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Massachusetts Stormwater Technology Evaluation Program

Evaluating Stormwater BMPs

Spring 2013

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Massachusetts Stormwater Technology Evaluation Project, UMass

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Constructed WetlandsRemoval Efficiency:

65-80% average80% MassDEP TSS Removal Credit

Key Features:Large areaPeak flow controlBiological treatment

Maintenance: low to moderateCost: marginally higher than wet ponds

Source: MassDEP, 2008. Massachusetts Stormwater Handbook

http://www.txnpsbook.org, 2002

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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


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Water Quality SwalesRemoval Efficiency:

65-805 average70% MassDEP TSS Removal

CreditKey Features:

Higher pollutant removal rates than drainage channels

Transport peak runoff and provide some infiltration

Maintenance: low to moderateCost: low to moderate

http://www.txnpsbook.org, 2002


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Deep Sump Catch BasinsRemoval Efficiency:

9-35% average25% MassDEP TSS

Removal CreditDesign Features:

Debris removalPretreatment

Maintenance: moderate to high

Cost: low to high


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Innovative BMPs – Media Filtration

Removal Efficiency:50-80% averageDesign rate: case by

case evaluationDesign Features:

small areaOil and Grease

controlMaintenance: moderateCost: moderate


Stormwater Management Inc, 2002

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Innovative BMPs - HydrodynamicRemoval Efficiency:

No treatment to 35%Design rate: case by

case evaluationDesign Features:

small areaOil and Grease

controlMaintenance: moderateCost: moderate

Vortechs Inc, 2002

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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

CAILMAMDNJNYPAVATX

TARP- Technology Acceptance Reciprocity Program

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Performance Verification - TARPStorm 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.


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Performance Verification - TARPStormwater 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.

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Is There Enough Data?Field Studies

15+ storms

15 inches of rainfall

Lab Studies

15 test runs

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Are the Data Representative?

Weather conditions

Topography, land use

Soils, sediments

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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%

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Particle size: mean < 100 microns; distribution 55% sand, 40% silt, 5% clay

Influent concentration 100 – 300 mg/l

Are the Data Representative? Sediment

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Impact of Particle Size on Performance

U.S. Silica particle size distributions

0%

20%

40%

60%

80%

100%

0.0 0.0 0.1 1.0

Particle Size (mm)

Pe

rce

nt F

ine

r (%

)

F-95 OK-110 Sil-Co-Sil 106

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Impact of Particle Size on Performance

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Quality Control tests, data

Standardized methods

Are Results Accurate, Repeatable?

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Innovative BMPs - Advanced Sedimentation

Rinker Inc, 2002

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Summary – what to look for

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

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BMP Performance Comparison Table

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MASTEP Rating SystemCategory 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

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Higher rating does NOT mean better performance

MASTEP evaluates

quality of performance DATA

NOTBMP Performance Results

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BMP Performance Comparison Table

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Lab vs. Field TestsLab• Relatively inexpensive• Standardized – best for comparing 2 BMPs• “Ideal” conditions, not real world – simplified• Short term

Field• Real world. Problems are encountered• Can’t control conditions• Expensive• Long Duration

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Contact

Jerry Schoen MASTEP Project ManagerBlaisdell House UMass Amherst MA [email protected]

Massachusetts Stormwater TechnologyEvaluation Project

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“The effectiveness of Proprietary BMPs varies with the size of the unit, flow requirements, and specific site conditions. The UMass Stormwater Technologies Clearinghouse database evaluates the quality of proprietary BMP effectiveness studies. MassDEP urges Conservation Commissions to use this database when verifying the effectiveness of Proprietary BMPs: www.mastep.net”

-Excerpt from MA Stormwater Handbook Volume 2 Chapter 4

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Two Ways to Approve or Deny the Use of Proprietary Stormwater BMPs

Two Ways to Approve or Deny the Use of Proprietary Stormwater BMPs

1. MassDEP has reviewed the performance of a technology as determined by TARP or STEP and assigned a TSS removal efficiency.

If the conditions under which it is proposed to be used are similar to those in the performance testing, presume that the proprietary BMP achieves the assigned TSS removal rate.

Look at sizing, flow and site conditions.

2. Issuing Authority makes a case-by-case assessment of a specific proposed use of a proprietary technology at a particular site and assigns a TSS removal efficiency.

Proponent must submit reports or studies showing effectiveness of BMP.

MassDEP strongly recommends using UMass Stormwater Technologies Clearinghouse database to ensure that reports and studies are of high quality (www.mastep.net).

Look at sizing, flow and site conditions. For ultra-urban and constrained sites, proprietary BMPs

may be the best choice.

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Documents

umass slide

performance slide

sediment slide

umass stormwater management

moderate cost

stormwater bmps spring

basins removal efficiency

total storm flow