- Community & Quality of Life
- Sustainable Denton
- Business Watershed Protection
Business Watershed Protection
Watershed Protection is a division within the Environmental Services Department. The Watershed Protection Program was initiated in January 2001 as a part of a plan 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. As a NPDES phase II 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 discharges
- 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
- Mosquito surveillance program
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.
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 included E coli bacteria, metals, phosphorus, nitrogen, ammonia, nitrate, chlorides, sulfates, alkalinity, hardness, total solids and total suspended solids.
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, an instrument 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 public education, public involvement, and illicit discharge detection and elimination components of our program, visit the Residential Watershed Protection page.
- 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.
- To whom do I submit a Notice of Intent (NOI) to discharge?
The NOI is the application for authorization under the Industrial Stormwater Multi-Sector General Permit (MSGP) or Construction Stormwater permits. The NOI is in an interactive PDF document designed to be completed electronically and submitted to the TCEQ. Both the construction and industrial stormwater permits require that a copy of the NOI be sent to the Municipal Separate Storm Sewer System (MS4) which receives discharge from the permitted site. For sites that discharge stormwater to City of Denton, either email a copy to Watershed Protection or mail to:
City of Denton
Attn: Watershed Protection
1100 S Mayhill Road
Denton, TX 76208
- Where can I get a Stormwater Pollution Prevention Plan (SWPPP)?
View a list of SWPPP Preparation and Inspection Services.
This list is not to be considered comprehensive nor an endorsement for any organization. The City of Denton does not guarantee the quality of the work provided by any organization on this list. If you would like to have your organization added to this list of SWPPP preparers and inspectors, please send an email with your contact information to the City of Denton, Watershed Protection division.
- What is a Common Plan of Development?
A construction activity is part of a larger common plan of development if it is completed in one or more of the following ways:
- In separate stages
- In separate phases
- In combination with other construction activities
It is identified by the documentation that identifies the scope of the project including such things as the following:
- Building permits
- Marketing plans
- Public notice or hearing
- Zoning requests
It can include one operator or many operators.
Example: A subdivision is being built. You are grading 0.75 acres, another company is clearing 4 different acres and a contractor is excavating another 0.5 acres. In this case, the total area that would be disturbed is 5.25 acres, so each operator would fall under the requirements associated with disturbing 5 or more acres.
- Why is the control of construction site runoff necessary?
Polluted stormwater runoff from construction sites often flows to MS4s and ultimately is discharged into local rivers and streams. Sediment is usually the main pollutant of concern. Sources of sedimentation include construction, agriculture, urban runoff and forestry. Sediment runoff rates from construction sites, however, are typically 10 to 20 times greater than those of agricultural lands and 1,000 to 2,000 times greater than those of forested lands. During a short period of time, construction sites can contribute more sediment to streams than can be deposited naturally during several decades. The resulting siltation and the contribution of other pollutants from construction sites can cause physical, chemical and biological harm to our nation's waters. For example, excess sediment can quickly fill rivers and lakes, requiring dredging and destroying aquatic habitats.
Construction stormwater runoff is covered under regulations of the Clean Water Act. In Texas, the Texas Commission on Environmental Quality (TCEQ) has primacy and issues Construction Stormwater General Permits, also called TXR150000 permits. Sites which disturb one acre or more and sites which are a common plan of development that disturbs more than one acre, are required to complete a Stormwater Pollution Prevention Plan (SWPPP), post a TCEQ construction site notice that is publicly visible and provide a copy of the construction site notice to the MS4. Construction sites which are five acres or greater (or part of a common plan of development greater than five acres) are additionally required to complete a Notice of Intent (NOI) and provide a copy to the MS4 to which they discharge. All construction sites within the City of Denton must comply with the Land Disturbing Activities section of Denton Development Code, DDC Section 35.18 and the Drainage Criteria Manual.
- Why is the control of post-construction runoff necessary?
Post-construction stormwater management in areas undergoing new development or redevelopment is necessary because runoff from these areas has been shown to significantly affect receiving water bodies. Many studies indicate that prior planning and design for the minimization of pollutants in post-construction stormwater discharges is the most cost-effective approach to stormwater quality management.
There are generally two forms of substantial impacts of post-construction runoff. The first is caused by an increase in the type and quantity of pollutants in stormwater runoff. As runoff flows over areas altered by development, it picks up harmful sediment and chemicals such as oil and grease, pesticides, heavy metals and nutrients (e.g., nitrogen and phosphorus). These pollutants often become suspended in runoff and are carried to receiving waters, such as lakes, ponds and streams. Once deposited, these pollutants can enter the food chain through small aquatic life, eventually entering the tissues of fish and humans. The second kind of post-construction runoff impact occurs by increasing the quantity of water delivered to the water body during storms. Increased impervious surfaces (e.g., parking lots, driveways and rooftops) interrupt the natural cycle of gradual percolation of water and soil and into groundwater systems. Instead, water is collected from surfaces such as asphalt and concrete and routed to drainage systems where large volumes of runoff quickly flow to the nearest receiving water. The effects of this process include streambank scouring and downstream flooding, which often lead to a loss of aquatic life and damage to property.
- What types of BMPs can address the post construction runoff minimum measure?
- Planning Procedures: Runoff problems can be addressed efficiently with sound planning procedures. Local master plans, comprehensive plans and zoning ordinances can promote improved water quality in many ways, such as guiding the growth of a community away from sensitive areas to areas that can support it without compromising water quality.
- Site-Based BMPs: These BMPs can include buffer strip and riparian zone preservation, minimization of disturbance and imperviousness and maximization of open space.
- Stormwater Retention/Detention BMPs: Retention or detention BMPs control stormwater by gathering runoff in wet ponds, dry basins, or multi-chamber catch basins and slowly releasing it to receiving waters or drainage systems. These practices can be designed to both control stormwater volume and settle out particulates for pollutant removal.
- Infiltration BMPs: Infiltration BMPs are designed to facilitate the percolation of runoff through the soil to ground water and, thereby, result in reduced stormwater runoff quantity and reduced mobilization of pollutants. Examples include infiltration basins/trenches, dry wells and porous pavement.
- Vegetative BMPs: Vegetative BMPs are landscaping features that, with optimal design and good soil conditions, remove pollutants and facilitate percolation of runoff, thereby maintaining natural site hydrology, promoting healthier habitats and increasing aesthetic appeal. Examples include grassy swales, filter strips, artificial wetlands and rain gardens.
- Where can I find out more about Environmentally Sensitive Areas (ESA)?
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 ESA page.
- Why do I need an Industrial Stormwater Permit?
Through the Texas Pollutant Discharge Elimination System (TPDES) program, the Texas Commission on Environmental Quality (TCEQ) has established requirements to control stormwater discharges that could harm the quality of waterways (flowing or dry) in the U.S. These regulations require many types of businesses to obtain permits to discharge stormwater and to prepare a written Stormwater Pollution Prevention Plan (SWPPP), in order to address the necessary management of stormwater run-off.
Stormwater means precipitation runoff, surface water runoff or surface water drainage.
The purpose of an Industrial Stormwater Permit is to ensure that industrial facilities properly monitor and control stormwater to minimize its impact upon the environment.
Facilities mean any operation that engage in activities that are directly related to manufacturing, processing, or raw materials storage at a commercial or industrial site.
Industrial facilities that do not monitor and control stormwater run-off may allow pollutants to be transported off site. These contaminants may ultimately flow into streams, rivers, washes and other water resources.
- How do I determine whether or not I need an Industrial Stormwater Permit?
Industrial stormwater refers to water runoff related to certain business activities identified in the stormwater regulations of the Clean Water Act. The permits related to these types of activities are known as Multi-Sector General Permits. Some businesses in Denton are required to have these permits, use the decision tree and the questions and answers section to determine if your business needs a permit.
Determine whether your facility or site discharges to a municipal separate storm sewer system (MS4) or to waters of the U.S.
If your facility discharges to one or both go to Step 2, otherwise no stormwater permit is needed.
What is a Municipal Separate Storm Sewer System (MS4)?
A MS4 is a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains):
- Owned or operated by a state, city, county, district, or other public body, including special districts under state law such as a sewer district, flood control district or drainage district that discharges into waters of the U.S.
- Designed or used for collecting/conveying stormwater
- Which is not a combined sewer
- Which is not part of a publicly-owned treatment works
Industrial operators may ask their municipal government whether their facility discharges into an MS4 or into a sanitary sewer, which is not covered by the stormwater regulations.
Surface water in the state of Texas includes lakes, bays, ponds, impounding, reservoirs, springs, rivers, streams, creeks, estuaries, marshes, inlets, canals, the Gulf of Mexico inside the territorial limits of the state, and all other bodies of surface water, natural or artificial, inland or coastal, fresh or salt, navigable or non-navigable, and including the beds and banks of all watercourses and bodies of surface water, that are wholly or partially inside or bordering the state or inside the jurisdiction of the state (Section 26.001 of the Texas Water Code).
Determine if your facility's industrial activities fall within one of the eleven Categories of Industrial Activities. If your activities are listed, go to Step 3, otherwise no permit is needed. Industrial stormwater permits are required for specific types of activities. Some categories are defined by a Standard Industrial Classification (SIC) code and others are defined by a narrative description. If any of the following categories apply to your business, you may be required to obtain permit coverage.
Which industries are regulated?
- 40 CFR Subchapter N Industries: facilities subject to stormwater effluent limitations guidelines
- Heavy Industry: SIC 24 (except 2434), 26, (except 265 and 267), 28 (except 283), 311, 32 (except 323), 33, 3441, and 373 3) Mineral Industry: SIC 10, 12, 13, and 14
- Hazardous Waste Industry: hazardous waste treatment, storage, or disposal facilities
- Landfill Industry: industrial waste landfills, land application sites, and open dumps
- Recycling Industry: metal scrap yards, battery reclaimers, salvage yards, automobile junkyards, and SIC 5015 and 5093
- Power Generation Industry: steam electric power, including coal handling sites
- Transportation Industry: SIC 40, 41, 42 (except 4221- 4225), 43, 44, 45, 5171 that have vehicle maintenance shops, equipment cleaning operations, or airport deicing operations
- Wastewater (Municipal or Domestic Sewage) Treatment Industry
- Construction Industry: activities including clearing, grading, and excavation (NOTE: TCEQ has a separate permit for Construction Activities)
- Light Industry: SIC 20, 21, 22, 23, 2434, 25, 265, 267, 27, 283, 285, 30, 31 (except 311), 323, 34 (except 3441), 35, 36, 37 (except 373), 38, 39, 4221, 4222, and 4225
Determine if the listed facility or site may qualify for an exemption under the conditional no exposure exclusion and/or the ISTEA exemption. Facilities that can certify to having a condition of no exposure may be exempted from permit requirements upon completing and submitting a No Exposure Certification Form. If the facility cannot certify that a condition of exposure exists, then the facility must obtain coverage under and comply with, a stormwater permit.
No exposure means all industrial materials and activities are protected by a storm resistant shelter to prevent exposure to rain, snow, snowmelt and/or run-off. Industrial materials or activities include, but are not limited to, material handling equipment or activities, industrial machinery, raw materials, intermediate products, byproducts, final products, or waste products.
- How do I obtain an Industrial Stormwater Permit?
To obtain coverage under a Stormwater Discharge Permit for Industrial Activities, an owner or operator of a facility must fill out a Notice of Intent (NOI) with the TCEQ. Compliance with the provisions of a permit include preparation and implementation of a Stormwater Pollution Prevention Plan (SWPPP). A SWPPP must describe the site characteristics and list the pollutants that could impact stormwater quality. The plan must also identify appropriate stormwater control measures that will minimize pollutant loading in stormwater discharges. These measures are often referred to as best management practices (BMPs). Examples of BMPs include structural controls, spill response and prevention and yard maintenance.
- What are the consequences for failing to comply?
Owners or operators who fail to notify the permitting authority of their intent to be covered under a permit and who discharge stormwater associated with industrial or construction activities to waters of the state, waters of the U.S., or to a separate storm sewer system without an individual or group permit, will be in violation of the Texas Administrative Code and the Clean Water Act and may be subject to legal action.
- What is a Phase 2 Small 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, construction sites larger than five acres and certain industrial sectors.
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 Municipal Separate Storm Sewer Systems (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.
Stormwater discharges from MS4s in urbanized areas are a concern because of the high concentration of pollutants found in these discharges. Concentrated development in urbanized areas substantially increase impervious surfaces, such as city streets, driveways, parking lots and sidewalks, on which pollutants from concentrated human activities settle and remain until a storm event washes them into nearby storm drains. Common pollutants include pesticides, fertilizers, oils, salt, litter and other debris and sediment. Another concern is the possible illicit connections of sanitary sewers, which can result in fecal coliform bacteria entering the storm sewer system. Stormwater runoff picks up and transports these and other harmful pollutants then discharges them untreated to waterways via storm sewer systems. When left uncontrolled, these discharges can result in fish kills, the destruction of spawning and wildlife habitats, a loss in aesthetic value and contamination of drinking water supplies and recreational waterways that can threaten public health.
Polluted storm water runoff is often transported to MS4s and ultimately discharged into local rivers and streams without treatment. EPA's Stormwater Phase 2 Rule establishes a MS4 stormwater management program that is intended to improve the Nation's waterways by reducing the quantity of pollutants that stormwater picks up and carries into storm sewer systems during storm events. Common pollutants include oil and grease from roadways, pesticides from lawns, sediment from construction sites and carelessly discarded trash, such as cigarette butts, paper wrappers and plastic bottles. When deposited into nearby waterways through MS4 discharges, these pollutants can impair the waterways, thereby discouraging recreational use of the resource, contaminating drinking water supplies and interfering with the habitat for fish, other aquatic organisms and wildlife.
- 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 illicit discharge detection and elimination, municipal good housekeeping, public education and public involvement programs can be found on our Residential Watershed webpage.
- What is the Hickory Creek Watershed Protection Plan (WPP)?
Hickory Creek watershed is located within Denton County, with a substantial portion of the watershed located within the corporate limits of the City of Denton. In general, the Hickory Creek watershed extends westward from I-35E as the highway passes through the City of Denton and drains into Lewisville Lake directly upstream from the City of Denton's drinking water intake structure. The watershed of Hickory Creek is mainly rural, containing large amounts of open space and bottomland hardwood forests. The mainly undeveloped characteristics of the Hickory Creek watershed serve to enhance water quality, since surface water runoff in many areas of the watershed passes through substantial amounts of vegetated buffers. However, development pressures continue to cause alterations in land surfaces within Hickory Creek, resulting in a reduction in the ability of this watershed to assimilate pollutants.
Although Lewisville Lake is not currently on the Texas Commission on Environmental Quality (TCEQ) list of water quality impaired waters, there are significant water quality concerns for the lake. The Lewisville Lake watershed, for example, has one of the highest application rates in the State for new or amended wastewater permits. Development is increasing within the Hickory Creek watershed, creating increases in runoff volumes and reductions in open space. Past monitoring efforts by the TCEQ have resulted in Hickory Creek being listed as a "nutrient enrichment concern" due to high ammonia concentrations. The sources of ammonia are currently not well understood within this watershed and are generally listed as "originating from unknown point and non-point sources." Watershed monitoring and modeling efforts indicate that the current approaches to managing non-point source pollution in Hickory Creek are not sufficient. New tools are needed to stimulate best management practices development and reverse declining water quality trends.
Lewisville Lake Watershed area in 1990 and in 2000. Note the increase in developed area west and east of the main branch of the lake.
Hickory Creek Watershed Protection Plan Overview
The TCEQ asked the project team to develop a Watershed Protection Plan (WPP) for Hickory Creek in conjunction with the 319 grant and to include the nine USEPA WWP elements within this plan. These elements are:
- Identify the causes and sources of pollutants.
- Estimate load reductions.
- Describe the non-point source management measures that will need to be implemented.
- Estimate the amounts of technical and financial assistance needed.
- Describe the information / education component.
- Estimate a schedule for implementing the non-point source management measures.
- Describe the interim, measurable milestones.
- Develop a set of criteria that can be used to determine whether loading reductions are being achieved.
- Describe the monitoring component.
- What are stormwater requirements for gas wells?
Requirements for gas well development can be found in Denton Development Code subchapter 6. New gas wells are required to provide an Erosion and Sediment Control Plan for review as part of the review process. See Gas Well Erosion and Sediment Control Plan guidance document.