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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
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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
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
1 Techniques for Directing Water into Silva Cells
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
2 Image from Aurora Streetscape, Shoreline, Washington – Photo by DeepRoot
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
3 Why use the Silva Cells for Stormwater Management?
Techniques for
Directing Water into
Silva Cells
Three features in almost every
Silva Cell project for Stormwater:
• Pretreatment
• Distribution
• Overflow
4 Image from http://www.aerosnow.com/dejanaservices/catch-basin.html
Many variations available
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
5 Techniques for Directing Water into Silva Cells
METHOD OF CAPTURE #1 –
POROUS PAVEMENT Keep it simple.
Method of Capture: Porous Pavement
Porous Pavement 7
Keep it simple.
Pretreatment Distribution Overflow
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
8 Photo taken summer 2012, Kestrel Design Group
Method of Capture: Porous Pavement
9 Marq2 Silva Cell Installation - 2009
Method of Capture: Porous Pavement
10 Marq2 Streetscape – 2009, and again in 2013
Method of Capture: Porous Pavement
11 Marq2 Silva Cell Installation, tree monitoring images by Kestrel Design Group
METHOD OF CAPTURE #2 –
SHEET FLOW / CURB CUT Raingarden concept.
Method of Capture: Sheet Flow/Curb Cut
Sheet Flow / Curb Cut 13
Raingarden concept.
Method of Capture: Sheet Flow/Curb Cut
Sheet Flow / Curb Cut 14
Raingarden concept.
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
15 Image courtesy City of Calgary
Method of Capture: Sheet Flow/Curb Cut
16 2nd Avenue Streetscape – Detail by Kestrel Design Group
Pretreatment Distribution Overflow
Method of Capture: Sheet Flow/Curb Cut
17 2nd Avenue Streetscape Construction – Photos by DeepRoot
Method of Capture: Sheet Flow/Curb Cut
18 2nd Avenue Streetscape Construction – Photos by DeepRoot
Method of Capture: Sheet Flow/Curb Cut
19 2nd Avenue Streetscape – Before and After – Photo at left by DeepRoot, photo at right courtesy City of Calgary
METHOD OF CAPTURE #3 –
CATCH BASIN Slow things down.
Method of Capture: Catch Basin
Catch Basin 21
Pretreatment Distribution Overflow
Slow things down.
Method of Capture: Catch Basin
22 Catch Basin
Pretreatment Distribution Overflow
Slow things down.
Catch Basin Schematic
23 Image from http://www.aerosnow.com/dejanaservices/catch-basin.html
Elbow
Distribute to Silva Cell system
Slow things down.
Many variations available
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
24 Approximate drainage area for each tree, image adapted from Page, Winston and Hunt
Silva
Cells
Silva
Cells
Method of Capture: Catch Basin
25 NC State Research Site - Image from Page, Winston and Hunt
Method of Capture: Catch Basin
26 NC State Research Site – Photos by DeepRoot
Method of Capture: Catch Basin
27 NC State Research Site – Photos by DeepRoot
TECHNIQUES FOR DIRECTING WATER
INTO SILVA CELLS
Tuesday, June 17th, 2014
6/12/2014
Contact us: DeepRoot Blog:
http://www.deeproot.com/blog/ [email protected]
