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Locating small town India in a watershed

March 8, 2015

The tankers have started plying and it is not March yet. Small towns in semi-arid India see a crisis of water come summer. The months till the advent of the monsoon are going to be long and hard and full of fights for water in many places.

The next 90 days are sure to be trying ones. What can be done to redress the situation? For one, towns should start to place themselves in a watershed.

What is a watershed? Any area of land where the rainwater falling exits at a single point such as a river or a lake is called a watershed. It is a basic hydrological unit which can be planned for water collection and recharge. The map below shows some of the sub watersheds around the town of Devanahalli north of Bengaluru. Each area bordered by a red line is a sub-watershed usually culminating in a tank .

Devanahalli_24X20

The town of Devanahalli, the birthplace of the legendary Tippu Sultan,  in the centre red area used to draw water from bore-wells from a small tank to its North (in a circle) called the ‘Seehi Neeru kere’ or sweet water tank. The tank is now dry as are the bore-wells located there.

As can be seen from the map, there are 5 tanks  upstream of this sweet water tank. If all of them are de-silted and the channels connecting them kept in shape and without silt or encroachment come a good monsoon the tanks should fill up, overflow and eventually fill the sweet water tank. This will appropriately recharge the aquifers below and enable Devanahalli town to have good water. Unfortunately the jurisdiction of Devanahalli town ends with the Seehi Neeru Kere and does not extend to the tanks North of it. These come either under the purview of the Zilla Panchayath or the Minor Irrigation Department.

Only a coordinated District Plan encompassing the entire watershed upstream of Devanahalli and involving the inor Irrigation Department and the Zilla Panchayath can reasonably hope to provide water to the town as well as the villages and  innumerable townships springing around it.

Down to the South is another circle which shows the large Bettakote tank. This tank gains water from  run-off of rain falling on  the runway of the International Airport. The watershed of the Bettakote tank if maintained well can provide substantial recharge for groundwater. This too can be a source of drinking water for the town of Devanahalli as well as the surrounding villages in an area where groundwater levels are precipitously declining. Thanks to some de-silting works undertaken using the MGNREGA funds this tank has some water and the aquifers including open wells are recharged. A massive upscaling of the de-silting work to encompass all tanks would be most useful to the water situation in the area.

The time to plan for water is now in the summer and to execute tank rehabilitation as well as channel repair works and prepare for the rains. Adopting and understanding the bigger picture of the watershed will enable all users of water to get their fair share.

Planning for water at the appropriate scale is water wisdom.

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