THE RELATIVE INFLUENCES OF WATER SOURCE AND ANTHROPOGENIC IMPACTS ON WATER QUALITY IN THE MOSELEM CREEK, BERKS COUNTY, PENNSYLVANIA

Moselem Creek is a large limestone spring creek located in Berks County PA. Healthy limestone spring creeks typically provide excellent habitat for macro-invertebrates and cold-water fish species as a result of the chemical and thermal buffering effects of source waters. Moselem Creek is currently classified as a high quality cold-water fishery and is listed by the Pennsylvania Fish and Boat Commission as maintaining a naturally reproducing population of brown trout. Although the spring source may provide buffering, surrounding land use and historic stream alterations, present significant challenges to maintaining water quality and habitat for cold-water species in Moselem Creek. The rarity of surviving cold-water resources in southeastern PA and a relative lack of existing data motivate our investigation into the relative contributions of source water and anthropogenic influence to the current characteristics and health of Moselem Creek. Conductivity measurements taken from 20 sites suggest that ion concentrations in Moselem Creek are relatively constant throughout its course, despite multiple tributaries and a change in underlying bedrock. This suggests that source waters play a dominant role in ion concentration. Temperature, oxygen, and nutrient characteristics, however, indicate stronger anthropogenic impacts. Historic chemical data collected by the Reading Water Authority indicate potential pollution from surrounding golf courses and farmland with an eight year nitrate average of 6.71 mg/L and periodic spikes in phosphate above 0.06 mg/L. Data collected above and below a 1700s era millpond indicate a reduction in water quality due to impoundment, with a step change in both water temperature (6.2 °C average increase) and dissolved oxygen (average decrease of 2.4 mg/L). Multiple historic impoundments along the creek may explain excessive localized soft-sediment accumulation, and current impoundments may inhibit the system’s ability to purge legacy sediment due to artificially elevated base level. While these data suggest anthropogenic detriment to the Moselem Creek as a consequence of a heavily developed watershed and a long history of human activity, they seem to also indicate that the natural buffering effect of source water provides some resistance to anthropogenic influences.