A Traditional vs. Ecosystem Services Approach to Surface Water Management

1. A Traditional vs. Ecosystem Services Approach to Surface Water Management September 16, 2010 PRESENTED BY Carol Murdock, Clackamas County WES Mark Anderson, CH2M HILL WBG052710054733PDX 349800.GS.01.02 60110 kk

2. Introduction / Context • Ecosystem Services Approach to Facilities Planning – City of Damascus, OR • How are we defining Ecosystem Services? • Could an ES services approach be cost effective in the long-term? • Business Case Evaluation – cost/benefit analysis • Environmental benefit – regulatory compliance • Community – livability, healthy environment • Economic – lower long-term cost to ratepayers, economic growth • WES - Intent of BCE – inform policy decisions; develop implementation mechanisms; provide information on long-term cost savings

3. Clackamas County, Oregon – Rock Creek basin Pilot Study Area Rock Creek Basin Graphics courtesy Wikimedia, Clackamas County Service District #1 Rock Creek Watershed Action Plan, Brown and Caldwell

4. Rock Creek basin has 4 major ecosystem types Deciduous/Mixed Deciduous Forest Evergreen Forest Riparian Forest/Streams Wetlands

5. Mapped Ecosystem Extent and Quality

6. Methods of managing urban ecosystems for stormwater treatment are not new • Riparian Buffers • Conservation areas • Vegetated filter strips • Overland flow systems (NTS design)

7. The key for basin planning is balancing land resources • Ecosystems require land area but offer two benefits: • “Passive” benefits when land zoned for development is preserved. • “Active” benefits when ecosystem land manages runoff from development. • When land area is treated as a “facility”, public support and decision-making are essential

8. Active Benefits: RUSA meets TMDL limits for Roseburg wastewater discharge • Similar ecosystem mix to Clackamas County • Up to 70% slopes down to gentle slopes with a creek in incised valley bottom • Minimal changes to existing ecosystem were required to provide adequate treatment • DEQ-approved facility at 10% of the cost of built infrastructure .

9. We propose an integrated planning approach… Prioritization of Stormwater Control Strategies to Meet Level of Service Goals PRIORITY STRATEGY 1. Use ecosystem services of protected areas PRIORITY STRATEGY 2. Reduce development footprint PRIORITY STRATEGY 5. Implement built infrastructure PRIORITY STRATEGY 4. Maximize LID stormwater controls PRIORITY STRATEGY 3. Uplift

10. …that meets Level of Service goals Prioritization of Stormwater Control Strategies to Meet Level of Service Goals PRIORITY STRATEGY 1. Use ecosystem services of protected areas Combined 5 Strategies = Total Stormwater Management Solution PRIORITY STRATEGY 2. Reduce development footprint PRIORITY STRATEGY 5. Implement built infrastructure LOS Met PRIORITY STRATEGY 4. Maximize LID stormwater controls PRIORITY STRATEGY 3. Uplift

11. A business case identifies credible strategies that compare to conventional runoff management PRIORITY STRATEGY 1. Use ecosystem services of protected areas Strategy 5. Business as Usual PRIORITY STRATEGY 2. Reduce development footprint PRIORITY STRATEGY 5. Implement built infrastructure LOS Met LOS Met PRIORITY STRATEGY 4. Maximize LID stormwater controls PRIORITY STRATEGY 3. Uplift

12. We use a mix of conventional models and new resource balance concepts • Simple Method (runoff and pollutant load) • TR-55 (peak flows) • Clackamas County Pollutant Loadings Model • A new land balance tool to manage ecosystem and development area flow and load trade-offs • A new cost calculator that relates infrastructure, land, restoration, and ecosystem value to find efficient strategies

13. Pilot study area characteristics – 167 acres

14. Summary of preliminary results TSS (LOS = 90% volume to 70% removal) Runoff (LOS = 2x existing)

15. Stormwater function by ecosystem type

16. Some early results • About 3 acres of natural area will manage impacts from 1 acre of residential development, depending on zoning • Uplift has little effect on treatment, but more important for volume – heavily dependent on assumptions • Ecosystem areas can be valued monetarily to help drive market behavior. • Assumptions about density and EDU buildout are highly sensitive

17. General site design considerations • Pre- and post-developed time of concentration • Typical slope • Limits of treatment area (due to topography, etc.) • Expected treatment infiltration loss (derived from ClackCo model) • Expected pollutant capture rate • Treatment area characteristics and effectiveness

18. Potential avenues for research and development • Treatment effectiveness in varied natural conditions • Infrastructure costs • Uplift costs

19. Planned next steps • Develop alternatives for BCE and policy selection • Refine and implement planning framework for Damascus • Engage with stakeholders to think about resource economics in a new way

20. Acknowledgements • City of Damascus, Oregon • Oregon Department of Environmental Quality

21. Questions or Comments? WBG052710054733PDX 349800.GS.01.02 60110 kk