On-site stormwater management and mimicking pre-development hydrology are becoming increasingly important design imperatives at every level. Trees and soils in suspended pavements are part of the toolkit for implementing meaningful stormwater control measures. This presentation walks through some of the most common techniques for directing stormwater into Silva Cells, including: catch basins, sheetflow/curb cuts, and pervious pavement. Each technique is examined using real-life project examples that address the logic behind each design, including: project goals, pre-treatment, water distribution, and maintenance. For further information on these topics, please refer to the recorded webinar found at the end of the presentation, which includes a detailed Q & A with expert panelists on the subject

1. TECHNIQUES FOR DIRECTING WATER
INTO SILVA CELLS
Tuesday, June 17th, 2014
PRESENTED BY:
Marcy Bean
Sustainable Landscape Architect
With Panelists:
Peter MacDonagh, Kestrel Design Group
Michael James, DeepRoot

2. Techniques for
Directing Water into
Silva Cells
Presentation Overview:
• Why use the Silva Cells for
Stormwater Management?
• Critical Considerations for using
the Silva Cells for Stormwater
Management
• Method of Stormwater Capture
with Case Studies
• Porous Pavement
• Marq2 Streetscape
• Sheet Flow/Curb Cuts
• 2nd Avenue Streetscape
• Catch Basins/Sumps
• NCSU Monitoring Site
• Questions & Answers with
Panelists
1Techniques for Directing Water into Silva Cells

3. Why use the Silva
Cells for Stormwater
Management?
Tree Soil System – Bioretention
• TSS Removal
• Pretreatment
• Pollutant removal
• Rate Reduction
• Slow runoff, or take offline
• Storage
• Design dependent
• Tree Growth
• Evapotranspiration &
Interception
2Image from Aurora Streetscape, Shoreline, Washington – Photo by DeepRoot

4. Why use the Silva
Cells for Stormwater
Management?
Critical Considerations:
• Adapt to your site
• Project Goals
• Treatment/Storage
• Design & Size per Project
• Offline
• Small storms
3Why use the Silva Cells for Stormwater Management?

5. Techniques for
Directing Water into
Silva Cells
Three features in almost every
Silva Cell project for Stormwater:
• Pretreatment
• Distribution
• Overflow
4Image from http://www.aerosnow.com/dejanaservices/catch-basin.html
Many variations
available

6. Techniques for
Directing Water into
Silva Cells
Method of Stormwater Capture
with Case Studies
Porous Pavement
Marq2 Streetscape
Sheet Flow/Curb Cuts
2nd Avenue Streetscape
Catch Basins/Sumps
NCSU Monitoring Site
5Techniques for Directing Water into Silva Cells

7. METHOD OF CAPTURE #1 –
POROUS PAVEMENT
Keep it simple.

8. Method of Capture: Porous Pavement
Porous Pavement 7
Keep it simple.
Pretreatment
Distribution
Overflow

9. Case Study:
Porous Pavement
Marquette & 2nd Avenues (Marq2)
Minneapolis, Minnesota
On-site stormwater management
through porous pavers and
infiltration through the Silva Cell
system.
Average soil volume per tree: 587 ft3
Catchment area: 1.15 acres
Number of trees: 167
Total Silva Cells: 4,909 frames, 9,818
decks
Installation date: 2008-2009
Project Designer: SEH and URS
8Photo taken summer 2012, Kestrel Design Group

10. Method of Capture: Porous Pavement
9Marq2 Silva Cell Installation - 2009

11. Method of Capture: Porous Pavement
10Marq2 Streetscape – 2009, and again in 2013

12. Method of Capture: Porous Pavement
11Marq2 Silva Cell Installation, tree monitoring images by Kestrel Design Group

13. METHOD OF CAPTURE #2 –
SHEET FLOW / CURB CUT
Raingarden concept.

14. Method of Capture: Sheet Flow/Curb Cut
Sheet Flow / Curb Cut 13
Raingarden concept.

15. Method of Capture: Sheet Flow/Curb Cut
Sheet Flow / Curb Cut 14
Raingarden concept.

16. Case Study:
Sheet Flow/Curb Cut
2nd Avenue Streetscape, Calgary,
Alberta
On-site stormwater management
and data monitoring through curb
cuts and distribution into the Silva
Cell system.
Average soil volume per tree: 19m3 (671
ft3)
Catchment area: 1,235 m2 (0.3 acres)
Number of trees: 7
Total Silva Cells: 470 frames, 270 decks
Installation date: June 2013
Project Designer: Kestrel Design Group &
Larson Engineering
15Image courtesy City of Calgary

17. Method of Capture: Sheet Flow/Curb Cut
162nd Avenue Streetscape – Detail by Kestrel Design Group
Pretreatment
Distribution
Overflow

18. Method of Capture: Sheet Flow/Curb Cut
172nd Avenue Streetscape Construction – Photos by DeepRoot

19. Method of Capture: Sheet Flow/Curb Cut
182nd Avenue Streetscape Construction – Photos by DeepRoot

20. Method of Capture: Sheet Flow/Curb Cut
192nd Avenue Streetscape – Before and After – Photo at left by DeepRoot, photo at right courtesy City of Calgary

21. METHOD OF CAPTURE #3 –
CATCH BASIN
Slow things down.

22. Method of Capture: Catch Basin
Catch Basin 21
Pretreatment
Distribution
Overflow
Slow things down.

23. Method of Capture: Catch Basin
22Catch Basin
Pretreatment
Distribution
Overflow
Slow things down.

24. Catch Basin Schematic
23Image from http://www.aerosnow.com/dejanaservices/catch-basin.html
Elbow
Distribute to Silva Cell system
Slow things down.
Many variations
available

25. Case Study:
Catch Basin
North Carolina State University
Stormwater Treatment
Performance Monitoring Sites,
Wilmington, North Carolina
On-site stormwater management
and data monitoring through catch
basins and distribution through the
Silva Cell system.
Comparison of two sites, Orange Street
and Ann Street
Soil volume per tree: 750 ft3
Catchment area: ~0.10-0.12 acres
Number of trees: 1 per treatment area
Total Silva Cells: 68 frames, 34 decks
Installation date: June-July 2012
Monitoring dates: Sept 2012-July 2013
Project Designer: North Carolina State
University with Kestrel Design Group
24Approximate drainage area for each tree, image adapted from Page, Winston and Hunt
Silva
Cells
Silva
Cells

26. Method of Capture: Catch Basin
25NC State Research Site - Image from Page, Winston and Hunt

27. Method of Capture: Catch Basin
26NC State Research Site – Photos by DeepRoot

28. Method of Capture: Catch Basin
27NC State Research Site – Photos by DeepRoot

29. TECHNIQUES FOR DIRECTING WATER
INTO SILVA CELLS
Tuesday, June 17th, 2014
6/12/2014
Contact us:
DeepRoot Blog:
http://www.deeproot.com/blog/
info@deeproot.com
marcy@tkdg.net