PEAIP Tracking, Quantifying, and Reporting for Phase II MS4 Permit - - PowerPoint PPT Presentation

PEAIP Tracking, Quantifying, and Reporting for Phase II MS4 Permit Compliance

Avery Blackwell, P.E

Geosyntec Consultants, Santa Barbara, CA

Cathleen Garnand

County of Santa Barbara, Project Clean Water Program

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Discussion Topics

• Requirements, Local Context, and Model Objectives
• LPR Model Overview and Lessons Learned
• LPR Model Benefits
• Questions

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Phase II MS4 Permit Requirements

• “Quantification of pollutant loads and pollutant load reductions

achieved by the program as a whole” (Section E.14.a.ii.a.6)

• “Assess BMP and program effectiveness in terms of the

following Outcome Levels: 4) Pollutant load reductions” (Sections E.14.a.ii.b.4)

• “Quantitatively assess BMP performance at reducing pollutant

loads wherever feasible, using … science-based estimates of pollutant load removal for BMPs where direct measurement of pollutant removal is overly challenging” (Sections E.14.a.ii.d.2)

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• Quantify Pollutant Loads

and Load Reductions (Yr 2)

• Evaluate and select flow and

pollutant loading models;

• Prioritize load quantification by

catchment; and

• Provide schedule for

completing pollutant load quantification to inform submittal of Stormwater Program Modifications by Year 5

• Map stormdrain system

(Yr 2)

Central Coast Regional Board Requirements

• Catchment delineation to

support catchment scale stormwater volume and pollutant loading (Aug 2016)

• Structural BMP Inventory (Yr 3)
• Volume and Pollutant Loading,

Catchment Ranking, without BMPs (Yr 3)

• Structural BMP Assessment,

Volume and Pollutant Loading, Catchment Ranking with BMPs (Yr 5)

July 2014 June 2016

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Santa Barbara County Context

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Primary Model Objectives

Perform minimum requirements from Permit and Central Coast Regional Board Ease of use Low cost Customizable with County-specific datasets Reflect County- specific water quality priorities

No models existed that could fulfill all these objectives, therefore it was necessary to create a new model

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Load, Prioritization, and Reduction Model (LPR Model)

LPR Model Components

• Quantify baseline annual average wet weather pollutant

loads and runoff volumes;

• Prioritize MS4 catchments;
• Track BMP implementation details;
• Quantify non-structural and structural BMP pollutant load

and runoff volume reductions; and

• Summarize, format, and graphically present all results

for easy reporting.

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Quantify Runoff Volumes and Pollutant Loads

Estimate Runoff Volume

• Runoff coefficients

developed using:

• detailed land use

(to estimate imperviousness)

• hydrologic soil

group

• Average annual

precipitation

• Drainage areas

1.

catchments

2.

MS4 Permit Area

3.

Watershed

4.

to BMPs

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Estimate Runoff Volume

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Lesson Learned: Land use data should be verified

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Calibrated Runoff Volume Multiplier

Statistical Comparison of Runoff Volumes

Annual Precipitation Data

Modeled Runoff Coefficients

Model-Predicted Runoff Volume

5,000 10,000 15,000 20,000 25,000 1980 1990 2000 2010 2020

Modeled Annual Runoff Volume (ac-ft)

Land use and Soil GIS data

Calibration of Runoff Volumes

5,000 10,000 15,000 20,000 25,000 1980 1990 2000 2010 2020

Observed Annual Runoff Volume (ac-ft)

Atascadero Creek USGS Flow Gauge

Observed Flow Data

Catchment and Land Use Loads

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MS4 Permit Area – by Land Use

Watershed Loads

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by MS4 & non-MS4 areas

Lesson Learned GIS analysis removed IGP parcels and Caltrans

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Prioritize Catchments

Catchment Prioritization

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Pollutant of Concern Identification Pollutant of Concern Prioritization Modelable pollutants that have land use EMCs above Basin Plan objectives or related TMDL WLAs for MS4 dischargers (Pollutants of Concern [POCs]) Pollutants with available land use EMC data (Modelable pollutants) All pollutants

Areas of highest priority to the Permittees

Final catchment priorities are made based on combined weighted POC-specific rankings POCs are assigned weighting factors based on watershed-specific 303(d) listings and TMDLs Pollutant-specific catchment priority rankings are calculated for each Modelable pollutant

Pollutant of Concern Identification

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Land Use

TSS TP DP NH3 NO3 TKN Diss Cu Tot Cu Tot Pb Diss Zn Tot Zn Fecal Col. mg/L mg/L mg/L mg/L mg/L mg/L ug/L ug/L ug/L ug/L ug/L #/100 mL

MS4 Area Land Uses

Single-Family Residential

124.2 0.4 0.32 0.49 0.78 2.96 9.4 18.7 11.3 27.5 71.9 15,600

Commercial

67 0.4 0.29 1.21 0.55 3.44 12.3 31.4 12.4 153.4 237.1 5,510

Industrial

219.2 0.39 0.26 0.60 0.87 2.87 15.2 34.5 16.4 422.1 537.4 18,700

Education

99.6 0.3 0.26 0.40 0.61 1.71 12.2 19.9 3.6 75.4 117.6 11,800

Transportation

77.8 0.68 0.56 0.37 0.74 1.84 32.4 52.2 9.2 222 292.9 1,680

Multi-Family Residential

39.9 0.23 0.2 0.50 1.51 1.8 7.4 12.1 4.5 77.5 125.1 11,800

Agriculture

999.2 3.34 1.41 1.65 34.4 7.32 22.5 100.1 30.2 40.1 274.8 24,800

Open Space

216.6 0.12 0.09 0.11 1.17 0.96 0.6 10.6 3.0 28.1 26.3 484

BPO or typical WLA:

0.3* 8* 13** 14** 82** 120** 120** 400*

Cells highlighted yellow have Land use EMCs that exceed BPO or typical WLAs * SMR Nutrient /Bacteria TMDL wet weather WLA for MS4 dischargers ** CTR default value (acute freshwater criteria, hardness -100 mg/l)

Pollutant of Concern Prioritization

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Catchment Prioritization Maps

TSS only Multi- pollutant Lesson Learned: 50% of the top ranked catchments are different if prioritized using County-specific water quality priorities instead of traditional surrogates

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BMP Tracking and Reductions

Model Framework

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* Percent Load Reduction (P) or Effluent Concentration (E)

Table 7. BMP Reductions (Additional BMPs may be added to the next empty row) *Note: units shown under pollutants represent concentration. Unit reductions are in units specified in Table 2 and percent reductions are in %. BMP Type Reduction Method* % Capture Volume TSS Tot P Diss P NH3 NO3 TKN Diss Cu Tot Cu Tot PbDiss Zn Tot Zn Fecal Col. Pollut ant Pollut ant Pollut ant cu ft mg/L mg/L mg/L mg/L mg/L mg/L ug/L ug/L ug/L ug/L ug/L #/100 mL unit unit unit 85th – Redevelopment (100% Infiltration) E 89% 100% 18.1 0.14 0.07 0.18 0.37 0.98 8.3 8.8 4.2 34.7 37.6 5,890 85th – Redevelopment (50% Infiltration) E 89% 50% 18.1 0.14 0.07 0.18 0.37 0.98 8.3 8.8 4.2 34.7 37.6 5,890 85th – Redevelopment (100% Treatment) E 89% 0% 18.1 0.14 0.07 0.18 0.37 0.98 8.3 8.8 4.2 34.7 37.6 5,890 95th – Redevelopment (100% Infiltration) E 100% 100% 18.1 0.14 0.07 0.18 0.37 0.98 8.3 8.8 4.2 34.7 37.6 5,890 Brake Pad Copper Phase-out Legislation p 100% 0.0275 0.0275 Other Non-structural BMPs (CBSM) P 100% 0.05 Other Non-structural BMPs (WAAP BMPs - Tanglewood & Orcutt only) P 100% 0.1 0.1 0.1 0.1 0.1 0.1

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BMP Reductions

Lesson Learned: It was important to incorporate advanced logic to accurately estimate BMP reductions when multiple BMPs treat the same area

BMP Reductions

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LPR Model Benefits

Future LPR Model Uses

• Prioritize catchments (or land uses) for MS4 cleaning, street

sweeping, outreach, structural BMP placement, etc.

• Prioritize BMPs – e.g., compare relative cost-benefit of

different BMP options

• Support grant applications and/or Stormwater Resource

Plans

• Use maps as educational tools for public, PW managers,

and/or elected officials

• Forecast long-term cost of compliance (TMDL WLAs, etc.)
• Identify/prioritize potential BMP retrofit opportunity sites
• Quantify water supply benefits of structural BMPs

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Key Benefits of the LPR Model

ability to model 12 water quality parameters for current or planned BMP implementation exceeds Permit requirements a simple to navigate interface and report ready figures provide a user-friendly experience a non-proprietary Excel model owned by the jurisdictions reduces long-term cost of Permit compliance and other modeling requirements capacity for streamlined updates and modification to GIS data and all pre- populated datasets provides maximum customization meaningful catchment prioritization and BMP reductions are based on locally important water quality concerns

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For More Information

http://centralcoastbmploadmodel.net

Download:

• Approach Memo - discusses the modeling approach and

the default model values

• Guidance Document - describes the model organization,

how users can add new BMPs and extract model results for future annual reports, how to modify model defaults, and how model calculations are performed

• CASQA presentation – Available for download next week

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http://centralcoastbmploadmodel.net

Cathleen Garnand - cgarnan@cosbpw.net Avery Blackwell - ablackwell@geosyntec.com

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