For:
Dr. Mindy Lalor – Committee Chair
Dr. Robert Angus
Dr. Paul D. Blanchard
Dr. Sarah Culver
Dr. 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
ESV method:
The
was successful
is reproducible
can be used by policy
makers
3

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

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

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

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
Concept
Non-Utilitarian
(Typically Intangible Values)
Concept
Utilitarian
(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

TOTAL ECONOMIC VALUE
(TEV)
USE VALUE NON-USE VALUE
Existence Value
Indirect use value
CATEGORIES
Direct use value Option value
Consumptive Bequest value
TEV
Nonconsumptive Quasi-option value
1. Changes in 1. Changes in 1. Changes in 1. Contingent
productivity productivity productivity valuation
COMMONLY USED
2. Cost-based 2. Cost-based 2. Cost-based
VALUATION
METHODS
approaches approaches approaches
3. Hedonic prices 3. Contingent 3. Contingent
4. Travel costs valuation valuation
5. Contingent
valuation
17

TEV Categories
Direct 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 Categories
Indirect 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 Categories
Option 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 Categories
Existence 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

Substitute Cost Method is
TOTAL ECONOMIC VALUE
the focus of this research
(TEV)
USE VALUE NON-USE VALUE
Existence Value
Indirect use value
CATEGORIES
Direct use value Option value
Consumptive Bequest value
TEV
Nonconsumptive Quasi-option value
1. Changes in 1. Changes in 1. Changes in 1. Contingent
productivity productivity productivity valuation
COMMONLY USED
2. Cost-based 2. Cost-based 2. Cost-based
VALUATION
METHODS
approaches approaches approaches
3. Hedonic prices 3. Contingent 3. Contingent
4. Travel costs valuation valuation
5. Contingent
valuation
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

24

Research Question
can the monetary
How
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
V ES (C Ci C Oi )
i1
Where:
VES = Ecological Services Value
CC = Capital costs of the construction of the stormwater control
CO = Operations and maintenance costs of the stormwater control
26

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

B o u n d a ry
fo r e a ch
AOI
Geoprocessing D e fin e e xte n t fo r
e xtra ctin g L ID A R
Terrain Data b y se le ctin g e a ch
AOI
Source Data

AOI L ID A R
 1ft. dispersion LiDAR E xtra ct L ID A R b y
A O I e xte n t
Derived Data
 L ID A R o f
AOI
 Mean Aspect Surface G e n e ra te su rfa ce
u sin g ID W
Model in te rp o la tio n
 Mean Slope Surface S u rfa ce
M odel
Model
U se su rfa ce m o d e l
U se su rfa ce m o d e l
Purpose of data
 to g e n e ra te slo p e
to g e n e ra te a sp e ct
m odel
m odel
 To ascertain the A sp e ct S lo p e
M odel M odel
inclination direction
C a lcu la te th e C a lcu la te th e
and severity m e a n a sp e ct fo r m e a n slo p e fo r th e
th e a re a o f in te re st a re a o f in te re st
u sin g zo n a l u sin g zo n a l
sta tistics sta tistics
M e a n a sp e ct M e a n slo p e
29

D e fin e m a xim u m
sym m e trica l e xte n t
Geoprocessing M a xim u m C o lo r o rth o
Hydrologic Data e xte n t p h o to g ra p h y
E xtra ct a e ria l
p h o to g ra p h y
Source Data

O rth o
 6 in. resolution aerial
p h o to s b y
m a xim u m
e xte n t
photography
D e fin e A O I
 Site observations
AOI
Derived Data

D e fin e S o u rce
 Source areas A re a s
A d d S o u rce A re a
Purpose of data
 typ e a ttrib u te s
D isso lve b y
 Describes the sizes, S o u rce A re a typ e
divisions, and surface A d d a re a fie ld s
characteristics of the
C a lcu la te a re a
land cover types
C o n ve rt a re a to
m o d e l u n its
S o u rce
A re a s 30

D e fin e A O I
Geoprocessing AOI
Soils Data E xtra ct so ils d a ta
by AO I
Source Data

NRCS
AOI SSURGO
S o ils
 NRCS 1:24,000
SSURGO S o ils b y
AOI
Derived Data
 D isso lve b y M a p
U n it S ym b o l
(M U S Y M )
 Hydrologic Groups
 Type distribution A d d a re a a n d
p e rce n ta g e fie ld s
Purpose of data
 C a lcu la te a re a
 Describe the
type, distribution, and C o n ve rt m o d e l
u n its
ability of the soil to
infiltrate stormwater C a lcu la te
p e rce n ta g e s
S o ils
31

Geoprocessing U n io n S o u rce
A re a s a n d S o ils
Model Parameter
 S o u rce
S o ils
Consolidation A re a s
 Source areas and S o u rce
soils were combined A re a s w ith
S o ils
 Distributions of
source areas and A d d a re a fie ld
soils types were C o n ve rt to m o d e l
calculated u n its
 Units converted to O u tp u t a re a p e r
so il typ e b y S o u rce
match requirements A re a
for WinSLAMM
M o d e l P a ra m e te rs
32

Modeling
WinSLAMM
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

Modeling
WinSLAMM
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.
Costs of Urban Nonpoint Source Water Pollution Control Measures
1.
prepared by Southeastern Wisconsin Regional Planning
Commission, 1991.
Costs of Urban Stormwater Control by Heaney, Sample, and Wright
2.
for the US EPA, 2002.
BMP Retrofit Pilot Program prepared by CALTRANS, 2001.
3.
Engineering News Record (ENR) Cost Indices
4.
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
Commercial Site
1.
High Density Residential Site
2.
Low Density Residential Site
3.
36

Site 1 Results
37

38

S o u rc e A r e a D el in e ati on s
F LA T R O O F S
P A R K IN G
SM AL L L AN D S C A PE D AR EA
STR EE T S
39

40

41

42

43

44

45

46

Soils Distribution by Type
Docena complex, 0 to 4 percent slopes
Etowah loam, 2 to 8 percent slopes
Gorgas-Rock outcrop complex, steep
Allen fine sandy loam, 8 to 15 percent slopes
Sullivan-Ketona-Urban land complex, 0 to 2 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
47

Site 2 Results
48

49

S o u rc e A r e a D el in e ati on s
F LA T R O O F S
P A R K IN G
SM AL L L AN D S C A PE D AR EA
ST R EE T S
50

51

52

53

54

55

56

57

58

Soils Distribution by Type
Fullerton-Urban land complex, 8 to 15 percent slopes
Sullivan-Ketona-Urban land complex, 0 to 2 percent slopes
Docena complex, 0 to 4 percent slopes
Decatur silt loam, 2 to 8 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
59

Site 3 Results
60

61

S o u rc e A r e a D el in e ati on s
F LA T R O O F S
P A R K IN G
SM AL L L AN D S C A PE D AR EA
ST R EE T S
62

63

64

65

66

Soils Distribution by Type
Decatur-Urban land complex, 2 to 8 percent slopes
Holston-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
67

68

WinSLAMM Control Condition
Results
Site 1 Site 2 Site 3
2,335,415.000 1,263,731.000 243,570.300
Runoff Volume (cf)
1290.994 21.321
Particulate Solids Yield (lbs) 573.931
Particulate Solids
8.862 7.281 1.403
Concentration (mg/L)
Cost per cubic foot Runoff
$0.58 $2.15 $0.63
Volume Reduced ($/cf)
Cost per pound Particulate
$127.72 $49.18 $22.09
Solids Reduced ($/lb)
69

ESV Calculation
Assumptions
Predevelopment is the optimal
1.
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

Thank you for your
patience, time, and
support.
For:
Dr. Mindy Lalor – Committee Chair
Dr. Robert Angus
Dr. Paul D. Blanchard
Dr. Sarah Culver
Dr. Alan Shih
75