City Interventions

Siem Reap Wastewater Collection Network Development

Country: Cambodia
City: Siem Reap

Key Stakeholders and PartnersMinistry of Public Works and Transport, Phnom Penh, Cambodia; Siem Reap Department of Public Works and Transport; The World Bank

Project Preparation Study PeriodMay 2018 – May 2019

CDIA SupportUS$ 777,000

Expected Downstream FinancingUS$ 25.5 million (WB loan)

Infrastructure sectorsWastewater Management

CDIA priority impact areasClimate Change Mitigation and Adaptation; Environmental Improvement; Good Governance; Poverty Reduction

Key City Development Issues

Access to improved sanitation (sewerage and other on-site sanitation) in the city is estimated to be 75%, with 19% of the population still practicing open defecation. While the city is rapidly growing with many hotels being developed, only a small amount of the sewage is collected through a combined system (which has been somewhat improved over time) plus a relatively small-scale separate sewerage system and treatment scheme. It is estimated that only 9% of the fecal waste in Siem Reap city is collected and properly treated. Most domestic sewage is discharged directly into the rivers and canals in the city causing water pollution and environmental and hygiene concerns, particularly during times of flooding.

Details of Cooperation

CDIA worked with the Siem Reap Department of Public Works and Transport to prepare the project which was divided into three consecutive phases:

  • Phase 1: Inception Phase and development of a Wastewater Development Plan;
  • Phase 2: Feasibility Study Phase including development of Environmental and Social Safeguards Documents;
  • Phase 3: Detailed Engineering Design, Tender Documents and finalisation of documents for World Bank loan processing.

Three sets of tender documents were prepared as follows: (i) East Trunk Sewer and West Trunk Sewer; (ii) Pumping stations; and (iii) Wastewater treatment plant improvement

Expected Development Outcomes

The proposed intervention is expected to lead to significant environmental improvement in the city, including improved quality of water bodies. More specifically, the separation of wastewater and surface run-off drainage systems in the city is expected to reduce fecal contamination resulting from drain overflow in this flood prone city. Flood water is one of the main pathways for fecal exposure among children in the city, thus the reduction in fecal load in the environment would reduce disease risks for children as well as the broader population including tourists.


Key City informationLand Area: 10.3 sq. km.
Estimated Population: 140,000 (2015)
City website: n/a

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