Stormwater Management Feasibility Study

Transcription

1 WEAO Student Competition 2017 Stormwater Management Feasibility Study Exhibition Place, Toronto, ON

2 Team Nicole Ludzki Emily Angermann Everett Snieder Madelaine Prince Environmental Engineering Water Resources Engineering Water Resources Engineering Water Resources Engineering

3 Background Information Overview Exhibition Place, Toronto ON Recreationally, historically, culturally significant 192 acre site, 5.3 million visitors annually, 4,359 parking spaces Existing Challenges: Conventional parking lots drain polluted stormwater into system and Lake Ontario Flooding of Lake Shore Blvd. External drainage onto site from Gardiner Expressway Urban heat island effect, poor microclimate & air quality

4 Project Description Develop stormwater management feasibility design for the Exhibition Place using low impact development practices in order to achieve an environmentally and socially valuable site Study site: 27.4ha 89.3% impervious Surface runoff collected by onsite sewer system Phase I & Phase II combined solution

5 Innovative Stormwater Management Retention Improves the water balance through increased infiltration and evapotranspiration Detention reduce peak flows and mitigate flooding At the Source Treatment infiltration, sedimentation, filtration, soil adsorption, microbial processes, and plant uptake Best Management Practices sized to accommodate projected increases in storm intensity and frequency due to climate change Vegetation aids in reducing urban island heat effect and improves local air quality

6 Hydrological Maximize removal of TSS onsite Virtually eliminate toxins using source controls as pollution prevention Capture and treat 26.5mm of rainfall Water Quality Eliminate or minimize threats to life and property from flooding Convey peak flow from 100-year storm Preserve and re-establish a more natural hydrologic cycle Retain a minimum of 5 mm rainfall onsite Flood Management Water Balance Manage Climate Change projected events developed from Ontario s Climate Change Data Portal Climate Change

7 Social and Economic Maximize aesthetic appeal Achieve high standard for water discharge quality into Lake Ontario for body contact recreation Value added component Minimize site disruption during installation, operation, and maintenance Value for Public Improve air quality on the study site Improve microclimate of the study site Value for Environment Minimize excavation onsite Minimize installation, operation, and maintenance costs Economic Analysis

8 M Data Collection and Site Analysis Model Development Identification of Key Locations LID Selection and Model Final

9 Model Development Defense Stormwater infrastructure digitized and input into PCSWMM Site DEM created from TINs provided by the City of Toronto Land cover categorized based on site maps Subcatchment areas created based on SW system and flow direction raster Large buildings and Gardiner Expressway have unique catchments Aquifer modelled based on well records

10 Model in PCSWMM Defense

11 Simulation Defense IDF applied to AES distribution for simulated storm events Primarily evaluated 1 and 12 hour events for 10 and 100 year return periods Continuous modelling uses local hourly rainfall and daily average temperature data Kinematic wave routing Green-Ampt infiltration

12 LID Green Roof Vegetative Swale with Perforated Pipe System Tree Box

13 LID : Gardiner Expressway Runoff Raised Planter

14 Final Overview Defense

15 Flood Management and Climate Change 10 year 1 hr storm peak flooding from 2.1 m3/s to 0.1 m3/s Flooding eliminated for events less than 10 years 100 year 1 hr 6.5m3/s to 2.1m3/s

16 Water Balance: Event Based Modelling Defense

17 Water Balance: Continuous Modelling For continuous modelling, events with a minimum intensity of 5mm/hr and a 12 hour interevent period were isolated 11 events were identified during for a 1 year simulation Defense

18 Water Quality 47.6% of the site is routed to LID controls directly Focus on effective placement Pollutant hot spots Routing recommendations TSS and Toxin/pollution removal Sand and geotextile layers Pre-treatment gravel diaphragms Tolerate plant species Filter layers Mass load vs. concentration

19 Value Added for Public Local Artist Murals Community Garden Educational Posters

20 Value Added for Environment Salt tolerant plants selected Plants selected to promote ecosystem development Cooling effects from vegetation and increased evapotranspiration Plants/trees act as a carbon sink improving air quality Fragrant Sumac Rhus Aromatica Chokeberry Ariona Melanocarpa Cherry Birch Betula Lenta Red Cedar Juniperus virginiana Elderberry Sambucus Nigra Winterberry Ilex Verticillata Black eyed Susan Rudbeckia Hirta Milkweed Aslepias Syriaca Improved water quality due to LID quality control improves waterfront ecosystems Creeping Juniper Juniperus Horizontalis New England Aster Aster Laevis Gray Dogwood Cornus Racemosa Switchgrass Panicum virgatum

21 Economic Feasibility: Cost Analysis LID Control Cost of Installation ($) Yearly Maintenance Cost ($) Rain Garden Raised Planter 28, ,000 Vegetated Swale ,120 Tree Box 15, per unit Bioretention Cell 172,935 2,000 Green Roof 3,636, ,000 (0 after year 2) Permeable Pavement 36, ,000 Total Cost year 1 $3,965, Total Annual Cost (year 2) $18,620 Total Annual Cost (year 3 onwards) $8,620

22 Economic Feasibility: Construction Schedule Impact the use of parking spaces as little as possible Minimize impact on site operations Avoid scheduling construction during major events on the site LID Control ID LID Control Total Construction Time Construction Time (days) A Rain Garden 3.5 A Bioretention Cell 3.5 B Bioretention Cell 3.5 B Permeable Pavement 10.5 C Rain Garden 3.5 C Green Roof 2 D Tree Box 3.5 E Vegetated Swale 3.5 F Tree Box 3.5 F Tree Box 3.5 G Tree Box 3.5 H Raised Planter 3 H Raised Planter 3 I Raised Planter 3 J Green Roof 4 L Raised Planter 3 M Rain Garden 3.5 N Raised Planter 3 O Bioretention Cell 3.5 P Rain Garden 3.5 Q Green Roof 1 R Permeable Pavement 10.5 S Bioretention Cell 3.5 S Bioretention Cell 3.5 S Bioretention Cell 3.5 Total Time 88.5 days

23 and Recommendations Recommendations: Implementation of permeable pavement in parking lots Harvesting rainwater to supplement water demands of the on-site irrigation system and fountains Closing of selected storm drains The final design vastly improves existing stormwater conditions at the site

24 Acknowledgements Andrea Bradford, PhD, P.Eng, University of Guelph School of Engineering Computational Hydraulics International Graham Seggewiss, WEAO City of Toronto Ministry of the Environment and Climate Change

25 Questions