Water for people.pdf - WHO Thailand Digital Repository

3 9 6 / P I L O T C A S E S T U D I E S : A F O C U S O N R E A L - W O R L D E X A M P L E SChao Phraya River Basin, Thailandgreatest in these areas although there are also initiatives toencourage industrial expansion in a number of provincial centres.The amount of water used for industrial purposes in the wholebasin is uncertain. Estimates for groundwater use are onlyavailable for the Chao Phraya sub-basin. Considerableinconsistencies are found in the data collected, and it isunknown whether figures also take account of inefficiencies inthe system. A study (Binnie & Partneis, 1997) of industrial wateruse for the eight sub-basins estimated an industrial waterdemand of about 758 Mm 3 in 1996, of which 94 percent wasattributed to use in the Chao Phraya/Tha Chin sub-basins.Surface water supplies are less important to industry with about75 percent of water use derived from groundwater resources.Pipe water use, which is a more economical method oftransporting water because of low evaporation and better waterquality, represents 70 percent of water used. Indicators showthat the polluter pays principle applies to 10 percent, while 50percent of the water is reused.Water and energyHydropower in the Chao Phraya basin is managed by theElectricity Generating Authority of Thailand (EGAT). Currentlythere are only two major hydropower installations, at Bhumiphol(713,000 kilowatts [kW]) and Sirikit (500,000 kW), with asmaller installation at Mae Ngat (9,000 kW) in the Upper Pingbasin. At present, EGAT is not actively pursuing new hydropowerprojects in the basin. The construction of further large reservoirswith hydropower potential would involve large-scaleresettlement, making such projects problematic. New reservoirconstruction in the upper basin has also encountered increasingopposition on environmental grounds. The economic value is notused in water allocation for hydroelectricity generation, butthere is an Environmental Impact Assessment (EIA) for allhydroelectricity infrastructure.Water for citiesAcross Thailand, potable water supplies are generally provided bytwo agencies: the Metropolitan Waterworks Authority (MWA) andthe Provincial Waterworks Authority (PWA). The MWA engages inproduction and distribution of potable water in the Bangkokmetropolitan region while the PWA is responsible for all provinces inThailand. The PWA is also responsible for water resourcedevelopment, conveyance, pumping, treatment, storage anddistribution facilities from all urban and rural communities in theprovinces. Total domestic water requirements in 1993 wereestimated at 3,194 Mm 3 per year. In contrast to industrial watersupply, it was estimated that only 12 percent of domestic supplywas being met from groundwater sources. There is no cross-subsidyfrom richer beneficiaries downstream to pay for the expense ofprotecting the upper watershed. Economic incentives are used inabout 70 percent of the municipal areas, and the polluter paysprinciple is applied in an additional 10 percent of municipal areas.NavigationSince early times, the Chao Phraya River has been a majornavigation route far into the central part of the basin. Ships andbarges have provided a very important means of transport forcommercial goods. However, the increasing diversion of riverflow for irrigation has reduced minimum flow in critical reachesof the river, and navigation is now restricted during the dryseason for vessels over a certain size. A study done for theHarbours Department in 1996 proposed construction of twobarrages to restore navigation capacity in the main Chao PhrayaRiver and into the lower reaches of the Nan River. Minimum riverflow is also required for navigation in other waterways. Althoughgenerally restricted to a smaller and declining number ofcommercial craft, the Pasak (below Rama VI barrage) and theTha Chin Rivers are still important waterways as are a number ofthe RID’s supply canals in the lower part of the basin. Allocationof the basin’s water supplies must take into account the need tomaintain sufficient flow for river transport.Management Challenges:Stewardship and GovernanceOwnership and responsibilityThe Chao Phraya basin has a long history of informal waterallocation. In some northern areas, informal systems have beensuccessfully implemented for over 200 years. The waterallocation systems in the northern parts of the basin differ fromthose in the middle and lower areas. This is primarily due totopography. In the north, the river valleys are small and sociallymore defined. In the middle and lower sections, there wasusually enough water for a rice crop in the wet season, whichwas sufficient to sustain a farm family and allow for homeconsumption throughout the year.The water allocation system in the lower basin is as follows:EGAT controls the water release from both reservoirs. RIDroutinely checks the downstream water level at the Chainatdiversion dam. If this level is lower than what it should be,considering the quantity released by EGAT, then too much waterhas been drawn off by users between the reservoirs and theChainat diversion dam. This phenomenon has led the workinggroup to design a rotation system to conserve water.Organizational and individual users in each province along the