BENGALURU:Aghanashini is a most unusual river. It takes birth in the Western Ghats near Sirsi in the Uttara Kannada district and flows west unhindered by any dam until it pours itself into the Arabian Sea in Kumta taluk. Along the way it glides by some beautiful riverside scenery, supporting some ecologically important vegetation such as the mangroves in its estuary.
Other than the Aghanashini, the Shastri in Ratnagiri district of Maharashtra is the only river in the Western Ghats that enjoys such freedom. Together, the Aghanashini and the Shastri are living proof that minimal human interference by way of dams, townships and water-intensive agriculture is a crucial element in preserving the health of a riverine system.
Spanning five states — Gujarat, Maharashtra, Goa, Karnataka and Kerala — the Western Ghats are so abundant that new endemic species of flora and fauna are still being discovered. The Aghanashini used to be an exception among the river ecosystems of the range, which have suffered irreversible damage due to exploitation.
Now, changing climatic conditions, increasing agricultural activity, depleting river resources, intensive fishing and depleting groundwater table threaten the remaining tinge of green. Rainfall studies in the Western Ghats have clearly indicated that the region is witnessing fewer rainfall days but there’s sharp bursts of rain during those days. This can have a disastrous impact on the flora and the fauna of ecosystems like the Aghanashini: swifter runoff, more erosion and siltage of reservoirs and droughts punctuated by sharp floods.
Parineeta Dandekar of the South Asian Network on Dams, Rivers and People (SANDRP) interprets what this can mean for the Western Ghats: “If you want rain water to percolate, you need gentle rain. On the steeper slopes of the Ghats, heavier rains increase the chances of landslides. So levelling and terracing of these areas can have a bad impact is ill-advised. The surface run-off has an adverse impact as the water-retaining laterite soil gets washed away.”
Dandekar is a dam sceptic. The topography of the Ghats is such that dams can be built but not canals. If you do manage to construct canals, flow is hindered or there is a lot of seepage. Dandekar tells you of the fruitless efforts of the Maharashtra government over the last 15-20 years to ‘develop’ the Western Ghats. The state spent spent Rs 6,000 crore on dams here but not a single is completed. “They now say they might need Rs 10,000 crore.” But governments continue to plan large dams even if they submerge forest land, are not suitable for the topography and have no relevance to local cropping patterns.
If not by dams, then the fragile ecosystem is damaged by the numerous mini hydel projects peppered generously along the Western Ghats. Taking shelter under a clause of the Environment (Protection) Act which does not require green clearance for projects below 25 MW, they are creating havoc. Many of these projects are owned by influential people who get around scrutiny through fraudulent claims, says Himanshu Thakkar of SANDRP. If you want to know why the people living along the Aghanashini are fortunate, you need to look at the Sharavathi. It used to have water round the year, now it’s down to 6-8 months.
Dammed vs undammed
The Centre for Ecological Science at the Indian Institute of Sciences compared the estuaries of the Aghanashini and the Sharavati. Here’s a summary of findings of the case study by Mahima Bhat, V N Nayak and others
There were 90 fish species observed in Aghanashini estuary and only 43 in the Sharavathi.
There are 20 fishing villages in the Aghanashini estuary and 10 in the Sharavathi estuary. The fisherfolk in the undammed Aghanashini were more than 6000, while the Sharavathi estuary supported only 283.
The 1977 hectare open estuary of the Aghanashini generates an annual fisheries income of Rs 553,905 per hectare. The 977 hectare Sharavathi estuary produces a low Rs 13,155/ ha in comparison.
More marine species
More marine fish species migrate up the Aghanashini than the Sharavathi.
What’s happening in the Western Ghats?
Studies show that climate change events and the drift of ‘development’ are combining to produce deadly effects
Short bursts of heavy rain = landslides + swift runoff
Rainfall time series data analysed by the energy and wetlands research wing of the Indian Institute of Science (IISc) project a decreasing trend in rainfall over forest and agricultural grasslands in the northern, central and southern Western Ghats from 2013 towards 2020. The changed pattern can have a disastrous impact on the flora and the fauna of ecosystems like the Aghanashini.
Levelled land = erosion + low infiltration
One study conducted on the Laxmantheertha watershed of the Cauvery, showed water availability in watersheds was higher in areas with higher forest cover. “The presence of forests in the Western Ghats has its role in slowing down surface runoff, increased infiltration, higher water storage capacity in the vadose (below the surface and above the groundwater table) and higher recharge into the ground water,” the study says.
Loss of catchment vegetation = Water scarcity
Studies point out that vegetative cover of catchments is down to 14.4 per cent, compared to the national mandate of 33 per cent. Greater forest cover in a catchment would help to meet the demand for water during the post monsoon months. TV Ramachandra, who headed the study on changing rainfall patterns says: “Rainfall has gone down from 4,500 mm to 1,800 mm.”