Lake Travis Nonpoint Source Pollution
The Lake Travis Nonpoint Source Pollution Control Ordinance was developed by the Lower Colorado River Authority (LCRA) to protect water quality in a critical drinking water supply reservoir for the Austin, Texas, metropolitan area. The ordinance establishes a performance-based regulatory framework for managing stormwater runoff and nonpoint source (NPS) pollution from new development and redevelopment activities within the Lake Travis watershed. As a regional authority, the LCRA’s jurisdiction for this ordinance extends across municipal boundaries within Travis County, making it a valuable example of watershed-scale source water protection.
The ordinance’s primary mechanism is a permitting system that requires developers to implement Best Management Practices (BMPs) designed to meet specific, quantitative pollutant removal goals. Unlike purely prescriptive ordinances that mandate certain types of BMPs, this performance-based approach provides design flexibility while holding projects accountable to clear water quality outcomes. The standards are tiered, imposing more stringent requirements on sites with steeper slopes or in close proximity to the lake, directing the highest level of protection to the most sensitive areas.
Key Provisions
Applicability and Exemptions
The ordinance applies to all land modification and development activities within the designated jurisdictional area of the Lake Travis watershed in Travis County. This includes construction of buildings, roads, parking lots, and other impervious surfaces, as well as land-disturbing activities like clearing, grading, and filling.
Certain activities do not require a formal permit, provided that temporary erosion controls are used during construction. These include:
- Construction of a single-family residence.
- Redevelopment that does not cumulatively add 5,000 square feet or more of impervious cover.
- Projects undertaken by a county or political subdivision that has an interlocal agreement with the LCRA ensuring compliance with the ordinance’s standards.
The ordinance provides full exemptions for agricultural activities as defined in the ordinance and for municipalities that have adopted an equivalent or more stringent local water quality ordinance.
Permitting
For activities not exempt or authorized without a permit, the ordinance establishes several permit types:
- Type I NPS Development Permit: The standard permit for most development activities, including subdivisions with new roads.
- Type II Utility Permit: A general permit for public utilities covering routine construction, maintenance, and repair work across the jurisdictional area, avoiding the need for individual project permits.
- Type III Standard Dredge and Fill Permit: For dredge and fill activities that fall under the U.S. Army Corps of Engineers’ Nationwide Permit program.
- Type IV Shoreline Development Permit: For all other dredge and fill activities not covered by a Type III permit.
For large projects developed in stages (over 250 acres), the ordinance requires the submission and approval of a Master Plan before any individual phase permits are issued. This ensures that the overall project design meets the ordinance’s performance standards on a cumulative basis.
Performance Standards
The core of the ordinance is a set of numeric performance standards for pollutant removal from post-development stormwater runoff. Permitted projects must implement BMPs designed to remove a target percentage of the increased annual pollutant load for Total Suspended Solids (TSS), Total Phosphorus (TP), and Oil and Grease. The required removal efficiency varies based on site slope and proximity to the lake, with higher standards for steeper slopes and for land within a 500-foot shoreline zone, measured from the 691-foot mean sea level (msl) contour.
| Pollutant | Site Slope | General Area Requirement | Shoreline Zone Requirement (<500 ft from 691′ msl) |
|---|---|---|---|
| Total Suspended Solids (TSS) | 0% – 10% | 70% | 75% |
| >10% – 20% | 80% | 90% | |
| >20% | 90% | ||
| Total Phosphorus (TP) | 0% – 10% | 70% | 75% |
| >10% – 20% | 75% | 85% | |
| >20% | 85% | ||
| Oil & Grease* | 0% – 10% | 70% | 75% |
| >10% – 20% | 75% | 85% | |
| >20% | 85% | ||
| *Oil & Grease standards do not apply to single-family residences. | |||
Other Requirements
In addition to the pollutant removal standards, the ordinance includes several other key requirements:
- Streambank Erosion: Drainage systems must be designed so that the post-development peak discharge rate for the 1-year design storm does not exceed the pre-development rate, preventing increased erosion in receiving streams.
- Erosion and Sedimentation Control: All development must implement and maintain temporary erosion and sediment controls throughout the construction process, in accordance with the associated Technical Manual.
- Alternative for Low-Density Subdivisions: Single-family subdivisions can be exempted from the numeric pollutant removal standards if they meet two criteria: a minimum lot size of one acre, and a street and drainage design that uses overland flow and vegetated buffers instead of curbs and gutters.
- Sub-basin Averaging: The ordinance allows for averaging compliance across a project site, provided that standards are fully met in areas draining to adjacent properties or sensitive areas, and no single discharge point falls more than 10% below the standard.
Selected Provisions, Annotated
Development of single-family subdivisions that meets all of the following criteria need not comply with subsections (a) and (b) of this Section: 1. Minimum lot size of one acre; and 2. Street and drainage network is designed without curbs or gutters…so that runoff is treated using over-land flow methods to a vegetated buffer.
Lake Travis NPS Pollution Control Ordinance, Section 5.D
This provision creates a powerful incentive for low-impact development design. By offering a streamlined compliance path for subdivisions that preserve open space and use natural drainage techniques, the ordinance encourages site designs that generate less runoff and pollution from the outset.
It is the intent of the Ordinance to have a project, as a whole, meet the performance standards… As such, averaging of performance standards between sub-basins is allowed under the following conditions: 1. Performance standards shall be met or exceeded where drainage impacts an adjacent land owner or environmentally sensitive area.
Lake Travis NPS Pollution Control Ordinance, Section 5.E
This section on sub-basin averaging provides critical design flexibility. It allows an engineer to over-treat runoff in one part of a site to compensate for an area where meeting the standard is more difficult, as long as sensitive receiving areas and neighboring properties are fully protected. This pragmatism can reduce costs without compromising the project’s overall water quality performance.
All development located within 500 feet of the 691 msl contour line…and on slopes over ten percent (10%), must have ninety percent (90%) of the total suspended solids removed after development is complete.
Lake Travis NPS Pollution Control Ordinance, Section 5.B.1
This clause exemplifies the ordinance’s risk-based approach. It establishes a shoreline protection zone and combines it with a slope criterion to trigger the most stringent performance standard (90% TSS removal). This focuses the greatest regulatory and engineering effort on the land areas that pose the highest risk to the reservoir’s water quality.
What Makes It a Useful Model
The Lake Travis ordinance is a strong model for communities seeking to protect sensitive water bodies through a robust stormwater management program. Its primary strength lies in its use of clear, quantitative performance standards. This approach defines the required environmental outcome—a specific percentage of pollutant removal—and gives designers the freedom to select the most cost-effective BMPs from a design manual or propose innovative solutions to achieve that goal.
The ordinance’s structure is also notable for its adaptability. The tiered standards, which increase in stringency based on slope and proximity to the water, provide a logical framework for applying a higher level of protection where it is most warranted. Furthermore, its application at a watershed scale by a regional authority, rather than by individual towns, represents an effective governance model for managing water resources that cross political boundaries. The inclusion of exemptions for low-impact design and streamlined permitting for utilities adds a layer of practicality that can improve implementation and buy-in.
Adaptation Checklist for Municipalities
A local government adapting this ordinance should review and customize several key elements to fit local conditions, regulations, and water quality goals:
- Define Jurisdictional Area: Clearly map the specific watershed or management district boundaries where the ordinance will apply.
- Designate an Authority: Identify the specific municipal department (e.g., Public Works, Planning, Environmental Services) responsible for permit review, issuance, and compliance. Replace all references to “LCRA” with this entity.
- Calibrate Performance Standards: Review the pollutant removal percentages. Adjust them based on local water quality impairments, TMDL requirements, or specific pollutants of concern in the target watershed.
- Set Local Thresholds: Evaluate the slope categories (10%, 20%) and the shoreline zone width (500 feet) and adjust them to reflect local topography and land use patterns. Define the reference water elevation contour for the specific lake, reservoir, or river being protected.
- Adopt a Technical Manual: Develop or formally adopt a local or state stormwater design manual to provide technical guidance on calculating pollutant loads and designing approved BMPs.
- Establish Permit Fees: Create a fee schedule for application, review, and inspection services to ensure the program is adequately funded.
- Incorporate Enforcement Provisions: Add specific sections detailing inspection authority, notice of violation procedures, stop-work order authority, and a schedule of civil penalties for non-compliance.
- Integrate with Existing Codes: Ensure the permit process aligns with existing subdivision, zoning, and site plan review procedures to create a seamless workflow for applicants.
- Review Definitions: Modify definitions as needed to be consistent with state law and other local ordinances.
- Establish Interlocal Agreements: Develop standard agreement language for partnerships with neighboring jurisdictions, counties, or utility districts operating within the watershed.