Sustainable Management of Groundwater Resources in the Gash Basin, Sudan
In the Gash Basin, Kassala State, Sudan; Domestic and horticultural irrigation water supplies depend entirely on groundwater. The basin is annually recharged from the Gash River which is shared with Eritrea, Sudan and Ethiopia. Recently, groundwater level has been significantly dropped in the unconfined Gash aquifer in Sudan due to over pumping. The objectives of this study were to determine the future safe utilizable amounts of groundwater under different developed scenarios by the year 2050, to investigate the sensitivity of the aquifers to changes in the recharging rates and to develop a sustainable operation plan. Datasets of 1194 discharging wells and 51 observation wells were collected and analyzed. A one-layer conceptual model was built for representing the unconfined aquifer based on the Modflow model. The calibration and validation of the model were carried out via the hydraulic heads of 12 observation wells (2008 – 2017). The results showed that due to the decreasing trend in the Gash River flows of 9% in the period 2000 –2018, the recharging rate experienced a decrease of 0.7%. The scenario “running the business as usual” stated a drawdown of 2m to 13 m relative to the year 2018. To stabilize the current head, annual recharge amounts of 228 million m3 is required. Under the conditions that there is no recharge (no stream flows of the Gash River), a drawdown up to 20% will occur. Spatially, the upstream and middle parts of the River were the most sensitive part of the no recharging conditions. The described sustainable operation model of this study is recommended for managing groundwater resources in the Gash basin, Sudan.
Chiang, W. H., & Kinzelbach, W. (1998). Processing Modflow. A simulation program for modelling groundwater flow and pollution. User manual.
Elkrail, A. B., & Ibrahim, A. E. (2008). Regional groundwater flow modelling of Gash River basin, Sudan. Journal of Applied Sciences in Environmental Sanitation, 3(3), 157-167.
Genthon, P., Hector, B., Luxereau, A., Descloitres, M., Abdou, H., Hinderer, J., & Bakalowicz, M. (2015). Groundwater recharge by Sahelian rivers—consequences for agricultural development: example from the lower Komadugu Yobe River (Eastern Niger, Lake Chad Basin). Environmental Earth Sciences, 74(2), 1291-1302.
Groundwater & Wadis Directorate GWD- Kassala Office (2009-2016) Annual Technical Report of the Gash basin.
Hamid, H. M. (2011). Gash Sustainable Livelihoods Regeneration Project, Sudan.
Hogeboom, R. H., van Oel, P. R., Krol, M. S., & Booij, M. J. (2015). Modelling the influence of groundwater abstractions on the water level of Lake Naivasha, Kenya under data-scarce conditions. Water resources management, 29(12), 4447-4463.
Izady, A., Abdalla, O., Joodavi, A., & Chen, M. (2017). Groundwater modeling and sustainability of a transboundary hardrock–alluvium aquifer in North Oman Mountains. Water, 9(3), 161.
Jochem, D. (2015). Modeling of the groundwater level in the Gash River delta, Sudan with a transient coupled surface-groundwater model in MODFLOW, Msc. Thesis, HWM -80436, Wageningen University.
Johnston, R., & Smakhtin, V. (2014). Hydrological modeling of large river basins: how much is enough?. Water resources management, 28(10), 2695-2730.
Khadri, S. F. R., & Pande, C. (2016). Ground water flow modeling for calibrating steady state using MODFLOW software: a case study of Mahesh River basin, India. Modeling Earth Systems and Environment, 2(1), 39.
Pokrajac, D., & Howard, K. W. (2010). Advanced Simulation and Modeling for Urban Groundwater Management-UGROW: UNESCO-IHP. CRC Press.
Rapantova, N., Tylcer, J., & Vojtek, D. (2017). Numerical modelling as a tool for optimisation of ground water exploitation in urban and industrial areas. Procedia engineering, 209, 92-99.
Rejani, R., Jha, M. K., Panda, S. N., & Mull, R. (2008). Simulation modeling for efficient groundwater management in Balasore coastal basin, India. Water Resources Management, 22(1), 23.
Saeed, E. M. (1969). Groundwater Appraisal of the Gash River basin at Kassala, Kassala Province, Democratic Republic of the Sudan. Ministry of Industry and Mining, Geological and Mineral Resources Dept. Bull. 17, 88 pp.
Siebert, C., Rödiger, T., Mallast, U., Gräbe, A., Guttman, J., Laronne, J. B., ... & Geyer, S. (2014). Challenges to estimate surface-and groundwater flow in arid regions: The Dead Sea catchment. Science of the total environment, 485, 828-841.
Uddameri, V., Singaraju, S., Karim, A., Gowda, P., Bailey, R., & Schipanski, M. (2017). Understanding Climate‐Hydrologic‐Human Interactions to Guide Groundwater Model Development for Southern High Plains. Journal of Contemporary Water Research & Education, 162(1), 79-99.
Van Engelenburg, J., Hueting, R., Rijpkema, S., Teuling, A. J., Uijlenhoet, R., & Ludwig, F. (2018). Impact of changes in groundwater extractions and climate change on groundwater-dependent ecosystems in a complex hydrogeological setting. Water resources management, 32(1), 259-272.
Y. Abu Shora. (2012). Water resources in Sudan: Planning and Management.
Zekri, S., Triki, C., Al-Maktoumi, A., & Bazargan-Lari, M. R. (2015). An optimization-simulation approach for groundwater abstraction under recharge uncertainty. Water resources management, 29(10), 3681-3695.