Cauvery riverine ecosystem on decline

Introduction:

The Cauvery has become a never-ending water-sharing dispute between Tamil Nadu and Karnataka. The complete riverine ecosystem in terminal decline.

Problems at the source:

The loss of forest cover and change in land use has meant a decline in rainfall levels, adversely affecting the inflow of water into the Cauvery and its tributaries upstream. 
A rise in temperature has been caused due to the rapid loss of tree cover due to reckless urbanisation in the town. A research shows how the doubling of land under coffee plantations, and developmental projects such as the construction of dams and roads, has resulted into the loss of 28% of the forest cover during the 30-year study period starting in 1977.

Inter-State dispute:

The inter-State water dispute is over a century old. The fight is over an overexploited river basin where demand has far outstripped the supply of water.
Despite many attempts at resolving the dispute, neither the orders of the Cauvery Water Disputes Tribunal nor those of the Supreme Court have been implemented faithfully.

• The Centre has not yet framed a Cauvery ‘scheme’ despite the court’s orders.
• Political parties and farmers in Tamil Nadu have been pressing hard for the constitution of a Cauvery Management Board. 
  According to the court, the Board’s mandate is to manage the distribution of water between the States during distress periods and control the schedule of release of water from the reservoirs.

Concerns:

• Deep borewells- Excessive withdrawal of groundwater using bore wells has caused a significant decline in the base flow of the river. 
  The Bengaluru-based environmental research organisation ATREE has documented how the Arkavathi, a major tributary of the Cauvery in Karnataka, has been sucked dry by farmers using deep bore wells.
• Reclamation of riverbed- In the Cauvery delta districts of Tamil Nadu too, similar unsustainable farm practices are common. 
  With the riverbed remaining dry for most of the year, farmers are reclaiming it for cultivation. In the 25-km stretch from Melur in Tiruchi to the Grand Anicut, there are several banana plantations and coconut trees on the riverbed, irrigated by motor pumps sunk deep into the river.

• The riverbed is heavily encroached on both sides in several stretches. In Tiruchi, for instance, large chunks of the riverbed have been taken over for construction of residential apartments and hotels.
• In parts of Kodagu, sand mining on the banks has widened the course of the river, reducing its pace. 
  While sand mining on the riverbed was a major issue in Karnataka and Tamil Nadu until recently, judicial interventions and a concerted effort to switch to M-sand (manufactured sand produced from crushed granite) for construction has curbed this menace to a considerable extent.
• Hydel power projects on the river are also diverting too much water into reservoirs, thereby affecting the natural flow of the river. 
  In 2013, the South Asia Network on Dams, Rivers and People drew attention to how 98 mini-hydel power plants commissioned or allotted on the Cauvery basin were diverting drinking water meant for Bengaluru.
• Construction of dams on the river- A Central Water Commission report in 2015 pointed out that sediment flow to the Cauvery delta has stopped due to siltation in the dams.

Way ahead:

• Sustainable alternatives such as getting factories to use recycled industrial waste water and rainwater harvesting for domestic use, should be explored.
• Rain harvesting- In the Cauvery basin in Karnataka, at present only 23% of rainwater is harvested. In Tamil Nadu too, rainwater run-off flowing towards Kerala in the Cauvery basin has not been adequately tapped.
• The issue of rampant groundwater extraction, which directly impacts the flow of water in the river, has remained outside the purview of the Tribunal and the court. This needs to be checked by involving all the stakeholders, most importantly, the farmers.

Connecting the dots:

• The complete Cauvery river ecosystem is on decline. Discuss the reasons behind.