water, water, everywhere?...introduction richard boase, p.geo., ccep environmental protection...
TRANSCRIPT
Water, Water, Everywhere?
Is It Really So?
Introduction
Richard Boase, P.Geo., CCEPEnvironmental Protection OfficerNorth Vancouver District355 W Queens Rd.North Vancouver, B.C., V7N 4N5Tel (604) 990-2365Email [email protected]
Introduction
Urban Hydrology
Hydrological CycleImportance of near surface groundwaterInfluencing the hydrological cycle
Introduction
Urban Hydrology Around the Home
Design ideasLandscaping ideasPlant and soil ideasOperation & Maintenance
Introduction
Future Considerations
Climate ChangePolicy & BylawsTrends
Urban Hydrology
Hydrological CycleThe process by which water, in liquid, solid and gaseous states, is cycled through the ecosystem within the hydrosphere
Condensation
PrecipitationTranspiration
Evaporation
Groundwater flow
PercolationStream flow
Hydrological Cycle
Urban Hydrology
Near Surface Base flow
Importance of near surface groundwater
Urban Hydrology
Time
Flow
Influencing the hydrological cycle
Poor sediment & water quality
High sediment loads
Reduced coverReduced complexity
Increased bank erosion
Influencing the Hydrological Cycle
Urban Hydrology around the Home
Urban Hydrology around the Home
The single largest factor we can control, and make a difference with, is the
landscaping in our yards.
Part of the problem
Part of the solution
Urban Hydrology around the Home
www.waterbalanc
74% 71%
21% 23%
4 % 6%
0
2 0
4 0
6 0
8 0
1 0 0
Pe
rce
nt
of
To
tal
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nR
ain
fall
L e s s th a n 5 0 % o fM A R
5 0 % o f M A R to M A R G re a te r th a n M A R
R a in fa ll E v e n t S iz e (m m )
T y p ic a l V o lu m e D is tr ib u tio n o f A n n u a l R a in fa l l
S o u th C o a s t (B u rn a b y M o u n ta in ) O k a n a g a n (K e lo w n a A irp o rt)
N ote : B urnaby M oun ta in M A R * = 7 0 m m K e low na M A R * = 20 m m (*2 4 -h o u r ra in fa ll )
20%Large Storms
75%Small Storms
5%Extreme Storms
RAINFALL SPECTRUM
SITE
Infiltrate or Harvest Small Storms at the Source to Reduce
Total Runoff Volume
Provide Storage to Control the Rate of Runoff from Large Storms
WATERSHED
Ensure that the Downstream Systemcan Safely Convey
Extreme Storms
NEIGHBOURHOOD
LIGHTSHOWERS
HEAVY RAIN
EXTREME STORMS
KEEP RAIN ON SITE
DELAY THE RUNOFF
REDUCE FLOODING
INTEGRATED STRATEGY
LIGHT HEAVY EXTREME
The Design Objective is to Infiltrate the First 30mm of Rainfall
Design Ideas
How the Water Balance Model can help improve our landscape
• Ask questions & get answers• Spend your time & money wisely• A free resource• Brings design people together
Design Ideas
Typical SFD lotNo BMP
1630 m3 runoff
Same lot with Rain Garden
1083 m3 runoff
Design Ideas
• Think NATURAL (Hydrological Cycle)
Standard Sump
Exfiltration Sump
700 square foot garage
No storm connection at rear of property
Condition of permit
Design Ideas
Landscaping Ideas
• Think of cascading systems
Practical Site Level Solutionsare Typically Landscape-based
Plant & Soil Ideas
Absorptive Landscapes
Up to 50% less runoff
Less water
Less chemicals
Plant & Soil Ideas
Compost and amended soils
•GVRD produces about “biosolids” 70,000 tonne/yr
•Used in mine reclamation, ranchland enrichment, silviculture and landscaping
•Restores poor or depleted soil with nutrients and organic matter
•20%biosolids, 20% yard compost, 20% wood shavings, 40% sand
•Use a minimum 300 mm depth amended soil
Plant & Soil Ideas
Compost and amended soils
• Adsorb more water, less run off
•Less weeds, less fertilizer, less competition for water
•Deeper root systems, healthier lawns
Plant & Soil Ideas
Plant & Soil Ideas
• Native species have adapted to our climate making them a (personal) first choice
• Asses your yard for wet areas, sandy areas, light areas then chose plants
Future Considerations
Climate change
Policy & Bylaws
Trends
Future Considerations
Future ConsiderationsTemperature rise
More rain
Sea level rise
Water Resources
Supply
Quality
Competition
Forest impact
Composition
Range
Health & Productivity
Loss of species
Lower biodiversity
Less habitat
Future Considerations
The City of Courtenay was thefirst municipality to adopt a Minimum Soil Depth Policy
Trends
More Local Governments adopting rain barrel programs
Burnaby, Coquitlam, Delta, Langley City, Langley Township, Vancouver all have some form of rain barrel program
Trends
Natural Lawn Care
Composting & Mulching
Organic Gardening
Water wise gardening
Biological pest control
In Closing70% of our water reserve falls in autumn & winter
Highest demand falls in July, typically we’ll use 35% more water in July than December
Average consumption is 1x107 L/day this can double on a hot summer day
Even a poor lawn only requires 2.5cm water once a week
Water early in the am, use sprinklers that produce drops rather than spray, water ONLY your lawn
Plants need more water than grass use a watering can
Aerate and add compost to your lawn
In Closing
Thanks to Liz Haan and the BC Master Gardener’s Assoc.