The paper reviews the potential for administrative problems/disputes associated with western prior appropriation water rights in those sub-regions experiencing increasingly early spring snowmelt and the lengthening of growing seasons. In those areas, potential problems of two general types are envisioned. First, in those states that link water rights to specific calendar dates (that are becoming increasingly out-of-step with natural hydrographs), the yield and/or utility of those rights increasingly out-of-step with natural hydrographs), the yield and/or utility of those rights can theoretically become increasingly devalued. Second, in states that do not attempt to limit the exercise of rights to specific dates, water consumption under a given right may increase, thereby threatening the yield and reliability of other (particularly more junior) users.
