Vembanad Lake — the most-visited wetland in the State — provides recreational ecosystem services worth more than ₹700 crore, finds a new study by scientists from the Kerala State Pollution Control Board (PCB) and Israel’s University of Haifa.
The study estimates that an improvement in water quality to a level that supports fish and wildlife well could bring an annual increase of ₹26 crore from domestic tourists alone, aiding not just tourism but local livelihoods too. For the study, published in the November issue of Science of the Total Environment , researchers assessed, valued, and mapped recreational benefits (one of the several ecosystem services) that Vembanad Lake and almost 80 wetlands around it provide to tourists.
Crowdsourcing tool
For this, they used a novel crowdsourcing tool: 4,328 geo-tagged photographs uploaded by Vembanad visitors on Flickr, a social photo-sharing site. Based on these, the researchers predicted where the visitors came from and developed models to estimate the average value of each visit.
By combining this with predictions of visit frequencies from the Flickr photographs, they found that on an average, a visit to Vembanad was worth between ₹2,227 and ₹3,953 to domestic tourism.
Currently, the annual domestic recreation benefits amount to between ₹753 crore and 1,337 crore, despite the water quality in Vembanad Lake being in Category 6 or ‘Below-E’ (the least quality, as per the Central Pollution Control Board’s water quality criteria). By increasing the quality to Category 4 or ‘D’ or better (ideal to support fish and wildlife), the study estimates an increase of ₹26 crore annually in recreation benefits. Similarly, restoring 7% of the lake’s area lost to encroachment since the 1970s could increase annual benefits by almost ₹5 crore.
Compiling the PCB water-and-air-quality data for the project that included more than 80 wetlands paints a “worrying picture of deterioration”, wrote the lead author of the study and doctoral scholar Michael Sinclair (University of Haifa, Israel) in an e-mail to The Hindu .
Wetlands
“The vast majority of wetlands has deteriorated year on year for a decade, specifically coastal wetlands such as Vembanad, Ashtamudi, and Akkulam-Veli.... If these wetlands continue to degrade, it is ultimately them [stakeholders who depend on these wetland ecosystem services] who will pay the price through loss of livelihood,” he said.
Water pollution
To reduce water pollution, the Constructed Wetland (CW) technique — commonly used in developed countries to treat waste water — was highly recommended, wrote Sinclair. Unlike a piped, common sewage system, the CW technique is decentralised and involves installing small units to treat water from a maximum of 10-15 households.
Eliminating underground pipes this way decreased 80% costs; the system did not have operational costs, unlike conventional treatment facilities, explained A.M. Sheela, chief environmental engineer at the PCB in Thiruvananthapuram and co-author of the study.
“In Kerala, contamination of water resources is mainly owing to sewage and sullage from homes and other establishments,” said Dr. Sheela. “Therefore, treating this sewage properly is the need of the hour.”
The research is part of a 3-year international project titled ‘Ecosystem service assessment and mapping for sustainable management of wetlands in Kerala, India’, conducted in partnership with Israeli and Indian institutions and jointly funded by the UGC in India and the Israel Science Foundation.
