Ground water flow and water budget for tharthar lake

Abstract EN

Ground water inflow to Tharthar lake and leakage from it, in time and space were evaluated using hydrologic data and simulation model (Processing Modflow Pro) of the ground water system adjacent to the lake.

The temporal parameters include the time unit, stress period, time steps and transport steps.

The spatial parameters include the initial hydraulic head, horizontal and vertical hydraulic conductivities and the effective porosity.

The simulation model indicates that ground water inflow to the lake and leakage from the lake to the ground water system are the dominant components in the total inflow (precipitation, surface water inflow and ground water inflow) and total outflow (evaporation, surface water outflow and leakage) budgets of Tharthar lake.

Simulated ground water inflow and leakage were approximately (5 ) and (10 ) times larger than precipitation plus surface water inflow to the lake and evaporative losses plus surface water outflow respectively, during years 1992-1996.

Exchange of water between Tharthar lake and the ground water system was larger than atmospheric lake exchange.

A consistent pattern of ground water inflow was also evident throughout the study period.

The residence time for ground water that discharge at Tharthar lake was estimated to be within a range of (4 ) to (11 ) years.

Flow- path evaluations indicated that the Lower Fars formation probably has negligible influence on the ground water inflow to Tharthar lake.

The water budget and flow-path evaluation provide critical information for developing the budgets for Tharthar lake, and for improving the understanding of the relative importance of various processes that regulate the movement of water for lakes in Iraq.