|Abstract or Summary
- The City of Damascus, Oregon has a current population of nearly 10,000 people and expects to grow to 50,000 residents by 2060. On the eastern edge of the Portland metropolitan area, the City is located in the Clackamas and Willamette basins with an area of almost 12,000 acres. Semi-rural in character, the recently incorporated city will require water, wastewater, and stormwater infrastructure to serve expected growth. The City developed an Integrated Water Resource Management (IWRM) Plan, in cooperation with several regional service providers, to capitalize on a unique opportunity to consider urban water management from a local watershed perspective, while considering water supply, environmental health, drainage and flood control, water reuse, treatment, and disposal as part of a single system.
The IWRM Plan used a structured decision process, community and stakeholder outreach, and a water balance simulation model to develop and evaluate fifteen financial and non-financial criteria for eleven scenarios, including sensitivity analysis of regulatory uncertainty and climate change impacts on recommended solutions. Scenarios included treatment, storage and conveyance infrastructure for potable use, indirect non-potable reuse, and discharge at local basin, city-wide, and regional scales to find an efficient and resilient system solution. Rainwater capture, environmental flow requirements, groundwater availability, and use of existing ecosystem services to provide stormwater and wastewater treatment and disposal were also considered in the analysis.
The IWRM Plan built on the City’s core values and an earlier Public Facilities Plan that identified ecosystem services as both a “facility” to be protected and developed, as well as a possible alternative to built infrastructure solutions. The Voyage™ model used for simulation and reporting of results facilitates decision-making and assists to visualize alternatives. The IWRM Plan builds a portfolio for water management that balances risk, cost, and long-term uncertainty to establish a fundamental direction for water management in the next century in Damascus.