Report of the Joint Task Force Instream Flow Needs Analysis for Northern New Castle County, Delaware Phase One: 7Q10 Assessment
Date
1995-06-15
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Abstract
The issues of instream flow needs and passby requirements for public water supply intakes on the streams of Northern New Castle County, Delaware were brought into focus by action of the Delaware River Basin Commission which imposed a 7010 passby on the Wilmington Suburban Water Corporation's intake (now United Water Delaware) at Stanton in 1993.The Commission had taken similar action on the City of Newark's White Clay intake in 1991. Under terms of the DREC allocation permits, the City of Newark and Wilmington Suburban Water Corporation must curtail withdrawals when minimum passby flows along the White Clay Creek reach 14 mga and 17.2 mga, respectively. The water allocation permits issued by the Delaware Department of Natural Resources and Environmental Control contained no such passby requirements and no state regulation exists which would mandate the imposition of such a flow regime on the public water purveyors.
However, in April 1993, DREC's Water Resources Division conducted a workshop regarding a proposed Statewide Policy for Minimum Pasaby Streamflow Requirements for Major Surface Water Withdrawal Projects. The policy also proposed the exemption of agricultural irrigation. The rationale advanced by the Department for the formulation of the proposed policy emphasized the steady increase over time of withdrawals from the surface waters for public water supply and other uses and a reasonable potential for such withdrawals to create competition and conflict with other beneficial uses such as the propagation of fish, aquatic life and wildlife, especially during the time of critical low FlOW.