CRWA Pres 20100524

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CRWA Pres 20100524

  1. 1. Building Blue Project Spruce Pond Sub-watershed, Franklin A Practical Example of Pollution Prevention in a Typical New England Suburban Town. Charles River Watershed Association
  2. 2. Study Area: Spruce Pond Sub-watershed
  3. 3. Sub-watershed Drainage Areas
  4. 4. Existing Phosphorus Load by Drainage Area
  5. 5. Design Parameters • Reduce phosphorus in stormwater runoff by 43% to comply with expected permit • Design with no credit given for street sweeping, fertilizer control or other practices • Evaluate existing stormwater treatment for credit and/or retrofit
  6. 6. Site 4A - 1: Central Park Terrace/ North Park Street
  7. 7. Fletcher Field Infiltration Area Proposed underground infiltration chamber to infiltrate 1” storm INFILTRATION CHAMBER DRAINAGE AREA 1,096,682 sqft % IMPERVIOUS 32% BMP AREA (AB) 14,775 sqft BMP DEPTH (AD) 3 ft ACTUAL WQV 30,941 cuft ACTUAL WQD 1.00 in
  8. 8. Site 4A – 3: Peck Street lot, Fletcher Field
  9. 9. Peck Street Lot, Fletcher Field Bioretention area placed within reorganized parking lot BIORETENTION- 1” Storm DRAINAGE AREA 34,474 sqft % IMPERVIOUS 100% WQV 2873 cf DEPTH MEDIA (DF) 2.00 ft PONDING HEIGHT (2X HF) 9 in TF (FILTER TIME) 2 days SURFACE AREA REQUIRED 1210 sqft
  10. 10. Visualization: Bioretention garden in Parking Lot
  11. 11. Peck Street lot – alternative design in park area Alternative 2- Bioretention system placed on field instead of reorganizing parking lot BIORETENTION- 0.4” Storm DRAINAGE AREA 34,474 sqft % IMPERVIOUS 100% WQV 1149 cf DEPTH MEDIA (DF) 2.00 ft PONDING HEIGHT (2X HF) 9 in TF (FILTER TIME) 2 days SURFACE AREA REQUIRED 484 sqft
  12. 12. Site 4B-2: Wachusett Street lot, Fletcher Field
  13. 13. Parking lot alternatives
  14. 14. Visualization: Vegetated Swale
  15. 15. Visualization: Rain Garden in Fletcher Field
  16. 16. Site 4c: Parmenter School
  17. 17. Drainage Areas - Parmenter School Four Bioretention areas dispersed across site to treat 1” storm BIORETENTION - 1" storm DRAINAGE AREA 93,422.05 sqft IMPERVIOUS AREA 49,933.31 sqft PERVIOUS AREA 43,488.74 sqft WQV 4,107 cf DEPTH MEDIA (DF) 2.00 ft PONDING HEIGHT 6 in TF (FILTER TIME) 2 days SURFACE AREA REQUIRED 1826 sqft
  18. 18. Drainage Area- Parmenter School (4C)
  19. 19. Visualization: Rain Gardens in Front Lawn
  20. 20. Visualization: Rain Gardens in Front Lawn
  21. 21. Site 3G – 2: Cottage St./Union St. Dispersed bioretention areas treating 1” storm across sub-drainage areas including: • Cottage and Union Street on and off ROW retrofits • On site retrofits on hardware store site, etc. • Bump-outs at intersection of Geb & Saxon St. BIORETENTION - 1" storm DRAINAGE AREA 340,774.00 sqft IMPERVIOUS AREA 270,628.70 sqft PERVIOUS AREA 70,145.30 sqft WQV 20,882 cf DEPTH MEDIA (DF) 2.00 ft PONDING HEIGHT (2X HF) 6 in TF (FILTER TIME) 2 days SURFACE AREA REQUIRED 9,281 sqft
  22. 22. Visualization of Cottage Street Retrofits
  23. 23. Computer optimization process • “Best Engineering Judgment” design – S0 • Computer Optimization: – Define possible treatment types – Establish requirements for treatment types – Assign costs to treatment types Optimal Design – S2
  24. 24. Estimated cost range Spruce Pond Subwatershed Restoration 51 potential sites for stormwater improvements • “Best Engineering Judgment” – 28 sites selected – ~ $4.6 m • Optimized – 41 sites selected – ~ $2.9 m
  25. 25. Preliminary Cost Comparison Cost Per Impervious Acre Treated $30,000.00 $/impervious acre $25,000.00 $20,000.00 D o lla r ($ $15,000.00 $10,000.00 $5,000.00 $0.00 CRWA S0 CRWA S2 EPA S1 EPA S2 EPA S3 Scenario
  26. 26. Proposed Drainage Area Retrofits Plan S0 Plan S2 S0
  27. 27. Lessons Learned • Model optimization can save you money! • Treat the first flush • Infiltration is the most cost effective strategy • Treating large volumes is cost effective but may not solve the whole problem
  28. 28. Next Steps for Franklin • New stormwater permit, expected by end of 2010 – Develop a Phosphorus Control Plan within 5 years – Implement Phosphorus Control Plan within 10 years • Install several pilot projects to learn from experience
  29. 29. Special Thanks • Jeff Nutting, Town Administrator • Bill Yadisernia, Robert Cantoreggi, Franklin DPW • James Esterbrook, Franklin GIS Department • Nick Alfieri, Franklin Conservation Commission • Beth Dahlstrom, Franklin Planning Department • Franklin Technical Advisory Committee

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