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

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

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

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

Mapped Ecosystem Extent and Quality

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

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

. 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

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 3. Uplift PRIORITY STRATEGY 4. Maximize LID stormwater controls PRIORITY STRATEGY 5. Implement built infrastructure 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 3. Uplift PRIORITY STRATEGY 4. Maximize LID stormwater controls PRIORITY STRATEGY 5. Implement built infrastructure LOS Met Combined 5 Strategies = Total Stormwater Management Solution …that meets Level of Service goals

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

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

Pilot study area characteristics – 167 acres

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

Stormwater function by ecosystem type 100-year flood volume (gallons) Annual Runoff Volume (gallons)100-year Peak flow (cfs)TSS load (lbs) Existing condition/LOS83,343164, Zoned development (1 acre)117,251549, Difference - amount that needs to be managed by stormwater system33,908384, Acres required to manage difference shown above Evergreen Forest AN/A Evergreen Forest BN/A Evergreen Forest CN/A Deciduous Forest AN/A Deciduous Forest BN/A Deciduous Forest CN/A Riparian corridor A Riparian corridor B Riparian corridor C Wetlands A0.40.1<0.4N/A Wetlands B0.40.1<0.4N/A Non-native/non-builtN/A

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

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

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

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

Acknowledgements City of Damascus, Oregon Oregon Department of Environmental Quality

Questions or Comments? WBG PDX GS kk