Numerical modeling of drainage schemes in layered formations: A Kuwait City case study

A computer modeling technique is developed to simulate ground water drainag e considering a heterogeneous, discontinuous layered formation with pumping wells screened in several layers and drawdown-induced recharge/discharge u nder complex urban hydrological conditions. A composite finite-difference m esh is used to simulate both the more distant areas (coarse mesh) and the a ctual drainage site (fine mesh). The skin loss parameters of screens are in volved to control the aquifer yield. A pilot drainage scheme is being opera ted in Kuwait City to eliminate the harmful effects of water table elevatio n, The scheme involves six multiscreened pumping wells and numerous observa tion wells. Calibration through computer simulation indicated that the tran smissivity exhibits relatively little areal variation, whereas the leakance of partially cemented silty beds and lenses fluctuates significantly over the study area. This heterogeneity effect as well as the induced recharge f rom various man-made sources have considerable impact on the drainage effic iency. Skin loss parameters of pumping wells affect the amplitude of drawdo wn in different aquifer units.