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1. What is a watershed?

A watershed is the area of land that catches rain and snow and drains or seeps into a marsh, stream, river, lake or groundwater, and eventually even to the ocean. Watersheds can range from acres to hundred or even thousands of square miles. Some watersheds extend across county, state, and even international borders. Just as creeks drain into rivers, watersheds are nearly always part of a larger watershed.

2. Why is watershed protection important?

Surface and groundwater resources are tied directly to all watersheds. Anything that can be picked up with rainfall runoff or any other drainage can end up in the watershed. This includes trash and pollutants that can upset the ecosystem and threaten our resources for water supply and recreation.

3. How do I report a spill or discharge impacting a waterway?

Use Engage Denton to report a spill or illegal dumping.

If material spilled or dumped appears hazardous or is on fire, call 911.

4. Where should I drain the water from my pool?

• Into your landscape for irrigation. Pools may be discharged onto your property if the water does not run off into streets or cause stagnant water.
• Into the sanitary sewer system via your home’s sewer clean-out. The sewer clean-out is usually a threaded cap about three to four inches in diameter.
• After approval by the Watershed Protection Department, into the storm drain system. Watershed Protection can be reached at (940) 349-7153 or (940) 349-7141 or send an email to [email protected].

To obtain permission, pool water will have to meet the following criteria:

• Discontinue use of pool chemicals at least three days prior to discharge
• Dechlorinate water to non-detectable level of chlorine (< 0.1 mg/L)
• Clean any vegetation and debris from pool
• Monitor discharge rate to prevent erosion
• Freshwater pool water only (saltwater pools cannot be discharged to the storm drain)

5. Where can I discharge pool filter backwash water?

Swimming pool filter backwash should be discharged to the sanitary sewer. Though low in volume, it has a higher concentration of contaminants compared to pool water.

Denton City Code of Ordinances Ch. 26-189 prohibits discharge of pollutants to storm sewer or natural outlet except where suitable treatment has been provided or where a Federal National Pollution Discharge Elimination Systems (NPDES) permit is issued. Fines for violating section 26-189 of the City Code could equal up to $2,000 per violation, per day.

6. Where can I find out more about Environmentally Sensitive Areas?

The City of Denton's Development Code protects riparian stream buffers, Cross Timber upland habitat, water related habitats and undeveloped floodplains. Information can be found on the Environmentally Sensitive Areas page.

7. What is a Stormwater Management Plan?

The City of Denton has developed a Stormwater Management Plan (SWMP) as required by TXR040000. The SWMP outlines the goals, strategies and programs formulated to improve water quality, address existing and future conflicts between flooding and development, and preserve and enhance valuable natural resources. The recommendations will directly affect the City's capital improvement and operating programs. It describes the City's responsibilities and authority regarding stormwater management implementation, and provides detailed descriptions of stormwater management best management practices.

8. What Is a Phase 2 Small Municipal Separate Storm Sewer Systems (MS4)?

Phase 1 of the U.S. Environmental Protection Agency's (EPA) stormwater program was promulgated in 1990 under the Clean Water Act (CWA). Phase 1 relies on National Pollutant Discharge Elimination System (NPDES) permit coverage to address stormwater runoff from incorporated places with a population of 100,000 or greater on the 1990 U.S. census and construction sites larger than five acres.

The Stormwater Phase 2 Final Rule is the next step in EPA's effort to preserve, protect, and improve the nation's water resources from polluted stormwater runoff. The Phase 2 program expands the Phase 1 program by requiring additional operators of MS4s in urbanized areas and operators of small construction sites, through the use of NPDES permits, to implement programs and practices to control polluted stormwater runoff. Phase 2 is intended to further reduce adverse impacts to water quality and aquatic habitat by instituting the use of controls on the unregulated sources of stormwater discharges that have the greatest likelihood of causing continued environmental degradation.

9. What Are the Phase 2 Small MS4 Program requirements?

Operators of regulated small MS4s are required to design their programs to:

• Reduce the discharge of pollutants to the Maximum Extent Practicable (MEP)
• Protect water quality
• Satisfy the appropriate water quality requirements of the Clean Water Act

Implementation will typically require the development and implementation of Best Management Practices and the achievement of measurable goals to satisfy each of the six minimum control measures.

1. Public Education, Outreach, and Involvement
2. Illicit Discharge Detection and Elimination
3. Construction Site Stormwater Runoff Control
4. Post-Construction Stormwater Management in New Development and Redevelopment
5. Pollution Prevention/Good Housekeeping for Municipal Operations
6. Industrial Stormwater Sources (if serves population more than 100,000)

Additional information on our construction site stormwater and industrial site stormwater programs can be found on our Business Watershed Protection webpage.

10. What is an illicit discharge?

Federal regulations define an illicit discharge as "...any discharge to an MS4 that is not composed entirely of stormwater..." with some exceptions. These exceptions include discharges from groundwater, NPDES-permitted industrial sources, fire-fighting activities, water line flushing and air conditioner condensate. Illicit discharges are considered "illicit" because MS4s are not designed to accept, process, or discharge such non-stormwater wastes.

Common sources of illicit discharges:

• Sanitary Wastewater
• Effluent from septic tanks
• Car wash wastewaters
• Improper Oil disposal
• Radiator flushing disposal
• Laundry wastewaters
• Swimming pool filter backwash and pool discharges
• Spills from roadway accidents
• Improper disposal of auto and home toxic chemicals

Illicit discharges often enter the system through storm drain inlets. The result is untreated discharges that contribute high levels of pollutants, including heavy metals, toxics, oil and grease, solvents, nutrients, viruses, and bacteria to receiving waterbodies. Pollutant levels from these illicit discharges have been shown in EPA studies to be high enough to significantly degrade receiving water quality and threaten aquatic, wildlife, and human health.

11. What is required of an illicit discharge detection and elimination program?

Recognizing the adverse effects illicit discharges can have on receiving waters, the Phase 2 rule requires an operator of a regulated small MS4 to develop, implement, and enforce an illicit discharge detection and elimination program. This program must include the following:

• A storm sewer system map, showing the location of all outfalls and the names and location of all waters of the United States that receive discharges from those outfalls.
• Through an ordinance, or other regulatory mechanism, a prohibition (to the extent allowable under State, Tribal, or local law) on non-stormwater discharges into the MS4, and appropriate enforcement procedures and actions.
• A plan to detect and address non-stormwater discharges, including illegal dumping, into the MS4.
• The education of public employees, businesses, and the general public about the hazards associated with illegal discharges and improper disposal of waste.
• The determination of appropriate best management practices (BMPs) and measurable goals for this minimum control measure.

12. What is Municipal Good Housekeeping?

Municipal Good Housekeeping for municipal operations minimum control measure is a key element of the small MS4 stormwater management program. This measure requires the small MS4 operator to examine and subsequently alter their own actions to help ensure a reduction in the amount and type of pollution that both: 

• Collects on streets, parking lots, open spaces, and storage and vehicle maintenance areas and is discharged into local waterways
• Results from actions such as environmentally damaging land development and flood management practices or poor maintenance of storm sewer systems

13. What is required of Municipal Good Housekeeping?

• Recognizing the benefits of pollution prevention practices, the rule requires an operator of a regulated small MS4 to develop and implement an operation and maintenance program with the ultimate goal of preventing or reducing pollutant runoff from municipal operations into the storm sewer system.
• Include employee training on how to incorporate pollution prevention/good housekeeping techniques into municipal operations such as park and open space maintenance, fleet and building maintenance, new construction and land disturbances, and stormwater system maintenance.
• Determine the appropriate best management practices and measurable goals for this minimum control measure.

14. What is Integrated Stormwater Management (ISWM)?

As development increases in urban areas, natural landscapes are altered. Grasslands and forests are removed along with their natural abilities to stabilize the existing landscape. Natural features are replaced with impervious surfaces such as concrete and asphalt. The ability for stormwater to naturally soak into the ground is then reduced and the increased quantity of stormwater runoff can contribute to flooding and can transport urban pollutants such as fertilizers, pesticides, oils, animal wastes and trash to our streams and rivers. These bodies of water serve as sources of our drinking water, so it is very important to be proactive and protect them from the impacts of urbanization.

In 2002, the North Central Texas Council of Governments, a voluntary association of more than 60 local governments in the North Central Texas region, developed ISWM Program. The ISWM program is a cooperative initiative that assists cities and counties in the North Central Texas region in achieving their goals of protecting local water resources.

The ISWM Program is designed to 1) encourage environmentally sustainable development and design for the long term and 2) address the impacts of urbanization during the temporary construction phase.

Primary Focuses

The ISWM Program for Development consists of three primary focus areas using the principles of Green Infrastructure and Low Impact Development to protect, restore, or mimic the natural water cycle. The first area of focus deals with protecting water quality.

The goal of this measure is to simply remove pollutants in stormwater. This can be achieved through either:

• The preservation of natural features that can effectively filter out pollutants
• The construction of features onsite which can treat pollutants
• The implementation of measures downstream that can mitigate pollution

The second area of focus is designed to protect streambanks from the increase in water velocity that causes erosion. This can be achieved through either:

• Downstream reinforcement or stabilization
• Installation of onsite stormwater controls
• The controlled release of excessive amount of stormwater

The third area of focus addresses flood mitigation and the transport of floodwaters to minimalize local flooding. This can be achieved through either:

• Providing adequate downstream systems to safely convey floodwaters
• Installing onsite stormwater controls
• Simply maintaining existing conditions onsite

Best Management Practices

The ISWM Program for Construction addresses stormwater runoff while construction is in process. Temporary controls that are used to do this are called Best Management Practices (BMPs). These measures are designed to:

• Proactively prevent soil erosion on-site
• Capture sediment on-site when erosion prevention is not feasible
• Prevent construction materials and wastes from contaminating stormwater

The City of Denton has been recognized as a regional leader in the efforts to protect our water resources. Currently, the City of Denton is recognized as a Silver Level Participant in the ISWM Program and is committed to improving quality of life and protecting the environment while creating economic opportunities for its citizens, businesses and institutions. The City of Denton also has adopted ISWM as part of the Stormwater Design Criteria Manual (PDF).

Benefits of ISWM

• Keeps safe from the effects of flooding
• Protects property values by reducing the effects of streambank erosion,
• Improves water quality
• Helps local governments address issues of water resources protection and compliance with state and federal regulations

Currently, more than 60 local governments are participating in the ISWM program in order to proactively mitigate the effects of urban development in the region. Find more on the ISWM website.