1. 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

2. Valley Branch Watershed District Silver Lake Watershed Provided by N. St Paul

3. Current Stormwater Control Measure (SCM) Bio-infiltration Basin Photograph by Nathan Warner

4. Current TP Loading Bucheck, et al. 2013 ●40 ug/L 4.57 lb/year

5. Initial P8 Model ● Precipitation File ● Particle File (National Urban Runoff Program (NURP)) ● Subwatershed Data

6. Initial P8 Model Bio-infiltration Basin Parameters

7. Additional Rain Gardens Methods Bio-retention Cell -3’ Mixed Media, 40% voids -14.4” ponding depth (B soils) Minnesota Stormwater Manual

8. Additional Rain Gardens Methods Image: City of N. St Paul, GIS work: Nathan Warner Placement: -R.O.W. -Soils/Infiltration -Groundwater -Road Grading -Drainage Area -Current Land Use -Curb Cuts

9. Additional Rain Gardens Results Bio-retention (Rain Gardens) (Weiss, et al., 2007) $ = 152 x (WQV)^0.776 WQV = water quality volume ~ volume infiltrated in m^3 Adjustment for 2014 Cost (CPI, Bureau of Labor and Statistics) 2007 Cost ($) x 1.14“Unit” WQV = 503 cf 30’ x 7’

10. Additional Street Sweeping Methods ●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

11. Additional Street Sweeping Results Street Sweeping Frequency TP removed [lb] Cost per lb TP removed [$/lb] Current Condition: 4 times a year 15.7$47.81 6/year (spread from April to October) 20.7$54.52 7/year from April to November 25.7$58.54 10/year (from April to November) 31.4$60.00

12. ●SHASAM model by BARR Engineering ●Create Plot: % Removal vs. Avg Runoff ○Det % Removal for Silver Lake ●Convert TSS to TP Additional Sumps Methods * Based on http://revolutionarybaffle.com/store/.http://revolutionarybaffle.com/store/ **Maintenance costs account for two cleanouts per year priced at $80 each.

13. Additional Sumps Results *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

14. Summary SCM (Most Efficient)TP Removed [lb/yr]Cost/lb TP removed Standard Sump (per unit) 0.007-0.102$6,583-39,013 SAFL Baffle (per unit) 0.013-0.196$6,267-33,302 Rain Gardens* (per unit) 0.098-0.145 Avg = 0.109 $8,008-13,739 Avg =$8,197 Street Sweeping (4/year) 15.7$47.81 *based on 1% imp.

15. Conclusions and Recommendations Recommend: Street Sweeping Further work: develop more realistic particle file more hydrologic data