Groundwater management for Lower Indus Basin N.K. Garg * , A. Ali Department of Civil Engineering, I.I.T. Delhi, New Delhi 110016, India Accepted 5 March 1999 Abstract The present study aims to find out an optimum policy for pumping out the optimized volume of groundwater obtained from the authors' earlier Two Level Optimization Model [N.K. Garg, A. Ali, 1998. Two level optimization model for Lower Indus Basin. Agric. Water Manage. 36, 1±21] for the Dadu Canal Command of the Lower Indus Basin. It is shown that the tubewells in this canal command may be operated at their maximum capacities to pump out the required volume of water to get the overall benefits. The groundwater hydraulics simulation model results show the development of serious waterlogging problem in the lower reaches of the command. It has also been studied that by suitably increasing and placing the tubewells, the waterlogging problem can be tackled very effectively. # 2000 Elsevier Science B.V. All rights reserved. Keywords: Groundwater management model; Groundwater simulation model; Waterlogging; Conjunctive use 1. Introduction The authors have proposed a two level optimization model in their earlier paper Garg and Ali (1998) to obtain the optimal cropping pattern and the sowing dates. The model was applied to the Dadu Canal Command of the Lower Indus Basin. The coupling of groundwater hydraulics with canal water was not considered in the optimization model because it was found from the irrigation project reports (Harza Engineering International, 1991) that the canal water was always much cheaper (actual operation and maintenance cost) than the tubewell water for the Lower Indus Basin. However, the interaction between surface water and groundwater was considered in the model by imposing a groundwater balance constraint on the groundwater withdrawals. Monthly optimal canal and groundwater withdrawals were also obtained by Garg and Ali (1998). However, no Agricultural Water Management 42 (2000) 273±290 * Corresponding author. Fax: +91-1168-62037 E-mail address: nkgarg@civil.iitd.ernet.in (N.K. Garg) 0378-3774/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII:S0378-3774(99)00043-8