GIS Based Decision Support System for Conjunctive Water

Use in Irrigation Projects

N.H.Rao

NAARM

GIS : art, science, engineering and technology associated with spatial patterns and processes;

computer hardware and software system to collect, manage, analyze, and display spatially referenced data

Decision Support System: Interactive computerised tool under user control to help in making decisions;• Have analytical capabilities

(graphical and modelling)• Allow combining computer input

and output with judgment• Are custom fit (no general

package)

Conjunctive Use

Integrated management of surface water and ground water resources in a region to meet specified objectives:

• augment canal supplies

• control water table

• maximize production/income

• control groundwater pollution

f(weather, soils, water, land use economics)

f (spatially variable resources, time)

f(geographically referenced data, time)

GIS

Maps, Computers

Process with

Conjunctive use involves dealing with spatial patterns/processes

Conjunctive use decisions require :

Tools to:

• identify relatively homogenous spatial units over which weather, resources, land use etc. are homogenous ---GIS

• assess recharge/unit and its spatial distribution (percolation + seepage models)

• assess impact of recharge and pumping distribution on water table (groundwater flow model)

• identify suitable conjunctive use strategy (simulation, optimization)

USER

DecisionsProblem situation

Input Information

Decision Support System

Knowledge/ Expert system

Data Models Reports

GIS

GIS based DSS for conjunctive use