Urban Water Development Flashcards
How To Grow Sustainable Cities?
Start with better stormwater management.
The Hydrological Cycle
When it rains that contributes to the ocean which then get evaporated into the sky restarting the cycle.
When it snows that falls on the mountains, falling off into water supply which then gets evaporated restarting the cycle.
What is stormwater? Why should we care about it?
Urban, suburban and rural agricultural land use practices generate substantial surface run-off
- increased soil erosion
- sedimentation
- flooding
- water quality degradation
- loss of biodiversity
- aquifer depletion
- climate change
Precipitation, infiltration, Run-off relationship
Runoff rate = function of (precipitation rate and infiltration rate)
Infiltration = function of (soil texture, soil moisture, vegetation cover)
Water in Canada
Water and Canadian identity
25% of world’s wetlands
9% of Canada’s total area covered by freshwater
10% of world’s flow of freshwater
More lakes than any other country (8% of area)
More water per capita than any other large country
Water Realities in Canada
85% of Canada’s population lives within 300 km of US border
Regions of water scarcity within Canada
60% of our water supply flows North
Climate change uncertainty, variability.
Canadians pay very little for water.
Canadians among world’s highest users of water
Stormwater in Modern History
Before 1990s
Objective: to provide drainage away from development, to control flood flows
Means: structural methods, pipes, culverts, armour natural channels
Design Method: Size capacity based on 100 year return event
Financing / implementation: public works funded by tax dollars
1990s - NOW
Objective: on-site mitigation of storm flows; enhanced infiltration; support base and low flows of streams; protect/restore natural drainage channels
Means: Decentralized runoff control, bioengineering; swales; bioengineering; on-site retention of storm water
Design Method: Computer models; multi-function land uses; appropriate on-site measures
Stormwater Management
From conveyance to retention (btw 1970-2000)
Green infrastructure
From pipes to retention on ground
CLIMATE CHANGE, Global Warming a game changer
Hurricane Katrina, August 25-30, 2005
1800 fatalities
$108 billion damages
More recent hurricane events … impacts on cities … have we planned for these events … will they be more common?
