Determining the economic value of a wetland of Dhaka

Abstract

Wetlands are the most productive ecosystems on earth. They provide many important services to human society. But most of these services are not evaluated in a monetary term. As a result, loss of wetland for urban expansion is a common phenomenon in all over the world. The recent trend of development in Dhaka has also becoming an alarming threat for the existence of wetlands. Unplanned expansion of Dhaka is encroaching flood plains, depression and storm water retention areas by land filling. As a result, the city is becoming more vulnerable to river flooding and heavy rainfall. It is now high time to assess the economic values of various functions and services provided by the conserved wetlands to prevent its subsequent losses. In this research, an attempt is made to valuate various direct and indirect use benefits of wetland. Nearly 11 sq. km area of the western flood plain of Dhaka is selected as the study area. This area is mainly a low lying flood flow zone designated by Detailed Area Plan (DAP). Direct use of this flood plain includes agriculture, fisheries and recreation. Among various indirect use benefits of flood plains, only ground water recharge function and flood control function are selected for the study. This site is valued as fertile agricultural land in dry season. Local people cultivate paddy during this season from the month of November to April. During the wet season from the month of May to October this area becomes a productive source of fish farming. Variety of fishes is available in this period which is a significant source of earnings for local people. As the site is turned into vast water body in monsoon, at that period it also becomes a place of attraction for city dwellers. The visitors mostly enjoy the scenic beauty of the countryside and also the boating facilities. In the study, the economic benefits of agricultural products and fisheries of the site are derived from Market Price Method. In this method, the prevailing market prices of paddy and fishes traded in domestic markets are used for valuation. Required data for the valuation of agricultural products and fisheries are obtained through focus group discussion of Participatory Rural Appraisal (PRA) method. A cost-benefit analysis is also conducted for these productions. To valuate the recreational benefits of the site, Individual Travel Cost Method is applied. It is a demand based model in which the value an individual attach to a site is estimated from the cost they expend in travelling to that site. For this purpose, an extensive questionnaire survey with nearly 310 user responses is conducted. Flood control function of the area is determined by Damage Cost Avoided Method in which the potential flood loss due to the absence of the flood plain is calculated. In valuing the ground water recharge function, at first per year recharged quantity of water is calculated and then it is priced. Finally, the estimated total economic value of the site amounts to Tk 0.71 million per hectare. Investigating the economic benefits of a wetland is the first step in the direction of formulating a comprehensive wetland conservation plan. Thus, this research would help the policy makers, environmentalists, socialists and planners to figure out the yearly benefits that can be earned from various services and goods of wetland. This would guide the government in identifying the sectoral priorities regarding conservation of wetland and to formulate strategies for the short term as well as the long term effective management of wetland of Dhaka.