Hydrological Modeling of the Kobo-Golina River in the Data-Scarce Upper Danakil Basin, Ethiopia

Abstract

A proper understanding of hydrological processes is vital for water resource assessment, management, and conservation at a local, national, and global scale. The role of hydrological models is critically important in rarely studied ungauged catchments including of Kobo-Golina, in the Danakil basin of Ethiopia. The main objective of this research is to model the hydrology of the Kobo-Golina catchment using the completely restructured SWAT (SWAT+) model. Validated reanalysis river flow from the Global Flood Awareness System (GloFAS) and actual evapotranspiration (AET) from Moderate Resolution Imaging Spectroradiometer (MODIS) were used for single and multi-variable calibration. It is found that the multi-variable calibration scenario reasonably attained the minimum satisfactory performance limit for both variables (NSE = 0.67, R2 = 0.68, PBias = −9.68%, and RSR = 0.57 for calibration of GloFAS flow; and NSE = 0.56, R2 = 0.63, RSR = 0.66, PBias = 3.86 for calibration of MODIS AET). The model simulation showed that evapotranspiration accounts for 47% of the input water while surface runoff, lateral flow, and groundwater recharge account for 30%, 1.53%, and 21.4%, respectively. The simulated mean annual streamflow at the Basin outlet is 10.6 m3/s. The monthly low flow occurs in June with a median flow of 1.43 m3/s and a coefficient of dispersion of 0.67. High flows occur in August, with a median flow of 16.55 m3/s and a coefficient of dispersion of 1.55. The spatial distribution of simulated runoff was depicted as being higher in the floodplains and along the riparian/drainage lines, whereas upland areas showed lower runoff. The maximum monthly recharge occurs in September with a recharge value of 78.2 mm. The findings of the study suggested that both surface water harvesting and groundwater exploitation can be sought in floodplain areas while conserving the uplands.

Recharge Estimation Approach in a Data-Scarce Semi-Arid Region, Northern Ethiopian Rift Valley

“…As a surrogate for AET, remotely sensed data were used. Remote-sensingbased AET estimates from the Moderate-Resolution Imaging Spectrometer (MOD16 AET) and the Food and Agricultural Organization of the United Nations (FAO) portal (water productivity open access portal, WaPOR) have been widely used as options to calibrate and validate hydrologic models in Ethiopia [58][59][60][61] and other countries [62,63]. For this study, we used WaPOR as it offers continuous actual evapotranspiration data across Africa and the Middle East at three spatial resolutions (250 m, 100 m, and 30 m).…”

Global hydrological reanalyses: The value of river discharge information for world‐wide downstream applications – The example of the Global Flood Awareness System GloFAS

“…For the period 2005–2010, this methodology of calibration led to an increase in skill of the simulation of monthly river discharge compared to observations. Abate et al (2023) also found positive results by using GloFAS hydrological reanalysis and actual evapotranspiration (AET) from Moderate Resolution Imaging Spectroradiometer (MODIS) to calibrate the SWAT model for the ungauged Kobo‐Golina catchment in Ethiopia. Alternatively, hydrological reanalyses can be used to extend existing observational records (Mbuvha et al, 2022) creating a longer record on which to calibrate hydrological models.…”

Representation of Hydrological Components under a Changing Climate—A Case Study of the Uruguay River Basin Using the New Version of the Soil and Water Assessment Tool Model (SWAT+)

“…To date, SWAT+ has been applied mostly in the United States, Africa [6][7][8][9][10], Europe [1,3,[11][12][13], and in some watersheds in Asia [14,15]. Examples of SWAT+ applications include determining the impact of climate change on water and sediment yield [2,9,11,16], hydrological mass balance calibration and reservoir representation [6], and reproducible model studies [17].…”