Ecosystem valuation of wetlands: a case study of Vellayani lake

Abstract

The study entitled “Ecosystem Valuation of Wetlands: A Case Study of Vellayani Lake” was conducted during the year 2013- 2014 at College of Agriculture, Vellayani. The major objective of the study was to assess the Total Economic Value (TEV) of the Vellayani lake. The main ecosystem services provided by the lake system were provisioning services such as drinking water, fishing, duck rearing, lotus collection, irrigation, bathing and washing; regulatory services such as ground water recharge, stabilising microclimate; cultural services such as bird watching, photography, boat race, religious rituals and training centres in water sports and finally supporting function such as biodiversity conservation. Based on the ecosystem services, relevant stakeholders were identified and valuated using suitable techniques. The income generation activities of the lake such as fishing, lotus collection and duck rearing were valuated using the market price method and it accounted to Rs.1.83 crores year-1. The drinking water supply schemes installed by Kerala Water Authority, Central Public Works Department and College of Agriculture, Vellayani draws nearly 98,677 lakh litres of water from the lake per year, the value of which is Rs. 370.05 crores year-1. Provision of irrigation water by the lake valuated using opportunity cost method accounted to Rs. 20.69 crores year-1. The economic value of bathing and washing in the lake estimated using opportunity cost method was Rs. 0.009 crore year-1. The lake is also a part of religious activities, cultural activities, and recreational activities. The ecosystem service use by Centralized Sports Hostel for Canoeing, Kayaking and Rowing and Ayyankali Boat Race, valuated using public pricing method accounted to Rs.0.24 crore year-1 and Rs.0.07 crore year-1 respectively. People visit the lake for bird watching, photography, enjoying the scenic beauty, enjoy annual boat race and to attend religious ritual, Karkidaka vavubali. The value of recreational and spiritual services valuated using Travel Cost Method was Rs.0.56 crore year-1. The estimation of aesthetic value of the lake employing Hedonic Pricing Method revealed that, the marginal implicit price of getting one cent of land with lake view evaluated at mean property price of Rs. 2,44250/- was Rs. 79171/- and the aesthetic value of the lake was Rs.275.92 crores year-1. This illustrates the preference given by individuals for land with lake view. The monetary valuation of supporting and regulating functions of the lake was done using a double bounded dichotomous choice contingent valuation method. The mean stated Willingness to Pay (WTP) was Rs.225.22 year-1 for local residents. The economic value of the lake estimated using Contingent Valuation Method was Rs.2.91 crores year-1. Thus the Total Economic Value, which is the total value of ecosystem service use of the Vellayani lake estimated by summating the value of goods and services provided by the lake was Rs. 672.28 crore year-1. Analysis of temporal variation in area of the water body indicated a drastic reduction in area from 558.73 ha in 1973 to 243.39 ha in 2011. The reduction in area was not the result of natural geological process alone, but the major reason is irrational human activities due to demographic pressures. Based on the study it was concluded that the major reason for degradation and loss of wetland services provided by Vellayani lake is the lack of awareness on the value of its ecosystem services, non enforcement of property rights and lack of lake management policies. The major anthropogenic stressors on lake are unsustainable agricultural and fishing activities, watershed impact due degradation and destruction of canals carrying water to the lake and habitat modification. Vellayani lake management policy was formulated based on the study suggests the proper enforcement of property rights by bringing the lake under single management authority with statutory powers including members from line department and stakeholders. The authority may address the present threats on the sustainability of the lake and also chalk out action plan for prevention of further degradation. The low WTP by people indicated that conserving the lake with contribution of stakeholders alone is not practical and so at least one rupee per 70 litres may be fixed as cess to realize a minimum of 13.97 crores per year for the lake conservation. This amount is meager when compared to the TEV of the lake per year. Today’s critical need is to recognize the benefits that could be obtained if the lake is managed in an integrated manner. If not properly managed and degradation and loss continue in the same manner, we are going to lose the invaluable services provided by the lake which cannot be replaced by any other means. Management of lake is a very challenging task and requires actions at many levels and involvement of many stakeholders. The recommendations of the study, along with the values of the ecosystem services of the lake, if properly taken care of, may help in developing sustainable strategies for conservation of this unique freshwater source.