1 University of Massachusetts, Amherst, © 2005 Storm Water Best Management Practices Evaluation, Testing and Technology Transfer New England Stormwater.

University of Massachusetts, Amherst, © 20051

Storm Water Best Management Practices

Evaluation, Testing and Technology Transfer

New England Stormwater Technology WorkshopJune 14, 2005

Eric Winkler Ph.D. University of Massachusetts – Amherst


Massachusetts Department of Environmental Protection

University of Massachusetts

at Amherst

MA Stormwater Technology Evaluation Project

S319 Non-Point Source Pollution Program

www.mastep.net


Factors Affecting Stormwater Sampling

Rainfall and pollutants

Sampling challenges Site-related issues Solids sampling Particle size issues Technology design

limits


Regional Rainfall Differences


Recurrence vs. Precipitation Depth

Boston MA - Logan Airport1920 - 1999 Daily Precipitation Frequency

4158

14131150

455541363 348254 216164

286 191185 74 27 17 5 3 2 1

42

56

6873

7882

85 88 90 9295 97 99 99 100 100 100100 100100

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.3 1.5 2.0 2.5 3.0 4.0 5.0 6.0 7.0 8.0

Precipitation (inches)

Nu

mb

er

of

Even

ts

0

10

20

30

40

50

60

70

80

90

100 Perc

en

t of T

ota

l Even

ts


Sampling Criteria:Pollutant Load Decreases Over

Event


Sample Composition

Sampling location is key Avoid bed load sampling –

sampling at the bottom of the collection or piping network

Ensure sample is mixed by sampling one or more locations along pipe cross section that best represent all of the flow

Potential bias in performance efficiency

Pollutant specific sampling techniques Solids sampling may be

affected by inlet velocity of sampling equipment

Want samples to reflect the load in all flow


Particle Size Issues

Removal efficiencies can vary greatly with particle size distribution (PSD)

Poorly graded solids scheme can exaggerate performance claims

Well-graded distributions present the most accurate performance data

Sample volume must be considered in order to collect for PSD


-75%-55%-35%-15%5%

45%65%85%

0 50 100 150 200 250

Evaluating TSS Removal RatesBased on ConcentrationR

em

oval Effi

ciency

(%

)

Influent Concentration (mg/L)


Detail of Data Generation and Acquisition Requirements

(Quality Assurance Project Plan)

1. Sampling process design (experimental design)2. Sampling method requirements3. Sample handling and custody requirements4. Analytical methods requirements5. Quality control requirements6. Instrument/equipment testing, inspection, and maintenance

requirements7. Instrument calibration and frequency8. Inspection/acceptance requirements for supplies and

consumables9. Data acquisition requirements (non-direct measurements)10. Data management


Protocol Minimum Criteria Identifying Qualifying Storm Event

(Section 3.3.1.2 and Section 3.3.1.3, TARP Tier II Protocol)

Minimum rainfall event depth is 0.1 inch.

Minimum inter-event duration of 6 hours

(duration beginning a cessation of flow to unit).

Base flow should not be sampled.

Identification of qualifying event needs to

verify flow to the unit and rainfall

concurrently.TARP: http://www.dep.state.pa.us/dep/deputate/pollprev/techservices/tarp/


Qualifying Event Sample TARP Tier II Protocol Criteria

10 water quality samples per event 10 influent and 10 effluent If composite - 2 composites, 5 sub-

samples

Data for flow rate and flow volumeAt least 50% of the total annual

rainfall CA – monitor 80-90% of rainfall.


Qualifying Event Sample (continued)

Preferably 20 storms, 15 minimum

Sampling over the course of a full year of sampling to account for seasonal variation

Compositing flow-weighted samples cover at least 70% of storm flow (and as much of the first 20% as possible)

Examples of variation within TARP community: PA - Temporary BMPs sized using 2 year event

NJ – Water Quality design based on volume from a 1.25 inch event.


Efficiency Ratio (ER)TARP Protocol Recommended

Method

Where Event Mean Concentration (EMC):

V=volume of flow during period in=total number of events C=average concentration associated with period jm=number of events measured


Efficiency Ratio Interpretation

EMCs weight all storms equally. Most useful when loads are directly proportional to the

relative magnitude of the storm – accuracy varies with BMP type.

Minimizes impacts of smaller/cleaner storms. Allows for use of data where portions of data are missing –

would not significantly effect the average EMC.

• Can apply log normalization to avoid equal weighting of events.


Variation in Performance Values

Removal Efficiencies for all Events:

Removal Efficiency by Efficiency Ratio:57%

Removal Efficiency by Summation of Loads:44%

Removal Efficiency by Regression of Loads:40%

Removal Efficiency by Efficiency of Individual Storm Events:

59%


System Efficiency v. Unit Efficiency

BMP 1 BMP2 BMP3

(Unit) 10% 25% 80%

(Removal) 10% 22.5% 54%

(Passing) 90% 67.5% 13.5%

System Efficiency = 10% + 22.5% + 54% = 86.5%


System Efficiency v. Unit Efficiency

BMP 1 BMP2 BMP3

(Unit) 10% 25% 70%

(Removal) 10% 22.5% 47.25%

(Passing) 90% 67.5% 20.25%

System Efficiency = 10% + 22.5% + 47.25% = 79.75%


Stormwater Database ProjectWWW.MASTEP.NET

Project Goal: Provide technology transfer information about innovative stormwater Best Management Practices (BMPs) to MADEP, conservation commissions, local officials, and other BMP users to help them make appropriate technology implementation decisions.

Project Scope of Work: Needs survey, develop searchable database, develop screening tool, evaluate 30-40 technologies, provide fact sheets for TARP Tier II qualified technologies.


Category 0 Technology entry is in process or incomplete.

Category 1 There is sufficient reliable data on this technology to be able to provide a scientifically valid evaluation

Category 2 Studies are underway that offer promise for reliable data in the near future

Category 3 There is insufficient reliable data with which to evaluate this technology

Stormwater Database Entry Protocol




Contact:

Eric Winkler, Ph.D.University of Massachusetts [email protected]

MASTEP – www.mastep.net

NSF International – www.nsf.org

International Stormwater BMP Database – www.bmpdatbase.org

WA Dep. of Ecology - www.ecy.wa.gov/programs/wq/stormwater/newtech

New Jersey Corporation for Advanced Technology (CAT) – www.njcat.org

Environmental Technology Verification Program (ETV) - www.epa.gov/etv

Resources:

1 University of Massachusetts, Amherst, © 2005 Storm Water Best Management Practices Evaluation, Testing and Technology Transfer New England Stormwater.

Documents

event slide

flow slide

minimum sampling

psd slide

sampling criteria

data management slide

bed load sampling sampling

year of sampling