Module 2:1
Managing Shoreline Erosion
Erosion: A Natural Process
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Proceeds very slowly Important part of ecosystem function
Courtesy of: Ed Klekowski
Natural Causes of Erosion Wind Ice Water movement
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Wave energy Currents Changing water levels Rain/run-off
Gravity
Human Disturbances
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Removal of shoreline vegetation Run-off from paved surfaces Boat wake
Human Disturbances
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Construction on or near the shoreline
Heavy foot traffic
Shoreline alteration
The Impacts of Erosion
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1.
Loss of valuable waterfront property
2.
Unsafe areas
3.
Loss of habitat
The Impacts of Erosion 4.
5. 6.
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7.
Changes the characteristics of the bottom Reduces water clarity Increases water temperature Releases chemicals/nutrients into the water
Signs of Erosion
Areas of exposed soil
Rills and gullies
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Slumping, undercut banks Formation of sandbars and “islands”
More Signs of Erosion
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Cloudy water Stream or river becoming wide and shallow Receding shorelines Leaning & downed trees & exposed roots
How To Prevent Erosion 1.
2.
3.
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4.
Protect the natural shoreline Reduce run-off from impermeable surfaces Minimize wake from boats and other motorized watercraft Take precautions during construction
How To Prevent Erosion 5. 6.
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7.
Limit foot traffic in erosion prone areas Contour and cover pathways Avoid alterations to water courses
How to Control Erosion 1. Identify:
Cause of erosion Type of erosion Extent of problem Site conditions
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2. Select most suitable control method
Control Methods A. Natural buffers B. Bioengineering
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C. Hardened structures
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A. Natural Buffer
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B. Soil Bioengineering
Slope Preparation
• 45° = 1:1 slope 27° = 2:1 slope Module 2:16
18° = 3:1 slope
Photo credit: Rian Myers 1993
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Bioengineering Techniques above the Water
Live staking
Fascines (wattles/bundles)
Brush layers
Brush mattresses
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Live Staking
Courtesy of: Carolyn Dindorf
Fascines
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Courtesy of Maccaferri Ltd.
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Brush Layers
Photo credit: Environment Canada
Brush Mattresses
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ď ľ
Courtesy of: Maccaferri Ltd.
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Maintenance
Recommended Native Species
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Red-Osier Dogwood (Cornus stolonifera) Silky Dogwood (Cornus obliqua) Grey Dogwood (Cornus racemosa)
Recommended Native Species
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Pussy Willow (Salix discolor) Shining Willow (Salix lucida) Shrub Willow (Salix eriocephala)
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Gathering Plant Material
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Bioengineering Techniques In the Water
Fibre rolls
Brush bundles
Plant anchors
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Fibre Rolls
Courtesy of Maccaferri
Courtesy of: Douglas Fuller Courtesy of: Douglas Fuller
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Brush bundles
Courtesy of: Carolyn Dindorf
Plant Anchors
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Fibre mats Fibre bags
Courtesy of Maccaferri Ltd.
Case Study
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C. Hardened Structures
Break walls
Gabion baskets
Riprap
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Breakwalls
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Retiring Your Breakwall
Photo credit: Cottage Life Magazine
1.
Dig it out
2.
Break it down
3.
Plant it
Gabion Baskets
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ď ľ
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Riprap
Courtesy of: Douglas Fuller
Approvals Contact: Conservation Authority Ministry Of Natural Resources Department of Fisheries and Oceans
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Parks Canada
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Managing Erosion 1.
Practice erosion prevention
2.
Understand the source of erosion
3.
Research your options
4.
Make an informed decision