Stormwater can be rainwater runoff or runoff from melting ice and snow. When stormwater encounters a city, part of it is absorbed by the ground, but there is a large volume that runs off. This runoff is not exclusive to impervious surfaces such as streets, roofs, and parking lots; but also runs off of other surfaces such as parks, lawns, and the exposed soils of construction sites. When this happens the nearly pure rainwater picks up various items such as sediment, bacteria, trace metals, yard pesticides, trace phenolic compounds from the asphalt, road salts, oils from vehicles, floatable litter and many other items.
The stormwater then makes its way to the various playa lakes within our city via our storm sewer drainage system. Here is where various regulatory concerns arise for Stormwater Quality. The storage lakes cycle through evaporation and precipitation periods. The quality of the water within our lakes and potentially discharged to receiving streams must be monitored. This monitoring is performed during live storm events to capture flow as it is leaving Thompson Park Lake and Medi Park Lake and discharging into East Amarillo Creek and West Amarillo Creek.
For more information please see: Stormwater Quality
Most of the chemical items are at a low trace level and do not harm the environment. Public contact with stormwater runoff is not a danger. However, nutrients from fertilizers and other lawn care products encourage algae growth that over time can degrade the water body.
The intensive monitoring performed by the Stormwater Quality Program and analyzed by the Environmental Laboratory provides data that can reveal trends and provide information as to the levels of pollutant in the monitored lakes.
Sediment can also degrade water bodies over time. In the playa storage lakes, bacteria, fish, and aquatic plants are very busy at doing what nature does everywhere-- that is, purifying the water. Sediment that runs off into the lake becomes silt on the bottom of the water body. Silt is not part of this natural digestion, and we must be very careful to reduce the amount of sediment and other pollutants that enter the surface waters through our storm sewer system. For these reasons the city implements a Municipal Separate Storm Sewer (MS4) Permit as required by the State of Texas with oversight from the EPA.