Land use, snow, and streamflow regimen in central New York

Abstract

Over a 23‐year period the winter‐spring high runoff regimen from a reforested watershed in central New York was compared with that of a nearby agricultural watershed. Techniques for analyzing regimen over a large range of flow and time were developed from Court's half‐flow date and duration concepts and selected daily flow data. The techniques revealed that runoff during snowmelt periods is gradually concentrated in a shorter time following reforestation of open lands. There is also a gradual desynchronization with runoff from the agricultural watershed, so that concentrated snowmelt runoff comes later in the season in the years following reforestation. The desynchronization is apparent over the entire range of flow and time studied, from mean daily flows of 7 cubic feet per second per square mile to half of the annual flow, which appears over a period as long as several months. The techniques used are evaluated in terms of their applicability as measures of streamflow regimen and their validity in detecting changes in regimen resulting from changes in land use.