Groundwater management for Lower Indus Basin

https://doi.org/10.1016/S0378-3774(99)00043-8Get rights and content

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.

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 policy for the optimal groundwater withdrawal was determined based on groundwater hydraulics. The present paper aims to find out the optimal pumping rates and the regional changes in hydraulic heads caused by the optimal groundwater withdrawals from the aquifer.

Section snippets

Previous work

Burt (1967) has developed an economic model for allocation of groundwater. The economic consequences of altering various parameters in the model were examined with respect to the effect on the groundwater equilibrium and rate of pumping. Gisser and Sanchez (1980) have discussed the problem of groundwater pumping. They conducted an analytical comparision between a free market behaviour (no control) and optimal control and shown that if the storage capacity of the aquifer is relatively large then

Formulation of groundwater simulation model

The finite element method is used to solve the Boussinesq equation by Galerkin weighted residual criteria. Shape functions are used to approximate the spatial distribution of the variables and the finite difference has been used to approximate the temporal distribution. Eight noded isoparametric elements are used for the domain subdivision. The resulting approximate equations have been solved by frontal solution technique.

The unconfined aquifer hydraulics are described by Boussinesq equation

Formulation of groundwater management model

An algebraic technological function (ATF) relates in a simple algebraic manner the draw down to the pumping stress, which is the behavior that stress produces in an aquifer. Groundwater and economic models can be tied together in a management model through the use of ATF. An ATF relating draw down in wells to the pumping was determined by Maddock (1972). The same concept has been used here.

The draw down at the pth well at the end of qth time period assuming pulse pumping, s(p,q) is given by the

Objective function

The objective function is to minimize the pumping cost which comprises of the variable energy cost and is function of the total lift (draw down plus initial lift), and rate of pumping. The objective function can be expressed as:Minimizep=1Mq=1NT[s(p,q)+L(p)]Q(p,q)In which M is the number of wells penetrating the aquifer; NT the number of pumping periods; L(p) the initial lift at pth well; s(p,q) the draw down at pth well at the end of qth time period and Q(p,q) the pumping at pth well during q

Application

The groundwater hydraulic management model has been applied to the Dadu Canal Command of the Lower Indus Basin. Aquifer testing undertaken during Lower Indus Project at 26 sites indicated that alluvial sediments constituted an aerially extensive, fairly homogeneous unconfined aquifer system.The Dadu Canal Command consists of 210 000 ha irrigated area underlain by homogeneous unconfined aquifer. Mean lateral hydraulic conductivity of the aquifer can be taken as 42 m/day and storage coefficient as

Groundwater management model

To assess the interfering effects on the optimal pumping rates, the groundwater management model is applied to a well field consisting of four wells, chosen arbitrarily from the Dadu Canal Command. Table 1 gives the monthly optimal water releases from different sources for the Dadu Canal Command, obtained from the two-level optimization model (Garg and Ali, 1998) corresponding to existing tubewell capacity of the command. The tubewell capacity is exhausted in peak months, giving an average

Groundwater simulation model

The simulation model has been applied to obtain the groundwater flow pattern for the pumping of optimal amount of groundwater. The monthly optimal groundwater withdrawals have been taken from the two level optimization model (Table 1). Optimal pumping rates are taken from the groundwater management model. The losses are taken to be the same as per the data given in Garg and Ali (1998). The water table contours have been obtained for each month considering the available groundwater recharge

Proposed groundwater development

It is clear from the Fig. 4 that the recharge is getting accumulated in the lower reaches over the years and is causing waterlogging problem. Hence, there is a necessity to increase the groundwater withdrawals. In order to estimate the increased groundwater withdrawals, Garg and Ali (1998) model was run on the same previous data but relaxing the limit on maximum groundwater withdrawals by tubewells. The groundwater withdrawals were allowed at the most equal to the annual groundwater recharge.

Conclusions

Groundwater management studies are carried out for the Dadu Canal Command aquifer of the Lower Indus Basin. It has been shown that the tubewells may be operated at their maximum capacities to pump the required volume of water to get an overall optimum management policy. The simulation model is applied to determine the waterlevel contours for the optimal pumping schedule. The groundwater level contours indicate a serious waterlogging problem in the lower reaches with the existing tubewell

Acknowledgements

The authors express their sincere thanks to Mr. Quamrul Hassan for helping in the preparation of this document.

References (18)

  • N.K. Garg et al.

    Two level optimization model for Lower Indus Basin

    Agric. Water Manage.

    (1998)
  • E. Aguado et al.

    Groundwater hydraulics in aquifer management

    J. Hydraulic Div. ASCE

    (1974)
  • E. Aguado et al.

    Groundwater management with fixed charges

    J. Water Resou. Planning Manage. Div. ASCE

    (1980)
  • O.R. Burt

    Temporal allocation of groundwater

    Water Resou. Res.

    (1967)
  • Bear, J., 1979. Hydraulics of Groundwater. McGraw-Hill International Book Company, New...
  • W.H. Casola et al.

    Optimal control model for groundwater management

    J. Water Resou. Planning Manage. ASCE

    (1986)
  • Chaturvedi, M.C., and Srivastava, V.K., 1979. Study of a induced groundwater recharge. Water Resou. Res. 15,...
  • M. Gisser et al.

    Competition verses optimal control in groundwater pumping

    Water Resou. Res.

    (1980)
  • S.M. Gorelick

    A review of distributed parameter groundwater management modeling methods

    Water Resou. Res.

    (1983)
There are more references available in the full text version of this article.

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