TMDLs and How They Are Implemented
Describes what total maximum daily loads (TMDLs) are, how they are developed and implemented, and provides a status report for the Texas TMDL Program
- What the TMDL Program Does
- How TMDLs and Implementation Plans Are Developed
- Status Report for the TMDL Program
- Surface Water Quality: How It Is Measured
- Preserving and Improving Water Quality: Programs of the TCEQ
- For More Information
- Join the TMDL E-Mail News List
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Upper Oyster Creek
Site of a TMDL Project
for Dissolved Oxygen |
What the TMDL Program Does
The Total Maximum Daily Load (TMDL) Program works to improve water quality in impaired or threatened water bodies in Texas.
A TMDL is like a budget for pollution. It defines an environmental target by determining the extent to which a certain pollutant must be reduced. TMDLs are developed for surface waters that are quality-limited due to a pollutant or adverse condition. Based on the environmental target in the TMDL, the state develops an implementation plan to mitigate sources of pollution within the watershed and restore impaired uses.
An implementation plan (IP) usually puts the TMDL into action by outlining the steps necessary to reduce pollutant loads through regulatory and voluntary activities. In some instances, TMDLs are implemented through watershed protection plans (WPPs).
The TMDL program is authorized by and created to fulfill the requirements of Section 303(d) of the federal Clean Water Act and its implementing regulations.
For an overview of the TCEQ's approach to managing the quality of surface waters in Texas, see Preserving and Improving Water Quality.
How TMDLs and Implementation Plans Are Developed
TMDLs are developed by TCEQ personnel, by cooperating state agencies, or by independent contractors working for the TCEQ. Ultimately, the TCEQ is responsible for the development and adoption of all TMDLs in Texas.
The development of TMDLs is a scientifically rigorous process of intensive data collection and analysis. After adoption by the TCEQ, TMDLs are submitted to the U.S. Environmental Protection Agency for review and approval.
What Happens When TMDLs Are Established?
TMDLs and their implementation plans describe the actions that local, regional, and state organizations must take to reduce pollutants to levels established in TMDLs. For example, the TCEQ might impose more stringent wastewater permit limits. This may in turn require wastewater-treatment plants to implement additional or new treatment technology.
Cities may be required to control and treat runoff from their streets. Farmers and ranchers may be asked to use new practices that prevent fertilizers, manure, and pesticides from reaching lakes and rivers.
How Are TMDLs Funded?
The Texas Legislature appropriates funds to the TCEQ and the Texas State Soil and Water Conservation Board to support the development and implementation of TMDLs. Both agencies also use federal money to support the program. Other funding approaches include leveraging existing grants or seeking in-kind services or expertise from stakeholders, government agencies, or academic institutions. Funding for implementation is frequently from local governments or privately-owned facilities that discharge wastewater.
Status Report
Status Report: Implementing TMDLs in Texas, October 2006 (PDF. Help with PDF)
Highlights of the TMDL Program’s activities to restore impaired surface waters in Texas, including environmental results, program management, and summaries of restoration projects being implemented. The report covers the program’s progress through August 2005.
Surface Water Quality: How It Is Measured
For an overview of the TCEQ's approach to defining and managing the quality of surface waters in Texas, see Preserving and Improving Water Quality.
Standards Define Water Quality
To measure water quality, we must first define it. The Texas Surface Water Quality Standards are rules designed to:
- designate the uses, or purposes, for which a water body should be suitable;
- establish numerical and narrative goals for water quality throughout the state; and
- provide a basis on which TCEQ regulatory programs can establish reasonable methods to implement and attain the state’s goals for water quality.
All standards are protective; that is, they signal a possibility that water quality may be inadequate to attain its designated uses.
The Texas Water Quality Inventory and 303(d) List
The Texas Water Quality Inventory and 303(d) List is an overview of the status of surface waters of the state, including concerns for public health, fitness for aquatic species and other wildlife, and specific pollutants and their possible sources. The 303(d) List, a subset of the Inventory, identifies waters that do not attain one or more standards for their use. Water bodies identified in Category 5a of the 303(d) List require TMDLs. Texas assesses more than 700 water bodies.
Read Texas Surface Water Quality: What Is It, and How Is It Measured? (PDF) for a brief overview of water quality standards and the means by which surface water quality is evaluated.
Preserving and Improving Water Quality: Programs of the TCEQ
The publication Preserving and Improving Water Quality provides an overview of the way the TCEQ evaluates the quality of surface waters in Texas, and the programs and practices the TCEQ employs to protect and restore surface water quality. Order printed copies from our Publications section.
For More Information
For more information about the TMDL Program, contact Louanne Jones at 512/239-2310, or send us an e-mail at tmdl@tceq.state.tx.us.
