The Clean Streams Project

Tributary Sampling for E. coli in Allegheny County:
Toms Run, Squaw Run, Streets Run, Saw Mill Run, and Pine Creek

Kathy Knauer, M.S. (2003)

The 3 Rivers 2nd Nature project conducted watershed sampling in 5 watersheds with a primary interest in E. coli: Five watersheds: Toms Run, Squaw Run, Streets Run, Saw Mill Run and Pine Creek were selected to provide a variety of conditions of watershed size, stream order and relative percentage of development. The goals of this sampling program were to develop a low-cost strategic testing program that will identify substandard water quality as well as the likely sources of impairment. We present this as the first step to a regional water quality monitoring program. The sampling plan was designed to determine if these watersheds meet the ORSANCO E. coli standard by sampling 5 times within a 30-day period and based on geographical information system databases for sample site selection. Sampling was performed regardless of weather to keep within the 30-day period. The USEPA approved Colilert E. coli methodology was used to enumerate E. coli because of its relative analytical ease, relative rigor and possible application with community and watershed groups.

Only 4 sampling locations out of all of the watersheds met the monthly geometric mean standard of 130/100ML for a minimum of 5 samples/month: Streets Run Locations STE and STD (STD affected by low pH and mine drainage); Saw Mill Run Location 16F, also affected by mine drainage; and Toms Run Location 4C, although only 4 samples were taken and does not meet the minimum 5 samples/month.

Squaw Run and Pine Creek were sampled during rain events. The wet weather E. coli results for Squaw Run increased to 103 or 104 MPN/100ML at all sites. The 3R2N macroinvertebrate study undertaken in 2001 indicated that Squaw Run is moderately impaired. This level of E. coli concentrations (103 or 104 MPN/100ML) would indicate a human source of fecal contamination, rather than animal runoff.

Wet weather also impacted Pine Creek. The lower end of Pine Creek at 18A and C and West Little Pine Creek were most affected by the rain events, reaching E. coli concentrations of 104. This is not surprising due to sewer problems in these areas, including obvious sanitary sewer overflows. Other locations had increased E. coli concentrations during the rain events, though sources cannot be confirmed.

Overall, each watershed, except for Toms Run, had locations with high E. coli concentrations. Wet weather dramatically affected Squaw Run and sites along Pine Creek. These E. coli impacts warrant further investigation.