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Developing algorithms for better water resource management

Scientists at IISc may have the solution to one of the major problems faced in our country – water resource management. By applying a technique called the 'Multi-criteria Decision Making' they are trying to address various water management and irrigation challenges.

Multi-criteria Decision Making (MCDM) is a process that helps us choose suitable alternative amongst many possible options. Solutions to such problems could be choosing the "best" alternative from a set of available alternatives or choosing a small set of good alternatives, or grouping alternatives into different preference sets.

Prof. D. Nagesh Kumar from the Department of Civil Engineering is leading a team behind this effort.  Prof. Nagesh, with his colleague Prof K. Srinivasa Raju, Department of Civil Engineering, BITS Pilani Hyderabad Campus, has also written a book on the same, titled “Multicriterion Analysis in Engineering and Management” published by PHI Learning Pvt. Ltd. (ISBN 978-81-203-3976-7).

Irrigation planning is a complex process. Dams and reservoirs collect water during the rainy season and make it available to us throughout the year. Apart from agriculture, cities also have large water requirements. It is essential to store and use water efficiently. Deciding how and where to store water, the volume to be released from a reservoir and the schedule of release to be followed are complex decisions to make. “Multiple-criteria Decision-making process can be a very powerful tool for making irrigation plans”, says Prof. Nagesh. He and his team have developed algorithms and software that help make better decisions.

The newly developed irrigation planning models require engineers to specify input parameters like rainfall pattern, topography, crop type, soil type, inflows to the reservoir etc. They can also specify desirable outputs like crops to be grown, non-agricultural demand for water, etc. The decision making software then calculates the suggested water storage and release schedule. “Though computers do the major part of the work using computational methods, the skill and knowledge of the engineer is still important. The inputs and their weights need to be specified carefully”, comments Prof. Nagesh.

The team has conducted many case studies using their algorithms on water management. Kherthal is a water-catchment area in Rajasthan, a state that receives the lowest rainfall among all states in India. Micro-catchments are small areas where water naturally accumulates after rainfall and they can be enhanced to store water for future use. It is important to decide which micro-catchments are the best candidates for such enhancements. The team used their decision-making algorithms to evaluate 22 micro-catchments in Kherthal and ranked them based on seven different parameters. This sort of analysis can be extremely useful for governments to decide where to spend the money. The team is now working on utilizing non-potable water for irrigation and water distribution of Jaikwadi dam in Maharashtra.

The MCDM algorithms can also be used in evaluating the climate models for predicting the weather. The team has used this process to evaluate the suitability of global climate models for 4 river basins in India  - Godavari, Krishna, Mahanadi and Cauvery.

This new computational aid, developed using solid research, can go a long way in managing water – a resource that is not just unevenly distributed, but also very poorly managed.

About

Prof. D. Nagesh Kumar is with the Department of Civil Engineering, Indian Institute of Science, Bangalore. He is also the Chairman, Centre for Earth Sciences, IISc, Bangalore.

Webpage: http://civil.iisc.ernet.in/~nagesh/

Prof K. Srinivasa Raju is with Department of Civil Engineering, BITS Pilani Hyderabad Campus, Hyderabad.

Webpage: http://universe.bits-pilani.ac.in/hyderabad/ksraju/Profile