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Environmental notice: Sheppard storm water outfalls

  • Published
  • By Leeni Vilpas
  • 82nd Civil Engineer Squadron environmental supervisor
Sheppard directs all of its storm water discharges to one of three outfall structures: Outfall 001S, Outfall 002S, and Outfall 003S. These storm water discharges eventually reach the Wichita River via Bear Creek, Plum Creek and other tributaries. The Wichita River flows into the Red River, which is a major tributary of the Mississippi and Atchafalaya Rivers located in the Southern United States. The Atchafalaya River flows eastward or southward and eventually discharges to Gulf of Mexico.

Storm water originates during rainfall. The storm water that does not soak into the ground becomes surface runoff, which either flows directly into surface waterways or is channeled into storm sewers, outfalls, etc. An outfall is the discharge point of a storm water drain into a body of surface water, which may be a river, lake or sea.

Storm water is of concern for two main issues. The volume and timing of runoff water (flooding) can become an issue, as well as the contaminants that the water is carrying, i.e. water pollution. Pollutants can enter the storm drain system in numerous ways. Sometimes a person or company has illegally dumped oil, automotive fluids, or other substances in or near a storm drain. Municipal sanitary sewer lines might be leaking, blocked, or overflow. A private septic system might have failed and leaked effluent into a nearby storm drain. Other times a pipe is illegally connected to the storm drain system. The pollutants resulting from these sources are often intermittent and not present or detectable during dry weather inspections.
Storm water that drains within industrial areas on Sheppard may be exposed to potential contaminated materials. Therefore, the outfalls that are associated with the industrial drainage area require monitoring in accordance with Texas storm water regulations. In addition to storm water outfall monitoring, Sheppard conducts chemical monitoring, biological surveys and evaluation of the physical condition of streams. Together, the data helps identify the streams that are at risk and contributes to creating an informed plan to reduce pollutants and improve water quality.

The Sheppard storm water drains direct all storm water discharges to one of three outfall structures. Outfall 001S is located on the eastern property line, south of runway 33R. This outfall can be described as a concrete culvert system. The outfall is a 30-feet wide concrete ditch. It drains a total surface area of 2,376 acres, of which 641 acres are impervious surfaces. The drainage area consists of the northwest portion of the base including much of the airfield. A variety of industrial activities are conducted within the drainage basin for outfall 001S. These activities cover aircraft maintenance, bulk fuel storage, deicing activities and vehicle maintenance.

Outfall 002S is located on the southeastern Sheppard property line, south of runway 33C. This outfall can be described as a concrete piping structure, where two storm water pipes drain into a pond intersecting the base property line. It drains a total surface area of 875 acres of which 105 acres are impervious surfaces. The drainage area consists of the central and eastern portions of the base covering much of the airfield.

Outfall 003S is located on the southern Sheppard property line, east of the southwestern corner of the base. This outfall can be described as a concrete and natural lined creek which flows through the golf course inside the base perimeter fence. It drains a total surface area of 1,073 acres of which 441 acres are impervious surfaces. The drainage area consists of the southwest and south port ions of the base.

Storm water is a natural resource and ever growing in importance as the world's population demand exceeds the availability of water. Techniques of storm water harvesting with point source water management and purification can potentially make urban environments self-sustaining in terms of water. There are a number of systems that control the flow of storm water on Sheppard base. Working together, we can control the quality of storm water in our outfalls which can play a vital role when making our environment safe.