The NY DEC’s solution to regulating water withdrawals in the face of varying flow conditions is the use of a passby flow. This is also a method used by the Susquehanna River Basin Commission and the Delaware River Basin Commission
in their streams and rivers. Passby flow is defined as the “prescribed quantity of [water] flow that must
be allowed to pass a prescribed point downstream from a water supply intake at any time during which a
withdrawal [for hydraulic fracturing] is occurring”4These passby flows are determined by the entities that govern withdrawal for each stream or river (see below) from which water will be withdrawn. If weather conditions or amount of water withdrawal cause a stream to fall below its passby flow, withdrawals must cease.