rom ia ▁Region , ▁close ▁to ▁the ▁capital ▁and ▁largest ▁city ▁of ▁Eth iop ia , ▁Add is ▁Ab aba , ▁the ▁K oka ▁Res er voir ▁is ▁popular ▁with ▁tour ists ▁and ▁city - d well ers . ▁There ▁is ▁a ▁variety ▁of ▁wild life ▁and ▁birds ▁around ▁the ▁lake . ▁The ▁res er voir ▁supports ▁a ▁fish ing ▁industry ; ▁according ▁to ▁the ▁Eth iop ian ▁Department ▁of ▁Fish eries ▁and ▁Aqu ac ulture , ▁ 6 2 5 ▁t onnes ▁of ▁fish ▁are ▁land ed ▁each ▁year , ▁which ▁the ▁department ▁estimates ▁is ▁either ▁ 5 2 % ▁or ▁ 8 9 % ▁of ▁its ▁sust ain able ▁amount . ▁Both ▁the ▁res er voir ▁and ▁the ▁dam ▁are ▁threatened ▁by ▁increasing ▁sed iment ation ▁caused ▁by ▁environmental ▁de grad ation ▁as ▁well ▁as ▁the ▁invas ive ▁water ▁hy ac inth . ▁ ▁The ▁K oka ▁dam ▁consists ▁of ▁concrete ▁with ▁a ▁length ▁of ▁ 4 5 8 ▁meters ▁and ▁a ▁maximum ▁height ▁of ▁ 4 7 ▁meters . ▁The ▁head ▁util ized ▁is ▁ 3 2 – 4 2 ▁meters . ▁The ▁transmission ▁lines ▁have ▁voltage ▁ 1 3 2 ▁k V . ▁The ▁primary ▁contract or ▁was ▁Im pr ese ▁Italian e ▁all ' Est ero . ▁The ▁sub cont ractor ▁who ▁provided ▁the ▁equipment ▁was ▁Gru ppo ▁Indust ri ale ▁Ele tt ro ▁Me cc an iche ▁per ▁Imp iante ▁all ' Est ero , ▁and ▁sub cont ractor ▁for ▁mount ing ▁the ▁equipment ▁and ▁the ▁ere