The national water resource system of Cambodia consists of a number of river basins, most of them tributaries of the Tonle Sap Lake and Mekong river systems, and a few river basins in the Southwestern part which drain directly to the coast. All of the river basins experience a set of common challenges, while those in the environmentally delicate Tonle Sap Lake region share a unique set of issues and challenges.
The overall IWRM goal of the Royal Government of Cambodia (RGC) is to develop its water resources, mainly for irrigation and hydropower, by rehabilitating old defunct irrigation systems, and by planning dams for hydropower generation, irrigation and flood control. The RGCâ€™s IWRM vision is as follows
- Access for all people to safe, adequate and affordable drinking water, hygiene and sanitation.
- Freedom for all people from the threat of loss of life and livelihood as a result of floods and droughts.
- Sufficient water where it is needed, to provide for food security, people’s livelihoods, and economic activity.
- A water environment that is unpolluted and supports healthy fisheries and aquatic ecosystems.
Cambodia faces many water-related issues. They can be grouped as follows:
- Competition for water: Sharing the resource.
- Sustaining the resource: Water quality and aquatic ecosystems.
- Extreme events: Mitigating the effects of floods and droughts.
- The knowledge base: Knowledge, information and technology.
- Institutional arrangements and management capacity.
Water shortages in the dry season, exacerbated by occasional droughts, makes the people dependent on wells and rainwater for their basic water needs in the upper catchments. Also, in-stream users such as urban water supplies have to either extract from the riverbed water or reduce services. There is also additional agricultural water use during the dry season that will lead to competition between the farmers themselves, and between farmers and other water users.
The following is an overview of the IWRM status in Cambodia for the key water management issues in Cambodia.
- Water Supply Management
The percentage of the population having access to piped drinking water in Cambodia is about 7% in 2000 and 18% in 2012. The average hour of water supplied per day is 16 hours in 2010. Table 1 shows the Millennium Development Goal (MDG) for urban water supply for Cambodia.
Figure 1 shows the number of urban people having access to clean water versus the total urban population from 2008 to 2012.
Phnom Penh Water Supply Authority (PPWSA)
Phnom Penh is the capital city of Cambodia. The following is a brief description of the water supply services provided by PPWSA.
Figure 2 shows the rapid expansion of the water supply service coverage areas for Phnom Penh city by PPWSA from 1993 to 2015 and the future coverage areas in 2020. It also shows the locations of the four major Water treatment Plants (WTP) in the city.
Figure 3 shows the rapid expansion of the water supply metering by PPWSA for Phnom Penh city from 1993 to 2013.
Figure 4 shows the rapid expansion of the water supply production capacity by PPWSA for Phnom Penh city from 2003 to 2012.
- Irrigation Management
Irrigation development have a rich history in Cambodia and can be trace back to the Angkor period, especially from the 11-14th century. During the Khmer rouge regime period from 1975 to 1978, forced labours were used to build several hundred irrigation schemes across Cambodia within a 3 years period. Currently, irrigation development is still an important issue for Cambodia. Currently, there are more than 2,000 irrigation schemes in Cambodia, but the total irrigated area during the dry season is only about 15% and in the wet season it is about 35% of the total cultivated area.
In August 2010, the Cambodian government has set the goal of exporting milled rice of up to a million tons by 2015. To achieve this goal many strategies have been developed and implemented. One of them is to expand the construction and rehabilitation of irrigation systems across the country, so that rice production can be carried out the whole year round, instead of being dependent on rainwater.
Thus, there is a need for water storage reservoir to store water from the wet season for use during the dry season. Also, water shortages during the short spells of small dry seasons during the wet season, can also adversely affect irrigated agriculture if there are no water storage reservoirs. The low water use efficiency and productivity in irrigated agriculture has also resulted in excessive water use and low irrigation productivity. Also, there is underutilization of the irrigation potential in the Cambodian part of the Mekong delta.
- Flood Management
Floods occur during the rainy season throughout the country when rainfall is above average from August to November. During the peak monsoon period from about the end of May the capacity of the Mekong river is not enough to convey the flood waters, and the water level at the Mekong/Tonle Sap confluence rises to about nine metres. At this time of year the flow direction in the Tonle Sap reverses and the flood water from the Mekong river flows to the Great Tonle Sap Lake, thus adding to the flood runoff from the Great Tonle Sap Lake catchment. When the river flow in the Mekong reduces sufficiently in October, the flow in the Tonle Sap reverses direction again and it drains the stored flood waters from the Great Tonle Sap Lake back towards the Mekong river.
- Water Pollution Management
The following are some laws on Environmental Protection and Natural Resource Management in Cambodia:
- Law on Water Resources Management
- National Policy on water resources
- Mekong River Agreement (1995)
- IWRM strategy and roadmap in Cambodia
- Sub-Decree on Water Pollution Control
Water quality monitoring has also been carried out in Cambodia so as to regulate and reduce the water pollution of public water areas for the protection of human health and conservation of bio-diversity. Figure 5 shows the water quality monitoring sites in Cambodia. The water quality monitoring parameters are pH, DO, TSS, BOD, Conductivity, TN, TP, Temperature, including a few heavy metals.
- Sanitation Management
Cambodia has developed a National Strategy for Rural Water Supply, Sanitation and Hygiene (2011-2025). The aim of the strategy is to define the water supply, sanitation and hygiene services to be made available to people in rural areas, institutional arrangements and alignment with decentralization and deconcentration (D&D) process, programmatic approaches, and financial and human resources necessary to deliver and sustain the services.
The targets of the Strategy are as follows:
- Water Supply: 50 per cent of rural population will have access to improved water supply by 2015, and 100 per cent by 2025.
- Sanitation: 30 per cent of rural population will have access to improved sanitation and live in a hygienic environment by 2015, and 100 per cent by 2025.
- Hygiene: 30 per cent of rural population will practice basic safe hygiene behavior by 2015, and 100 per cent by 2025.
- Enabling environment: By 2015, institutional arrangements, legal instruments and human resources will be in place and be able to rapidly increase and sustain services.
- Financing: Funding for capital and recurrent expenditure will be available.
Figure 6 shows an aerial view of the Wastewater Treatment Plant in Siem Reap City.