Total Maximum Daily Load Program TMDLs and Stormwater Chris Loft Total Maximum Daily Load Program Texas Commission on Environmental Quality

Texas TMDL Program Texas is required under Section 303(d) of the federal Clean Water Act to list impaired waters and to take action to restore them. Impaired waters are identified every two years on the Texas Integrated Report of Surface Water Quality. A surface water body is considered impaired if it does not meet the criteria for support of one or more of its beneficial uses, as defined in the Texas Surface Water Quality Standards (307.1-307.10 TAC).

Texas TMDL Program TMDL – Total Maximum Daily Load Determines the maximum amount (load) of a pollutant that a water body can receive and still maintain uses Allocates this load to broad categories of sources in the watershed Adopted by TCEQ Approved by EPA

Typical TMDL Pollutants Bacteria Bacteria (Oyster Waters) Chloride, Sulfate, Total Dissolved Solids Dioxin in Edible Tissue Depressed Dissolved Oxygen Impaired Aquatic Life Mercury in Edible Tissue Metals in Water PBCs in Edible Tissue pH Sediment Toxicity Water Toxicity

Texas TMDL Program Implementation Plan A stakeholder developed plan to improve water quality Includes a description of regulatory and voluntary management measures Includes a plan for sustaining the implementation effort over time Approved by TCEQ

Texas TMDL Program Update New Strategy CWA 303 (d) Vision Developed by the states and EPA in 2013-2014 New performance measure replaces the current number of TMDLs per year measure The goal is the number of watershed acres covered by a TMDL or other approved plan 7 year effort

TMDL Allocations TMDL (MPN/day) = Criterion * flow (cfs) * conversion factor Expressed in units per day

TMDL Allocations TMDL = WLAWWTF + WLAPSW +LA + MOS WLAWWTF – Waste Load Allocation for WWTF Discharges WLAPSW – Waste Load Allocation for Permitted Stormwater Discharges LA – Load Allocation MOS – Margin of Safety Expressed in units per day

TMDL Allocations Waste Load Allocations – Regulated Sources Load allocation for wastewater treatment facilities Load allocation for all permitted stormwater sources Load Allocations – Unregulated

TMDL Allocations WLAWWTF Required by EPA Individual facilities receive load allocations based on target concentrations Based on full permitted flow Based on a criterion (Enterococci or E. coli) Updated quarterly through the Water Quality Management Plan

TMDL Allocations WLAPSW = (TMDL – WLAWWTF – FG – MOS) * FDASWP WLAPSW – Sum of all Regulated Stormwater Loads TMDL – Total Maximum Daily Load WLAWWTF – Sum of all WWTF Loads FG – Sum of Future Growth Loads from Potential Permitted Facilities MOS – Margin of Safety FDASWP – Fractional Portion of Drainage Area under Jurisdiction of Stormwater Permits

AU Subwatershed Area (mi2) Percentage Stormwater Regulation (%) TMDL Allocations FDASWP Urbanized Area / Subwatershed Area AU AU Urbanized Area (mi2) AU Subwatershed Area (mi2) Percentage Stormwater Regulation (%) 5505_01 2.68 15.81 16.95 5506_02 88 120.5 73.02 5506A_01 12.7 40.56 31.31 Table showing examples for three AUs of AU Urbanized Area, AU Subwatershed Area, and Percentage Stormwater

TMDL Allocations WLAPSW Single aggregate load limit For municipal, industrial, and construction stormwater permits combined Loads are not assigned to individual permits Determination of allocation based on proportion of urbanized area in watershed covered by a municipal separate storm sewer system (MS4) entity

TMDL Allocations LA = TMDL – WLA – FG – MOS LA – Allowable loads from unregulated sources TMDL – Total Maximum Daily Load WLA – Sum of all WWTF Loads and all regulated sources FG – Sum of Future Growth Loads from Potential Permitted Facilities MOS – Margin of Safety

TMDL Allocations Final TMDL Units expressed as billion MPN/day Enterococci AU TMDL WLAWWTF WLASW LA MOS 5505_01 137.8 11.20 18.79 100.92 6.89 5506_02 150.3 10.5 0.05 132.7 7.5 Table showing examples for two AUs of TMDL, WLAWWTF, WLASW, LA, and MOS.

Implementation Plans Water quality improvement plans developed by stakeholders in the affected watershed Implementation plans are collaborative and involve a wide variety of stakeholders in the affected watershed Citizens, watershed interest groups State, local, and federal agencies Regulated organizations

Implementation Plans General Strategy Develop a Coordination Committee Identify and organize Work Groups Develop a Water Quality Improvement Plan Promote Plan to gain cooperation in the watershed

Implementation Plans Plans describe the activities that will be implemented over a specific time period by the stakeholders to improve water quality Strategy for continuing the effort is crucial Stakeholders meet annually to review progress The stakeholders revise the plan as needed

Implementation Plans in Texas Map of Texas showing location of TMDL and I-Plan development and implementation watersheds

Implementation Plan The Implementation part of the “TMDL” can establish the “consistent” requirements for WWTFs Permitted municipal stormwater requirements agreed upon in the Implementation Plan may be submitted as part of a Stormwater Management Program for an MS4 Industrial Stormwater Permits and Construction Stormwater Permits may be affected.

Stormwater Management Measures Considered in an Implementation Plan Generally the same measures an MS4 can use under its MS4 permit Management of runoff (Best Management Practices or BMPs) Detention basins, filter strips, infiltration basins, porous pavement, detention ponds, swales Create and maintain an online library of best practices Organize and conduct training sessions Develop recognition program Retrofit and inspect existing BMPs

Stormwater Management Measures Considered in an Implementation Plan Generally the same measures an MS4 can use under its MS4 permit continued Management of operations to decrease or eliminate pollutants in runoff Spill prevention and control, source controls, public outreach, and education Street sweeping Storm drain stenciling Support or encourage Low Impact Development

Other Management Measures That May Be Considered Map stormwater system Monitoring Additional instream monitoring Outfall monitoring to identify sources BMP effectiveness sampling Search for specific pollutant sources Illicit Discharges System mapping, detection, and elimination

Other Management Measures That May Be Considered Sanitary Sewer Overflows Reporting Cleaning and inspection of collection system Video surveys Consider sanitary sewer overflow initiative Develop, conduct Fats, Oil, and Grease (FOG) reduction program

Examples from other Implementation Plans Consider instream structural modifications that do not increase flood risk Decrease impervious cover Incorporate bacteria reduction requirements as a secondary priority of flood control projects and any other new or retrofitted infrastructure projects Modify outfalls to 'treat' water before it enters channels

Examples from other Implementation Plans Conduct research to identify the biggest bacteria sources from stormwater Apply implementation activities to the biggest sources that are most cost effective Double the urban tree canopy Construct treatment wetlands

Examples from other Implementation Plans Install filters or vegetative strips at inlets to capture materials Review animal control ordinances and implement measures to control nuisance animals Install pet waste disposal stations Clean sewer lines and outfalls and fit with stormwater wetlands

Implementation Plans It is the stakeholders in the watershed who contribute to the development of the Implementation Plan that determine what will be required to manage the loads from all sources, including stormwater.

For More Information on TMDLs TCEQ TMDL Program Website: http://www.tceq.texas.gov/waterquality/tmdl/ Chris Loft chris.loft@tceq.texas.gov (512) 239-4715