Can GIS rescue South India's deteriorating tank systems?

Several lakhs of farming communities in Tamil Nadu depend on the 39,202 tanks spread around the state. These tanks capture the runoff water from the monsoon rainfall that occurs in a short span of time, and also provide water for irrigation and other uses for the community.

However, these water bodies have been degenerating in the recent past due to reasons such as:

• sedimentation
• encroachments
• damaged water regulating structures
• weak bunds
• disappearance of traditional community governance structures
• over-extraction of ground water
• changes in the land use of their catchment areas and
• inadequate maintenance and neglect

GIS technology to revive the deteriorating tanks irrigation systems

The paper titled 'GIS Technology for Agricultural Management of Tank Irrigation Systems in South India' published in the journal International Journal of Advanced Remote Sensing and GIS, discusses the relevance of using GIS technology to help revive these tanks.

It has been found that the tank irrigation is a profitable technology in economic, environmental and social terms, but its output has deteriorated rapidly. Its output was raised by 12% in 1996-97 and just 6% in 2009-10.

Effective management and utilisation of tanks for use of water for agriculture and irrigation thus requires a thorough understanding of the tank command area by developing a well-designed and comprehensive tank information system.

The study and its findings

Conducted at the Maragathapuram village tank of Villupuram, Tamil Nadu, this study aimed to develop a GIS-based tank irrigation information system to facilitate its planning, operation and management to help the agricultural development of the area. This involved collecting information of the command area, which was recorded and stored as different layers in the GIS in the form of spatial and non-spatial data . The database consisted of two components:

• spatial data representing the distribution of features in the command area, and
• attribute database representing agricultural, irrigation and social data of each of the land holdings.

The study found that:

• The GIS had the capability to integrate and analyse spatial, non-spatial and multi-layered information available in different formats.
• The GIS was capable of generating outputs in the form of maps, tables and graphs that could help irrigation engineers, agriculturalists, farmers and government officials monitor the performance of the tank and manage resources effectively.

A copy of the paper can be downloaded below.