Determining the economic value of surface water quality improvements to trout farmers

Abstract

Water quality exerts certain effects on fish farming. This study determined the economic value of strategies for improving surface water quality to trout farmers, with such economic valuation regarded as a decision-making approach for further development. For this purpose, the Kabkian River in southwest Iran was sampled and simulated using QUAL2 K. Here, the dissolved oxygen (DO) profiles of the river under four waste load allocation (WLA) scenarios were obtained. The economic value of water under each of the scenarios was estimated with respect to the net incomes of farmers, DO deficit, and probable losses due to water degradation. Analytical results indicated that the WLA scenarios only slightly increased the economic value of water which minimally compensates for treatment costs. Therefore, implementing strict standards and using advanced technologies for wastewater treatment are uneconomical approaches. Despite the profits generated by increased water allocation for developing fish farms, this strategy is also unfavorable because it degrades the self-purification potential of rivers and reduces the economic value of water in vulnerable areas. The findings indicated that the optimal solutions are to recycle fish farm discharges and implement moderately intensive treatment that preserves water quality and stabilizes the economic value of water at US$0.027/m3