Water Management of Turtle Lake Watershed

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Water Management of Turtle Lake Watershed

• Sept 29, 2007
• by
• Don Dill

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Presentation Outline

• Watershed Characteristics
• SWA Sask Water
• Involvement with Water
• Levels since 1984
• Roles SWA Plays in Water
• Management in Watershed
• Questions

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Watershed characteristics

• Gross Drainage Area
• 649 km 2
• Effective Drainage
• Area
• 555 km 2
• Area of Turtle Lake
• 64 km 2
• Net evaporation
• About 340 mm

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Watershed Characteristics

• Inflow Volumes (1 dam 1000m3 or 220,000
  gallons)
• Volumes (dam3) Peaks (m3/sec)
• 1 2 18,700 5.6
• 15 26,800 9.0
• 110 33,000 12.0
• 125 42,000 15.5
• 150 49,000 20.0
• Annual net evaporation 21,200 dam 3

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Water Level Peaks

• Water level peak this year 655.24 m.
• 1100 peak water level 655.16 m.
• used in hydrology
• studies
• The 100 level is being reviewed to determine if
  changes need to be made.

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Historical Water Levels
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Outlet of Turtle Lake
April 1990
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Silt from ditching carried out July 19, 1984
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Obstruction placed July 19, 1984
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Obstruction May 25, 1985
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Obstruction in Channel May 28, 1985
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Outlet July 16, 1985
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Sask Water Timber Weir

• Overflow elevation varied between 654.62 m. and
  654.93 m. between 1970 and 1984.
• Set weir at historical average level
• Set at 654.78 m.
• Supposed to be temporary until consultation
  completed and new structure designed

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Temporary Wood Structure Installed April 25, 1986
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Temporary Wood Strucutre Installed April 25, 1986
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Planning Study Initiated in 1986

• Public Opinion Survey carried out in June of 1986
• Public Meetings held in the summer of 1986.
• Petitions circulated with hundreds
• signing to object to the elevation of the timber
  weir ( too low)
• Lots of consultation but no consensus

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Watershed Authority Water Management Roles

• Regulate Water Use
• Example water lines into cabins
• Regulate Drainage Activity
• Example farm drainage or diversions for flood
  control.
• Deal with Drainage Complaints
• Example municipalities impounding water with
  road grades

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Watershed Authority Water Management Roles

• Deal with Water Management Inquiries
• Example municipalities seeking advice on
  proper placement of culvert
• Review sub division applications and advise on
  Estimate Peak Water Levels (Vary between 656.65
  and 655.7 m. for various locations around lake )
• Review Forest Management Plans
• Review projects going through the Environmental
  Assessment Process

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Changing Watershed from Forest Harvesting

• White blocks areas
• north and east of lake
• are harvested
• areas in 1990

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Watershed Authority Water Management Roles

• Undertake water quality monitoring with
  Stewardship groups
• Provide advice and assistance to protect riparian
  areas
• Take a lead role in preparing Source Water
  Protection plans for the north Sask. Watershed
  including Turtle Lake

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Main Role of SWA

• We are working on behalf of you to protect
  surface and groundwater supplies and quality.
• Your views and comments are essential for
  successful management of our water resources

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Questions