Total Maximum Daily Loads (TMDLs): Overview of the Texas TMDL Program Good morning. I’m going to be presenting a brief overview of the TCEQ’s Total Maximum Daily Load program in Texas with an emphasis on the role TMDLs play in water quality restoration and protection. 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… Set Water Quality Standards Monitor Water Quality Identify Water Quality Problems Fix the problems In order to achieve the Clean Water Act’s goal of maintain water bodies swimmable and fishable, the law requires all states and territories to (1) set standards (and associated criteria) for water quality in surface bodies of the state (Uses first), (2) monitor water quality in these water bodies, (3) identify water bodies that do not meet these standards and (4) restore water quality in water bodies that do not meet the standards. The TCEQ has established programs to address all four of these requirements…

The Federal Clean Water Act Requires States and Territories to… Set Water Quality Standards Monitor Water Quality Identify Water Quality Problems Fix the problems The TCEQ’s program designed to restore water quality in water bodies that do not meet Texas Water Quality Standards (and therefore its designated uses) is the TMDL Program.

Texas TMDL Program Section 303(d) of the federal Clean Water Act Texas Integrated Report of Surface Water Quality – State of Texas 303(d) List Texas Surface Water Quality Standards (TAC 307.1-307.10) Texas Surface Water Quality Monitoring Program & Texas Clean Rivers Program Total Maximum Daily Loads (TMDLs) So, under Section 303(d) of the federal Clean Water Act, Texas, like all other states, is required to list impaired water bodies. Impaired waters are identified every two years on the Texas Integrated Report of Surface Water Quality, which includes a subsection of impaired water bodies called the 303(d) list named after the section of the CWA that requires it. A surface water body is considered impaired if it does not meet the criteria used to assess support of one or more of its designated uses, as defined in the Texas Surface Water Quality Standards (307.1-307.10 TAC). The TCEQ compares surface water quality data collected under its SWQM and Clean Rivers Programs to criteria in the TSWQS. To restore uses, the State of Texas must schedule a TMDL for water bodies on the 303(d) list (WPPs now work too – more on this later).

Total Maximum Daily Load (TMDL) How bad is the problem? Where is it coming from? How much is too much? The process of addressing water quality impairments through the development of Total Maximum Daily Loads is a comprehensive one. Once the 303(d) list has established there is a water quality impairment, regulators must determine… (1) the severity of the problem, (2) the sources of the water quality impairment, and, to set limits on the pollutants of concern, they must also know how much of that pollutant is too much, which can vary from water body to water body depending on a rather large number of factors.

Total Maximum Daily Load (TMDL) How bad is the problem? Where is it coming from? How much is too much? It is this last question that is at the heart of what we do in the TMDL Program.

Texas TMDL Program Total Maximum Daily Load (TMDL) 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 Not to bore you too much, but it is important to know that each environmental law, including the Clean Water Act, has a set of implementing federal regulations. Ours (or more precisely the USEPA’s) is Section 130.7 of Title 40 of the Code of Federal Regulations. Regulations have a lot more detail than the laws they are meant to implement… Under Section 130.7 of 40 CFR, TMDLs are defined as the maximum amount (load or other measure) of a pollutant a water body can receive and still maintain uses (expressed in load or other measure/day). The regulation then requires that the TMDL be allocated to broad categories of sources with a margin of safety. TMDLs are legal instruments formally adopted by the state or territory, but they must be approved by the EPA.

Typical TMDL Pollutants Bacteria (recreation) Bacteria (Oyster Waters) Depressed Dissolved Oxygen Chloride, Sulfate, Total Dissolved Solids pH PCBs in Fish Tissue Pesticides in Fish Tissue Volatile Organic Compounds (VOCs) in Fish Tissue Metals Fish and Shellfish Tissue Here are some typical pollutants we address in the TMDL program. Over 40% of the impaired water bodies in Texas waterbodies are impaired for bacteria. Every river basin in the state has at least one bacteria impairment. And we have lots of experience working with stakeholders, contractors, and water quality partners in addressing bacteria impairments.

TMDLs in Texas As of April 2019 TMDLs Stream Segments Stream Miles Watershed Area (Mi2) 284 198 2,412 25,892 The TCEQ’s TMDL Program is in its 20th year and, in this time, the program has developed 284 TMDLs in 198 Stream Segments in Texas. Our TMDL counts have evolved since the beginning of the program. Whereas once we counted only TMDLs and stream segments, now due to 303(d) Vision Program requirements, which I’ll explain in the next slide, we also count stream segment miles and watershed area.

Texas TMDL Program Update Vision Strategy CWA 303 (d) 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) Beginning in 2013, the EPA, in partnership with state and tribal governments, developed an alternative strategy or “Vision” for addressing impairments in surface water bodies…new performance measures for state TMDL programs were developed (in an effort to reform unproductive bean counting)…the goal now is to account for the stream miles and watershed area covered by a TMDL or other approved plan. Other mechanisms such as Watershed Based Plans or Watershed Protection Plans, as we call them here in Texas…can also be counted as TMDL-like water quality restoration efforts. The 303(d) Vision Program was originally envisioned as a 7 year effort (2016-2022).

TMDLs 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 (m3/sec) * 1,000 (L/ m3 ) *1/1000 (Kg/mg) * 84600 (sec/day) TMDLs must be expressed as a daily pollutant flux. The “daily” part was reinforced by the “Anacostia River Decision” in 2011, which concluded that “daily means daily” in the TMDL definition. But, the “load” part is flexible. TMDLs can also be expressed as counts, heat or even concentration. Shown here is a simple, back-of-the-envelope TMDL calculation that uses the in-stream criterion, which is usually expressed in terms of mass per volume and the flow at critical conditions. Flow is always in terms of volume per unit time. In the case of a dissolved solid the criterion would typically be in mg/l and the flow in this case is in cubic meters per second. Applying our conversion factors…

TMDLs 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 (m3/sec) * 1,000 (L/ m3 ) * 1/1000 (Kg/mg) * 84600 (sec/day) = Kg/day …our milligrams then would go away, as would our liters, cubic meters and seconds and we’re left with Kilograms per day of the dissolved solid as our in-stream TMDL.

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 are the best possible estimates of assimilative capacity of a waterbody for a specific pollutant under consideration. This is the equation used by EPA to define TMDLs…

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 Some times you may see an extra term in the equation, “FG” for future growth, but it is not required. I’ll explain what these terms mean in the following slides, but it is important to point out that the future growth term is a term the TCEQ tries to include in all TMDLs, although we are not required by federal regulations to do so.

TMDL Allocations TMDL = Σ WLA + Σ LA + FG + MOS Waste Load Allocations (WLA) – Regulated Sources Load Allocations (LA) – Unregulated Sources Future Growth (FG) – Potential Regulated Sources Margin of Safety (MOS) – Explicit or Implicit So let me explain what some of these terms mean. The waste load allocation, or WLA, is the sum of loads from regulated sources. In other words, discharges that require a permit. The load allocation, or LA, is the sum of loading from all unregulated sources (these might include stormwater from non-urbanized areas or irrigation return flows from agricultural land, etc.). I’ve already mentioned future growth. It is a term that is expressed in terms of potentially regulated future pollutant sources. Think of it as a reserve of the assimilative capacity used to accommodate population growth. And a margin of safety is required of all TMDLs; it is used to address uncertainty in the TMDL analysis and it can be expressed explicitly or implicitly – (explanation provided)….

TMDL Allocations WLA = WLAWWTF + WLAPSW WLAWWTF – Waste Load Allocation for Wastewater Treatment Facility Discharges WLAPSW – Waste Load Allocation for Permitted Stormwater Discharges Expressed in Units Per Day There was a time, early in the TCEQ’s TMDL program, in which the waste load allocation (WLA) referred strictly to the portion of the TMDL that was allocated to point source discharges, such as wastewater treatment facilities. However, with the advent of Phase II SW regulations, and the establishment of the TCEQ’s stormwater program, we started splitting the TMDL WLAs into separate allocations for wastewater treatment facilities (WLAWWTF) and regulated (or permitted) storm water (WLAPSW). This presents a bit of a technical challenge, as stormwater discharges do not occur on a daily basis. I wish I could explain how we calculate WLAPSW, but I don’t have enough time during this presentation to do so.

TMDL Allocations WLAWWTF 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 For the WLAWWTF, an aggregate TMDL allocation is made in the TMDL equation to permitted wastewater treatment facilities. The allocation is typically the sum of individual waste loads for existing WWTFs, calculated as their full permitted flow times the water quality criterion or other concentration limit (much like the back-of-the envelope calculation we saw earlier). Wastewater treatment facilities discharging to the TMDL segments are assigned an effluent limit based on the TMDL allocation. The individual allocations for each wastewater treatment facility in the watershed are specified in the TMDL document. Changes in wastewater treatment plant outfalls (e.g., a new permit, or increases [or reductions] in the current permitted flows) are handled through updates to the TCEQ’s Water Quality Management Plan and must be consistent with the TMDL (i.e., future growth allocations or reallocation of the WLA or reallocation from another source category).

TMDL Allocations WLAPSW Single aggregate load allocation For municipal, industrial, and construction stormwater permits combined Loads are not assigned to individual permits Determination of the aggregate WLAPSW is based on the proportion of urbanized area in the TMDL watershed The WLAPSW is expressed as a single aggregate load for all permitted stormwater in the TMDL watershed or subwatershed; it subsumes all land permitted under municipal, industrial, and construction stormwater permits. Allocations for individual stormwater permitees are not specified in Texas TMDLs.

TMDL Allocations LA = TMDL – ΣWLA – FG – MOS LA – Allowable loads from unregulated sources TMDL – Total Maximum Daily Load 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) The Load Allocation, or LA term, is meant to be an allocation of assimilative capacity to unregulated sources. These are generally nonpoint sources and typically enter the impaired segment through diffuse, nonspecific locations and usually as rainfall runoff (but not always – e.g., irrigation return flows). LA is typically calculated simply by subtracting all other source categories (equation terms) from the TMDL. As I mentioned previously, future growth addresses the requirement to account for future loadings that may occur due to population growth and commensurate changes in community infrastructure and development. It is based on population projections. Again, I wish I had more time to explain how we calculate this load allocation, but unfortunately, I don’t.

TMDL Allocations Final TMDL AU TMDL WLAWWTF WLAPSW LA FG MOS 0666_01 100.0 10.0 16.0 64.0 5.0 Final TMDL 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) This is a table you would typically see in one of our TMDLs, showing an example for Assessment Unit 0666_01 with simple round numbers for a bacteria impairment (Enterococci). Let’s assume our TMDL is an even 100 billion MPN/day….MPN stands for most probably number, which is an estimate of individual bacteria counts or colony forming units. As you can see much of the load allocation typically goes to unregulated sources (LA) and our margin of safety is typically 5% of the TMDL as is also our allocation for future growth. Reallocations of an adopted and approved TMDL are allowed, as long as the TMDL remains intact (i.e., the pieces of the pie can change in size, but the size of the pie must stay the same). New wastewater permits or increased discharge from existing wastewater treatment plants result in shifting allocations from Future Growth to WLAWWTF. Increases in urbanized areas under MS4 permits results in shifting allocations from LA to WLAPSW.

TMDL Implementation Plans (I-Plans) 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 Describe the activities that will be implemented over a specific time period by the stakeholders to improve water quality I want to talk a little about TMDL Implementation Plans also known as I-Plans: They are designed to satisfy the TMDL regulatory requirements for “reasonable assurance” of implementation. An I-plan determines what will be required to manage the loads from all sources, including regulated and unregulated stormwater. They describe the activities that will be implemented over a specific time period by the stakeholders to improve water quality

Management Measures - Examples I-Plans (continued) Management Measures - Examples Structural Oil Well Plugging for Salinity Control Stormwater Retention Basin Retrofits Installation of Pet Waste Stations in Public Areas Nonstructural Pet Waste Ordinances Education (for professionals and the general public) Outreach (PSAs, pamphlets, ect.) Some of those activities might include structural controls, such as… Or nonstructural controls such as…

I-Plans (continued) Developed by stakeholders in the affected watershed with support and guidance from the TCEQ Collaborative effort involving a wide variety of stakeholders in a TMDL watershed Citizens, watershed interest groups State, local, and federal agencies Regulated organizations I-Plans are developed by stakeholders in the affected watershed with support and guidance from the TCEQ. When we talk about stakeholders we are talking about individuals and organizations that: Live in the watershed or use the resource Contribute pollutant loadings or impact water quality in some way Are directly or indirectly effected by water quality problems Have statutory or regulatory responsibilities linked to water quality And/or can help develop or implement actions to improve water quality

I-Plans in Texas Area = 25,892 Mi2 Segments = 198 Stream Miles = 2,412 May 2019 This is a map of Texas showing location of TMDL and I-Plan development and implementation watersheds Area = 25,892 Mi2 Segments = 198 Stream Miles = 2,412 AUs = 413 Not only urban areas but also large portions of rural areas. A significant amount of area in Texas (almost 10%).

Adaptive Management Make Changes Make Changes Develop Plan Implement Plan Implement Plan Evaluate Plan Evaluate Plan I-Plans must be thought of as living documents subject to adaptive management… Language in our TMDL states that an adaptive management approach is used to implement TMDL load allocations. This approach encourages the implementation of structural or non-structural controls, implementation of mechanisms to evaluate the performance of the controls, and finally the allowance to make adjustments as necessary to protect water quality

www.tceq.texas.gov/waterquality/tmdl Our website provides a lot of the general information I’ve presented…

As well as detailed information about our program, including the water bodies we have worked on and are currently working on and…

…detailed information about each of our TMDL projects, including maps, documents and project summaries

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 Here is our web address again, but you can also feel free to contact me anytime for information. I have time to answer a few questions if you all would like to ask me some. Thanks.