Antelope Creek Pollution Sources
In order to assemble management strategies to improve water quality a 'basin inventory' was completed by the project team during the summer and fall of 2010. Information collected included; water sampling data, field notes, outfall locations, historical records, and a land use breakdown. The information collected is being used to help identify possible sources of pollution in the watershed. Below is a summary of some possible pollutant sources:
Wildlife and Pet Waste -
Twenty-nine bridge crossings were found, many of which are older and allow birds to nest and perch, where their droppings may contribute to some contaminants in the creek. Many new bridges nearly eliminate areas for birds to perch. Existing habitat in the watershed provides room for wildlife such as raccoons, squirrels, and feral animals that contribute to pollution sources. Domesticated pets, such as dogs and cats, can also provide a significant source of pollution if waste is not properly disposed.
Fertilizers and Phosphorus in Soils -
Excess nutrients in the stream, which may originate from over-fertilizing and soil erosion, contribute to algal blooms in the water. Improper storage and disposal of fertilizers or incidental application to impervious surfaces, such as concrete driveways and sidewalks, can lead to nutrients entering the creek through stormwater runoff.
Antelope Creek Watershed Land Uses and Pollutant Loads
|Table 1: Land Use Type||Total Acres||Percentage of Project Area|
|Single Family Residential||1,879||38%|
|Multiple Family Residential||309||6%|
|Commercial (Shopping Areas)||182||4%|
Due to the urbanized nature of the Antelope Creek Watershed, the pollution in stormwater runoff (particularly E.Coli bacteria and ammonia) has become a concern to the City of Lincoln and Lower Platte South Natural Resources District (NRD). Stormwater runoff originates from precipitation events such as rainfall or snowmelt. As stormwater drains through the watershed towards the creek as runoff, pollutants, such as fertilizers from lawns and animal waste, travel with the water into the creek. The City of Lincoln and the NRD are working together to improve water quality, by managing the amount of pollutants in stormwater runoff as part of the Antelope Creek Watershed Basin Management Plan (Basin Plan).
The Storm Drain System
Stormwater runoff is collected through a system of curbs and gutters, open channels, and pipes that create the storm drain system. Runoff is discharged into the creek at approximately 221 known locations along the 5.5 miles of Antelope Creek in the Basin Plan project area. The project team has been collecting and testing water samples at approximately 17 of the outfalls during dry-weather. Nine locations along Antelope Creek have also been sampled both during dry weather and after a rain.
Land Uses in Antelope Creek
Land use categories describe how property owners utilize the land, such as residential for homes, commercial for businesses, and industrial for manufacturing. The amount of stormwater runoff can vary greatly depending upon the type of land use. Lower intensity land uses, such as residential lots, allow a greater amount of stormwater runoff to infiltrate into the ground, while higher intensity land uses (commercial or industrial areas) allow runoff to move rapidly across impervious surfaces and travel more rapidly into the creek. Impervious surfaces, such as parking lots and rooftops, convey stormwater runoff quickly compared to more permeable surfaces such as lawns, golf courses, and open spaces. A breakdown of land uses in the Basin Plan project area is found in Table 1.