Sustainable Methods for Reducing Shoreline Erosion Chris Randall Master s Student Natural Resources Institute University of Manitoba
Disclaimer For advise on specific problems relating to erosion and bank stability I recommend you consult a a Professional Engineer (P.Eng) But also talk to an ecologist!
Contents Understanding Erosion Conventional Erosion Protection The Bioengineering Alternative Some Examples of Bio-engineering Projects
Understanding Erosion -slumping Red River St Adolphe
Understanding Erosion -slumping Red River, Nth Dakota from Schwert 2003 A geologist s perspective on the Red River of the North: history, geography, and planning/management issues. Proceedings 1st International Water Conference, Red River Basin Institute, Moorhead, MN
from Schwert 2003 Understanding Erosion -slumping
Understanding Erosion -corrosion South Tobacco Creek, Miami
Understanding Erosion -corrosion Lake Winnipeg, Camp Morton
Understanding Erosion Overhang fractures and debris collects at toe wave or flow action
Conventional Techniques -RipRap
Conventional Techniques -concrete or lumber sea walls
Rock fill trenches and columns -Swan Lake cemetary www.fortgarrycemetary.ca
Environmental Impacts GHG emissions from production and transport Loss of habitat from mining Habitat loss from construction Harms wildlife migration routes Prevents natural recovery Increases invasive species
The Bioengineering Alternative Incorporating vegetation as a key part of the bank protection system Much more than just a landscaping scheme
The Bioengineering Alternative Combining both ecological principles and engineering laws merging both ecological systems and human activity for the beneficial coexistence of both Key attribute is that its resistance to the erosion increase over time
strength bioengineering Hard engineering time
techniques for stabilizing banks live staking horizontal and vertical willow bundles Increased energy and/or greater consequence of failure requires increasingly more complex and more costly solutions brush grids brush layers branch packing woven live walls live timber crib walls geogrid structures combined with erosion blanket combined with stone rip rap
Selecting materials Shrub willows Select multiple sources if possible Cut while dormant Can be stored if kept damp, cold and out of wind Choose stems bigger than a fat thumb Trim side branches and ends Soak before use
St Malo Lakeshore
Riverton- Icelandic river
Dormant sandbar willow poles Tightly packed willow branches 3ft minimum 6ft by 4 fence posts
Minnedosa- Lt. Saskatchewan River
Existing bank Natural fibre erosion control blanket 15cm Woven willow fence Live sandbar and yellow willow stakes Brush layer Notes Brush bundle layer laid at 90 to bank, staked into place Woven fence of willow branches over bundle layer Erosion control blanket laid over brush layer and wrapped up and over re-graded bank, secured in trench at top of bank. Insert live stakes at 500-600mm intervals 90cm Softwood stake
Killarney- Pembina River
Sandbar willow poles Sandbar willow stakes Notes 1. Re-grade bank to approx. 1 in 3 or shallower 2. Sandbar willow poles 20mm-25mm dia., >1800mm long staked in shallow trenches and covered with soil/water mix. Lower end below low water level, upper end exposed. 4. sandbar willow stakes 25-50mm dia. >1500mm long. Leave 500mm- 600mm exposed.
Deloraine Lake
Balaton Beach
Willow Island, Lake Winnipeg
Problems! Lack of water much worse on clay soils
Problems! Lack of water Too much water Though normal spring flooding not an issue
Problems! Lack of water Too much water Early Impacts Summer storms wash sand away
Problems! Lack of water Too much water Early Impacts Pests Impact likely worse for drought stressed trees
Problems! Lack of water Too much water Early Impacts Pests And more! Beaver cutting doesn t appear to affect survival
Thank You mr.chris.randall@gmail.com