progress report – design of native wetland nursery facility design of native wetland nursery...

Progress Report – 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 EngineeringSenior Design Class - 2009

2Native 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

ProposedWetlandNursery

Site

NativePlant Center

N



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



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



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



Survey Results

Contours from Metro New GPS Survey Contours

10’ Contours 1’ Contours

Water linetie-ins

SepticSetback



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 Test Soil Sampling



Geotechnical InvestigationResults• Soil is low-plasticity ML silt, uniformly

distributed• Measured infiltration rates –

0.052 in/min (sample A)0.058 in/min (sample F)

A

F

A

B

C

D

E

F

Soil collectionSites

(0 – 9 ft deep)

InfiltrationTests



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 Case Basins

I 1, 2, 3, 4

II 1, 2, 3, 4, 5, 6, 7

III 1, 2, 3, 4, 7



Surface Water Model - ResultsCase I - QLongest route

(time, min) 23.3 tc

i (in/hr) Q (cfs)Q2 0.9 2.37Q10 1.6 4.21Q50 2 5.26Q100 2.3 6.05

Case II - Q

Longest route (time, min) 41.4 tc

i (in/hr) Q (cfs)Q2 0.6 6.70Q10 0.9 10.05Q50 1.2 13.40Q100 1.5 16.75

Case III - Q

Longest route (time, min) 33.6 tc

i (in/hr) Q (cfs)Q2 0.7 2.79Q10 1.3 5.19Q50 1.6 6.39Q100 1.8 7.19



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



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

Class BeginsSite Plan - CADSpecificationsCost EstimationConstruction ScheduleConstruction BeginsConstruction ObservationClass Ends



Special Thanks

• Marsha Holt-Kingsley – Metro Native Plant Center Coordinator• Brad Bogus, PE – Kennedy/Jenks Consultants• The survey guy <name>



Questions?

progress report – design of native wetland nursery facility design of native wetland nursery...

Documents

native wetland nursery

design survey

native plants

design considerations

metros native plant

d visualization of design

survey data

metronew gps survey