Impacts of small-scale irrigation water use on environmental flow of ungauged rivers in Africa

Abstract Failure in Environmental flow quantity, timing, and quality leads to failure support ecosystems, human livelihoods, well-being. Irrigation water use is one of the main actors impacting rivers quantity time but was not well investigated many ungauged catchments under smallholder irrigation systems. This study examined impact on environmental Arata's small catchment. The estimated sub-catchment using area ratio method, crop requirement F.A.O. cropwat 8.0, balance Water Evaluation Planning System tool Tennants, Q95, asnd local thumb rule. result showed that minimum Arata catchment 290, 310, 60 li/sec Tennant, consumes only 9% resources while 91% contributed downstream lake Ziway via Ketar river. January February have unmet demand zero flow. In December Tennant's 10% Q95 recommended had 19% 24% deficit rule 291% more than requirement. rest months are by far Given result, meeting system throughout year needs installation a storage facility from upstream downstream, introduction different water-saving technologies, farmers' capacity building management, standardized estimation mechanism.