Mhadei River also known as Mandovi River in Goa gets about 3,538 MCM (million cubic meters) or 200 Thousand Million Cubic feet (tmc ft) of water every year. Neighboring states are planning to divert 214 MCM or 7.5 tmc ft of water from the River. Although it may not seem much when calculated in total. But what is missed by the eye is that the proposed diversion is actually from the non – monsoon period.
During the non – monsoon season the quantity of water available in Mhadei will decrease due to lack of rain. News reports have been substantially ambiguous over it. Reports in two prominent news organizations have confusing figures to show.
One organization wrote that 204 mcm would be diverted while another organization said 255 mcm. From the varied sources it is evident 3% to 6% of the total water will be diverted. A study at a later period claimed that the water diverted during the non – monsoon season will actually measure up to 22% of the capacity of the river.
The Karnataka Government has proposed to build dams on the Mhadei River upstream. However dams may not be a sustainable idea. Dams have been a norm in dealing with water crisis; but it has many negative impacts to it.
Negative impacts of building dams,
- A large area goes under water.
Dams store a huge amount of water and that needs large quantity of land as well. Hence when a dam is proposed the storage area will engulf everything and that amounts to loss of life. This includes animals, plants, insects etc.
Water carries particle with itself and these particles are deposited at the dam. The soil over the years ends up decreasing the capacity of the dam to hold water unless regular dredging is carried out.
This too is not a permanent solution as the river carries sediment downstream to replenish the ecosystems. If a dam is built the eco – system will receive water but nutrients it requires will be stuck at the dam.
- Reduced flow.
Flow the water source enjoyed before the dam was built is affected. Downstream the water level dips or totally dries up.
Although dams are bad, there is no strong enough cure for them or there is no sustainable alternative to replace them. Goa in the 80’s, under the then Chief Minister Pratapsingh Rane signed a MoU with then Chief Minister of Karnataka S R Bommai, to give 45 tmc ft of water from Mhadei to Karnataka and a power station would be set-up upstream. The power generation would be shared with Goa.
The plan never came to fruition because Bommai government collapsed very soon. In the subsequent years the project was renamed to Kalasa-Banduri nala project. Goa has opposed any such plan on Mhadei River because of the impact it will have on the ecology downstream of the projects.
Karnataka’s quest began in 1980, when people from Navalgund and Naragund taluk began agitating, demanding the government for water. Violence during the agitation cost 4 lives. This included two policemen. This eventually became the issue it is today.
Picture – The Mhadei river during low tides, the mangrove trees on its bank are considered to be environmentally important.
Credit – Harvinder Chandigarh
License – https://creativecommons.org/licenses/by-sa/4.0/deed.en