Instream Flow Issues: Connoquennessing Creek and Thorn Run
Pennsylvania-American Water Company
Butler, PA
During Water Allocation permitting, the Pennsylvania Department of Environmental Protection (PA DEP) recommended conservation
releases from Pennsylvania-American’s reservoirs in western Pennsylvania. The PA DEP recommendation would potentially cause
the water company to fail to maintain safe yield during most years unless costly new pumps and pipelines were installed to
import additional water from another river basin. The recommendation was challenged in court and found to be deficient. The
court gave all parties eighteen months to resolve the issue by conducting an acceptable instream flow study.
Kleinschmidt was asked to assist all parties in resolving the issue. This case set a precedent in Pennsylvania that has lead to more scientific standards for permitting habitat-based instream flow conservation releases. Kleinschmidt scientists conducted a fishery and habitat reconnaissance survey of the affected parts of the watershed, thus identifying appropriate habitat protection targets.
Kleinschmidt led an inter-agency study team including a local industrial discharger (an adversarial party to the issue) in the execution of the first Instream Flow Incremental Methodology (IFIM) study ever conducted in Pennsylvania to resolve this type of issue. Kleinschmidt successfully met several challenges in this work. The aggressive court schedule required that field work be conducted during winter months. Due to drought conditions, high flow releases needed for model calibration were extremely limited in duration, and thus innovative field techniques were required to obtain data under difficult conditions. The river basin was also ungaged; Kleinschmidt hydrologists therefore synthesized monthly flow duration curves for the target areas of the basin by obtaining, selecting, and analyzing surrogate gage data from neighboring unregulated basins with similar basin characteristics. These data were then combined with the IFIM modeling results to predict effectively available habitat based on seasonal hydrologic cycles, and provide preliminary recommendations for a suitable minimum base flow below each dam.
Although with the data, the water company and PA DEP were agreeable to negotiating a satisfactory resolution, the adversarial position of one of the stakeholders resulted in further litigation. Kleinschmidt scientists and hydrologic engineers served as expert witnesses and successfully defended the studies and conclusions when challenged in deposition. Kleinschmidt was then appointed to lead a negotiation effort on the eve of the trial which resulted in a successful compromise, thus avoiding the need for a costly trial, and alleviating the need for construction and operation of an inter-basin pumping system.
Kleinschmidt’s assistance has enabled Pennsylvania-American to cost-effectively meet the water demand needs of its service community and provide an environmentally benign instream flow.