Articles | Volume 371
12 Jun 2015
 | 12 Jun 2015

Modifications to a rainfall-streamflow model to handle "non-stationarity"

B. F. W. Croke and M.-J. Shin

Abstract. This paper explores the variation in hydrological response (often termed as non-stationarity, though this is not necessarily the correct use in the statistical meaning of this term) through time for the Bani catchment in Africa (mostly located in Mali). The objective is to identify deficiencies in the ability of the model to capture the variation in the hydrologic response of the catchment, and modify the model to capture this variation. Due to the large catchment area (approximately 103 000 km2), the unit hydrograph component of the model was modified to permit the model to be used at a daily timescale. Further, an additional driver (population growth) needed to be included in order to adequately capture the transition from a perennial to an ephemeral river.

Short summary
Catchment response can be influenced by man’s activities as well as natural forces like climate, and understanding how stream flow is affected by such activities is important in a changing world, particularly in developing countries. Data for the Bani River in Africa show a steady decrease in the groundwater component of stream flow. This paper shows that the decrease appears to be driven by increased water use in the catchment, and has resulted in the river ceasing to flow in the dry season.