The Contribution of Groundwater to the Salinization of Reservoir-Based Irrigation Systems

This study evaluates the cause of salinization in an irrigation scheme 100 ha supplied from a reservoir. The is located Gumselasa catchment (28 km2), Tigray region, northern Ethiopia. underlain by limestone–shale–marl intercalations with dolerite intrusion and some recent sediments. Water balance computation, hydrochemical analyses water quality methods were used this investigation. Surface waters (river reservoir) groundwater samples collected analyzed. table irrigated land ranging 0.2–2 m below ground level. majority effective watershed area river dam are fresh alkaline whereas command dominantly brackish alkaline. main facies Ca-Na-SO4-HCO3, Ca-Na- HCO3-SO4, Ca-Na-Mg-SO4-HCO3. Mg-Na-HCO3-SO4 HCO3-SO4-Cl types, respectively. In Ca-Na-HCO3-SO4 Irrigation revealed that salinity toxicity hazards increase to following direction flow. results also showed analyzed for purpose had no sodicity hazard. major composition controlling mechanisms chemistry was identified as dissolution carbonate minerals, silicate weathering, cation exchange. One impacts construction hydrologic environment on its potential. indirectly recharging aquifers enhances potential area. increment availability enhanced minerals (calcite, dolomite, gypsum), weathering exchange processes, which causes land. rising combined insufficient leaching contributed secondary development Installation surface subsurface drainage systems planting salt tolerant (salt loving) plants recommended minimize risk accumulation soils