Residential Watershed Protection

Areas of Concern for Watershed Protection

Non-point source pollution is water pollution that originates from surprisingly common sources such as our homes, yards, cars and even our pets. It is generated by a variety of everyday activities and is Denton's leading cause of water quality degradation. What may initially appear as harmless behaviors such as fertilizing, mowing, taking out the trash and walking the dog can clog or pollute a storm drain which drains to Lewisville Lake, a primary source of drinking water for much of the DFW Metroplex.

Importance of Watershed Protection

The Watershed Protection division administers programs to reduce the overall pollutants within the surface waters of Denton and to ensure compliance with the National Pollution Discharge Elimination System (NPDES) Storm Water Phase II rule. In Texas, the Texas Commission of Environmental Quality (TCEQ) administers the Texas Pollution Discharge Elimination System (TPDES). As a TPDES phase 2 City, Denton operates and maintains a 'municipal separate storm sewer system' or MS4 for residents and businesses within the City of Denton.

Watershed Protection Services

Detecting and eliminating illicit discharge

Construction stormwater inspections
Public education, outreach and involvement
Review of Stormwater Pollution Prevention Plans (SWPPPs) and erosion control plans
Ensuring regulatory compliance with TPDES
Environmentally Sensitive Area assessments
Coordination of volunteer citizen scientists
Industrial stormwater inspections
Municipal good housekeeping

Through routine monitoring, baseline conditions for the physical, chemical, and biological components of the city's surface water resources are established and monitored. Results from this monitoring program are used to support the requirements of the Phase II storm water program and assess water quality for the purposes of source water protection.

Main Denton Watersheds

Cooper Creek, Hickory Creek, Pecan Creek and Clear Creek are the four main watersheds that convey water through Denton. Using topographical information, approximately 85 sub-basins have been delineated within the city. Sampling stations were established within these sub-basins at locations that would likely represent the water quality of the sub-basins. Monitoring of these sub-basins during base-flow conditions was initiated in January 2001 and has continued on a monthly basis ever since. Parameters analyzed in the tributary samples include flow status, temperature, dissolved oxygen, pH, conductivity, turbidity, salinity, litter index, visual evaluation and odor. Bimonthly, ten sampling stations are randomly selected for more intense analysis which includes E coli bacteria, metals, phosphorus, nitrogen, ammonia, nitrate, chlorides, sulfates, alkalinity, hardness, total solids and total suspended solids.

Watershed Monitoring

Permanent monitoring stations are established near the downstream ends of the three major watersheds (Hickory, Pecan and Cooper Creeks) prior to the confluences with Lewisville Lake and an additional station is established in Lewisville Lake near the drinking water intake. Real time monitoring is conducted at these locations by datasondes, instruments with multiple sensors. These stations provide a more comprehensive assessment of the combined effects of sub-basin water quality just prior to entering the City's main drinking water source as well as near our primary drinking water intake on Lewisville Lake.

The data from the stream monitoring program are analyzed with the following objectives:

Characterize the general water quality condition of the stream
Identify illicit discharges
Identify long-term water quality trends

To learn more about the construction and industrial components of our program, visit the Business Watershed Protection page.

Frequently Asked Questions

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.

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.

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.

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)

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.

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.

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.

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.

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.

Public Education, Outreach, and Involvement
Illicit Discharge Detection and Elimination
Construction Site Stormwater Runoff Control
Post-Construction Stormwater Management in New Development and Redevelopment
Pollution Prevention/Good Housekeeping for Municipal Operations
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.

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.

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.

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

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Residential Watershed Protection

Areas of Concern for Watershed Protection

Importance of Watershed Protection

Watershed Protection Services

Main Denton Watersheds

Watershed Monitoring

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Frequently Asked Questions

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