The link with a hole

At a time when river networking is being touted as a panacea for the entire country’s water woes, the tide of opinion in Karnataka is turning against the concept. The dissent is moored to a proposed local scheme to divert Nethravathi river.

The issue was broached in the state assembly on March 19. Citing technical and environmental reasons, opposition legislators asked the Karnataka government to do a rethink on the matter. They further buttressed their argument by highlighting the acute water scarcity in the Nethravathi basin during summer, and demanded the constitution of a committee to study the possibility of tapping eastward flowing rivers.

It was in 2002 that Karnataka chief minister S M Krishna put forward the proposal to redirect the Nethravathi, which runs in a westward direction, for providing drinking water to some drought-prone districts located in the northern and eastern parts of the state (see map: Rerouting a river).

A committee that was set up under the state irrigation department on August 26, 2000, is evaluating the plan. While its chairperson, G S Paramasivaiya, mentioned that the river would be diverted “purely by gravity”, he refused to divulge details about the scheme’s assessment criteria on the pretext that the interim feasibility and technical reports were “confidential”. Down To Earth has, however, obtained copies of the two documents dated March 23, 2001, and October 2002, respectively. From a logical viewpoint, they are an awkward read.
Ins and outs The Nethravathi River Water Diversion Scheme was originally conceptualised as the biggest groundwater recharge and drinking water supply project in the country. The plan revolves around the construction of four “garland canals” covering 1365 kilometres (km) on the Western Ghats, and 13 service canals stretching across 2237 km in northern and eastern Karnataka (see table: Grandiose dimensions). The 10 districts that would benefit from the scheme include Bangalore urban, Bangalore rural, Chikmagalur, Hassan, Chitradurga, Kolar, Bellary, Tumkur, Davangere and Mandya. Of these, Bangalore urban is to be supplied 12 thousand million cubic feet (tmc) of drinking water.

Grandiose dimensions
The scope of the Nethravathi river diversion project

Schemes

Length of
garland canals
(in km)
Length of
service canals
(in km)
Total catchment
area (in square km)
Water to be diverted
(in thousand million cubic feet)
Number of
reservoirs
East scheme 785 1217 846 179 27
Northeast scheme 580 1020 514 85 11
Total 1365 2237 1360 264 38

Source: G.S. Paramasivaiya 2002, Technical note on the Nethravathi River Water Diversion Scheme, Irrigation department, Bangalore, October, p 9 and 13


The project is divided into the eastern and northeastern schemes. As per the former, the Nethravathi is to be linked with Hemavathi river in the Cauvery basin. In the latter, it would be connected with Tunga and Bhadra rivers in the Tungabhadra basin.

The garland canals would collect water from the ridges, transferring it by gravity to the command areas with the help of service canals.

The interim feasibility and technical reports assume that 264 tmc of water, out of a total of 450 tmc that drains into the Arabian Sea, can be diverted from the Western Ghats to the eastern border of the state. Interestingly, the committee has found this technique “ingenious” since it would entail providing water to parched areas rather than letting it flow into the sea.

The main objectives of the scheme as outlined in the two preliminary reports are:

To supply drinking water to 2.5 million people residing in central Karnataka and Bangalore Urban district.

To recharge water tables in drought-affected districts of the state.

To provide water to 12,000 mini irrigation tanks in the command areas of the state.
Does it hold water? The feasibility report is premised on “some” site inspections, and “four” committee meetings which “unanimously” gave the green light to the eastern and north-eastern schemes. This outright endorsement raises questions about the depth of the study.
Indeed, some experts are of the opinion that the project is not practicable. They have put some pertinent posers:

quantity inadequate? The study pegs average rainfall in the catchment area at 6000 millimetres (mm). This figure is derived from data collected by a rain gage station which is sited at a low level. But the garland canals are located at a greater height where the rainfall received is much lesser. Furthermore, the Karnataka government’s records reveal an average precipitation of only 1000 mm over the past 10 years. The wide discrepancy has not been accounted for in the report. “The runoff is assumed to be 100 per cent, which is also debatable,” says S Raja Rao, former secretary, minor irrigation and environment, Karnataka.

against newton’s law? It is claimed that gravitational force will carry Nethravathi river’s water from the Western Ghats to the Deccan plains over several ridges. According to A N Yellappa Reddy, chairperson of the eco-restoration task force, state irrigation department, water is not known to flow from lower to upper regions on the basis of gravity. Paramasivaiya’s assertion that no tunnels will be dug and no pumps used has further confused the issue.

groundwork not done? To execute projects of such magnitude, it is imperative to first understand how hydrological regimes operate. Paramasivaiya’s report relies heavily on studies in which toposheets have been used. “Toposheets do not provide information regarding various streams, cross drainage work and ground strata,” points out Rao.

experts excluded? The credibility of the feasibility report is in doubt because specialists from various fields were not consulted. “This is a drinking water supply scheme, but does not contain the views of any expert on the subject,” laments an irrigation department official.

environmentally unsound? Toposheets indicate that garland canal No. 1 cuts across Kudremukh forest as well as the state reserve forest. In order to construct 38 mini reservoirs, approximately 7717 hectares (ha) of land will be submerged. Eighty per cent of this is forestland. According to Reddy, “The Western Ghats are among the world’s best biomass production zones. Sadly, the estuaries in the region will be destroyed by this scheme.” Paramasivaiya feels such fears are unfounded as the canal alignment will run along grasslands. These tracts, he avers, are not a part of the forest biodiversity. One statement in the report succinctly sums up the committee’s insouciance: “In the name of maintenance of ecology, there shall not be obstructions for development.”

financially unviable? There is still a lot of ambiguity regarding the economics of the Nethravathi scheme. Though Paramasivaiya estimates its cost to hover around Rs 170 crore at current prices, no funds have been allocated for the project in the 2003 state budget. All the same, the committee chairperson is confident about getting financial assistance from Dutch and Danish funding agencies. Meanwhile, he has informed dte that compensation packages for coffee plantation owners

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