Articles | Volume 21, issue 6
Hydrol. Earth Syst. Sci., 21, 3145–3165, 2017
Hydrol. Earth Syst. Sci., 21, 3145–3165, 2017

Research article 29 Jun 2017

Research article | 29 Jun 2017

Modeling the water budget of the Upper Blue Nile basin using the JGrass-NewAge model system and satellite data

Wuletawu Abera1,2, Giuseppe Formetta3, Luca Brocca4, and Riccardo Rigon1 Wuletawu Abera et al.
  • 1Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
  • 2Department of Geography and Environmental Studies, Mekelle University, Mekelle, Ethiopia
  • 3Centre for Ecology & Hydrology, Crowmarsh Gifford, Wallingford, UK
  • 4Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Italy

Abstract. The Upper Blue Nile basin is one of the most data-scarce regions in developing countries, and hence the hydrological information required for informed decision making in water resource management is limited. The hydrological complexity of the basin, tied with the lack of hydrometeorological data, means that most hydrological studies in the region are either restricted to small subbasins where there are relatively better hydrometeorological data available, or on the whole-basin scale but at very coarse timescales and spatial resolutions. In this study we develop a methodology that can improve the state of the art by using available, but sparse, hydrometeorological data and satellite products to obtain the estimates of all the components of the hydrological cycle (precipitation, evapotranspiration, discharge, and storage). To obtain the water-budget closure, we use the JGrass-NewAge system and various remote sensing products. The satellite product SM2R-CCI is used for obtaining the rainfall inputs, SAF EUMETSAT for cloud cover fraction for proper net radiation estimation, GLEAM for comparison with NewAge-estimated evapotranspiration, and GRACE gravimetry data for comparison of the total water storage amounts available in the whole basin. Results are obtained at daily time steps for the period 1994–2009 (16 years), and they can be used as a reference for any water resource development activities in the region. The overall water-budget analysis shows that precipitation of the basin is 1360 ± 230 mm per year. Evapotranspiration accounts for 56 % of the annual water budget, runoff is 33 %, storage varies from −10 to +17 % of the water budget.

Short summary
This study documents a state-of-the-art estimation of the water budget (rainfall, evapotranspiration, discharge, and soil and groundwater storage) components for the Upper Blue Nile river. The budget uses various JGrass-NewAGE components, satellite data and all ground measurements available. The analysis shows that precipitation of the basin is 1360 ± 230 mm per year. Evapotranspiration accounts for 56 %, runoff is 33 %, and storage varies from minus 10 % to plus 17 % of the annual water budget.