WWAP Chapter 16/6 27/1/03 1:37 PM Page 387 Table of contents General Context 390 16 Location 390 Map 16.1: Locator map 390 Map 16.2: Basin map 391 River Basin, Thailand Chao Phraya Major physical characteristics 390 Table 16.1: Hydrological characteristics of the Chao Phraya basin 390 Major socio-economic characteristics 391 Population characteristics 391 Economic activities 391 Table 16.2: Population, per capita income and Gross Provincial Product (GPP) in the sub-basins in 1996 392 Water Resources: Hydrology and Human Impacts 392 Surface water 392 Riverine resources 392 Surface water storage 392 Table 16.3: Annual average runoff in the sub-basins 393 Table 16.4: Characteristics of major reservoirs 393 Barrages 393 Groundwater 393 Aquifer distribution 393 Table 16.5: Groundwater storage and renewable water resources of the sub-basins 394 Recharge, flow and discharge 394 Water quality 394 Surface water quality 394 Groundwater quality 394 Rainfall variation 394 Flooding 394 Human impacts on water resources 394 Data and information on water resources 395 By: The Working Group of the Office of Natural Water Resources Committee (ONWRC) of Thailand* *For further information, contact [email protected] WWAP Chapter 16/6 27/1/03 1:37 PM Page 388 388 / PILOT CASE STUDIES: A FOCUS ON REAL-WORLD EXAMPLES Challenges to Life and Well-Being 395 Water for basic needs 395 Water for food 395 Surface water irrigation systems 395 Groundwater irrigation systems 395 Water and ecosystems 395 Water and industry 395 Water and energy 396 Water for cities 396 Navigation 396 Management Challenges: Stewardship and Governance 396 Chao Phraya River Basin Ownership and responsibility 396 Institutions 397 National boards and committees 397 Regional offices, provincial government and local bodies 397 Water user organizations 397 Legislation 398 The 1997 Constitution 398 Existing water laws 398 Draft water resources law 398 Groundwater 399 Finances 399 Management approaches 399 Policy and policy implementation 399 Government development plans 399 Water resource development 399 Water quality 400 Conclusions 400 Box 16.1: Development of indicators 400 References 400 WWAP Chapter 16/6 27/1/03 1:38 PM Page 389 CHAO PHRAYA RIVER BASIN, THAILAND / 389 Scoop up the water, the moon is in your hands. Zen saying by Kido Chigu (1185–1269) HAILAND’S CHAO PHRAYA RIVER BASIN supplies a major metropolitan region. It covers 160,000 square kilometres (km2), T representing 30 percent of the country’s total area, and is home to 23 million people. Of these, some 8 million live in the capital city of Bangkok. Unlike Japan and France, however, the country has been slow to adopt a comprehensive approach to reform and legislation. It also cannot afford high-tech solutions to such critical water problems as floods, droughts and pollution. When drought conditions lead to water shortages in Bangkok, the result is overpumping of groundwater and subsequent land subsidence and more flooding. Deforestation in the basin’s rural areas leads to flash floods, erosion and landslides. There is hope that the newly created River Basin Committees will bring about a more equitable sharing of the resource and that participatory approaches will lead to wiser governance. WWAP Chapter 16/6 27/1/03 1:38 PM Page 390 390 / PILOT CASE STUDIES: A FOCUS ON REAL-WORLD EXAMPLES HE CHAO PHRAYA RIVER BASIN, traditionally the centre of rice Map 16.1: Locator map production, is in transition from water richness to water scarcity due to the increasing demands on this limited resource. A more T CHINA systematic and comprehensive approach to water management is needed to achieve three purposes: equitability (among the diverse stakeholders), sustainability (for the basin’s rapidly deteriorating aquatic environment) South and efficiency (for international competition). These cannot be INDIA MYANMAR LAO PDRChina Sea accomplished, however, without first carrying out an accurate and up-to- Chao Phraya VIET NAM date analysis of the basin’s water situation. Assessment tools are therefore River basin CAMBODIA essential, and foremost among these are indicators measuring the various THAILAND PHILIPPINES conditions in the basin. This chapter is a first attempt to describe the development of such indicators for the Chao Phraya River basin. Indian Ocean Source: Prepared for the World Water Assessment Programme General Context (WWAP) by AFDEC, 2002. Both initiatives, national and international, are overseen by for trade, government and South-East Asia air transportation, as Chao Phraya River Basin, Thailand Thailand’s National Water Resources Committee (NWRC) through well as being the gateway to Indochina and south China. its secretariat, the Office of National Water Resources Committee (ONWRC). To coordinate these efforts, the NWRC set up a Major physical characteristics subcommittee. As Thailand’s bureaucracy is being reformed1 to The Chao Phraya basin is mountainous with agriculturally increase popular participation and self-governance, as required productive valleys found in the upper region. The lower region by its constitution, a working group represented by involved contains alluvial plains that are highly productive for agriculture. government agencies was created under the subcommittee. This The Chao Phraya River drains from north to south. Monsoon working group’s responsibility is to develop, test and, eventually, weather dominates, with a rainy season lasting from May to transfer the indicators and their uses to River Basin Committees. October and supplementary rain from occasional westward storm The ONWRC is currently working to establish these committees, depressions originating in the Pacific. Temperatures range from and, at the time of writing, all eight sub-basins of the Chao 15°C in December to 40°C in April except in high altitude Phraya River basin have been equipped with River Basin locations. The whole basin can be classified as a tropical Committees. The legislative framework of water management is rainforest with high biodiversity. The lower part has extensive also undergoing reform. The ONWRC is drafting a Water irrigation networks and hence intensive rice paddy cultivation. In Resources Law, updating old laws and facilitating the country’s recent years, however, encroachment of people into forest area systematic water management. in the upper part of the basin and its conversion to agricultural use has become problematic. Location The Chao Phraya River basin covers an area of approximately Table 16.1: Hydrological characteristics of the Chao Phraya basin 160,000 km2 and is located entirely within Thailand. The basin drains into the gulf of Thailand, part of the South China Sea and Surface area of the basin 159,283 km2 the Pacific Ocean. Bangkok, a city of more than 8 million people, Annual precipitation 1,179 mm/year is located near the mouth of the Chao Phraya River. Bangkok is Annual discharge 196 m3/s not only Thailand’s official capital city, but also the capital city Annual potential evapotranspiration 1,538 mm/year 1. As a result, ONWRC together with a few other agencies was combined to become the Department of Water Resources under the new Ministry of Natural Resources and Environment. This new Department became effective in October 2002 and acts as Thailand’s Apex Body in water management planning and implementation. WWAP Chapter 16/6 27/1/03 1:38 PM Page 391 CHAO PHRAYA RIVER BASIN, THAILAND / 391 Map 16.2: Basin map Prakan, Nonthaburi and Pathum Thani are located. Similarly, there is a large concentration of population in the Upper Ping Salween Mekong LAO PDR where Chiang Mai (the second largest city in Thailand) is located. Overall, about 68 percent of the total population of the basin is rural, but there is considerable variation with over 90 percent of the rural population in the Upper Chao Phraya Chiang Mai Muang basin compared to 45 percent in the Lower Chao Phraya basin. It N Nan 2,600 m is projected that in the next decade, the rural population will L Ping Mekong decrease by an annual rate of about 1.31 percent and that the Ping Lampang N basin Muang population growth rate will remain low at about 1 percent per Wang Phrae Sirikit annum. These trends should ultimately induce aggregation of basin dam g farming land with a consequential increase in household n a Nan W 2 Bhumiphol basin incomes. The average population density is 136 inhabitants/km , dam THAILAND 2 L 2,316 m but varies greatly from 44 inhabitants/km in the Nan sub-basin 2 Yom to 533 inhabitants/km in the Chao Phraya sub-basin. Bangkok basin Phitsanulok Tak and its vicinity have the highest population density, with Yom Phetchabun 1,497 inhabitants/km2. Ping Economic activities Pasak basin As Bangkok is located in the Chao Phraya sub-basin, this is Nan Sakae Bung MYANMAR economically the most important sub-basin, contributing Krang Borophet Pasak 78.2 percent of the total GDP of the basin. The sub-basins can be basin Nakhon Chao Sawan Phraya divided into three groups based on their economic growth rate: 1,805 mL basin C Nakhon h a I o Tha Chin, Chao Phraya and Upper Ping, which have higher Noi P h growth rates than the national average; Srinagarind r Bay a Khao Laem dam y of Tha Chin a dam basin Bengal I Pasak and Wang, at about the national average; and Nakhon Chai Si Ayutthaya Ramsar site N Pathom Bang Pakon N Biosphere reserve g Mae Khlong Nonthaburi I the Lower Ping, Upper Yom, Lower Yom, Upper Nan, Lower National park BANGKOK Chao Phraya River Nan and Sakae Krang sub-basins, all of which have lower basin Sub-basins Samut N Prakan Chon Buri growth rates. International Samut boundary Songkhram Gulf Cities of Thailand 100 km The division of the basin into a prosperous north and south and a Source: Prepared for the World Water Assessment Programme (WWAP) by AFDEC, 2002.