Numerical Groundwater Flow Modeling of the Megech River Catchment, Tana Sub Basin, North Western Ethiopia

Abstract

The study area is found in Amhara Regional State, North Gondar Administrative Zone, Gondar town and surrounding Keble of river catchment. It’s total area coverage is 785 km² with main lithologic units of lacustrine deposit, Middle Basalt (Aiba) and Upper basalt (Alajie).Numerical Groundwater Flow Modeling of the Megech River Catchment, Tana Sub Basin is conducted with  the  objective  of  simulating  the  groundwater  flow  system  of  the  area  and  to  evaluate  the  response  of  the hydrogeological system under different stress, so that the  resulting consequence on the system can be estimated.The calibrated statistics of the model area with Mean Error (ME) of 4.8, Absolute  Mean  Error (AME) of 4.9, and  Root  Mean Square Error value  of  6.8 (RMSE), which is an indicator  of good calibration. The sensitive parameter of the model was identified during calibration process. Based on this, hydraulic conductivity and recharge is sensitive in RMSE than River Conductance values. The simulated water budget at steady state condition of Megech river catchment is analyzed. The simulated inflow of  the  model  is 1.0703551E+06 m³/day which  is equal to simulated outflow 1.0703559E+06 m³/day with  difference -7.9617882E-01(-0.79617882) m³/day. The groundwater system of Megech Catchment total withdrawals of the well is 1.78853E+04m3/day. Scenario analysis was conduct in recharge decreasing and increasing of withdrawals rate.

Keywords: calibration, water budget, simulation, Scenario, steady state, numerical groundwater flow modeling, sensitive, Tana sub basin, Megech River, groundwater withdrawal.

DOI: 10.7176/JEES/12-6-01

Publication date:June 30^th 2022