Total Maximum Daily Loads TMDLs Overview of the

Total Maximum Daily Loads (TMDLs): Overview of the Texas TMDL Program Roger Miranda, P. G. Total Maximum Daily Load Program Texas Commission on Environmental Quality May 14, 2019

The Federal Clean Water Act Requires States and Territories to… Ø Set Water Quality Standards Ø Monitor Water Quality Ø Identify Water Quality Problems Ø Fix the problems

The Federal Clean Water Act Requires States and Territories to… Ø Set Water Quality Standards Ø Monitor Water Quality Ø Identify Water Quality Problems Ø Fix the problems

Texas TMDL Program Ø Section 303(d) of the federal Clean Water Act Ø Texas Integrated Report of Surface Water Quality – State of Texas 303(d) List Ø Texas Surface Water Quality Standards (TAC 307. 1 -307. 10) Ø Texas Surface Water Quality Monitoring Program & Texas Clean Rivers Program Ø Total Maximum Daily Loads (TMDLs)

Total Maximum Daily Load (TMDL) Ø How bad is the problem? Ø Where is it coming from? Ø How much is too much?

Total Maximum Daily Load (TMDL) Ø How bad is the problem? Ø Where is it coming from? Ø How much is too much?

Texas TMDL Program Ø Total Maximum Daily Load (TMDL) l l l CFR Title 40 Section 130. 7 Determines the maximum amount (load) of a pollutant a water body can receive and still maintain uses (expressed in load/day) Allocates this load to broad categories of sources in the watershed Contains a Margin of Safety (MOA) Adopted by the state (TCEQ) Approved by EPA

Typical TMDL Pollutants Bacteria (recreation) Ø Bacteria (Oyster Waters) Ø Depressed Dissolved Oxygen Ø Chloride, Sulfate, Total Dissolved Solids Ø p. H Ø PCBs in Fish Tissue Ø Pesticides in Fish Tissue Ø Volatile Organic Compounds (VOCs) in Fish Tissue Ø Metals Fish and Shellfish Tissue Ø

TMDLs in Texas As of April 2019 TMDLs Stream Segments Stream Miles Watershed Area (Mi 2) 284 198 2, 412 25, 892

Texas TMDL Program Update Ø Vision Strategy CWA 303 (d) l l Developed by the states and EPA in 2013 -2014 Vision performance measure replaces the current number of TMDLs per year measure The goal is to account for the stream miles and watershed area covered by a TMDL or other approved plan 7 year effort (2016 -2022)

TMDLs must be expressed as a daily pollutant flux. It is often expressed as a daily mass or load, but it can also be expressed as counts, heat or even conc. Simplified Example: TMDL (mass/day) = criterion (mass/volume) * flow (volume/time) * conversion factors Dissolved Solid: TMDL = criterion (mg/L) * flow (m 3/sec) * 1, 000 (L/ m 3 ) *1/1000 (Kg/mg) * 84600 (sec/day)

TMDLs must be expressed as a daily pollutant flux. It is often expressed as a daily mass or load, but it can also be expressed as counts, heat or even conc. Simplified Example: TMDL (mass/time) = criterion (mass/volume) * flow (volume/time) * conversion factors = mass/time Dissolved Solid: TMDL = criterion (mg/L) * flow (m 3/sec) * 1, 000 (L/ m 3 ) * 1/1000 (Kg/mg) * 84600 (sec/day) = Kg/day

TMDLs and TMDL Allocations The maximum amount (load) of a pollutant a water body can receive and still maintain its uses. TMDL = Σ WLA + Σ LA + MOS

TMDLs and TMDL Allocations The maximum amount (load) of a pollutant a water body can receive and still maintain its uses. TMDL = Σ WLA + Σ LA + FG + MOS

TMDL Allocations TMDL = Σ WLA + Σ LA + FG + MOS Ø Waste Load Allocations (WLA) – Regulated Sources Ø Load Allocations (LA) – Unregulated Sources Ø Future Growth (FG) – Potential Regulated Sources Ø Margin of Safety (MOS) – Explicit or Implicit

TMDL Allocations WLA = WLAWWTF + WLAPSW l l l WLAWWTF – Waste Load Allocation for Wastewater Treatment Facility Discharges WLAPSW – Waste Load Allocation for Permitted Stormwater Discharges Expressed in Units Per Day

TMDL Allocations Ø WLAWWTF l l Individual facilities receive load allocations which can also be expressed in terms of effluent limits (i. e. effluent flows and concentrations) Based on full permitted flow Based on an instream criterion (for example E. coli or Enterococci to support PCR) Updated quarterly through the Water Quality Management Plan

TMDL Allocations Ø WLAPSW l Single aggregate load allocation l For municipal, industrial, and construction stormwater permits combined l Loads are not assigned to individual permits l Determination of the aggregate WLAPSW is based on the proportion of urbanized area in the TMDL watershed

TMDL Allocations Ø LA = TMDL – ΣWLA – FG – MOS l LA – Allowable loads from unregulated sources l TMDL – Total Maximum Daily Load l l l WLA – Sum of all WWTF Loads and all other regulated sources (includes WLAPSW) FG – Sum of Future Growth Loads (i. e. , Potential Permitted Facilities) MOS – Margin of Safety (can be explicit or implicit)

TMDL Allocations Ø AU TMDL WLAWWTF WLAPSW LA FG MOS 0666_01 100. 0 16. 0 64. 0 5. 0 Final TMDL l l l In this example units are in billion MPN/day Enterococci WLAWWTF = 10% of total load WLApws = 16% of total load LA = 64% of total load FG = 5% (5 billion counts) Explicit MOS = 5% (5 billion counts)

TMDL Implementation Plans (I-Plans) Ø Designed to satisfy the TMDL regulatory requirements for “reasonable assurance” of implementation Determines what will be required to manage the loads from all sources, including stormwater Ø Describe the activities that will be implemented over a specific time period by the stakeholders to improve water quality Ø

I-Plans (continued) Management Measures - Examples Structural Ø Oil Well Plugging for Salinity Control Ø Stormwater Retention Basin Retrofits Ø Installation of Pet Waste Stations in Public Areas Nonstructural Ø Pet Waste Ordinances Ø Education (for professionals and the general public) Ø Outreach (PSAs, pamphlets, ect. )

I-Plans (continued) Ø Developed by stakeholders in the affected watershed with support and guidance from the TCEQ Ø Collaborative effort involving a wide variety of stakeholders in a TMDL watershed l l l Citizens, watershed interest groups State, local, and federal agencies Regulated organizations

I-Plans in Texas May 2019 Area = 25, 892 Mi 2 Segments = 198 Stream Miles = 2, 412

Adaptive Management

www. tceq. texas. gov/waterquality/tmdl

For More Information on TMDLs TCEQ TMDL Program Website: http: //www. tceq. texas. gov/waterquality/tmdl/ Roger Miranda roger. miranda@tceq. texas. gov (512) 239 -6278