Estimating runoff from ungauged catchments for reservoir water balance in the Lower Middle Zambezi Basin

Abstract

The Lower Middle Zambezi Basin is sandwiched between three hydropower dams; Kariba, Kafue (Itezhi-tezhi) and Cahora Bassa. The operation of the upstream dams impacts on the inflows into the downstream Cahora Bassa Dam which, in turn, affects the area inundated upstream of the Cahora Bassa Dam. This study applied a rainfall-runoff model (HEC-HMS) and GIS techniques to estimate both the gauged and ungauged runoff contribution to the water balance of Cahora Bassa. The rivers considered in the study are the Zambezi, Kafue, Luangwa, Chongwe, Musengezi and Manyame. Missing data were generated using the mean value infilling method. The DEM hydro-processing technique was used to determine the spatial extent of the ungauged area. A hydrological model, HEC-HMS, was used to simulate runoff from the ungauged catchments.

Climate change/variability and hydrological modelling studies in Zimbabwe: a review of progress and knowledge gaps

“…Other data access challenges relate to (1) inaccessibility due to bureaucratic red-tapes and prohibitive costs for long-term climatic datasets charged by government agencies such as the Meteorological Department, (2) inconsistent and poor spatial coverage which often renders it of limited use in climate research in the country. This is also confirmed by Gumindoga et al [ 144 ] who noted that historic temperature and rainfall data for Zimbabwe is incomplete and often costly to purchase thus a limiting factor in climate research in general. In light of such limitations, researchers such as Chikodzi [ 145 ], Dlamini et al [ 126 ], Kamusoko, Aniya [ 146 ] and Mpala et al .…”

“…For example, Love et al [ 305 ] used an empirical model (the Hydrologiska Byråns Vattenbalansavdelning (HBV) model) to simulate hydrological processes in the Northern Limpopo basin (Mzingwane catchment), while the HEC-HMS model has been successfully used in simulating run-off in the gauged and ungauged Upper Manyame sub-catchments of Zimbabwe [ 306 , 307 ]. The same model has been applied by Gumindoga et al [ 144 ] in modelling the water balance of the Lower Middle Zambezi Basin, successfully estimating the total inflows into the Cahora Bassa Dam and recommending ways of managing artificial floods in this basin. Mazvimavi [ 308 ] successfully demonstrated the application of two lumped conceptual models, i.e.…”

Applicability of a Spatially Semi-Distributed Hydrological Model for Watershed Scale Runoff Estimation in Northwest Ethiopia

“…HEC-HMS is one of those models significantly used in different parts of the world for estimating runoff by considering different modelling approaches, in which both lumped and distributed modelling approaches and concepts are embedded in the programme [16,17].HEC-HMS is hydrological modelling software developed by the US Army Corps of Engineers Hydrologic Engineering Centre (HEC), which is designed to simulate the precipitation runoff processes within a wide range of geographic areas, such as large river basins and small urban or natural watersheds [17,18]. Because of its ability in the simulation of runoff both in short and long time events, ease to use, and use of common methods, HEC-HMS has become very popular and been adopted in many hydrological studiesin relation to the simulation of runoff volume in integrated water resources and watershed management projects and for estimating flood peaks in flood forecasting, irrespective of the size of the catchment [12,[18][19][20][21][22][23][24][25][26][27][28][29][30]. A special extension programme of the HEC-GeoHMS in ArcGIS has been applied in some of the studies and allowed researchers to generate relevant spatial data in relation to terrain characteristics which cloud be used as input data for HEC-HMS mode [2,12,21,[24][25][26][27][28][29][30].…”

“…Because of its ability in the simulation of runoff both in short and long time events, ease to use, and use of common methods, HEC-HMS has become very popular and been adopted in many hydrological studiesin relation to the simulation of runoff volume in integrated water resources and watershed management projects and for estimating flood peaks in flood forecasting, irrespective of the size of the catchment [12,[18][19][20][21][22][23][24][25][26][27][28][29][30]. A special extension programme of the HEC-GeoHMS in ArcGIS has been applied in some of the studies and allowed researchers to generate relevant spatial data in relation to terrain characteristics which cloud be used as input data for HEC-HMS mode [2,12,21,[24][25][26][27][28][29][30]. After appropriate calibration and validation tasks in each selected loss, transform methods, and routing reaches in the HEC-HMS programme, reasonable and reliable simulation results of runoff volume and peak values were obtained as compared to observational data in all the studies.…”

Evaluación del Sistema de Modelamiento Hidrológico HEC-HMS para la Simulación Hidrológica de una Microcuenca Andina Tropical

“…La ecuación de intensidades correspondiente a la estación de Gualaceo (Ver Tabla 2) está codificada en la zona 4 del estudio realizado por Estrella (2016). (2007) establece que para el valor obtenido de densidad de drenaje la microcuenca en estudio tiene una eficiente red de drenaje, parámetros importantes en el análisis de escorrentía de captación y otros procesos hidrológicos (Gumindoga et al, 2016). Pendiente media del cauce principal km/km 0,08…”