Bioretention Facilities in Retrofit Conditions City of Calgary Pilot Projects at Carburn and Deerfoot Parks
Overview 2 1. City of Calgary bioretention pilot project 2. About the Parks 3. How bioretention facilities work 4. General lessons 5. Lessons at Deerfoot Athletic Park 6. Lessons at Carburn Park
Introduction 3 City of Calgary pilot program City stormwater priorities: TSS removal Retention Two City Parks: THE CITY OF CALGARY LOW IMPACT DEVELOPMENT GUIDELINES MODULE 2 BIORETENTION AND BIOSWALES FINAL REPORT MAY 2016 Carburn Park Deerfoot Athletic Park Implemented in retrofit condition as showcase
Carburn Park 4 Photo Credit: www.calgary.ca
Deerfoot Athletic Park 5
How the Bioretention Facilities Work 6
Lessons - General 7 1. The Right growing medium mix 2. Vegetation selection 3. Protecting layers of material
General Growing Medium Balancing Act 8 1. Infiltration capacity Factor of safety of 5 70 mm/hr 5 = 14 mm/hr 2. Plant health Nutrients Water retention 3. Local availability
General Vegetation Selection 9 Early discussions with stakeholders at same time? Consideration for: local availability options in case changes native species in some locations Stakeholders to include Preliminary list available
General Vegetation Selection 10 Module 2 Bioretention Bioswales Trees and Shrubs 1 Plant Botanical Name Common Name Native Moisture Tolerance Cautionary Notes Sourcing Other Notes Type Y/N Moist Wet Salt Velocity Sediment T Amelanchier alnifolia Saskatoon Y x N Y May sucker, which may or may not be desirable. Available Specify clumping or tree form T Betula occidentalis Water Birch Y x N Y May sucker, which may or may not be desirable. Available Specify clumping or tree form T Betula papyrifera Paper birch Y x Y/N bronze birch borer Available Specify clumping or tree form T Betula platyphylla 'Fargo' Dakota Pinnacle Birch N x Available Columnar T Malus spp. Flowering Crabapple N x Choose fireblight resistant varieties. Choose non fruit producing varieties. Available T Populus balsamifera 'Paskapoo' Paskapoo Poplar Y x Y Y May have weak branch attachment. Available More upright and drought tolerant than the species T Populus tremuloides Trembling Aspen Y x N May sucker, which may or may not be desirable. Available Specify clumping or tree form T Populus tremula 'Erecta' Swedish Trembling Aspen N x Available Columnar T Prunus maackii Amur Cherry N x susceptible to black knot Available Small varieties, e.g., 'Jeffspur' T Prunus pensylvanica Pincherry Y x suckers, which may or may not be desirable; susceptible to black knot Available T Prunus virginiana Chokecherry Y x N may sucker; susceptible to black knot Available T Prunus virginiana 'Schubert' Schubert Chokecherry N x invasive in natural areas Available T Pyrus ussuriensis Ussurian Pear N x may have weak branch attachment Available Fruit may be messy T Quercus macrocarpa Bur Oak Y x Y Acorns may be messy Available Taprooted. Long lived but about 5 years to establish. S Alnus crispa / viridis Thinleaf Alder Y x N Readily browsed Available Fixes nitrogen S Artemisia cana/ tridentata Silver Sagebrush/Big Sagebrush Y x Y good for erosion control S Atriplex spp. Saltbush/Saltsage Y x Y good for erosion control S Betula pumila/ glandulosa Bog / Dwarf Birch Y x N Available S Cornus sericea (formerly stolonifera) Red osier dogwood Y x Y Y Y Only the species is recommended Available Can be propagated from live stakes (e.g., bioengineering application). Good for metals, oil and grease uptake; good erosion control S Lonicera caerulea var. edulis/ var. Emphyllocalyx Sweetberry / Haskap Honeysuckle Y / N x Available S Lonicera involucrata Bracted Honeysuckle Y x Y Available S Eleagnus commutata Wolf Willow Y x Y Y Y Aggressive spread will occur. Rangey. Available S Potentilla fruticosa Potentilla Y x Y Only the species is recommended Available S Ribes aureum Golden Currant Y x Y Available S Ribes lacustre Black Swamp Currant Y x S Ribes oxyacanthoides Gooseberry Y x N Thorny Available Good erosion control S Rosa acicularis Prickly Wild Rose Y x Y Y Y Thorny. Aggressive spread can occur. Rangey. Available S Rosa glauca Red Leaf Rose N x Available S Rosa woodsii Common Wild Rose Y x Y Y Y Throny but less so than acicularis Available S Salix bebbiana Bebb's Willow Y x N stakes need to be harvested and planted during completely dormant period (Nov Mar) Available Can use live stakes. Prefers drier positions. S Salix brachycarpa Fox Willow Y x Blue Fox' is not recommended S Salix candida Hoary Willow Y x S Salix discolor Pussy Willow Y x N Y Y Available S Salix drummondiana Drummond's Willow Y x S Salix exigua Coyote/Sandbar Willow Y x x N Y Y Rangey. Aggressive spread will occur. Available Very effective propagation from live stakes. Highest tolerance for storage and non ideal cutting times after breaking dormancy. S Salix glauca Grey Leaf Willow Y x Y Good erosion control S Salix integra 'Albomaculata', 'Hikuro Nishiki' Tri colour, Dappled Willow N x Available long term performance unknown S Salix lucida Shining Willow Y x Y Y Y Best propagated from hardwood cuttings. Less tolerant with timing and storage than Sandbar Willow. Good erosion control.
General Protecting the Material Layers 11 *Critical* Construction ESC and sequencing Protection if completion delays Equipment Compaction Operation
Deerfoot Athletic Park 12 Volume reduction target 30 mm/year (Nose Creek) + low infiltration rates 5 mm/hr + space constraints
Deerfoot Athletic Park 13 5-year Storm - July 15, 2016 September 12, 2015 September 15, 2016
Lessons - Carburn 14 1. Scour Protection 2. Tying into Existing Infrastructure
Carburn Park Scour Protection 15 The Problem 1. Erosion of plants and soil or 2. Sediment dam
Carburn Park - Scour Protection 16 The Solution 1. Non erodible transition and 2. Elevation drop 100 mm
Carburn Park - Scour Protection 17 Concentrated flow points Sheet flow
Carburn Park Scour Protection 18 Sheet Flow Grass (sod) 100 mm drop (pavement to top of sod) 100 mm
Carburn Park Scour Protection 19 Major Concentrated Flow Point 225 mm deep 150 mm Riprap Approximately 100 mm drop (pavement to top of rock) 100 mm
Carburn Park Scour Protection 20 Concentrated Flow Points 3 x 3 concrete pavers each 300mm x 300mm 100 mm drop (pavement to top of pavers) 100 mm
Carburn Park Tying Into Existing 21 Little depth between pavement & existing pipe inverts / pond surface 400 mm instead of 450 mm growing media depth Flat subdrain very close to top surface of drain rock 200 mm instead of 300 mm ponding in bioretention
Carburn Park 22 5-year Storm - July 15, 2016 September 12, 2015 September 15, 2016
Learning Points - Summarized 23 1. Growing medium: Talk to your supplier & city early 2. Vegetation: Early stakeholder input and central list 3. Protecting material: Oversight at all phases 4. Volume reduction + low infiltration rate + space constraints = Site specific infiltrating testing 5. Scour protection: Material + drop, pavers on slopes 6. Tying into existing: Possible, strategic compromise
Questions? 24 Caroline Gort, P.Eng cgort@kwl.ca Kerr Wood Leidal Associates Ltd. www.kwl.ca