The document summarizes cost effective practices for clean water based on a study of the James River Basin in Virginia. It finds that removing illicit discharges from storm sewer systems, such as sewer repairs and eliminating cross connections, is among the most cost effective ways to reduce nitrogen, phosphorus, and sediment levels. Urban stream restoration is also highly cost effective for sediment removal. Initial estimates found addressing stormwater pollution in Richmond could cost $305 million using older practices, but improving identification and removal of illicit discharges could lower the cost to $84-100 million. Proper identification and removal of illicit discharges is an important yet overlooked method for nutrient management that governments should receive credit for.

1. COST EFFECTIVE PRACTICES FOR
CLEAN WATER
Hye Yeong Kwon, Executive Director
Center for Watershed Protection, Inc.

2. • 501c3, started in 1992; offices in MD, VA,
PA, NY
What we do
• Distill research into practical tools
• Provide local watershed services
• Train others to manage watersheds
• Association/ membership services
Your first source for best
practices in watershed/
stormwater management

3. Stormwater BMP Cost-Effectiveness Study
James River Basin, VA
• Evaluation of all urban practices
• Costs and pollutant removal
• Case study in the City of Richmond

4. Methods: BMP Selection
• 34 urban practices
– 26 CBP practices with approved efficiencies
– 5 CBP practices with recently approved expert
panel recommendations
– 2 CBP practices under review by expert panel
– 1 additional practice reviewed: pet waste
programs
• Status of CBP BMP review panels available on
Chesapeake Stat website

5. Methods: Cost Estimates
• King and Hagan (2011): Costs of Stormwater
Management Practices in Maryland Counties
• Additional studies, data and assumptions used
for pet waste programs, illicit discharge
elimination, stormwater retrofits, and urban
growth reduction
• Considered 20-year life cycle costs, including:
– Design and construction
– Land values and financing
– Operations and maintenance

6. Methods: Cost-Effectiveness Formula
Cost effectiveness ($/lb) =
Annual pollutant reduction (lbs)
Average annual cost over 20 years ($)
For TN, TP, and TSS:

7. Results: Most Cost-Effective Practices
for Nitrogen Removal
1. Pet waste programs
2. Illicit discharge elimination: sewer repair
3. Illicit discharge elimination: cross
connections
4. Forest buffers
5. Urban stream restoration

8. Results: Most Cost-Effective Practices
for Phosphorus Removal
1. Pet waste programs
2. Illicit discharge elimination: sewer repair
3. Illicit discharge elimination: cross
connections
4. Urban stream restoration
5. Forest buffers

9. Results: Most Cost-Effective Practices
for Sediment Removal
1. Urban stream restoration
2. Illicit discharge elimination: sewer repair
3. Urban growth reduction
4. Retrofit of existing dry pond (conversion to
wet pond or wetland)
5. Vegetated open channels (A/B soils, no
underdrain)

10. Case Study
Three scenarios developed:
1. Old CBP approved practices, no
implementation constraints
2. Current CBP approved practices, with
implementation constraints
3. All practices, with implementation
constraints

11. Case Study
Initial estimates for stormwater pollution reduction in the City of Richmond = $305 million
$84 million
$64 million
$68 million

12. Illicit Discharge
A discharge to storm sewer system that is not
composed entirely of storm water except permitted
discharges and fire fighting related discharges

14. Findings from recent studies
27-40% of outfalls have dry weather flow
Average Dry Weather Flow "Hit" Frequency
for 5 Mid-Atlantic Watersheds
0
20
40
60
80
100
120
Any Wastewater Tap water Washwater Bacteria (co-
indicator)
Type of Indicator
Percent

15. 57%
43%
Other activities
Removal of illicit
discharges
Estimated percent of required total nitrogen reduction that can be met through
removal of illicit discharges in Western Run
*Illicit discharge load estimates based on single grab sample
Sligo Creek required 79% reduction and 17% could met be through illicit
discharge elimination

16. *Assumes 50K per repair for 47 repairs
**Assumes 100% of the water quality volume provided by treating 1" of rainfall
Cost Comparison
$0
$20,000,000
$40,000,000
$60,000,000
$80,000,000
$100,000,000
$120,000,000
IllicitD
ischarge
R
epair*
D
ry
Swale
C
onstructed
W
etlands**
Bioretention**
W
etSw
ale
Perm
eable
Pavem
ent**
Practice
Cost
Total Nitrogen
Total Phosphorus
Illicit discharge elimination is a cost effective approach to nutrient
management

17. Why should governments get credit for
something that they are required to do?
• Illicit discharges fall through the cracks of MS4
permits and Consent Decrees
• MS4 permit requirements and guidance for IDDE is
deficient
• Pollution load from illicit sources has not been
accounted for in the Bay Model – coordinated action
and response is needed
• We need more tools in the toolbox

18. What are gross solids?
• Litter: Human derived trash such as
paper, plastic, Styrofoam, metal and
glass greater than 4.75 mm
• Organic Debris: Leaves, branches, seeds,
twigs and grass clipping greater than
4.75 mm
• Coarse Sediments: Inorganic breakdown
products from soils, pavement, or
building materials greater than 75
microns (0.075mm), & fragments of
litter and organic debris not included in
the other two categories

19. Stormwater Gross Pollutant Filters

20. Cost Summary Comparison
Annual cost to remove equivalent annual TN
load
The cost-effectiveness of stormwater controls for nitrogen removal.
Practice Type of practice Equivalent Annual cost
($/lb N/IC1 ac)
Bag filter Structural $691
Bioretention (new, suburban) Structural $335-$6342,3
Wet pond (new) Structural $7334
Street sweeping Non-structural $1655
1 Based practice life expectancy of 10-years.
2 Costs for other practices based on King and Hagen (2011) over a 20-year period and an urban loading rate of 14.1 lb TN/acre.
3 Range represents a removal efficiency of 45% and 85% from Simpson and Weammert 2009.
4 20% removal efficiency for TN from Simpson and Weammert 2009
5 Berretta et al. 2011 expressed as lb N/year

21. Discharge Flow Types
•Pathogenic & toxic discharges
•Sanitary wastewater
•Commercial & Industrial discharges
•Nuisance & aquatic life threatening discharges
•Landscaped irrigation runoff
•Construction site dewatering
•Automobile washing
•Laundry wastes
•Unpolluted discharges
•Infiltrating groundwater
•Natural springs
•Domestic water line leaks

22. Other Tools
Stream Restoration
Maintenance of Stormwater BMPs
Crediting New from EPA/ CBP
Low Impact Development/
Green Infrastructure

23. Hye Yeong Kwon,
Executive Director
hyk@cwp.org
410-461-8323
ext 212