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North St. Paul Resilient Communities Reduction in Total Phosphorus to Silver Lake. Prepared by: Matthew Bonnema, Gwyneth Perry, Nathan Warner and Christopher Young Prepared for: Prof. John Gulliver and the City of North St. Paul. Valley Branch Watershed District Silver Lake Watershed.
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North St. Paul Resilient Communities Reduction in Total Phosphorus to Silver Lake Prepared by: Matthew Bonnema, Gwyneth Perry, Nathan Warner and Christopher Young Prepared for: Prof. John Gulliver and the City of North St. Paul
Valley Branch Watershed DistrictSilver Lake Watershed Provided by N. St Paul
Current Stormwater ControlMeasure (SCM) Bio-infiltration Basin Photograph by Nathan Warner
Current TP Loading Bucheck, et al. 2013 • 40 ug/L 4.57 lb/year
Initial P8 Model • Precipitation File • Particle File (National Urban Runoff Program (NURP)) • Subwatershed Data
Additional Rain GardensMethods Bio-retention Cell -3’ Mixed Media, 40% voids -14.4” ponding depth (B soils) Minnesota Stormwater Manual
Additional Rain GardensMethods Placement: -R.O.W. -Soils/Infiltration -Groundwater -Road Grading -Drainage Area -Current Land Use -Curb Cuts Image: City of N. St Paul, GIS work: Nathan Warner
Additional Street SweepingMethods • Modeled in Dr. Baker’s spreadsheet • Prior Lake Study • Tymco Model 600 regenerative air sweeper • Simple Inputs • Frequency: 4 sweeps/year to 10 sweeps/year
Additional SumpsMethods • SHASAM model by BARR Engineering • Create Plot: % Removal vs. Avg Runoff • Det % Removal for Silver Lake • Convert TSS to TP * Based on http://revolutionarybaffle.com/store/. **Maintenance costs account for two cleanouts per year priced at $80 each.
Additional SumpsResults *Based on Installation, Unit, and Maintenance costs for the 20 years of removal design life. **SLV-7 has pipe diameter 30”, all others are 15”. • Efficiency comparison • Removal efficiency depends highly on flow through sump and pipe diameter • Only considered NURP for SCM comparison
Summary *based on 1% imp.
Conclusions and Recommendations • Recommend: Street Sweeping • Further work: • develop more realistic particle file • more hydrologic data