DRAINAGE MAINTENANCE
FREQUENTLY ASKED QUESTIONS
Q: Why isn’t the City of Abilene widening or deepening the creeks in Abilene?
A: Federal regulations prohibit the widening or deepening of a creek that is identified as a “water of the United States”, which all the creeks in Abilene are labeled. However, removal of sediment that has accumulated within the creeks may be removed as long as the original grade of the creek bed is maintained. Additionally, federal regulations prohibit the use of steel tracked vehicles and bladed vehicles (such as motor graders and bulldozers) within the boundaries of the creek. Therefore the City of Abilene is limited to the changes that can be made to the creeks.
Q: What are "Best Management Practices" (BMP)?
A: Best Management Practices are the techniques (buffers, silt fences, detention ponds, swales, etc.), schedule of activities, prohibitions of practices and maintenance procedures to prevent or reduce the discharge of pollutants.
Q: What is a detention pond?
A: A detention pond is an engineered drainage structure designed to temporarily hold a set amount of water while slowly draining to another location. They a best management practice installed for flood control when large amounts of rain could cause flash flooding if not dealt with properly. Additionally, detention ponds act as a trap where pollutants picked up by the initial surge of storm water settle out before leaving the detention pond.
When an area is paved, or covered with a building, water runs off the property much faster than when it is in a natural state. The total amount of discharge is the same, but the discharge happens over a shorter amount of time. A hydrologist will design a detention pond to temporarily detain the water and keep the runoff to the desired rate. When the rain ends, though, the detention pond will be empty shortly afterwards.
Q: Are sewers and storm drains the same thing?
A: No. They are two completely separate drainage systems. Effluent in the sewer system receives extensive and thorough filtration prior to being discharged. The storm drain system on the other hand, receives no filtration whatsoever, and discharges directly into the local creeks and empties into Lake Fort Phantom Hill untreated.
Q: Do detention ponds and storm drains get cleaned out?
A: Yes. The Stormwater Utility Division within the city maintains and cleans out the many detention basins and miles of channels, washes and storm drains in the system on a regular basis. However, there are a number of problematic locations throughout the city where certain detention ponds, because of either topographical location or from repeated illegal dumping, are cleaned with more frequency.
Q: Can drainage structures be cleaned out before a storm event?
A: There are miles of channels, creeks, and storm drains within the City of Abilene to maintain. Stormwater’s maintenance crews clean out detention ponds, storm drains, channels, and drainage ways throughout the year as they are reported. Unfortunately there are just too many drainage structures and not enough resources or crews to keep them all in proper functioning order at all times. The Stormwater maintenance crew performs maintenance operations on a day-to-day basis; however, it simply can not keep up with daily illegal dumping of debris into these open channels. Therefore, we rely heavily on the citizens of Abilene to assist in keeping us informed of clogged drainage ways, illegal dumping, and illegal discharges.
Q: Can filters or screens be installed at the inlets of detention ponds and storm drains?
A: It sounds like a good idea. But during a rainstorm, trash is quickly swept to detention ponds and storm drains and any screen or filtration device placed in front of these structures would cause trash to accumulate and clog the grate, preventing proper drainage and end up flooding the street. With hundreds of miles of pipes and channels in the system alone, there would be far too many blocked detention ponds and storm drains to have crews cleaning them as the rain falls.
Q: Why isn't a net/fence/barrier installed at the end of the storm drain channels to catch all of the trash?
A: The City of Abilene manages the flood channels and, in fact, some do have a barrier or screen near the discharge point. Unfortunately, this only catches the trash that floats in the channels or detention ponds, leaving most of the toxins like pet waste, used oil, pesticides, fertilizers, etc. flow straight through into the local creeks.
Q: Why doesn't the City build a stormwater treatment facility?
A: Such a facility would be extremely costly to build and maintain. And, the massive amount of water coming through the facility during a rainstorm would easily overtax the system.
Q: What kinds of pollutants are found in the storm drain system?
A: Paint thinner and paint products, motor oil, pesticides, Styrofoam cups, paper, human and animal wastes, antifreeze, golf balls, dirty diapers, and dead animals are but a few of the pollutants found in the system on a daily basis.
Q: How much water passes thorugh the system?
A: On a typical dry summer day, many gallons flow through the system. This flow comes from over watered lawns, fire hydrant pressure releases, and car washes throughout the city, just to name a few. In a heavy rainstorm, this flow can increase by many, many gallons.