EXPLORING THE WATER BALANCE on your property Julie Wilson - - PowerPoint PPT Presentation

EXPLORING THE WATER BALANCE

• n your property

Photo: Ambleside Beach, WV February 25, 2017

Julie Wilson

julie.wilson@ubc.ca NSSK Workshop, Mar. 18, 2017

My Goal

geoweb.dnv.org geoweb.dnv.org geoweb.dnv.org geoweb.dnv.org dnv.waterbalance dnv.waterbalance dnv.waterbalance dnv.waterbalance-

• express.ca

express.ca express.ca express.ca

Image: NOAA National Weather Service

Water Balance

Image: US EPA

2 4 6 8 10 12 14 16 18 Stream Discharge (m3/sec) Time after Precipitation Starts

Stream Discharge Response after a Storm Event in a Forested Watershed

2 4 6 8 10 12 14 16 18 Stream Discharge (m3/sec) Time after Precipitation Starts

Difference in Stream Discharge between Urban and Forested Watershed

Water Quality Concerns

www.belairks.org

Photo credit: Charles Crawford; courtesy USGS

Pollutants

• Metals (Cu, Zn, Pb, Ni, Cr, Hg, Cd, As)
• Organics (Hydrocarbons, Oil, Grease)
• Nutrients (N, P)

Aquatic Ecosystem Health

Source: H. Schreier

Grey Infrastructure Green Infrastructure

Julien Interior

Rain Barrels Rain Gardens Green Roofs Constructed Wetlands Infiltration Swales

Flynn Canada

Mimic the Natural Water Balance

Three flow pathways:

1.

Surface runoff

2.

Seasonal interflow (shallow horizontal flow)

3.

Water stored deep in aquifers which then discharges at some future date.

Image: Auckland City Council (2010)

• Partnership for Water Sustainability in BC

“SLOW, SINK AND SPREAD” THE WATER!

Urbanization Trends

Source: D. Freudiger, 2012

2003 Impervious Area

23%

2009 Impervious Area

54%

Urbanization Trends

Source: D. Freudiger, 2012

2003 Impervious Area

23%

2009 Impervious Area

54%

20 40 60 80 100 120 140 160 1910-1914 1920-1924 1930-1934 1940-1944 1950-1954 1960-1964 1970-1974 1980-1984 1990-1994 2000-2004 2010-2014 2020-2024 2030-2034 2040-2044 2050-2054 2060-2064 Number of houses Time period (5 years) Age of Houses Houses rebuild (hypothetic)

Water Balance Model Express

Image: waterbucket.ca

Watershed-Specific Targets

• The flow-duration relationship is the cornerstone of the

methodology.

• By maintaining flow-duration,
• stream erosion is not increased during wet weather, and
• ‘environmental flows’ are sustained during dry weather.
• Considers local environmental constraints

Credit: Jim Dumont, Engineering Applications Authority, Partnership of Water Sustainability in BC

DEMONSTRATION

Check out the video tutorial at dnv.waterbalance-express.ca GeoWEB at geoweb.dnv.org

Design Considerations

• Be aware of your site limitations
• Consult a professional
• Resource: Metro Vancouver Stormwater Source Control

Design Guidelines (2012)

Relevant Policies

• Integrated Stormwater Management Plans
• Top Soil Bylaws
• BC Water Sustainability Act
• “Environmental Flow Needs” must be considered

Key Messages

• Goal: Water balance of the

urbanized watershed to mimic the water balance of the pre-development watershed.

SLOW, SINK AND SPREAD

• Try the WBM Express!
• Change the way you look at

rainwater and how it moves through the urban landscape.

Image: Tomas Castelazo, Wikimedia Commons

Singing in the rain!

mlws.landfood.ubc.ca mlws.landfood.ubc.ca mlws.landfood.ubc.ca mlws.landfood.ubc.ca wmcourses.landfood.ubc.ca wmcourses.landfood.ubc.ca wmcourses.landfood.ubc.ca wmcourses.landfood.ubc.ca

Happy World Water Day!

March 22

Waiting for Water

Linocut by Catherine Fenton