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