DEP News

Monday, May 07, 2012

Sligo Creek: Better stormwater management results in higher quality aquatic resources

Montgomery County’s Sligo Creek has been confirmed by EPA as a success story for improvements in aquatic life resulting from extensive stormwater pollution control and management in the watershed. Success Stories are used by EPA to request and justify continued funding for grant monies (known as Section 319 grants) ear marked for controlling nonpoint source pollution which carries pollutants from urban surfaces and agricultural lands into waterbodies in rainfall runoff.

Since 1989, the County has improved the stream banks down the length of the Sligo Creek, created wet ponds to capture stormwater runoff and treat it before it goes into the creek, restored pools for breeding habitat for fish and amphibians, retrofitted existing stormwater ponds by adding additional storage and retention capacity to capture rainfall runoff from more urban surfaces, and reshaped the stream channel itself by adding more meanders and curves which slows down flow and creates habitat niches for biological life. More recent investments by the County have included installations of low impact development bio-retention systems. These installations help to filter out the pollutants in stormwater runoff and help to absorb the rainfall in place through vegetation roots instead of allowing runoff to flow into gutters and into the stream conveying pollutants.

The County’s biological monitoring program has been sampling fish and other aquatic organisms in the stream for decades. Since 2000 when the fish complex found in the stream were of only four pollution-tolerant fish, steady incremental changes in the creek’s water quality and habitat opportunities have led to noticeable improvement. Today fourteen naturally sustaining fish species can be found in the creek, including some that require specialized habitat. The bioassessment done of the aquatic life in the creek shows that the overall Index of Biotic integrity scoring has improved from a “poor” rating to a “fair”rating.

More details on the Sligo Creek Success Story are available on EPA’s Nonpoint Source Program Success Story Web site .