The Nandi Hills range is the closest weekend hill retreat for many from Bengaluru who take off for a day trip in rather salubrious climes. It is of interest to note that six rivers originate from these ranges — Arkavathi, Chitravathi, Papagni, Uttara Pinakini or Pennar, Dakshina Pinakini or Ponnaiyar, and Palar.
For a long time i.e. from 1895 to 1972 the Arkavathi was the lifeline for Bengaluru. First the Hessarghatta reservoir, and then the Thippagondahalli reservoir provided fresh water to the city. Upstream, the river provides water for Doddaballapur town and a rapidly industrialising area around it.
The Chitravathi is a tributary of the Pennar. Near Bagepalle town at Paragodu a small reservoir on the river provides drinking water to the town as well as to many villages nearby. This water is free from fluoride since the groundwater, the other source, is mostly contaminated with it. On the Pennar, about 10 km. from Chikkaballapur town, a small reservoir has been enlarged and extended from an older silt trap reservoir to become the Jakkalamadagu dam. This continues to provide water to Chikkaballapur and now some water to Doddaballapur town. Water from the Pennar now reaches Doddaballapur which is on the Arkavathi, an inter-basin transfer of water. It is also true that water from the Pennar reaches Chikkaballapur town which is on the Chitravathi, though the Chitravathi eventually joins the Pennar and is therefore part of the Pennar basin.
Within 10 to 15 km of the Nandi Hill range reservoirs on the various rivers which arise here are providing drinking water to towns with populations of 50,000 to 100,000. These towns are growing and their economic need for water too is increasing. Agriculture in these areas is also dependent on groundwater.
The Nandi range is also home to many religious and spiritual shrines which are located on springs that emerge from the ground fed from rain on the upper part. The birthplace of Sir M. Visvesvaraya is just below one of the peaks, Skandagiri, and at his house in Muddenahalli are two wells. One of the wells is dry and the other, a large step-well, though having water is in a dilapidated shape.Restraint needed
If we have to ensure that the six rivers stay healthy and if we want the reservoirs to continue to supply waters to the towns then attention must be given to the forests and ecosystem of the range itself. Quarrying goes on in these places which are ecologically sensitive. Agriculture expands into forests and trees are being cut. Large institutional buildings are coming in. Layouts and resorts are being developed. Tourists throng the place unregulated.
In Jakkalamadagu reservoir one can see heavy siltation. An inauguration stone laid by Sir M. Visvesvaraya in 1955 mentions that this is designed as a silt reservoir to prevent the accumulation in Srinivasasagar tank downstream. Lack of attention to the catchment will see significant erosion and the rapid reduction of the holding capacity of the reservoir.
Protecting the ecology and the environment of the ranges will protect the rivers and fresh water. This will also help an orderly development of the place in a sustainable fashion. Unless an institution is created and armed with powers to manage this sensitive area we will see the gradual demise of a culture centered around water and the death of six rivers. The time to act is now and that would be water wisdom.