Massachusetts Stormwater Technology Evaluation Program Evaluating Stormwater BMPs Spring 2013

Massachusetts Stormwater Technology Evaluation ProgramEvaluating Stormwater BMPsSpring 2013

Massachusetts Stormwater Technology Evaluation Project, UMass

Constructed Wetlands • Removal Efficiency: • 65-80% average • 80% MassDEP TSS Removal Credit • Key Features: • Large area • Peak flow control • Biological treatment • Maintenance: low to moderate • Cost: marginally higher than wet ponds http://www.txnpsbook.org, 2002 Source: MassDEP, 2008. Massachusetts Stormwater Handbook

Extended Detention Basins • TSS Removal Efficiency: • 60-80% average • 50% MassDEP TSS Removal Credit • Key Features: • Large area • Peak flow control • Maintenance: low • Cost: low to • moderate Source: MassDEP, 2008. Massachusetts Stormwater Handbook

Water Quality Swales • Removal Efficiency: • 65-805 average • 70% MassDEP TSS Removal Credit • Key Features: • Higher pollutant removal rates than drainage channels • Transport peak runoff and provide some infiltration • Maintenance: low to moderate • Cost: low to moderate http://www.txnpsbook.org, 2002 Source: MassDEP, 2008. Massachusetts Stormwater Handbook

Deep Sump Catch Basins • Removal Efficiency: • 9-35% average • 25% MassDEP TSS Removal Credit • Design Features: • Debris removal • Pretreatment • Maintenance: moderate to high • Cost: low to high Source: MassDEP, 2008. Massachusetts Stormwater Handbook

Innovative BMPs – Media Filtration • Removal Efficiency: • 50-80% average • Design rate: case by case evaluation • Design Features: • small area • Oil and Grease control • Maintenance: moderate • Cost: moderate Stormwater Management Inc, 2002 Massachusetts Stormwater Technology Evaluation Project, UMass

Innovative BMPs - Hydrodynamic • Removal Efficiency: • No treatment to 35% • Design rate: case by case evaluation • Design Features: • small area • Oil and Grease control • Maintenance: moderate • Cost: moderate Vortechs Inc, 2002

TARP- Technology Acceptance Reciprocity Program • Address technology review and approval barriers in policy and regulations; • Accept the performance tests and data from partner’s review to reduce subsequent review and approval time; • Use the Protocol for state-led initiatives, grants, and verification or certification programs; and • Share technology information with potential users in the public and private sectors using existing state supported programs CA IL MA MD NJ NY PA VA TX

Performance Verification - TARP • Storm Event Criteria to Sample • More than 0.1 inch of total rainfall. • A minimum inter-event period of 6 hours, where cessation of flow from the system begins the inter-event period. • Obtain flow-weighted composite samples covering a minimum of 70 % of the total storm flow, including as much of the first 20 % of the storm as possible. • A minimum of 10 water quality samples (i.e., 10 influent and 10 effluent samples) should be collected per storm event. • Determining a Representative Data Set • At least 50 % of the total annual rainfall must be sampled, for a minimum of 15 inches of precipitation and at least 15, but preferably 20, storms. Massachusetts Stormwater Technology Evaluation Project, UMass

Performance Verification - TARP • Stormwater Sampling Locations • Sampling locations for stormwater BMPs should be taken at inlet and outlet. • Sampling Methods • Programmable automatic flow samplers with continuous flow measurements should be used • Grab samples used for: pH, temperature, cyanide, total phenols, residual chlorine, oil and grease, total petroleum hydrocarbons (TPH), E coli, total coliform, fecal coliform and streptococci, and enterococci. • Stormwater Flow Measurement Methods • Primary and secondary flow measurement devices are required.

Is There Enough Data? Field Studies • 15+ storms • 15 inches of rainfall Lab Studies • 15 test runs

Are the Data Representative? • Weather conditions • Topography, land use • Soils, sediments

Are the Data Representative?, Weather, Flows • Multiple samples per event • Field Studies: must include high flow/intensity storms • Consecutive storms • Sample all year • Lab Studies: Flow rates: 25%, 50%, 75%, 100%, 125%

Particle size: mean < 100 microns; distribution 55% sand, 40% silt, 5% clay Influent concentration 100 – 300 mg/l Are the Data Representative? Sediment

Impact of Particle Size on Performance

Are Results Accurate, Repeatable? • Quality Control tests, data • Standardized methods

Innovative BMPs - Advanced Sedimentation Rinker Inc, 2002

15 storm events 15 inches rain. 50% annual average. Particle size: mean < 100 microns - distribution: 55% sand, 40% silt, 5% clay Influent concentration: 100 – 300 mg/l Flows: range, up to 125% design capacity. Scour tests Summary – what to look for

BMPPerformance Comparison Table Massachusetts Stormwater Technology Evaluation Project, UMass

MASTEP Rating System Category 0: MASTEP has not yet reviewed performance data for this technology. Category 1: TARP-compliant field study or equivalent lab study data available for this product Cat. 2: Sound field or lab study data available – some caveats Cat. 3: Data of moderate scientific validity exists – significant caveats Cat. 4: Reliable performance lacking

Higher rating does NOT mean better performance MASTEP evaluates quality ofperformance DATA NOT BMP Performance Results

Massachusetts Stormwater Technology Evaluation Program Evaluating Stormwater BMPs Spring 2013