A framework to estimate continuous streamflow at the ungauged site with limited catchment’s hydrological data: Case study Isahaya Catchment

Abstract

This paper presents a framework for mapping flow information from the gauged to the ungauged river basins. The calibration and validation of a hydrologic model were conducted to establish basic watershed characteristics. The new framework was then applied to account for the two watersheds' proportionality in their similarity, such as the influence of land use on transplanting flow signatures. Three land-use scenarios-discharges at the ungauged and gauged sites formed the basis of an equation mapping the gauged discharge signal to the ungauged site. In comparison with intermittent observed data, the framework prediction attained a precision of 0.85≥NSE≤0.95, 0.80≥R2≤0.94, 0.56≥bR2≤0.89. Despite considerable differences in the watershed area, slope, soils, and land cover, the framework satisfactorily depicted the variation in flow pulses of each river. In the absence of established hydrological information, this provides an alternative flow estimation at ungauged sites, reducing uncertainties in the regionalization of model parameters.