron, D. R., Underwood, E. C., & Daily, G. C. (2006).
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Cobbaert, D. (n.d.). Industrial Heartland Wetland Management Project.
Cobbaert, D., Robinson, M., Trites, M., & Dam, A. (n.d.). An Assessment of Wetland Health
and Values in Alberta's Industrial Heartland.
Cobbaert, D., Robinson, M., Trites, M., & Dam, A. (n.d.). Appendix B: Wetland condition and
values in the Industrial Heartland: A GIS-based wetland assessment (Appendix to An
Assessment of Wetland Health and Values in Alberta’s Industrial Heartland).
Cobbaert, D., Robinson, M., Trites, M., & Dam, A. (n.d.). Industrial Heartland GIS
Processing (Supplementary to An Assessment of Wetland Health and Values in
Alberta’s Industrial Heartland).
Criteria for created or restored wetlands. (n.d.).
Euliss, Ned H., Smith, L. M., Liu, S., Duffy, W. G., Faulkner, S. P., Gleason, Robert A., &
Eckles, S. D. (2011). Integrating estimates of ecosystem services from conservation
programs and practices into models for decision makers. Ecological Applications,
21(sp1):S128-S134.
Gleason, R. A., Euliss, N. H., Tangen, B. A., Laubhan, M. K., & Browne, B. A. (2011). USDA
conservation program and practice effects on wetland ecosystem services in the
Prairie Pothole Region. Ecological Applications, 21(sp1):S65-S81.
Gleason, Robert A., Laubhan, Murray K., & Euliss, Ned H. (2008). Ecosystem services
derived from wetland conservation practices in the United States Prairie Pothole
Region with an emphasis on the U.S. Department of Agriculture Conservation Reserve
and Wetlands Reserve Programs. U.S. Dept. of the Interior, US. Geological Survey.
Grabs, T., Seibert, J., Bishop, K., & Laudon, H. (2009). Modeling spatial patterns of
saturated areas: A comparison of the topographic wetness index and a dynamic
distributed model. Journal of Hydrology, 373(1-2):15—23.
Grassland Vegetation Inventory (GV1) Specifications ( No. 5th edition). (2010). . Alberta
Sustainable Resource Development, Government of Alberta.
Hollis, T., & Bedding, J. (1994, July 2). Can we stop the wetlands from drying up?: From
southern Spain to northern Nigeria, conservationists are struggling to convince
governments of the value of wetlands. New Scientist, (1932).
Invasive Weed & Disturbance-caused Undesirable Plant List (For use in Riparian Health
Assessment and Inventory in Alberta). (2011). Cows and Fish—Alberta Riparian
Habitat Management Society.
Jeje, Y. (2006). Export coefficients for total phosphorus, total nitrogen and total suspended
solids in the southern Alberta region. Alberta Environment and Sustainable Resource
Development.
Kazmierczak, R. F. (2001a). Economic linkages between coastal wetlands and
habitat/species protection: A review of value estimates reported in the published
literature. Agricultural Economics and Agribusiness Staff Paper.
Kazmierczak, R. F. (2001b). Economic linkages between coastal wetlands and hunting and
fishing: a review of value estimates reported in the published literature. Agricultural
Economics and Agribusiness Staff Paper, 3.
Layke, C. (2009). Measuring nature’s benefits: A preliminary roadmap for improving
ecosystem service indicators. World Resources Institute: Washington.
Porter, Keith, Wein, Anne, Alpers, Charles, Baez, Allan, Barnard, Patrick, Carter, James,
Corsi, Alessandra, Costner, James, Cox, Dale, Das, Tapash, Dettinger, Michael,
Done, James, Eadie, Charles, Eymann, Marcia, Ferris, Justin, Gunturi, Prasad,
Hughes, Mimi, Jarrett, Robert, Johnson, Laurie, Dam Le-Griffin, Hanh, Mitchell, David,
Morman, Suzette, Neiman, Paul, Olsen, Anna, Perry, Suzanne, Plumlee, Geoffrey,
Ralph, Martin, Reynolds, David, Rose, Adam, Schaefer, Kathleen, Serakos, Julie,
Siembieda, William, Stock, Jonathan, Strong, David, Sue Wing, lan, Tang, Alex,
Thomas, Pete, Topping, Ken, and Wills, Chris; Jones, Lucile, Cox, Dale, (2011).
Overview of the ARkStorm scenario. U.S. Geological Survey Open-File Report 2010-
1312. U.S. Department of the Interior, United States Geological Survey.
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control practices. Advances in modeling the management of stormwater impacts, 7.
Rosen, B. H., Adamus, P., & Lal, H. (1995). A conceptual model for the assessment of
depressional wetlands in the prairie pothole region. Wetlands Ecology and
Management, 3(4).
Tallis, H., & Polasky, S. (2009). Mapping and Valuing Ecosystem Services as an Approach
for Conservation and Natural-Resource Management. Annals of the New York
Academy of Sciences, 1162(1):265-283.
The Ecosystem Services Approach Pilot on Wetlands: Glossary Document (Draft Version).
(2011). Government of Alberta.
Trepel, M. (2010). Assessing the cost-effectiveness of the water purification function of
wetlands for environmental planning. Ecological Complexity, 7(3):320-326.
Wealands, S. R., Grayson, R. B., & Walker, J. P. (2005). Quantitative comparison of spatial
fields for hydrological model assessment--some promising approaches. Advances in
Water Resources, 28(1):15-32.
Wetland 105 Health Assessment Summary. (2010). SNC Lavalin Environment, Calgary, AB.
Wetland 106 Health Assessment Summary. (2010). SNC Lavalin Environment, Calgary, AB.
Wetland 111 Health Assessment Summary. (2010). SNC Lavalin Environment, Calgary, AB.
Wetland 87 Health Assessment Summary. (2010). SNC Lavalin Environment, Calgary, AB.
Wetland 99 Health Assessment Summary. (2010). SNC Lavalin Environment, Calgary, AB.
Wetland Evaluation Technique (WET). (n.d.). U.S. Army Corps of Engineers. Retrieved from
http://el.erdc.usace.army.mil/emrrp/emris/emrishelp6/wetland_evaluation_technique_t
ools.htm
Zedler, J. B., & Kercher, S. (2005). WETLAND RESOURCES: Status, Trends, Ecosystem
Services, and Restorability. Annual Review of Environment and Resources, 30(1):39-
74.
9.0 APPENDICES
A1. COMPARISON OF METHODS FOR WETLAND INVENTORIES
TABLE A1.1: Comparison of different methods for wetland inventories available for ecosystem
service assessments of the Shepard Slough.
Name/
Method
Calgary-Rocky
View County
Intermunicipal
Development Plan
(IDP)
=
&
. = eae ca
“es tet - Tete
DU Wetland
Inventory
Probabilistic
shape analysis
(Creed
Probability
Method)
area object
recognition
GIS-based
é
open water
mapping
e Ser é
GiS-based
surface water
and saturation
classification
Relative cost
$$$3$
$$$$5
$
$$$
$
$$$
Manual or
automated
Manual
Manual
Automated
Automated
Automated
Automated
Wetland
description
Saturated +
inundated area
map (class 1 to 5
wetlands)
Saturated +
inundated area
map (dugout,
headland,
marsh, open
water)
Saturated +
inundated area
potential map
Saturated +
inundated area
map
inundated area
map
Saturated +
inundated area
probability map
Wetland area
threshold
> 0.001 ha
> 0.001 ha
> 0.01 ha
> 0.001 ha
>01ha
(Landsat)
> 0.01 ha
(SPOT)
Data Source
Air photos
Air photos
LIDAR bare
earth DEM
Air photos
Landsat/SPOT
Landsat/SPOT +
ERS/Radarsat-
1/ASAR SAR
Data Provider
City of Calgary
GOA
GOA
GOA (historic)
City of Calgary
(current)
USGS
(Landsat)
ATIC (SPOT)
USGS (Landsat)
ATIC (SPOT)
ASF (ERS SAR)
MDA (Radarsat-1
SAR)
ESA (ASAR
SAR)
Spatial
resolution
5 meter grid
1:30000 —
1:70000
(historic)
30 cm grid
(current)
30 meter grid
(Landsat)
2.5 — 20 meter
grid (SPOT)
25 meter grid
Temporal
resolution
1965
2005 growing
season
Long-term
potential
1947 — present
1984 — present
(Landsat) 1992
— present
(SPOT)
1992 — present
Coverage
Partial
Complete
Complete
Complete
Complete
Complete
Acronym Definitions:
ATIC: Alberta Terrestrial Imaging Centre (Lethbridge)
USGS: United States Geological Survey
GOA: Government of Alberta
ASF: Alaska Satellite Facility
MDA: MacDonald, Dettwiler and Associates Ltd.
ESA: European Space Agency
A2. COMPARISON OF METHODS FOR LAND USE/ LAND COVER MAPS
TABLE A2.1: Comparison of Land Use/ Land Cover (LU/LC) maps available for ecosystem
service assessments of the Shepard Slough.
Crop type a
mapping in the
Prairies 2009
ducal
ILE L!
Grassland
Vegetation
Inventory (GVI)
Intermunicipal
Development Plan
(IDP)
GOA Vector
Layers
"LANDSAT TM
Mvew
SPOT
Number of
LULC
Classes
22
32
11
3
Dependant on
classification
Dependant on
classification
Date range
2000 and 2009
2009
2008
Lakes and
Rivers = 2004,
Roads = 2008,
Rail = 2007
1985 to 2010
Spatial
resolution
56m
5m
30cm aerial photo
1m
30m
5m
Spatial
coverage
Complete
Complete
Incomplete
Complete
Complete
Complete
Data
provider
National Land and
Water Information
Service
Alberta
Sustainable
Resource
Development
City of Calgary
and Rocky View
County
Alberta
Sustainable
Resource
Development
United States
Geological
Survey
Pros
Complete
coverage of
Shepard Slough
Complete
coverage of the
Shepard Slough
Accurate coverage
of urban class for
2009
High resolution
provides greatest
definition of rare
classes such as
forest and shrub
land
Provides clear
delineation of
narrow linear
features
Time series
available
Time series
available
Urban class
coverage is not
consistent with the
2009 LANDSAT
TM urban
coverage. Poor
delineation of
roads, rail, lakes,
and rivers
No forest or
shrubland
classification
Incomplete
coverage of
Shepard Slough
Higher resolution
than other LULCs
No temporal
variation
captured
Non-ground-
truthed
classification
Data not
available
within project
timeline
To provide a LULC that covers the entire Shepard Slough and identifies each of the key
classes a composite of specific layers from LULC’s described in Table A2 was completed.
The Crop type mapping in the Prairies 2009 was chosen as the base layer for the LULC
because it provided complete coverage of the Shepard Slough in terms of agriculture and
natural (forest and shrubland) classes. Although the LULC was completed for 2009 the
urban Class is severely underestimated when compared with urban areas identified in the
2010 LANDSAT TM image. To overcome the underestimation of urban areas the urban
class defined in the Grassland Vegetation Inventory was overlain on the base layer. The
urban class closely matches the urban areas visible in the 2010 LANDSAT TM image. The
base layer classifies the canal infrastructure as urban land use. To define the canal
separately the canal features defined in the GVI were extracted and overlain on the base
layer. Due to the spatial resolution of the base layer (56m) finer features such as roads, rail,
lakes and streams are often not present in the LULC. To overcome this the vector layers for
these classes available from the Government of Alberta were rasterised and expanded
where necessary (roads expanded from 1m to 15m wide, Rail expanded from 1m to 10m
wide). Expansion was based on comparison with the 2010 LANDSAT TM image. Once
completed these layers were overlain on the base layer. Wetlands derived from the 2010
LANDSAT TM image using a threshold of 20 on Band 3 were also overlain on the base layer
to provide consistency with the wetland inventory developed for the ESPP.
A3: MAPS OF WATER PURIFICATION METRICS 1 TO 6 AND THE INTEGRATED WATER PURIFICATION SCORE
1990 2000
Figure A3.1: WP1 metric scores for wetlands in Shepard Slough
1990 2000
{ i
Figure A3.2: WP2 metric scores for wetlands in Shepard Slough
2000
Figure A3.3: WP3 metric scores for wetlands in Shepard Slough
1990 2000
Figure A3.4: WP4 metric scores for wetlands in Shepard Slough
1990 2000
Figure A3.5: WP5 metric scores for wetlands in Shepard Slough
1%,
be
]
} 9
| © or. of
le © | fea)
jo e rO. ge
; © | °
©, o : ©, @ ® vd |
e | L »00® | »®
Poo ce 38
:
é a
é eee
1990 2000
Figure A3.6: WP6 metric scores for wetlands in Shepard Slough
1990 2000
Figure A3.7: Water purification scores (WPS) wetlands in Shepard Slough
A4: DATA FOR WATER PURIFICATION METRICS 1 TO 6 AND THE INTEGRATED WATER PURIFICATION SCORE
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
rel
$27 563
} | $18,810 | $20,160
$1,058 |
en on
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
$195
$28,088
$97,410
$225
$14,040
$38,850
$165
$180
$390
$525
$10,800
$17,040
$21,525
$27,743
$13,860
$225
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
1990 2000 2010 1990 2000 2010 1990
$12,690
$34,170
$10,238
$2,160
$188
$4,185
$3,413
$863
$3,045
$10,350
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
$11,385
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
$29,138
$720
$22,478
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
complex Area Area Area 2 : oe | see ae Dollar Wetland
ae (ha) (ha) (ha) WP1 WP2 | WP3 . wP4 WP5 WP6 _ WPS . ts Value Benefit ($)
Year 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 $/ha) 1990 2000
$18,000
$173
$1,823
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no « 0en water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
WP2 WP3 WPS
1990 2000 2010 1990 2000 2010 1990
$3,600
$4,950
$24,998
$19,425
$1,050
$1,305
$608
$128
$7,755
$25,200
$33,480
$6,480
$7,290
$420
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
— :
complex Area Area Area | 2
ID (ha) (ha) (ha) WP1 WP2 we3 WP4 WP5 WP6 WPS
Year 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
4titil
POO
275 0.4 = oo 0.2
0.5
0.8
0.6
0.1
0.533
$5,000
$960
279 ae 0.9 0.3
04
0.8
0.4
0.9
0.1
0.433
$5,000
$1,950
280 1.4 0.5
0.1
0.8
0.6
0.667
$5,000
$4,800
281 6.2 5.4 9.3 0.7 0.7 0.7
0.1
0.1
0.1
0.8
0.8
0.8
0.4
0.4
0.4
0.8
0.6
0.8
0.1
0.1
0.1
0.483
0.450
0.483
$5,000
$15,008
$12,150
$22,403
286 0.6 0.1 me 0.2
0.1
0.1
0.8
0.6
0.6
0.6
0.600
0.617
$5,000
$1,890
$278
288 1.0 1.4 0.3 0.5
0.5
0.8
0.8
0.8
0.8
0.9
0.1
0.5
0.717
0.617
$5,000
$3,548
$4,440
304 7.5 0.3 0.7 0.2
0.1
0.1
0.5
0.6
0.6
0.6
0.1
0.1
0.500
0.433
$5,000
$18,675
$585
70
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
complex Area Area Area Dollar Wetland
ID
(ha) (ha) (ha) WP1 . WP2 WP3 wpe4 WP5 WP6 WPS Value Benefit (S$)
Year 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 $/ha) 1990
307 0.2 0.2 1 0.8 0.8 1 0.5 0.717 | $5,000 $645
315 0.2 0.5 0.2 0.2 1 1 0.8 0.8 0.8 0.8 1 1 1 0.5 0.800 | 0.717 | $5,000 $720 $1,613
327 5.4 0.7 0.1 0.8 0.4 1 0.1 0.517 $5,000 $13,950
328 243.2 | 238.2 | 2445 1 1 1 0.1 0.5 0.5 0.8 0.5 0.5 0.6 0.6 0.6 1 1 1 0.5 0.5 0.5 | 0.667 | 0.683 | 0.683 | $5,000 | $810,600 $813,953 $835,478
334 0.2 0.2 1 0.8 0.8 0.9 0.5 0.700 | $5,000 $630
336 0.6 0.3 0.1 0.8 0.4 0.1 0.1 0.300 $5,000 $945
338 0.1 0.2 0.2 0.2 1 1 0.8 0.8 0.8 0.8 0.6 0.6 0.5 0.5 0.650 | 0.650 | $5,000 $293 $585
71
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
Atitil
atitit
HOC
4titil
0.1
0.5
04
0.2
0.3
0.2
0.1
0.1
0.1
0.8
0.8
0.8
0.4
0.4
0.4
0.6
0.6
0.6
0.1
0.1
0.1
0.367
0.383
0.367
$5,000
$165
$1,035
$660
04
0.2
0.1
0.8
0.2
0.3
0.1
0.283
$5,000
$510
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
72
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2010. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
complex Area Area Area Dollar Wetland
(ha) (ha) (ha) WP1 WP2 WP3 wpe4 WP5 WP6 WPS Value Benefit ($)
1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 $/ha) 1990
390 0.2 0.2 0.1 0.8 0.4 0.1 0.1 0.283 | $5,000 $255
398 0.2 3.3 6.9 0.2 0.5 0.7 0.1 0.1 0.1 0.8 0.8 0.8 0.4 0.4 0.4 0.6 0.6 0.8 0.1 0.1 0.1 | 0.367 | 0.417 | 0.483 | $5,900 $330 $6,938 $16,748
404 1.2 3.0 0.5 0.5 1 1 0.8 0.5 0.4 0.4 0.1 0.1 0.1 0.1 0.483 | 0.433 | $5,000 $2,828 $6,435
407 0.5 0.7 0.3 0.3 1 1 0.8 0.8 0.6 0.6 0.1 0.1 0.1 0.1 0.483 | 0.483 | $5,000 $1,305 $1,740
73
Table A4.1: Metric and water purification scores (WPS) for all wetland complexes present in 1990, 2000 and 2019. NOTE: where there is no data present for a wetland complex, no open water was present during the year but open water has
been present at some stage during the period 1984 to 2010.
Dollar Wetland
Wetiand
complex Area Area Area 2
WP2 WP3 WwP4 WP5 WP6 WPS Value Benefit ($)
1990 2000 2010 1990 2000 2010 $/ha) 1990 2000 2010
iD (ha) (ha) (ha) WP1
Year 4990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010 1990 2000 2010
$1,060,313 $1,452,968 $1,310,423
Total 334.7 469.3 4044
74
A5: RESPONSES TO QUESTIONS FROM THE BIOPHYSICAL AND SOCIOECONOMIC
TEAM LEADERS ON THE REPORT PREPARED FOR THE ECOSYSTEMS SERVICES
PILOT PROJECT ENTITLED ECOSYSTEM SERVICE ASSESSMENT OF WETLAND
WATER PURIFICATION FOR THE SHEPARD SLOUGH STUDY AREA, dated
SEPTEMBER 3, 2011
Responses to questions from the biophysical and socioeconomic team leaders on the
report prepared for the Ecosystem Services Pilot Project entitled Ecosystem Service
Assessment of Wetland Water Purification for the Shepard Slough Study Area by rena F.
Creed Consulting dated September 3, 2011
This document details responses to questions received from the ESPP biophysical and
socioeconomic team leaders regarding the draft report Ecosystem Service Assessment of
Wetland Water Punfication for the Shepard Slough Study Area (submitted August 6, 2011). The
responses provided will be integrated into a final report that will be submitted September 6,
2011
Questions received August 29, 2011
Question 1
Please confirm. Definitions of key terms p.9 Table 2
The socio-economic team asked (in previous communications), “What is the definition you used
in this report for water purification and water quality?” It is our understanding that (based on
page 6), the definition used was: “wetlands provide natural water purification ...”; “... natural
purification processes provide clean drinking water ...and non-human (biodiversity) uses.”; and
“Natural purification is a function of the rate of water movement...related to the affinity of
substrate to adsorb or absorb (metabolize) contaminants in the water’
Response
Water purification: Water purification is the removal of contaminants from a water
supply. In this report, contaminants refer to sediments and nutrients (nitrogen and
phosphorus).
Water quality: Water quality refers to the physical, chemical and biological properties of
a water supply. In this report, water quality focuses on sediment and nutrient (nitrogen
and phosphorus) concentrations in the water supply.
Question 2
Page 6, section 3.0, third paragraph. Please clarify the first sentence: “unfiltered water than by-
passes the purification system and enters directly the water supply”, regarding human-induced
degradation. Does this refer to the next paragraph that discusses point and NPS inputs?
Response
The following change will be made to the section referred to in Question 2:
“Human activities can degrade the purification potential of wetlands by (1) altering water
flow pathways such that water bypasses (flows above or below) the natural purification
system of the riparian buffers; (2) increasing sediment and nutrient loads beyond the
purification potential; and/or (3) damaging the riparian buffers and thus its purification
functions. The consequence of these degradations to the purification potential of
wetlands is that non-point sources of sediments and nutrients may enter the water
supply attenuated.”
Question 3
Page 7, 1" paragraph. Please clarify “redox potential” as it relates to the service delivery,
particularly for a lay audience
Response
The following change will be made to the section referred to in Question 3:
“Changing water flow processes and/or pathways can result in changes to the oxygen
content of soils that may have differential effects on the fate of nutrients (e.g., N removal
depends on transformation to N,O/N2 that requires oxygen poor soils whilst P removal
depends on adsorption to soil particles that requires oxygen rich soils).
Question 4
Page 7, 1" paragraph. It’s noted that introducing non-native species may alter the nutrient
cycling potential of a wetland. We are not including the nutrient cycling services in the pilot
project but understand there is a linkage. To what extent does the composition of species
near/adjacent to wetlands influence the water filtration capacity? And, are there particular
species in this area that are essential for the delivery of this service (and if the information is not
available, are you aware of other studies that looked at wetland plant species important for this
function?)
Response
The three zones that provide an important function in water purification are emergent
zone, wet meadow zone and riparian upland zone. Changing the composition of
organisms within or adjacent to wetlands by introducing species with different nutrient
fixation, transformation, and/or uptake potentials may fundamentally alter the nutrient
cycling potential of a wetland. For example, an emergent zone dominated by Typha spp.
would result in the accumulation of nitrogen in the biomass (Zedler 2000), as could Alder
trees with symbiotic N2 fixing bacteria (Hurd et al 2001). Picard et al (2005) found that
monocrop microcosms of three plant species (Scirpus validus, Phalaris arundinacea and
Typha lIatifolid) removed nutrients under experimental conditions. An additional
treatment combining these three species with another (Carex lacustris) also removed
nutrients, suggesting that biodiversity can be maintained when planning for nutrient
removal.
Question 5
Page 7, 2™ paragraph. The report notes the importance of riparian areas. Are there guidelines
as to the size of ‘buffer’ required to maintain purification function (e.g., hectares, metres)?
Response
Provincial guidelines have been developed that define riparian buffers for streams (30m),
rivers (60m) and lakes (100m) (Alberta Environmental Protection 1994). Municipal
guidelines are more liberal, requiring a 6m riparian buffer from water sources for
development approvals (Municipal Government Act 2010). However, adaptive, rather
than standard, riparian buffer widths are advised, as the conditions required for effective
purification function may vary greatly among wetlands. For example, in the boreal
plains, Creed et al. (2008) found that hydrological flow pathways influence the formation
of surface or near surface saturated areas (i.e., wet areas), and that riparian buffers
should be defined by the extent of these wet areas to reduce sediment and nutrient (e.g.,
N) loads as the are transported to surface waters.
Question 6
Wetland inventory graphics (Pages 19 and 20): The variance between DU Historic and 2005
inventory, and the Landsat Satellite inventory is substantial. What is the reason for the
variance? As the method selected chooses the latter, would you consider your results highly
conservation estimates of function?
Response
The DU inventory is developed from manual digitization of wetland boundaries from fine
resolution aerial photography and includes both the inundated (open water) and
saturated zones. The Landsat inventory is developed from coarser resolution satellite
imagery and includes the inundated zone only. The class 1 and 2 wetlands and smaller
class 3 wetlands that are typically dry and do not have an open water zone will not be
captured in the Landsat inventory and are not included in the report. As a result, the
Landsat inventory is highly conservative because the saturated areas, which are
important in the water purification function of wetlands, are not included. The implicit
assumption is made that there is a constant ratio between inundated and saturated areas
that allows us to infer the value of the saturated zone from the inundated zone. However,
this ratio has not been defined or assessed as part of this report. It must be emphasized
that the Class 1, 2 and 3 wetlands that are not captured are still important for water
purification and other ecosystem services and should not be excluded from policy
decisions.
Question 7
Section 5.2.: What is the definition of “water budget” used in this report? (precipitation minus
evapotranspiration?)
Response
The water budget is defined as the water inputs [precipitation (P)] to the system versus
the water outputs [evapotranspiration (ET) and discharge (Q)] from the system and is
represented by the formula P = ET + Q. It is assumed that the change in water stored in
the wetland is negligible. This water budget is used to estimate the water surplus of the
system (P-PET) where potential evapotranspiration (PET) can be estimated using a range
of techniques available in the literature. In this report, PET was estimated using the
technique by Hamon (1963), because it is simple and requires readily available data
(temperature data only). If the annual P-PET is positive, a water surplus exists and it is
considered a wet year (i.e., energy limited). In contrast, if the annual P-PET is negative, a
water deficit exists and it is considered a dry year (i.e., water limited).
The Hamon (1963) equation is as follows:
Phd
(7. +273.2)
4
Where PET amon is in mm month", H, is number of monthly average daylight hours per
day, T, (°C) is the mean monthly temperature, e, is the saturated water vapor density
term calculated as follows:
17.277
237.347
0 6108 exp
Question 8
Section 5.2.2: Do you have maps with the LULC available? (e.g., agriculture, urban and open
water). Figure 6 provides on changes in urban land use
Response
Land Use Land Cover (LULC) figures are now presented in Appendix 2 of the report.
Question 9
VWP2 uses disturbed land use in the calculation (including residential, commercial and industrial,
and roads and rail infrastructure). Do the LULC maps you have available show these three land
use types? Section 5.2.2 only notes agriculture, urban and open water
Response
The urban land use category used in the 1990, 2000, and 2010 Land Use Land
Classifications incorporates residential, commercial, and industrial land use along with
road and rail infrastructure. These are not broken down into individual classes.
Question 10
Please explain why agriculture was removed from the WP2 metric (rationale provided notes that
“the metric allows us to account for spatial and temporal variation in wetland function resulting
from land use”. Would agriculture not be a key driver of wetland degradation and reduced
function? Or, is the inclusion of agriculture in WP3 sufficient to include the effect of this driver?
Response
WP2 addresses the potential pollutant sources to a wetland (see table 4) and is defined
by the presence of disturbed land within a wetlands contributing area. The metric scores
for WP2 are calculated as 0.1 for <20 per cent disturbed land, 0.5 for 20 to 50 per cent
disturbed land, and 1.0 for >50 per cent disturbed land within the contributing area.
When both urban and agricultural land use are included as disturbed land, WP2 metric
scores for all wetlands within Shepard Slough are 1.0 throughout the time series (1990 —
2010). To try and capture the change in land use over the time period, agriculture was
removed when determining the WP2 metric scores. The assumption made was that
runoff from urban areas has higher sediment and nutrient loads than runoff from
agricultural areas. This is not a hard and fast rule and is dependent on a range of
variables including urban land use (industrial compared to residential), fertiliser
application rates and tilling practices. Removing agriculture from the WP2 metric results
in a lower overall WPS for wetlands in Shepard Slough. If the technique is to be used
across Alberta, we advise that agriculture in WP2 be included to maintain consistency
across the province.
Question 11
Section 5.3.1.3. Is there an error in the “What is the metric” section? “WQ3 metric attempts
Should this be WP3?
Response
This is an error and will be corrected in the report to read “WP3.”
Question 12
Please explain the relationship between WPS and /ha value. A GOA reviewer commented, “If
WPS represents the quality of the filtration potential that presumably ones with higher WPS will
have higher /ha value.”
Response
The WPS is a value between 0 and 1. To achieve the range of $/ha range for the range of
WPS values, the WPS value is multiplied by $50/ha, $500/ha, or $5,000/ha (representing
the median and range of values from the literature). This results in a lower $/ha cost for
lower WPS values. For example, for a wetland with a WPS of 0.1 the $/ha cost is
determined by multiplying the median value of $500/ha by the WPS, 0.1 x $500 = $50/ha.
This is then multiplied by the area of the wetland (ha) to determine the overall $ benefit of
that wetland.
Question 13
Cumulative effects vs. cumulative benefits, p.10. Please clarify the differences between these
two terms used in the report
Response
Cumulative Effect — is the combined impact that anthropogenic activity is having on all
wetlands in the Shepard Slough area.
Cumulative Benefit — is the combined benefit that all wetlands are providing to water
purification in the Shepard Slough area
Question 14
Natural drivers vs. human drivers, p.22. How could you tease out/separate the impact of natural
drivers and human drivers?
Response
To tease out the effect of natural vs. human drivers, one has to establish a “reference
condition” that is representative of the range of natural variability in climatic conditions
in the region, and then compare the effects of human activity against this reference
condition. A challenge is when the range of natural variability in climatic conditions
translates into a broad range in wetland areas, causing the impacts of human activities to
be lost. In other words, the “signal” from human drivers cannot be distinguished from
the “noise” from natural drivers. We attempted to establish a reference condition by
exploring the relationship between climatic conditions (i.e., P-PET) and wetland areas.
We observed a complex relationship, where wetland areas appeared to fall within one of
two steady states — a relatively dry state (small wetland area) and a relatively wet state
(large wetland area). We were careful in selecting the time series (1990, 2000, 2009) that
was used to establish trends. We selected years that all fell on one of the two steady
states (the relatively dry state). Clearly more work is needed in this area to resolve the
processes leading to these two steady states and to develop a reference condition where
the system can naturally oscillate between wet and dry conditions.
Question 15
Wetland assessment framework, p.8, Table 1
The approach taken in this study in doing economic valuation (convert ES scores to dollar
values) is a different approach from the potential metrics identified in the last column. What is
the purpose of listing the last column since it's not undertaken in the study?
Table 1 - wetland assessment framework mentions avoided cost of water treatment as policy
indicator, is this what Table 8 is supposed to show?
Response
Table 8 provides an overview of the wetland assessment framework defined for the ESPP
by the Biophysical Team during the Calgary meeting (June 24, 2011). The report
attempts to demonstrate the different steps in the framework, including a basic economic
valuation that was developed in consultation with Dr. Paul Adamus, an advisor to the
ESPP. In no way is this basic economic valuation intended to replace the socioeconomic
team’s work; rather, it is to showcase one way of doing an economic valuation from
which the socioeconomic team may benefit. This has been emphasized in the final
report.
Question 16
Different definitions for wetland size, p.25
The wetland by definition here is the open water area, excluding saturated soil zone. Any
significant impact on the results and on the physical water purification capacity?
Previous Response: This is a complex question, which we will try to answer in two parts.
First, depending on the Stewart and Kantrud (1979) classification of wetlands, inundated
areas may constitute a minor (Class 1, 2) to major (Class 3, 4, 5) portion of wetland
surface. For this reason, we are not comfortable assigning a margin of error to the
wetland area by not including saturated areas. Second, the inundated vs. saturated
areas serve distinct functions in terms of removal of contaminants. For example,
inundated areas are important for P removal, but saturated areas are important for N
removal. This complementary role of inundated and saturated areas in water purification
processes is precisely why we advocated the Regional- Advanced wetland assessment
approach, as the Regional-Basic wetland assessment approach does not represent these
processes that are so important for water purification. In summary, we believe the main
benefit of this consulting project was to report on a mental exercise to showcase the
importance of considering ecosystem services of wetlands (albeit one that required a
great deal of number crunching!), but better data are needed before the theory is put into
practice.
---this could be made more explicit in the final report.
Response
We will make this more explicit in the final report.
Question 17
Wetland purification function score, p.30
17a. In the function score calculation, wetland open water size is the only factor that represents
the physical function/condition. Does that address enough for the physical condition of water
purification function?
Response
No, wetland area alone doesn’t capture the purification potential of wetlands. In the
Regional-Basic wetland assessment approach used in the report, wetland area is the
single wetland-specific feature that determines the natural purification potential of
wetlands. The assumption is that wetland area is directly correlated with other wetland
features that contribute to the purification potential of wetlands (e.g., wet meadow and
emergent vegetation areas). No assessment has been undertaken to determine the
validity of this assumption. In the Cobbaert et al. (2010) report, there is supporting
literature to suggest that wetland area is a simple proxy for many purification functions.
However, in the Regional-Advanced wetland assessment approach based on the Adamus
(2010) method, many features of the wetland contribute to the purification potential of
wetlands. Data and time constraints prevented adoption of further metrics of purification
potential of wetlands from being assessed.
17b. Water purification scores increase from 1990 to 2010, mainly due to an increase in the
number of wetlands. Do we know the changes in scores for individual wetlands? If it’s
generally positive, what is the reason?
Response
The sentence, “This is mainly due to an increase in the number of wetlands present in
2010 over 1990” will be removed from the final report. Figure 15 presents the percentage
of wetland complexes within each WPS score. There is no significant difference in the
percentage distribution of wetland complexes among WPS values from 1990 and 2000,
however it is noted that there is a shift towards higher WPS values in 2010, and this is
predominantly due to the increase in urban land use observed in the 2010 Land Use Land
Classification.
17c. In the function score equation, human settlement factors have more effects over the
function factor. Would the scores thus be biased by human disturbances on the landscape? As
increase in urban areas results in higher scores and thus higher values, e.g. the increasing
opportunity of a wetland to treat contaminated water. This makes sense generally. But is that
suggesting that more human disturbance results in more value, which may become a
justification for the developers to disturb the land?
Response
Yes, as wetlands are lost or degraded on the landscape, the remaining ones will have
higher value with respect to purification potential. This should not be interpreted as an
incentive to disturb wetlands, but rather a disincentive. With the loss of each wetland, it
becomes more critical to protect the remaining ones. Of course, some wetlands will
have higher value than others, and it is important to identify these before further
development occurs to ensure they are protected.
17d. The scores do not allow for calculation of physical quantity of nutrients being avoided. If
physical quantity was available then we could calculate the cost of treatment
Response
Yes, if data were available, the relative scores could be calibrated to actual quantities of
nutrients removed.
Question 18
Figure 16. p.31
The title of Figure 16 may change from “from current condition to historic condition” to “from
historic condition to current condition”
Response
The title has been changed in the report.
Question 19
Economic values, p.32
What's the context of the dollar values from the literature? Vhat valuation techniques have
been used to yield those estimates? It may be critical if we want to transfer those numbers.
Speaking of value, there is no reference cited for where the economic values are coming from
Some context about these values would be needed. Also, | would recommend biophysical
water quality report not go into values
Response
Dollar values for water purification were derived from Kazmierczak (2001). Kazmierczak
(2001) provides a synthesis of wetland water purification valuations throughout the US
found in the literature. The methods for determining wetland valuations vary but are
predominately based on cost savings from traditional water treatment alternatives.
Wetland types assessed also vary in the study and range from coastal marshes to
forested swamps. Kazmierczak (2001) identifies 22 wetlands studied in the US for water
purification valuations. Figure 17 of the report presents the distribution of the wetland
studies throughout the range of $/ha figures.
Question 20
lf available, please provide a map to present the function scores for individual wetlands (also in
the final report). This could show the hotspots for the wetlands with low and high function
scores. Maybe three levels of functions scores within some range (low, medium, high).
Response
Maps of Water Purification Scores will be provided in Appendix 4 of the report.
Question 21
lf available, please provide individual map for each of the 6 indicators. For example, a map of
recharge potential indicator on p.29.
Response
Maps of each of the six Water Purification Metrics will be provided in Appendix 4 of the
report.
Question 22
lf available, please provide sources to allow an understanding of the relationship between
wetland classes and water purification function? Also, the absorption rate of P and N related to
different vegetation within wetlands
Response
We assume by wetland classes you mean Stewart and Kantrud’s (1979) class 1 to 5
classification. If so, given that we used a Landsat wetland inventory, we are not able to
explore the relationship between wetland classes 1 to 5 and their relative water
purification function. This is, however, an important question, that could be pursued
using a combination of the City of Calgary’s class 1 to 5 wetland inventory, and
application of either the Remote-Basic or Remote-Advanced wetland assessment
approaches for water purification, with verification using the WESPUS site-based
wetland assessments completed by O2 Consulting.
We have already responded to the request for N and P removal rates related to different
species of plants in the riparian buffers within wetlands — we have not completed a
comprehensive literature review on sediment and nutrient removal rates in mineral
wetlands related to plant species that are present, but we offer some key reference
citations based on a quick survey of the literature.
Question 23
Please provide the data/maps (mid- and end-products) used in the calculation in this study,
including the spreadsheet used to calculate the values described.
Response
Maps for the following will be provided:
e Individual wetland purification metric scores (WP1-6) and the integrated wetland
purification scores (WPS) for each wetland for 1990, 2000 and 2010
e Land use/land cover maps for 1990, 2000, 2010
Tables for the following will be provided
e 1990, 2000 and 2010 wetland area, WP1-6 metric scores, WPS
e Metric score calculator
Questions received August 12, 2011
Questions 1 to 11 and 15 to 16 were included in the Questions received August 29, 2011. The
remaining questions are presented below.
Question 12
| am not convinced that wetland inventories are not "proper" if they do not consider year to year
variations. First of all, consideration of natural fluctuations in the area inundated requires
intensive use of multiple data sources. | am not convinced that during an atmosphere of
streaming approvals GOA staff (particularly within my department) are going to have time,
resources and data available to make such a calculation on an individual wetland basis. | am
also not convinced that there is a need to have an economic determination that considers such
fluctuations. Rather, | would think that the economic valuable consider "potential" for services
related to water purification and then could ignore the issues related to year to year variation.
Response
This is an important point in terms of developing wetland ecosystem service assessment
approaches that can be implemented in an atmosphere of streamlining approvals.
Natural drivers cause substantial variation in wetland structure and function, and it is
important to forecast this natural variation so that accurate estimates of ecosystem
services can be achieved. However, it was never intended that individuals would have to
monitor this natural variation annually. Rather, it was intended that historical data be
used to define realistic reference conditions or benchmarks for wetland structure and
function, against which human drivers of change could be monitored. In the report, we
show that wetland areas defined by open water show high variation due to climatic
variability, and that the associated wetland function can be significantly reduced in drier
years, which would lead to significant underestimates of the economic benefits of these
wetlands during these years. A simpler approach would be to use the maximum extent
of wetlands to estimate the maximum potential for ecosystem services related to water
purification, as the reviewer suggested (i.e., maximum rather than median or some other
reference condition). However, this maximum must be based on historical data available
for the region.
Question 13
The GOA's license for LIDAR currently excludes much of the white zone and some portions of
the green (forested) zone. Many of the metrics identified in Table 5 are not yet possible for vast
areas of Alberta's landscapes.
Response
LIDAR acquisition continues to be a priority for many government agencies. It is
becoming the standard for digital elevation models; but it will take time to obtain
complete coverage for many provinces and states, and it will take time before complete
coverage of LIDAR is available for the Province of Alberta. This should not be viewed as
a deterrent for site-specific wetland ecosystem service assessments. In Table 5, we were
strategic in identifying low, medium and high quality data options for defining the water
purification metrics. A few of the metrics require high quality data (i.e., LiDAR) data, as
they are currently defined (e.g., the metric for ratio of wetland to contributing area
requires LIDAR to capture the subtle changes in topography that define these
contributing areas). There are at least two options for dealing with such metrics when no
LiDAR data are available: (1) remove that metric from the calculation of the wetland
function score; and (2) develop proxies for the metric (e.g., in the absence of high quality
data needed for definition of contributing areas, one could use lower quality data to
define a fixed buffer width (such as 100 m from water’s edge instead of the contributing
area)). It is clear that wetland ecosystem service assessments are an evolutionary and
adaptive process — as finer datasets come online, better metrics can be defined — and
that we must start the process with whatever data are readily available with the promise
that we will review and refine the process as better data become available.
Question 14
| do agree with Irena’s overall comments on pages 35-36
Response
Comment only, does not require a response.
Questions received prior to August 10, 2011
August 4
Yihong Wang via Gillian Kerr
From my understanding of the work done on water quality (| may be wrong), they have modified
WESPUS but using GIS and Remote Sensing techniques to produce a water purification score,
which is a relative score of the function and value proxies. They also did an economic valuation
by assigning a range of dollar values (from literature) to compute a range of benefits. This is
similar to what we have discussed on integrating the WESPUS score into the economic
valuation. Generally speaking, it is a relative ranking assessment, which is quite different from
what we were expecting as a physical assessment of proper proxies/indicators of water
purification functions from wetlands. | have attached the email with the notes captured by
Geneva in our discussion with Dr. Creed about what they can deliver on July 22. It mentioned
some response variables (turbidity and chlorophyll) would be provided in the report to serve as
proxy for N and P as well as other info. | could be wrong but | didn't locate them in the report.
Response*
A lot of work was completed (including what was captured in Geneva’s email dated
Friday July 22, 2011), which was not included in the final report. The work related to
implementation of a “Regional-Advanced” wetland assessment approach modelled after
WESPUS (Adamus 2011) and the Index of Hydrologic Integrity and Index of Nutrient
Integrity developed as part of the AWRI funded Wetland Health project (Creed Unpubl.
Data). This would have incorporated the wetland specific turbidity and chlorophyll-a
measurements but was not included. Despite waiting until the latest possible date
(midnight, Friday July 22, 2011), we never received the data requested to complete the
Regional-Advanced wetland assessment approach, and that is why these analyses were
not included. Due to the problems in gaining timely access to the data from the GOA, we
had to start over and complete the Regional-Basic wetland assessment approach to meet
the ESPP contract deadline of August 2, 2011. Given this short timeframe, we not only
completed a wetland assessment for water purification, but we went beyond what was
committed by including a piece on monetary benefits associated with the water
purification. This is what was reported in the Final Report, with the draft submitted
August 2 and final report submitted August 6.
August 4, 2011
From Ciara Raudsepp-Hearne
Question 1
Figure 16: Title: ‘Water purification score change from 1990 to 2010' — it is unclear whether the
number represents % change or absolute change in scores. There are a few negative changes
of large magnitude (again what do numbers represent?). Can you tell us from your data why
those negative changes occurred there? (Fewer wetlands in those areas?)
Response
The wetland purification score ranges from 0 to 1.0 (it is the average of the wetland
purification metrics WP 1 to 6). The figure shows the absolute change in scores. Where
there are negative changes (i.e., where the wetland water purification has declined from
1990 to 2010) there has been a loss of wetland function related to water purification. This
could be either due to (1) loss of area from an individual wetland or (2) loss of wetlands.
Figure 16 shows a general increase in wetland purification scores due largely to the
apparent increase in wetland area (due to natural drivers, i.e., shift from dry to wet
conditions). There are a few exceptions to this generalization, and these are due to loss
of wetlands from increase in urbanization/industrialization.
If the recommended wetland assessment method could have been implemented, it is
expected that there would still be an increase in wetland purification scores at individual
wetlands as climate drivers would likely increase the wetlands function by increasing the
emergent and wet meadow zones (unless disturbance at the wetland decreases these
zones). However, the increase would not be as dramatic using our Basic-Advanced
approach as we would have identified far more wetlands in the drier years due to the
better wetland detection techniques we would have used.
Question 2
How certain are we about the change in number of wetlands over time? Can we contextualize
this trend within the pattern of wetting/drying years? Does this represent an ongoing trend or
simply a dry year and a wetter year? You talk about this towards the beginning of the report,
but for your conclusions, it would help me if you interpreted the results using your understanding
of longer-term trends in the system.
Response
Wetlands are defined by the combination of inundated and saturated areas. When
considered in combination, the wetland boundaries may change, but not to the same
degree as the inundated area of the wetlands. For this reason it is critical that wetland
assessments be conducted on inundated plus saturated areas. Given the time
constraints of the project, we were unable to do such an assessment. We were forced to
make a decision: abandon the request to do a “trend analysis” over recent time period
(i.e., last 30 years) and focus on DU wetland inventories of 1965 (an average year) and
2005 (a relatively dry year, which would have inflated wetland loss) versus accept the
limitations of a LANDSAT TM based wetland detection technique and do the trend
analysis. We chose to do the latter.
We are confident about the measured change in inundated areas over time. However, we
do not believe this can be a proxy for change in inundated plus saturated areas over
time. Given additional time and resources, we are confident that (1) we could create a
recent (past 20 years) time series of inundated plus saturated areas based on a
combination of optical and microwave imagery (see Recommendation #5); and (2) we
could create a baseline that reflects the natural range of variability in climatic conditions
in the region from which wetland gains or losses could be measured (see
Recommendation #6).
We would be happy to include this interpretation of climate drivers on wetland function
and value in the conclusions.
Question 3
The next question is linked to this: ‘Are we not losing any wetlands?’ In the introduction it says
we are, but the results suggest otherwise. Can you help me make sense of this for our report
readers?
Response
Wetlands are being lost in the urbanized/industrialized areas.
Question 4
What margin of error do we get for not including saturated areas (and not just open water
wetlands)? Vhat are the implications for not including those types of wetlands for the service of
water quality (are they more or less important for water filtration, or similar to open water
wetlands)?
Response
This is a complex question, which we will try to answer in two parts. First, depending on
the Stewart and Kantrud (1979) classification of wetlands, inundated areas may
constitute a minor (Class 1, 2) to major (Class 3, 4, 5) portion of wetland surface. Visual
assessment of Google Earth images suggests a large number of Class 3, 4, 5 wetlands in
the study area, so we feel that the margin of error may be considerable. For this reason,
we are not comfortable assigning a margin of error to the wetland area by not including
saturated areas. Second, the inundated vs. saturated areas serve distinct functions in
terms of removal of contaminants. For example, inundated areas are important for P
removal, but saturated areas are important for N removal. This complementary role of
inundated and saturated areas in water purification processes is precisely why we
advocated the Regional-Advanced wetland assessment approach, as the Regional-Basic
wetland assessment approach does not represent these processes that are so important
for water purification. In summary, we believe the main benefit of this consulting project
was to report on a mental exercise to showcase the importance of considering
ecosystem services of wetlands (albeit one that required a great deal of number
crunching!), but better data is needed before the theory is put into practice.
Question 5
At the top of page 26, there's a statement that 'removing ag from the metric allows us to account
for spatial and temporal variation in wetland function resulting from land use’. | don't quite
understand the context of this sentence, I'm assuming the original metric included ag land use,
and removing it is more appropriate for this system, can you give me a little more explanation
about this?
Response
This question is related to Section 5.3.1.2.
This is an important question that highlights the challenges we faced with the Land
Use/Land Cover data. We used the LULC map from AgCan (2009), from which we based
supervised classification techniques on LANDSAT TM imagery to create the required
LULC time series from 1990, 2000, and 2009 (referred to as 2010). This time series of
maps (with 30 m resolution) created some constraints in our assessments. Specifically,
the resolution meant that natural land covers, including forest and shrub land, were not
detected (as they are too small to be detected on the landscape), and therefore the
natural purification functions of natural cover could not be considered. A time series
based on finer resolution data, such as SPOT, would have enabled us to capture these
natural land covers. Unfortunately, the SPOT data in the ESPP database contained
panchromatic but not optical data, which precluded our ability to do this analysis. (See
Recommendation #3, and Section 5.2.2, last paragraph, p. 23).
This question also highlights the need to consider what our LULC baseline is. The major
LULC over the entire time series is agriculture; we would have to establish a historic
LULC as a baseline if we want to determine the effect of land conversion from natural to
agriculture on wetland purification scores, which was beyond the scope of the study.
Given the LULC reality of the Shepard Slough since our 1990 baseline has been
agricultural, with urbanization/industrialization being the contemporary development
pressure, we decided to remove agriculture from the WP2 metric to improve the signal
from urbanization/industrialization, which is expected to increase remarkably over the
next few decades.
Question 6
Page 27, ‘What is the condition’: The statement is that 'the majority of wetland complexes in
Shepard Slough in 2010 satisfy two of the elements of this metric. Due to the dominance of
agriculture within Shepard Slough all wetlands satisfied the requirements of A. The above is a
bit cryptic. What is the actual condition? The findings for the trends are also a bit cryptic,
referring to the metrics as opposed to stating simply what the trends are. | want to make sure |
understand the findings, could you provide a sentence that is a bit clearer?
Response
This question is related to Section 5.3.1.3.
We provide a statement of “condition” and “trend” for each of the wetland purification
metrics that are used in calculated of the wetland purification scores. In so doing, we
wanted to deconstruct the causes behind changes in wetland purification function over
the time period investigated. For example, for WP3 (pollutant removal opportunity), there
are three sub-metrics that define the metric: (1) the proportion of forested or shrub land
within the contributing area of the wetland; (2) the proportion of upslope wetland within
the contributing area; and (3) the proportion of the wetland itself. In our report, we
explain that the WP3condition for the majority of wetland complexes (the wetland
assessment unit) is defined by the lack of natural cover and upslope wetlands within the
contributing areas of the wetlands; and the WP3 trend shows no change in the pollutant
removal opportunity of each wetland, although the number of wetlands performing that
function increases.
Question 7
Finally, from what you understand of the major pollutants in the system, is it possible to identify
where the greatest risks for pollution might be occurring? For the moment, | understand the
major quality issues are measured in terms of loading from urban run-off. Is this the greatest
concern? Are there others?
Response
Our informal consultations with Karen Raven from GOA (via Geneva Claessen) indicate
that the “pollutant of primary concern” is phosphorus, although nitrogen should be a
concern as well (See Figure 2, p. 6). The greatest risk for phosphorus and nitrogen
pollution is from untreated sewage effluent and agricultural run-off carrying fertilizers.
Within the Shepard Slough, the surface hydrological pathways were assumed to be the
major pathways for phosphorus and nitrogen transport to surface waters. For the
Regional-Advanced wetland assessment approach, we compiled loading coefficients of
phosphorus and nitrogen from different LULC classes, so that we could identify where
the greatest risks for pollution were occurring. Unfortunately, we were unable to
complete this approach. For the Regional-Basic wetland assessment approach, we can
only infer where the greatest risk for pollution might be occurring from the LULC maps.
August 3, 2011
From Geneva Claesson and Ciara Raudsepp-Hearne
Question 1
Based on the data you’ve seen, can we calculate vegetated buffer zones?
Question 2
What type of vegetation contributes most to purification? Is this measureable with the data
available (e.g., GVI)?
Response
In terms of calculating a vegetative buffer around wetlands, we don’t currently have the
data needed to estimate it adequately (See Recommendation #3, and Section 5.2.2, last
paragraph, p. 23).
For the Regional-Basic wetland assessment approach, indicator WP3 looks at the
percentage of forest and shrub land within a wetland’s contributing area making the
assumption that contributing areas with a high proportion of forest and shrub will
remove more sediment and nutrients from overland flow before it reaches the wetland.
These wetlands will have less value (lower metric score) because the wetland is treating
less polluted water.
For the Regional-Advanced wetland assessment approach, metric RA16 (Natural land
cover in 100ft upslope buffer) determines the forest and shrub land vegetation within a
100 m buffer of the wetland. Higher percentage of native vegetation within this buffer
would increase the metric score. For future analysis it would be possible to determine
the vegetative buffer width. However the GVI will not be helpful in this case. The GVI
only identifies 10 polygons within Shepard Slough that are considered natural land cover
and these only contain < 30% forest and trees. Because of the low occurrence of forest
and shrub land within Shepard Slough, a finer scale SPOT LULC classification with
ground-truthing (by aerial photographs or ground inspections) would be needed to
identify natural vegetation cover adjacent to a wetland. With additional time and
resources, we could conduct this analysis.
For specific species that contribute to water purification, we encourage you to read the
material presented by Dr. Paul Adamus, both the manual and his literature review for the
prairie potholes. We have provided these references below, and can provide you with a
copy, if requested.
References
Adamus, P. (1992). Conceptual Process Model for Basin-type Wetlands of the Prairie Pothole
Region. United States Environmental Protection Agency.
Adamus, P. (2010). Strategies and Procedures for Testing Rapid Protocols Used to Assess
Ecosystem Services. Prepared for the Willamette Partnership o
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