Progress Report – Design of Native Wetland Nursery Facility Design of Native Wetland Nursery Facility For Metro’s Native Plant Center Prepared by: Portland State Department of Civil and Environmental Engineering Senior Design Class, 2009

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Project Overview Native Plant Center is a Metro-operated nursery in Tualatin, OR Located on south banks of Tualatin River Cultivates native plants for Metro’s various habitat restoration projects Project proposal is to expand the Native Plant Center by building a wetland nursery facility in adjacent lot ProposedWetlandNurserySite NativePlantCenter N

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Project Scope Design a series of shallow pools that will serve as planting beds for native wetland plants Supply pools using multiple water sources – surface runoff, Tualatin River water rights Pools will have overflow-protection system to guard against damage from extreme storm events Pools will have a water depth control system to accommodate growing requirements for different plant species Proposed facility must allow for access by personnel for planting and harvesting activities Cost will be significant in design considerations

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Feasibility Study 1.Survey – High resolution elevation contours, setback boundaries, water lines 2.Geotechnical – soil classification/distribution, water infiltration rates 3.Water runoff model – predict flow rates and volumes of water from various intensity storm events 4.Literature review – Overview current design provisions for constructed wetlands, relevant permitting issues and constraints

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Survey Pools will be constructed by grading, requires high-resolution elevation data (elevation contours from Metro were insufficient for design) Survey conducted with Leica SmartPole™ GPS survey station –simple, quick alternative to total station survey –position resolution capable of 0.02 feet (latitude, longitude, mean sea level) Positions recorded then downloaded into AutoCAD Land Development –Automatic generation of elevation contours from survey data –Allow for 3D visualization of design and development of grading plan

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Survey Results Contours from MetroNew GPS Survey Contours 10’ Contours 1’ Contours Water line tie-ins SepticSetback

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Geotechnical Investigation Field/Laboratory Tests Soil samples for soil classification and compaction tests Test infiltration rates on-site where pools will most likely be constructed Infiltration TestSoil Sampling

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Geotechnical Investigation Results Soil is low-plasticity ML silt, uniformly distributed Measured infiltration rates – in/min (sample A) in/min (sample F) A F A B C D E F Soil collection Sites (0 – 9 ft deep) Infiltration Tests

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Surface Water Runoff Model Pools will be supplied from multiple sources – (water pump rights, runoff) Surface water runoff model will help establish how much water is available from storm events Surrounding areas were partitioned into different basins Rational model used to predict peak flowrates for 3 cases Case I – runoff from Native Plant Center only Case II –runoff from Native Plant Center and all surrounding areas Case III – runoff from Native Plant Center and field to south Model CaseBasins I1, 2, 3, 4 II1, 2, 3, 4, 5, 6, 7 III1, 2, 3, 4, 7

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Surface Water Model - Results Case I - Q Longest route (time, min)23.3tctc i (in/hr)Q (cfs) Q2Q Q Q Q Case II - Q Longest route (time, min)41.4tctc i (in/hr)Q (cfs) Q2Q Q Q Q Case III - Q Longest route (time, min)33.6tctc i (in/hr)Q (cfs) Q Q Q Q

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Feasibility Summary Survey – –Elevation contours sufficient for grading design –Septic tank setback will prohibit construction of pool on north half of proposal site Geotechnical – –Uniform soil type and distribution across site –Infiltration rates too high to allow for sufficient hydraulic residence times for pool – amending soil with bentonite and soil compaction will be necessary Water Model – –Capture of water from neighboring sites may be costly and of low quality –Predicted flow rates from Case I suggest that irrigation from Tualatin River will be required to fill pools

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Tasks for Spring Term Pool Design – –Finalize specifications for decreasing infiltration rate (bentonite, compactions), Grading, overflow protection, water depth regulation, berm design Cost Estimates – –Addition of french drain for water runoff capture, irrigation piping, possible on-site storage outside of pools Final Proposal – –Design drawings and specifications, budget, feasibility report

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Special Thanks Marsha Holt-Kingsley – Metro Native Plant Center Coordinator Brad Bogus, PE – Kennedy/Jenks Consultants The survey guy

Department of Civil and Environmental Engineering Senior Design Class Native Wetland Nursery Design for Metro’s Native Plane Center Questions?