# Presentation: 497206

## Indian Creek TMDLInformational Meeting

- Lower Salford Township Building
- November 30, 2006

## Agenda

- Basis of TMDL
- Introduction to TMDLs
- Watershed Characterization
- Model Selection
- Data Collection and Monitoring
- Schedule

## Purpose of Meeting

- Present the plan and approach for developing nutrient and sediment TMDLs for the Indian Creek Watershed

## Slide 4

## Basis for Impairment Listings

- Field assessments and aquatic life surveys conducted by PADEP indicated that there are impairments to water quality

- Pictures taken June 2005

## Pictures taken August 2006

- At Rt 63 Bridge

## Pictures taken August 2006

- farm

## Slide 8

## Slide 9

## The Clean Water Act Process

- The TMDL process has three main steps
- Identify impaired or threatened waters (i.e., Section 303(d) List)
- Develop the load allocations necessary to attain and maintain the applicable water quality standards
- Identify the controls
- Standard  —›    TMDL   —›    Controls

## What is a TMDL?

*A TMDL is:*
- A calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards
- Determines sources of pollutants causing or contributing to impairment
- Allocates responsibility for reductions needed to achieve water quality standards

## TMDLs 101

- A TMDL is Composed of 3 Parts:
- Wasteload Allocation (WLA) – point source contributions (e.g. pipe, channel, etc.)
- Load Allocation (LA) – nonpoint source contributions (e.g. agricultural runoff, atmospheric deposition, etc.)
- Margin of Safety (MOS) – Accounts for uncertainty in data or modeling
**	****	*****TMDL =************WLA + LA + MOS***

## 		TMDL RequirementsTMDLs must...

- Be based on the applicable water quality standards
- Include a total allowable load as well as individual WLAs and LAs
- Consider the impacts of background pollutant contributions
- Consider critical environmental conditions
- Consider seasonal environmental variations
- Ensure there is reasonable assurance that the TMDL can be met
- Be subject to public participation

## Statutory, Regulatory, Legal Framework

- Statute – Clean Water Act Sections 301-308
- Regulations – 40 CFR Parts 130-131
- Legal - EPA under Consent Decree in PA
- Schedule to approve or establish TMDLs for waters identified on the 1996 Section 303(d) list
- All non-mining impairments by April 9, 2007
- All mining impairments by April 9, 2009
- Interim requirements

## How will the TMDL impact you?

- NPDES permit effluent limits must be consistent with the assumptions and requirements of the WLA
- This includes small municipalities (MS4s) that are covered under Phase II of the Stormwater Program

## What is an MS4?

- Municipal Separate Storm Sewer System
- Smaller MS4s = systems within “urbanized areas” and other systems serving populations <100,000
- Includes roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, storm drains

*EPA Memo – Nov. 2002*
- NPDES-regulated stormwater discharges must be addressed by the WLA component of a TMDL
- Water-quality based effluent limits (WQBELs) for NPDES-regulated stormwater discharges that implement WLAs may be expressed in the form of best management practices (BMPs)
- Particularly addresses discharges from smaller MS4s and stormwater discharges from construction sites that disturb 1-5 acres (Phase II)

## MS4 Allocation Process

- Each MS4 will be assigned an individual WLAs
- Usually based on acreage within watershed
- MS4 allocations may be broken down into land use
- WLAs may be modified as the service areas are determined

## What do the Allocations Mean?

- Next issuance of MS4 permit must fully comply with results of the TMDL
- Will include BMPs to meet TMDL
- Administrative record needs to support that BMPs are expected to be sufficient
- Include mechanism to adjust BMPs to ensure adequate performance
- Specify monitoring necessary to determine compliance with limits

- Public education
- Enforcement of existing ordinances
- New ordinances
- Construction site runoff
- Post construction
- Erosion and sediment controls
- Riparian zone limitations
- Re-development controls
- Illicit connections
- Other BMPs and controls

## Indian Creek Watershed

- Watershed Characterization
- TMDL Model Selection
- Schedule

## Land Use Breakdown

- Land Use Breakdown

- ~40% Urban
- (low and high intensity development)
- ~5% Forested
- ~53% Agriculture
- (hay/pasture and cropland)

## Point and Nonpoint Sources of Nutrients and Sediment

- Agricultural runoff
- Biosolids
- Septic systems
- Urban runoff/Municipal Separate Storm Sewer System (MS4s)
- Lower Salford
- Upper Salford
- Souderton
- Telford
- Franconia
- NPDES permitted facilities
- Telford STP
- Pilgrams Pride
- Lower Salford STP

## Critical Condition

- Nutrients
- Low flow conditions – considerable inputs of nutrients from point source facilities cause receiving waters to exhibit elevated levels of nutrients over ambient concentrations during periods of dry weather
- High flow conditions – nonpoint source nutrient loading during wet weather conditions
- Sediment
- High flow conditions

## Model Selection	

- Watershed Model – GWLF
- 	*Generalized Watershed Loading Function*
- GWLF provides the ability to simulate runoff, sediment, and nutrient loadings from the watershed
- Receiving Water Model – EFDC *Environmental Fluid Dynamics Code*
- To simulate hydrodynamics and water quality processes (e.g., nutrient-algae dynamics)
- Configured as a dynamic modeling system, representing temporal and spatially variable conditions in the stream

## Data Gathering - Completed

- Existing and readily available data have been compiled
- PADEP biological and habitat assessment data
- Streamflow and climate data
- DMR data
- Ambient monitoring data
- Land use activity information
- Biosolids application information
- Etc...

## TMDL Monitoring 

- Additional data collected on
- 	May 9, 10, and 11, 2006
- DO, Temperature, pH, Conductivity, salinity, TDS
- Diurnal DO
- Chemical data – BOD, TSS, dissolved phosphorus, dissolved nitrogen, TN, Alk, total ortho phosphorus, dissolved ortho phosphorus, nitrate + nitrite, ammonia
- Periphyton
- Physical data

## Slide 28

## Schedule (Tentative)

- Jan 2007
- Public notice, public comment period begins
- Draft TMDL report available to public
- Late Jan/early Feb 2007
- Public meeting
- Close of comment period (45-60 days)
- EPA considers written comment received and revises TMDL accordingly
- April 9, 2007
- TMDL finalized and established by EPA
- TMDL effective for CWA purposes
- Days after April 9, 2007
- TMDL report and response to comment document to be posted on EPA’s website

## EPA Region 3’s TMDL Website

- http://www.epa.gov/reg3wapd/tmdl/index.htm

## Questions

- Mary Kuo, EPA Region 3
- _[Kuo.mary@epa.gov](mailto:Kuo.mary@epa.gov)_
- 215-814-5721