Over the last 30 years, there has been significant progress in ensuring that communities in Cambodia have access to reliable supplies of reasonable to good quality water in line with the 2003 Drinking Water Standard issued by the Royal Government of Cambodia (RGC). Yet, the coverage and capacity of water supply systems serving domestic users across Cambodia are still highly variable. Although larger cities have well-developed water supply infrastructure, there is still a lack of connectivity to water supply infrastructure in rural areas, with only 17% of rural households serviced by piped water supply facilities. Overall, the water supply sector is highly exposed to seasonal flood and drought conditions which are becoming more severe due to widespread and increasing watershed degradation. Climate change, population growth, biodiversity loss and land-use change in watersheds of Cambodia present water supply systems with challenges in managing water quality and quantity. Nature-based solutions (NBS) are an essential and cost-effective strategy for increasing resiliency to these stressors and generate a variety of co-benefits beyond the water sector by supporting poverty alleviation, community health and wellbeing, biodiversity protection, and climate mitigation. Recognizing the values of NBS and supporting the RGC in strengthening the resilience of the water supply sector, the World Bank has engaged ICEM to conduct the project Assessment for mainstreaming nature-based solutions in the water supply sector. The project’s objectives are to explore the application of NBS in meeting the challenges and potential opportunities for sustainable water supply systems and to mainstream NBS in the water supply sector at operational and policy levels. From the 10th to 22nd of June, 2022, the ICEM team undertook an inception mission for the project to the districts of Samaki Meanchey, Toek Phos (Kampong Chhnang province), and Prasat Bakong and Banteay Srey (Siem Reap province). The mission aimed to assess the condition of the water supply systems in the three selected river basins and to scope out the suitability of NBS for water supply resilience within the catchments.
Figure 1: Stakeholder consultations near Boeung Khnar lake

Figure 1: Stakeholder consultations near Boeung Khnar lake (Photo by ICEM)

During the mission, the team met with the Ministry of Rural Development (MRD) to discuss rural water supply challenges and water needs in Kampong Chhnang and Siem Reap provinces. The team also consulted provincial stakeholders, including the Departments of Water Resources and Meteorology (PDoWRAM), Departments of Rural Development (PDRD), and Departments of Industry, Science, Technology and Innovation (PDISTI), as well as local stakeholders from commune and village chiefs (Figure 1), to community ecotourism groups, rangers, and water supply operators, to understand the status and conditions of the natural water supply assets and the water supply systems in the catchments. The team conducted field visits to several sites, including Boeung Khnar Lake (Figure 2), Takab River, Trav Kot Lake, and related streams and upstream watershed areas.  A drone was used to survey the lakes, rivers and catchments and assess water volume at the end of the dry season (Figure 3).    
Figure 2: Boeung Khnar lake (Photo by ICEM)

Figure 2: Boeung Khnar lake (Photo by ICEM)

Figure 3: O’Daun Poev weir and irrigation offtake in Takab River (Photo by ICEM)

The team conducted a mission debrief with senior-level representatives from the Ministry of Industry, Science and Technology & Innovation (MISTI) and the World Bank on potential NBS, the need for additional groundwater assessment, and data availability for further assessment. Key issues identified during the mission included water pollution from farms and surrounding settlement areas, for example, chemical fertilizer, pesticides and solid wastes; catchment erosion and sediment deposition; and insufficient water to meet growing demand.  The collected data, stakeholder experience, and views contributed to the baseline assessment of water supply assets and systems as a foundation for further identification of nature-based solutions. Visual images captured by drone will also be used for communication purposes around the use and benefits of NBS as part of the final project deliverables. Now, the team is developing models to assess water quantity and quality changes under different land use and land management scenarios and preparing the initial design of NBS options at each site. A second mission is planned for October  2022 to conduct environmental and social impact assessments and cost-benefit analyses for the water supply systems with and without NBS options.
Figure 4: Meeting with MISTI and the World Bank (Photo by ICEM)

Figure 4: Meeting with MISTI and the World Bank (Photo by ICEM)