Pongsak Suttinon

Financial feasibility is usually a concern in water reclamation projects. Aside from internal benefits, water reclamation in industrial parks delivers health and environmental benefits not normally considered in cost–benefit analyses (CBA). This study investigated the influence of environmental benefits on the feasibility of water reclamation projects with flow rate scenarios in accordance with industrial parks in Chonburi, Thailand. CBAs of water reclamation plants for industrial water supply, consisting of ultrafiltration (UF) and reverse osmosis (RO), with flow rates of 5200, 10,000, 15,000, and 25,000 m³/day and discount rates of 3%, 5%, 7%, 9% and 11% were conducted. Considering only the direct costs and benefits, none of the projects were financially feasible. However, when the environmental benefits were included, the projects became profitable in all cases except those with a flow rate of 5200 m³/day and discount rates of 5%, 7%, 9%, and 11% and those with flow rates of 10,000 and 25,000 m³/day and an 11% discount rate. Further, CBAs of water reclamation projects in industrial parks for irrigation were conducted with post-treatment processes consisting of sand filtration and chlorine disinfection for flow rates of 240, 480, 2400, 3600, and 4800 m³/day. The projects are profitable, regardless of environmental benefits.

Nan River Basin contributes about 25 to 40 percent of annual flows in the Lower Chao Phraya River Basin, Thailand. Land use and climate change result in change in meteorological and hydrological conditions in Nan River Basin. In addition, water demand in the basin has been increasing from the economic development. Understanding cross-sectoral interactions from both water resources and economic points of view provides better insight in planning and management. This study proposes an integrated framework of hydrological and economic analysis to assess impacts of water deficits under changing climate and regional development. The objectives of the study are to analyze water supply under climate change scenarios, estimate water demand under economic development scenarios, and assess cross-sectoral impacts of water deficits. A rainfall-runoff model, integrated flood analysis system (IFAS), was calibrated, verified, and used to simulate runoff. Regional input-output model was developed for Nan River Basin to assess economic impacts of water deficits. Analysis of water deficits under climate change scenarios and economic development scenarios was carried out during the period of 2040-2059. Runoff simulations under climate change scenarios using two GCMs, IPSL-CM5A-MR and MIROC5 under RCP4.5 and RCP8.5 showed increasing trend. Water demand projections of all sectors also showed increasing trend especially in agricultural sector. The uncertainty of water supply under the climate change scenarios is found to be relatively small compare to the uncertainty of water demand under the economic development scenarios. Assessment of indirect economic loss from cross-sectoral analysis is found to be two to three times higher than the direct loss. The results demonstrate the need to consider the indirect economic loss across sectors in water allocation planning and water deficit mitigation policy.

Nan River Basin contributes about 25 to 40 percent of annual flows in the Lower Chao Phraya River Basin where main agricultural, manufacturing, service, and domestic water use sectors located. Water allocation during dry season depends mainly on the amount of water storage at the end of rainy season in the four main reservoirs in the upstream of the Chao Phraya River. However, impacts across sectors are also important in developing strategies to mitigate drought. Understanding cross-sectoral interactions from both water resources and economic point of view provide better insight in decision making. This study proposes a framework of cross-sectoral analysis of water allocation during dry season between three sectors (agriculture, manufacturing, and service and domestic) in the Nan River Basin with the consideration of impacts to the Lower Chao Phraya River Basin. An assessment model in this study is based on the water budget and the Input-Output model. Preliminary results of economic analysis of cross-sectoral impacts of water allocation in the Nan River Basin show the importance of considering interactions between sectors and non-hydrologic factors in developing strategies to mitigate droughts.