Georgia Stormwater Management Manual - Volume 1 / Stormwater ...
Substitute Costs: A Method for Determining Ecological Service Values in Stormwater Management
-
Upload
steve-mckinney -
Category
Technology
-
view
1.890 -
download
2
description
Transcript of Substitute Costs: A Method for Determining Ecological Service Values in Stormwater Management
SUBSTITUTE COSTS: A METHOD FOR DETERMINING ECOLOGICAL
SERVICE VALUES IN STORMWATER MANAGEMENT
For:Dr. Mindy Lalor – Committee Chair
Dr. Robert AngusDr. Paul D. Blanchard
Dr. Sarah CulverDr. Alan Shih
1
Introduction Development pressures are increasing Stormwater runoff characteristics are changed by
development Stormwater runoff models exist that compare pre-
and post- development stormwater characteristics Models produce complicated scientific/engineering
data A methodology is needed to derive a common
metric to aid in comparing the value of an ecological service to the value of planned development
The Ecological Services Value (ESV) method provides an approach to deriving a common metric
2
Points of Interest
The ESV method:was successfulis reproduciblecan be used by policy makers
3
WHAT IS THE PROBLEM?
4
Stormwater Runoff Impacts It is often difficult for decision makers and political
officials to understand complex scientific and engineering analysis, as it relates to stormwater runoff
The desire for economic development and sources of new revenue is creating intense pressure on decision makers to allow development of lands
Without a common metric, it is difficult to compare the value of the environmental services currently provided (which may be lost) with the value of the potential development
5
WHY IS IT A PROBLEM?
6
Decisions Will Be Made Development decisions are often made without
respect to impacts of stormwater runoff
Few tools are available to evaluate complex development decisions with well recognized, simplistic terms
Without a common metric, decision makers may not consider the impacts of development on stormwater runoff
7
WHY IS IT IMPORTANT TO SOLVE IT?
8
Ecosystem Deterioration Assuming that predevelopment conditions are
optimal for downstream areas, if impacts are not mitigated, significant damage can occur in the form of pollution and/or flooding
Without the appropriate comparisons between the costs of impact mitigation and the financial benefits or other value derived from development, leaders may make poor decisions that could have negative impacts on society
9
WHAT IS “VALUE”?
10
What is “value”?
Webster’s Dictionary Defines Value as:
1 : a fair return or equivalent in goods, services, or money for something exchanged
2 : the monetary worth of something : marketable price
3 : relative worth, utility, or importance <a good value at the price> <the value of base stealing in baseball> <had nothing of value to say>
7 : something (as a principle or quality) intrinsically valuable or desirable <sought material values instead of human values -- W. H. Jones>
11
Utility in Value
Utility is defined as the level of happiness or satisfaction associated with alternative choices.
Economists assume that when individuals are faced with a choice of feasible alternatives, they will always select the alternative that provides the highest level of utility.
12
What is Environmental Economics?
A mechanism using economic theories and empirical analyses that characterizes relationships between the performance of the economy and environmental pollution control;
OR It can be defined as the study and in-depth
analyses of economic and policy issues relating to economic costs and benefits of environmental pollution control programs, policies, and guidance.
13
Why do we need to consider Environmental Economics?
To perform analyses of the economic impacts of environmental pollution control programs.
To address the development dimensions of environmental policy – evaluating the social and economic impacts, in particular the impacts on poverty, and designing policies that are both cost-effective and equitable.
To examine the environmental implications of development policy – making tradeoffs between poverty reduction and environmental protection.
14
Concepts of Value
Non-Utilitarian Concept(Typically Intangible
Values)
Utilitarian Concept(Typically Tangible Values)
15
Total Economic Value
Total Economic Value (TEV)
Concept is attributed to Pearce and Warford 1993, World Without End
Theoretical structure for assessing ecosystem value as a whole
16
TEV
CAT
EGO
RIE
S
CO
MM
ON
LY U
SED
VALU
ATIO
NM
ETH
OD
S
USE VALUE NON-USE VALUE
TOTAL ECONOMIC VALUE(TEV)
Direct use value
ConsumptiveNonconsumptive
Indirect use value Option value
Bequest valueQuasi-option value
Existence Value
1. Changes in productivity
2. Cost-based approaches
3. Hedonic prices4. Travel costs5. Contingent
valuation
1. Changes in productivity
2. Cost-based approaches
3. Contingent valuation
1. Changes in productivity
2. Cost-based approaches
3. Contingent valuation
1. Contingent valuation
17
TEV CategoriesDirect Use
Direct use values are based on consumptive or nonconsumptive uses.
Consumptive use is a use that reduces the overall supply of resource, while nonconsumptive use causes no reduction in quantity or supply of that resource
18
TEV CategoriesIndirect Use Indirect use values can be described as support and
protection provided to economic activity by regulatory environmental services.
Many ecosystem services are used as intermediate inputs for the production of goods, while other services indirectly contribute to consumption of goods.
An example of indirect use value of services through intermediate inputs would be pollination in food production, while indirect contribution to consumption would be water purification.
19
TEV CategoriesOption Value
Option value is about the value of preserving the choice to use ecosystem services in the future by not taking actions on the environment that are irreversible
20
TEV CategoriesExistence Value Existence values are non-use values often referred
to as conservation values, or passive use values. These are values applied to a resource that
individuals do not intend to use, but would feel a “loss” if the resource were to disappear.
This could be stated as value ascribed to the knowledge of existence.
Studies have linked these applied values to the knowledge of maintaining a resource for one’s descendents and the knowledge of assured survival for a resource like habitats or species
21
TEV
CAT
EGO
RIE
S
CO
MM
ON
LY U
SED
VALU
ATIO
NM
ETH
OD
S
USE VALUE NON-USE VALUE
TOTAL ECONOMIC VALUE(TEV)
Direct use value
ConsumptiveNonconsumptive
Indirect use value Option value
Bequest valueQuasi-option value
Existence Value
1. Changes in productivity
2. Cost-based approaches
3. Hedonic prices4. Travel costs5. Contingent
valuation
1. Changes in productivity
2. Cost-based approaches
3. Contingent valuation
1. Changes in productivity
2. Cost-based approaches
3. Contingent valuation
1. Contingent valuation
Substitute Cost Method is the focus of this research
22
Substitute Costs Method
This approach is based on the principle that the value of the resource may be assigned based on the cost of replacing or finding a substitute for the resource, or the cost of repairing damage caused by the use of the resource.
The central premise of substitute cost determination is that a “substitute” can be found for the resource in question and that a cost can be determined for that substitute.
Therefore substitution is technologically limited within the context of ecosystem valuation.
For the cost determination to be valid, the substitute must be equal to or greater than its predecessor.
23
RESEARCH
24
Research Question
How can the monetary value of the natural services provided by undeveloped lands with respect to stormwater runoff impacts be determined?
25
Hypothesis
The proposed methodology produces the required inputs for the ESV equation.
n
iOCES iiCCV
1
)(
Where:
VES = Ecological Services Value
CC = Capital costs of the construction of the stormwater control
CO = Operations and maintenance costs of the stormwater control26
RESEARCH METHODS
27
Approach Summary Geoprocessing
Definition: the use of GIS to manipulate data Used in this approach to derive the input variables and data for
stormwater modeling.` Modeling
The use of a modeling software to determine the pre- and post-development stormwater characteristics of a site
WinSLAMM was selected for this research ESV Calculation
Use of the Ecological Services Value equation with the results of the stormwater model to determine value of the stormwater management services by the undeveloped site
Amortization of the “Year One ESV” for 20 years at 6%
28
GeoprocessingTerrain Data
Source Data1ft. dispersion LiDAR
Derived DataMean Aspect Surface
ModelMean Slope Surface
Model Purpose of data
To ascertain the inclination direction and severity
Generate surface using IDW
interpolation
Calculate the mean slope for the
area of interest using zonal
statistics
Calculate the mean aspect for
the area of interest using zonal
statistics
Use surface model to generate aspect
model
Use surface model to generate slope
model
Surface Model
Aspect Model
Slope Model
Mean aspect Mean slope
Boundary for each
AOI
Define extent for extracting LIDAR by selecting each
AOI
AOI
Extract LIDAR by AOI extent
LIDAR
LIDAR of AOI
29
GeoprocessingHydrologic Data
Source Data6 in. resolution aerial
photographySite observations
Derived DataSource areas
Purpose of dataDescribes the sizes,
divisions, and surface characteristics of the land cover types
Define maximum symmetrical extent
Extract aerial photography
Define AOI
Define Source Areas
Add Source Area type attributes
Dissolve by Source Area type
Add area fields
Calculate area
Convert area to model units
Maximum extent
Color ortho photography
Ortho photos by maximum
extent
AOI
Source Areas 30
GeoprocessingSoils Data
Source DataNRCS 1:24,000
SSURGO Derived Data
Hydrologic GroupsType distribution
Purpose of dataDescribe the type,
distribution, and ability of the soil to infiltrate stormwater
Define AOI
AOI
Extract soils data by AOI
AOINRCS
SSURGO Soils
Soils by AOI
Dissolve by Map Unit Symbol (MUSYM)
Add area and percentage fields
Calculate area
Convert model units
Calculate percentages
Soils
31
Geoprocessing Model Parameter
ConsolidationSource areas and
soils were combinedDistributions of
source areas and soils types were calculated
Units converted to match requirements for WinSLAMM
Union Source Areas and Soils
Source Areas
Soils
Source Areas with
Soils
Add area field
Convert to model units
Output area per soil type by Source
Area
Model Parameters
32
ModelingWinSLAMM
WinSLAMM (Source Loading and Management Model) is a simulation model used to determine the volume and constituents of a stormwater runoff from a site
First, for the pre-development condition, the total site area is entered specifying the area of each soil hydrologic group
Next , for the “base condition”, is the entry of the “source areas” of a site without any stormwater controls.
Last , for the “control condition”, is the design, sizing, and input of stormwater controls to reach the targeted reductions in volume and particulate discharge
33
ModelingWinSLAMM
The ability to calculate the construction and operations costs of the stormwater controls inputted occurred as of version 9.2. These are the sources of costing data.
1. Costs of Urban Nonpoint Source Water Pollution Control Measures prepared by Southeastern Wisconsin Regional Planning Commission, 1991.
2. Costs of Urban Stormwater Control by Heaney, Sample, and Wright for the US EPA, 2002.
3. BMP Retrofit Pilot Program prepared by CALTRANS, 2001.
4. Engineering News Record (ENR) Cost Indices
34
ESV Calculation
Model results for the predevelopment, base, and control conditions are used to identify runoff volume and particulate solids
Capital costs and operations and maintenance costs are identified from the control condition results
The ESV equation is used to calculate year one
“Year One ESV” is amortized for 20 years at 6%
35
Research Sites
1. Commercial Site
2. High Density Residential Site
3. Low Density Residential Site
36
COMMERCIAL SITESite 1 Results
37
38
Source Area Delineations
FLAT ROOFS
PARKING
SMALL LANDSCAPED AREA
STREETS
39
40
41
42
43
44
45
46
47
Etowah loam, 2 to 8 percent slopes
Allen fine sandy loam, 8 to 15 percent slopes
Gorgas-Rock outcrop complex, steep
Sullivan-Ketona-Urban land complex, 0 to 2 percent slopes
Docena complex, 0 to 4 percent slopes
Allen fine sandy loam, 8 to 15 percent slopes
Docena complex, 0 to 4 percent slopes
Etowah loam, 2 to 8 percent slopes
Gorgas-Rock outcrop complex, steep
Sullivan-Ketona-Urban land complex, 0 to 2 percent slopes
Soils Distribution by Type
HIGH DENSITY RESIDENTIAL SITE
Site 2 Results
48
49
Source Area Delineations
FLAT ROOFS
PARKING
SMALL LANDSCAPED AREA
STREETS
50
51
52
53
54
55
56
57
58
Fullerton-Urban land complex, 8 to 15 percent slopes
Docena complex, 0 to 4 percent slopes
Decatur silt loam, 2 to 8 percent slopes
Sullivan-Ketona-Urban land complex, 0 to 2 percent slopes
Decatur silt loam, 2 to 8 percent slopes
Docena complex, 0 to 4 percent slopes
Fullerton-Urban land complex, 8 to 15 percent slopes
Sullivan-Ketona-Urban land complex, 0 to 2 percent slopes
Soils Distribution by Type
59
LOW DENSITY RESIDENTIAL SITE
Site 3 Results
60
61
Source Area Delineations
FLAT ROOFS
PARKING
SMALL LANDSCAPED AREA
STREETS
62
63
64
65
66
Holston-Urban land complex, 2 to 8 percent slopesDecatur-Urban land complex, 2 to 8 percent slopes
Decatur-Urban land complex, 2 to 8 percent slopes
Holston-Urban land complex, 2 to 8 percent slopes
Soils Distribution by Type
67
RESULTS
68
WinSLAMM Control Condition Results
Site 1 Site 2 Site 3
Runoff Volume (cf) 2,335,415.000 1,263,731.000 243,570.300
Particulate Solids Yield (lbs) 1290.994 573.931 21.321
Particulate Solids Concentration (mg/L) 8.862 7.281 1.403
Cost per cubic foot Runoff Volume Reduced ($/cf) $0.58 $2.15 $0.63
Cost per pound Particulate Solids Reduced ($/lb) $127.72 $49.18 $22.09
69
ESV Calculation Assumptions1. Predevelopment is the optimal
condition.
2. Predevelopment can be achieved through technology.
3. If predevelopment is not available for particulate solids, then 0 is assume.
4. Land cost is not factored.
70
ESV Results – Commercial Site
Control Cost to reach Predevelopment Runoff $4,766,005.00 Control Cost to reach Base or better Solids $3,852,282.98
Total Capital Costs $8,618,287.98 Operations and Maintenance Costs $1,053,491.00
Interest of a 20 year amortization @ 6% $21,358,650.32 Capital Cost + 20 years of O & M $29,688,107.98
Year One ESV $10,725,269.98 Total ESV $51,046,758.29
71
ESV Results – High Density Residential Site
Control Cost to reach Predevelopment Runoff $2,782,504.20 Control Cost to reach Base or better Solids $913,715.22
Total Capital Costs $3,696,219.42 Operations and Maintenance Costs $253,225.00
Interest of a 20 year amortization @ 6% $6,302,764.15 Capital Cost + 20 years of O & M $8,760,719.42
Year One ESV $4,202,669.42 Total ESV $15,063,483.57
72
ESV Results – Low Density Residential Site
Control Cost to reach Predevelopment Runoff $552,024.14 Control Cost to reach Base or better Solids $431,431.84
Total Capital Costs $983,455.98 Operations and Maintenance Costs $123,365.00
Interest of a 20 year amortization @ 6% $2,482,593.04 Capital Cost + 20 years of O & M $3,450,755.98
Year One ESV $4,975,937.98 Total ESV $5,933,349.03
73
Conclusions This research produces a methodology that:
1. Leverages GIS technology for the generation of the required inputs for stormwater runoff models
2. Implements a proven, calibrated, verified stormwater model in WinSLAMM that produces the results needed for the ESV calculations
3. Provides policy makers with a functional, reproducible approach to assessing the value of the stormwater management services provided by natural systems for use in cost-benefit analysis in development decisions
Lastly, this research contributes to the greater body of knowledge on the topics of stormwater runoff impacts, environmental economics, and geographic information sciences.
74
SUBSTITUTE COSTS: A METHOD FOR DETERMINING ECOLOGICAL SERVICE
VALUES IN STORMWATER MANAGEMENT
For:Dr. Mindy Lalor – Committee Chair
Dr. Robert AngusDr. Paul D. Blanchard
Dr. Sarah CulverDr. Alan Shih
75
Thank you for your patience, time, and
support.