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Identifying opportunities and evaluating stormwater practices in ultra-urban catchments. Neely L. Law Sally Hoyt October, 2006. About the Center for Watershed Protection. Non-profit 501(c)3, non-advocacy organization Work with watershed groups, local, state, and federal governments - PowerPoint PPT Presentation
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Identifying opportunities and evaluating stormwater practices
in ultra-urban catchments.
Neely L. LawSally Hoyt
October, 2006
About the Center forWatershed Protection
Non-profit 501(c)3, non-advocacy organization
Work with watershed groups, local, state, and federal governments
Provide tools communities need to protect streams, lakes, and rivers
20 staff in Ellicott City, MD
www.cwp.org
www.stormwatercenter.net
Watershed 263
Location Map Watershed 263 Catchments
Catchment O
Catchment F
Watershed 263
I. Deriving Reliable Pollutant Removal Rates for Street Sweeping and Storm Drain Cleanout Programs in the Chesapeake Bay Basin
• US EPA Chesapeake Bay Program– Center for Watershed Protection (CWP)– UMBC (Engineering, CUERE)– City of Baltimore, DPW– Baltimore County, DEPRM– USDA Forest Service, Baltimore Ecosystem Study
II. Watershed 263 BMP Theme Park
• Chesapeake Bay Trust Pioneer Grant• City of Baltimore, DPW• Maryland Department of Environment
– Center for Watershed Protection (CWP)– EA Engineering
Stormwater Management Strategy for Catchment O in Watershed 263
Prepared for:Parks and People FoundationPrepared by:Center for Watershed ProtectionThrough a grant from:Chesapeake Bay TrustApril 2005
Assessment of Relative Dirtiness of Streets in Catchment O (CWP 2005)
Streets and Storm Drain Inlet Conditions
The Bad The UglyThe Good
Storm EMCs for TSS, TN and TP(9/28/05 – 1/31/06)
Median pretreatment water quality
Parameter(mg/L)
Catchment OStormflow
Catchment Fstormflow
NationalStorm EMC
Suspended Solids
52.0 52.0 58.0
Total P 0.37 0.30 0.27
Total N3.5 2.4 2.0
Catchment O: Baltimore St; Catchment F: Lanvale St.
Street Sweeping and Storm Drain CleanoutStudy Purpose
Need more reliable estimates of the potential nutrient and sediment reductions achieved by
municipal street sweeping and storm drain cleanouts
• Municipalities are sweeping and cleaning storm drains – can it make a difference in reducing nutrient loads to Bay?
Project Study Tasks
Task 1: Literature Review and Reference Tracking System Task 2: Basin-wide Municipal Practices Survey
Field monitoring program
Task 3: Paired Street Sweeping Treatment
Task 4: Street Source Area Sampling
Task 5: Characterization of Stormdrain Sediment
Study Design for Street Sweeping Treatments
• 2 yr. (10-05 thru 9-07)• Paired watershed• Catchment F
– 85% reduction in curb miles swept
– 1x/week
• Catchment O– 48% increase in curb miles
swept– 2x/week
• Vacuum street sweeper• Bedload samples
Catchment F O
Area 38.4 ac 38.7 ac
Impervious 68% 77%
Pervious 32% 23%
Task 1: Literature Review
Interim Pollutant Removal Rates for Sweeping
Discounted for:– Solubility
– Washoff & fugitive dust loss
– Frequency
– Technology
– Parked cars
– Street conditions
– Runon
FrequencyTP removal
Monthly 4 %
Twice a week 8 %
Frequency of cleanout
% TN Removal
Annual 5
Semi-annual 10
Task 1: Literature ReviewInterim Rates for Catchbasin Cleanouts
• Discounted for– Frequency
– Particle size distribution of dirt load
– % catch basin or inlet full
– Cleanout method
Task 2: CB Municipal Practice Survey
• 43 questions• 4 section
– Community condition
– Street Sweeping practice
– Stormdrain maintenance
– Monitoring
• 73% response rate
Distribution of 37 surveys
Phase I communities and agencies (23, 16) 11 Maryland 11 Virginia 1 Pennsylvania Phase II permit communities (6, 4) 1 Maryland 3 Virginia 1 West VirginiaGreater United States (8, 7) Pennsylvania, Wisconsin, Minnesota,
Florida, Texas, California
Survey Key Findings
• $13 million/year sweeping and cleanouts
• 70% of Phase I and II communities sweep at least 1x/year
• 85% of Phase I and II communities sweep more frequently than annually
• $14.75 to $75/curb mile
• Aesthetics and residential demand
Key Findings: Storm drain cleanout
• Of 20 responses, – 8 regular schedule cleanouts– 12 response to complaints or clogging
• $1.40/linear ft; $55/catchbasin
What proportion of all storm drains, inlets or catch basins are cleaned out on an annual basis? (n=16)
Proportion 100% 75 < 100% 50< 75% Up to 50%
Response 0 6.3% (1) 31.3% (5) 62.5% (10)
Watershed 263 BMP Theme Park
City of Baltimore, DPW – Environmental Services DivisionCenter for Watershed Protection – Site and practice selection. Virtual Tour.EA Engineering – Final design and construction drawings.
• Design and Construct 5-7 BMP’s to filter rainwater
• BMPs that are new/seldom used in the Chesapeake Bay region
• Create a website “tour” so others – citizens and engineers – can learn.
BMP Theme Park - What
BMP Theme Park - Timeline
COMPLETE Stormwater Strategy (2005) – the universe of possible projects
COMPLETE Field work to find the projects that could work physically
Fall 2006 Local residents’ input on locations and types of practices
Fall 2006 Maintenance plans, concept designs
Winter 2007 Construction drawings
Summer 2007 Construction
2007 Website “Tour”
Retrofit types– Biofiltration in ROW– Biofiltration in vacant lots – Catch basin inserts– Stormwater planters– Sand filters in ROW/underground
Treatment of up to 26% of the 39-acre
catchment with 7 retrofits.
Biofiltration in ROW-15 Possible Locations
(Drainage areas 0.3-1.7 acres)
BMP Selection CriteriaBiofiltration
• Roadway slope (max 4%)
• Utility locations
• Street width (>40 ft.)
• Downstream inlet with invert minimum 2’ below grade
• On-street parking
• Traffic volume
Virtual Tour
• Website for the constructed and non-structural practices.
• Resources for citizens and technical audience.
• Practice descriptions and
technical spec downloads.
• Photos and a printable
brochure.
Other CWP Work of Interestwww.cwp.org
www.stormwatercenter.net
•Small Watershed Restoration Manual Series•Maryland Watershed Users Guide•Smart Watershed Benchmarking Tool •Urban Watershed Forestry Manuals •Wetland and Watersheds Articles
Catchment F(38.43 acres)
MonitoringStation
Catchment O(38.7 acres)
MonitoringStation