BHUBANESWAR: Bhitarkanika Wildlife Sanctuary, a key mangrove ecosystem of India, could face serious freshwater supply crisis in future since water discharge at Brahmani as well as Baitarani river basins is projected to dwindle due to excessive demand of development projects and population growth in the region, says a latest report.
The report titled "Hydro-Ecological Assessment for Integrated Management of Bhitarkanika Ramsar Site" computes freshwater supply at the sanctuary to drop to 46 per cent (pc) of the water resource availability in the next 30 years.
"The biggest threat seems to be coming from mining and industrial activities of Talcher, Angul area but reduced freshwater flow due to irrigation projects and diversions such as the proposed mega drinking water project in which water diversion is proposed from Kharasotra river to other areas may further amplify the threat many fold," the report stated.
The Ramsar site is home to the largest population of salt water crocodiles, rookery for Olive Ridley turtles as well as a cushion against natural calamities. Currently, the mega drinking water supply project on Kharasrota river in Kendrapara district by Odisha Government has already triggered a massive controversy.
The report used a modelling system to compute fresh water availability for the year 2051. It calculated that water availability at Brahmani basin will decrease to 31 pc in 2051 from 79 pc in 2001. In Baitarani basin, the water outflow will reduce to 35 pc in next three decades as against 61 pc in 2001.
Overall, water availability for the mangrove ecosystem will fall from 74.64 pc in 2001 to 46 pc after consumption of water in both the basins.
Using land use and land cover (LLUC), industrial as well as development activities, the future demand was calculated. Industrialisation, urbanisation and growing population would raise water demand by 306 pc from current demand in both the basins which the report said would reduce availability of freshwater to Bhitarkanika Wildlife Sanctuary.
The report combined field survey with secondary data to make the projections. It said demand of water for major and medium irrigation irrigation will grow past 10,000 million cubic metre (MCM) in 2051 from the 2001 level of 2,000 MCM.
The overall demand would have jumped from 5,332 MCM to 16,347 MCM during the period, says the report of Ministry of Environment, Forest and Climate Change funded by GIZ, New Delhi.
Bhitarkanika may starve for freshwater
It said that intensification of economic activities upstream, especially mining and industrial activities in Brahmani basin and number of multipurpose hydro power, irrigation dams and upcoming water projects along the rivers are likely to damage biodiversity of the area.
The project analysed flow data of gauge stations from 2002-03 to 2011-12 and also estimated freshwater availability at Bhitarkanika Sanctuary boundary during monsoon and non-monsoon seasons. A total volume of 23,551 MCM water enter the sanctuary boundary within a year of which 19,924 MCM (85 pc) and 3,625 MCM (15 pc) occur during monsoon and non-monsoon season respectively). It calculated that the sanctuary needs 8,561 MCM water each year for its sustenance.
The report said there may not be any significant change in overall future water availability due to increase in population though it might marginally be impacted by rainfall due to climate change. A 10 per cent reduction in rainfall would reduce water supply by six per cent.
However, developmental uses will severely affect the sanctuary ecosystem with reduced inflow from Brahmani river as maximum developmental activities are to be carried out in the basin.