Sources of Pollution
Much of the East Branch of Chester Creek is negatively affected by the fair-to-poor water quality of the large Goose Creek drainage area, which has a large percentage of impervious surfaces and a number of direct stream discharges. Municipal waste water treatment discharges on the East Branch and Goose Creek include:
West Chester Borough (913,000 gallons per day (GPD))
West Goshen regional plant (6,000,000 GPD)
Westtown Township (323,000 GPD)
Thornbury Township, Delaware County (180,000 GPD).
Sediment, nutrients, bacteria, and increasing temperature are all forms of pollution which are degrading Chester Creek and threatening its use for drinking water, aquatic habitat, and recreation.
Sediment from excessive alteration in stream hydrology, and the nutrients that bond to it, is the largest single source of impairment to Chester Creek.
The primary source of sediment is excessive stormwater runoff volume resulting from increased impervious surfaces and reduced tree canopy. Impervious surfaces ratios are in excess of 22% in the Upper Chester Creek watershed, nearly double the levels in the Upper Ridley and Upper Crum watersheds. This increased stormwater runoff leads to increased bank erosion, which releases nutrients into the stream flow and deposits sediment downstream, reducing desirable aquatic habitat and further destabilizing downstream sections.
Inadequately contained or designed construction sites are also a source of sediment, and should be reported to the Delaware or Chester County Conservation Districts.
High levels of nitrogen and phosphorus from Goose Creek, and their impact on nutrient levels in the main stem near the public water intake, have been documented by CRC’s monitoring water quality monitoring studies, USGS, and Aqua Pennsylvania.
High levels of nitrogen and phosphorus are correlated with municipal waste water discharges. However, algae blooms in the West Chester Reservoir and eroding streambanks also contribute phosphorus and nitrogen to the East Branch.
Since phosphorus is the limiting nutrient in the growth of algae in streams and ponds, phosphorus levels are the focus of the nutrient TMDL study currently being undertaken by DEP and EPA, and will be regulated in future discharge permits.
Elevated summer temperatures are also a concern for Chester Creek aquatic life. Municipal and institutional discharges to Chester Creek, reduced base flow from increased paved surfaces, as well as loss of streamside shading, have all contributed to increased stream temperatures
The majority of the East and West Branches are designated Trout Stocking Fishery, and are too warm to support the reproduction of cold water fish like trout. Cold water streams are Rocky Run, which supports trout reproduction, and Green Creek. Goose Creek and the main stem below Brookhaven are Warm Water.
The 2003 and 2004 CRC/DEP Pathogen Impairment Study of Goose Creek documented that the Creek was in violation of fecal coliform standards. Very high levels of fecal coliform were found starting in West Chester Borough, and although levels decreased downstream, they remained significantly in excess of federal standards for water-contact sports ( geometric mean of 200 cfu/100 ml during the summer months, and no greater than 10% above 400 cfu.100 ml).
Base line stream flow is a major factor in the ability of a stream to assimilate pollutants. Since a significant portion of Goose Creek's flow below West Chester is waste water effluent, the ability of the stream to assimilate pollutants is greatly reduced . To learn the flow of Chester Creek, see the real time readings from the United States Geological Survey (USGS) stream flow monitoring gauge, located near the Dutton Mill Road crossing in Aston: click here.