1. GIS Based Decision Support
System for Conjunctive Water
Use in Irrigation Projects
N.H.Rao
NAARM

2. 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)

3. 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

4. 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

5. 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)

6. USER
Decisions
Problem
situation
Input Information
Decision Support System
Knowledge/
Expert
system
Data Models Reports
GIS
GIS based DSS for
conjunctive use