ECONOMIC VALUATION

Economic valuation is an attempt to assign values in terms of market price for the goods and services offered by the ecosystem. In Economic terms, the goods and services are broadly grouped as use and non-use values⁶ as in Table 1. Valuation technique include “willingness to pay” reflecting individual’s choice for the ecological commodities (aesthetic value, recreational opportunities), wood products and intrinsic values^7,8 and also captures its values in an economic value framework⁹. The commonly used technique for the valuation is the contingent valuation technique based on personal interactions with the local people using questionnaires; information on willing to pay for something they value or willing to receive in compensation for tolerating a cost.

Table 1: Classification of total economic value for wetland

The zero ecosystem benefits imply zero human welfare³, thus economic value of a wetland varies from a pristine (natural benefits) to polluted (degraded ecosystem’s benefits) wetland; influenced by a defined set of environmental conditions. Wetland value increases with quality of goods and services derived and vice versa.

Numerous studies on economic valuation of wetlands have been carried out around the world; however, most of these studies have focused on wetlands in developed countries¹¹. Economic studies for Indian wetland are meager addressing serious threats due to agricultural conversion, hydrological alteration followed by urbanization in recent years owing to 60 % loss.

Several studies across countries in the past few decades support the estimation of economic value of a wide variety of goods and services. The annual value of wetland was estimated to be second highest, US$ 14 785/ha based on the assessment of 17 ecosystem services in 16 biomes which emphasize that ecosystem functions provide an important portion to the total contribution to human welfare³. Other studies include wetlands of Africa¹¹, China¹², Bangladesh¹³ and the European water framework directive of European Union (EU) (2000/60/EC). Assessment of the health of wetlands in China highlights that among all factors, water quality, ecosystem function and structure of waterfront area as the main factors that limit the wetlands value. Study of Mississippi Alluvial Valley focuses on the restoration of wetland ecosystem services in the floodplain area which has profound consequences due to habitat loss, fragmentation, flood storage loss and water quality degradation due to non point source runoff¹⁴.

Many wetlands in India including those in Bangalore are being degraded due to the apathy of the decision makers and planners. These wetlands, urban as well as rural paved way to residential layouts, industrial complexes and indiscriminate disposal of urban wastes which has led to the deteriorating water quality and significant changes in local climate. Number of wetlands has dwindled from 250 to 81 (1985) and 33 in 2006¹⁵. Population of Bangalore reached 7 million in 2007¹⁶ due to the spurt in unplanned urbanization and consequent land use activities. Effects of sustained inflow mainly of sewage, industrial effluents and agricultural runoff is evident from the results of regular monitoring of water quality at Hebbal, Varthur, Madiwala, Rachenahalli and Amruthalli wetlands¹⁷. A comparative evaluation of Amruthhalli lake with the relatively unpolluted Rachenahalli lake² brings out the impact of degrading ecological integrity of wetlands evident from the drastic decline of values from Rs.10, 435/ha/day (Rachenahalli lake) to Rs.20/ha/day (Amruthalli lake). Lower value is mainly due to eutrophication and water being unavailable for any use with an excessive nutrient inflow (sewage and industrial effluents) and storm water. Discharge and dumping of waste into catchment area lead to high levels of phosphates, Total Suspended Solids (TSS), Alkalinity, Hardness, Odour, weed infestation and low dissolved oxygen (DO). Study of Hebbal lake also reflect decreased water quality due to excessive sewage and industrial effluents inflow from surrounding area. The Contingency valuation technique employed for preliminary socio-economic survey reveal high level of dependency on wetlands for ground water, food, fodder, fuel and so on. The lake supports irrigation, provides food (fish, etc.) and fodder to the livestock in the surrounding areas. The investigation of causes of mass fish mortality in Sankey Lake¹⁸ revealed that the death was due to a sudden and considerable fall in dissolved oxygen (DO) levels in some locations caused by sewage let into the lake resulting in asphyxiation. An incidence of mass-scale fish mortality in Bangalore reported from Ulsoor Lake¹⁹ supported the above study. These studies highlight the significance of maintaining wetland’s quality to ensure sustained ecological functions contributing to economic values.

Bangalore was known for its lush greenery with numerous wetlands; Varthur wetland being one of the largest amongst all. Rapid unplanned urbanization coupled with the increase in population has affected both Bangalore and its surrounding towns and villages, including Varthur¹⁵. Varthur lake constructed 1000 years ago by Ganga rulers, today receives almost 40% of Bangalore sewage to the extent of 450-500 minimum lethal dose per day (MLD/day). Part of city’s untreated sewage passes through the network of interconnected lakes such as Bellandur and Ulsoor apart from many households directly in the immediate vicinity in a span of 220 hectares. The quantum of sewage exceeds the wetlands ability to assimilate contaminants and hence water quality has declined and has become unfit for human consumption. The contaminated water from Varthur ultimately flow downstream connecting Dakshina Pinakini River. Considering the dependence and impaired livelihood due to decline in ecological functional ability and capability consequent to sustained inflow of sewage and effluents, necessitates the ecological restoration of the lake. This entails understanding of the physic-chemical aspects with the wetland dynamics and the valuation of ecosystem services and goods. The study was carried out with a hypothesis that accumulation of contaminants has been responsible for degradation of water quality and consequent erosion of ecosystem services and goods. In this backdrop, Varthur wetland was investigated for water quality and valuation of the benefits to understand the drivers responsible for wetland degradation and impairment of economic benefits.

The study objectives are to:

1. assess physicochemical water quality variables and
2. economic valuation of wetlands through contingent valuation technique, focusing on the causes for wetland degradation and appropriate allocation of wetland use.