Assessment of implicit prices for water resource improvement of tap water users in the downstream of the Ma Sa watershed, Chiang Mai province

Abstract

Population growth and the expansion of economic activities in the Mae Sa watershed has led to an increase in water demand. Additionaly, water shortages, especially in the dry season, have increased, and there has been a degradation in water quality due to excessive uses of agrochemicals and wastewater from various industries in the watershed areas. As the raw water used in tap water production by the Mae Rim Water Works in Chiang Mai province is mainly derived from the Mae Sa watershed, these negative externalities have inevitably affected the welfare of tap water users. Choice Experiments are used to elicit downstream tap water users’ marginal willingness to pay for the improvement of water resources by specifying relevant attributes along with other socio-economic factors. The results indicate the implicit price or the marginal willingness to pay of approximately 90 percent in addition to their usual payments for clean, non-chemical contaminated drinkable water. The demand for water resource improvement also suggests possibilities in developing payment schemes to compensate for soil and water conservative activities that would eventually benefit all the water users in the watershed areas.