FOSC Chem/Bio WQ Monitoring Summary
June 2017

This is a brief summary of our June 2017 results from chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive
Last time out (end of April) we had the huge volume with suds and extraordinarily high chlorine readings. This time around, the outfalls were far less dramatic. Ammonia-N levels were average (0.11 and 0.12 mg/L), but salinity, temperature and TDS were all somewhat elevated in SA10. Chlorine levels were back down to their usual range. Surfactant levels were lower than last month, but still in the 3 ppm LAS range. As detailed below, Coliform levels were very high coming from SA10. Receiving pool was somewhat turbid, sediment lessened and water level high, so pool effectively as deep as we've seen here. Layer of silt over layer of algae on apron. Flow medium/low respectively (SA10/SA11). PM air quality was excellent, noise level at 49 dB. The snails are back, lots of birds heard, plus mosquitoes. Iron algae absent from SA11; unusual for this time of year.

Wayne Avenue
Ammonia-N remains near the 0.40 mg/L mark. Salinity, pH and TDS all slightly above summer averages. Chlorine at zero, but surfactants were elevated (2.9ppm LAS). Light brown algae on outfall's final 2 feet. Coliform levels quite high as per usual. About 60 fingerling and juvenile fish, 80% blacknose dace, 20% white suckers. Fewer suds than usual in pipe and main channel, but more trash along banks. Deep, wide flow in channel. Birds everywhere. PM readings excellent, dB at 57.

Fleetwood Terrace (main channel)
Numbers here were pretty standard for the main channel, except surfactants were lower (1.9 ppm) than usual. Free and total chlorine are still noticeable (.03 and .05 ppm). Ammonia-N came in at 0.17 mg/L and conductivity, TDS and salinity all near the summer lows. Coliform levels high (3K to 7K), especially given expected dilution in main channel. About a dozen small fish fry present. Algae covering the rocky substrate, some 2 to 3 feet long. Deep, wide flow in channel so that tree root collars are wet on both sides. PM readings excellent, dB at 53.

Maple Avenue
Pool received small detergent discharge just after we arrived. Laundry detergent scent from 01A easily detected. Flow strong, including 01C. Ammonia-N levels were about half of last month's, lower than average as well. Salinity, TDS and conductivity levels were low. Water level in pool was high, delta about 6 inches beneath water surface. Chlorine levels, however, were quite high (.09 to .34 ppm) and surfactants were between 1.0 and 2.1ppm. Copious raccoon tracks in iron algae of 01B. Some birds downstream. PM AQ levels excellent, noise levels at about 57 dB.

Park Ritchie
The pool here was as small as we've encountered, surrounded by mud filled with deer tracks. Mulch odor was apparent. All levels were extremely high, due to the concentration of pollutants into smaller volume of water. In particular, ammonia-N came in at 1.82 mg/L, chlorine was in the .75 ppm range, and surfactants registered a 6.1 ppm LAS. AQ excellent and noise dB at about 50.

You can view previous WQ Monitoring Summary reports here:

Results from
Periodic Outfall Monitoring
Along Sligo Creek

FoSC and the Center for Watershed Protection (CWP) Apply Scientific Testing to Improve Sligo Creek

Several outfalls into Sligo Creek are tested periodically by volunteer Pat Ratkowski. Pat tests for ammonia, temperature, and pH to discover illicit discharge problems which may then be reported to the County. An illicit discharge detection and elimination (IDDE) program is a requirement of the County’s Municipal Separate Storm Sewer (MS4) permit. Recent research conducted by the Center for Watershed Protection (CWP) in Sligo Creek and Baltimore City has indicated that illicit discharges are a much greater contributor of nutrient and bacteria pollution than was previously known. Their elimination can help make significant progress towards meeting local and Bay-wide total maximum daily loads (TMDLs). CWP has produced national guidance for developing and implementing IDDE programs, which includes identification of the most appropriate parameters to detect illicit discharges, many of which have sewage components. Volunteers can test for these recommended parameters at outfalls to help find illicit discharges and monitor problematic outfalls over time.

Outfall Photos December 2014

Map of Outfall Monitoring Sites