Traditional Technologies

Great Lakes Water Levels

have risen over 6′ since 2013 covering most existing beaches left after the last high-water event in 1986. The Great Lakes are projected to rise another 19 inches in 2020 putting most shoreline property and many structures at risk.

Traditional remedies to control bluff toe erosion include rock revetments, sea walls, and sandbags. Unfortunately, no erosion control structures are guaranteed due to the unpredictability of mother nature although most failures are due to inadequate design and improper installation. Most erosion control structures typically cost less to install with adequate landside access.

Rock Revetments

are an excellent solution when properly designed and installed at a cost usually exceeding $2,500 per running foot if correctly installed, obviously substandard installations with smaller amounts of smaller rocks will be much less expensive and often disappear in one good storm, less is defiantly not the more you will need. Typically, the beach is excavated as low as possible below water level, a geo textile is installed to keep the rock separated from the sand with a 24″ layer of small stone to protect the geo textile from puncture.  Progressively larger rocks are added with a front and top layer of large armor rocks to break up and dissipate wave energy. Proper installation and enough stone are critical.

Some negatives that drastically reduce rock revetment service periods include:

1. Improper design without enough rock and improper installation elevations
2. No geotextile or mattress bed allowing rocks to rapidly sink with wave action.
3. Unknow or short quantities of rock installed (demand all weigh slips from drivers)
4. Rocks move, sink, and disappear requiring multi year replenishment.
5. If shoring up under foundations ground water soil migration causes erosion and settling

Also rock revetments:

1. Make lake access for humans and animals difficult and dangerous.
2. Are very difficult and expensive to remove if lake levels go down.
3. Are not conducive to stairs, decks, or boats.
4. Require major logistics and cost to transport and install on site
5. Cause significant erosion and habitat damage with lakeside traverse

Seawalls

when properly designed and installed are a great solution as proved by the local piers. Cost are typically higher then rock revetments and vary with construction access. Typical failures are caused by;

1. Sheet piling not heavy enough allowing sheets to buckle and separate, especially from ice
2. Inadequate sheet length allowing scour (the underwater transport of sand/bottom caused by water currents resulting from wave energy dissipation) to undermine bottom sheet holdback support. (rough rule, 1/3 above water bottom, 2/3 below)
3. Inadequate tiebacks/anchors allow wall to fold lakeward bulge/fail
4. Dissipating downward wave energy creates a drop off in front of wall.
5. The change in water flow often enhances erosion on adjacent properties and sidewall extensions often need to be added creating a peninsula effect
6. No geo textile behind wall allowing backfill to erode through

Sand Bags

are a great temporary solution for holding back flood water and many have been installed on Lake Michigan, big ones, small ones, filled with sand and some filled with cement. Lack of consistent installation materials and methods make judging their relative effectiveness very difficult.

Overview

A very valid consideration is a client’s vision of his or her lake front property when and if the water levels recede. A huge slope of giant rocks or concrete construction waste, as recently allowed to be installed, creating a not so scenic and a dangerous and/or inaccessible path to the beach in not conducive to aesthetics or property values while requiring considerable expense to remedy and removal can cost more then installation if possible. These types of hard structures also create many challenges should steps, stairs, decks, or other typical lakefront amenities wish to be installed.

Unfortunately, there are little to no recent studies on the effectiveness of any erosion control structures performance since the last high water occurrence around 1986. The only remnants of that study period are some exposed rotting wood walls as the water level decreased, some steel seawalls that were correctly installed and a few barley visible rock revetments. Many property owners, understandably due to the capital expense, have chosen the least expensive option: gambling that the lake levels will go down which unfortunately created a shortage of both materials and competent contractors in both marine construction and house moving, resulting in a drastic increase of cost due to the newly developed demand. 

Our advice before committing to any erosion control method project is at the very least; request a construction drawing, a written contract detailing all materials to be used and their quantities, a construction timeline, and a proof of workmens compensation and public liability insurance from your contractor. 

If you have an erosion control project in mind but are now wondering if Shore Savers would be more beneficial to you and your property, please do not hesitate to contact us with any inquiries or questions. 

The Advantages…

• Installed only by reputable contractors with insurance proofs on file
• Cost effective compared to other options
• Fast installation (typically less than a week depending on weather)
• Recyclable and nonpolluting
• Robust construction exceeding ACI standards for reinforced concrete
• 120-ton mass to counteract wave forces
• Pile retention eliminates slope migration if needed
• Galvanized and coated connection hardware
• Corrugated surface causes turbulence to dissipate wave energy
• Corrugated surface retains suspended soils and allows for future re-vegetation
• Self-adjust for front and side scour
• Removable, can be stored and reused or sold
• Expandable to adjoining properties
• Can be installed in all weather with reasonable surf
• Can be installed from land side with suitable nearby crane access
• Eliminates wind scour from covered surfaces
• Uses local materials and local materiel suppliers
• Maintains bluff face regardless of water level
• Allows limited boat access
• Gradual slope profile has less adverse effect on adjoining properties
• Limits sedimentation of near shore and off shore aquatic breeding nursery’s
• Enhances shallow water breeding nursery depending on lake levels
• Allows reasonable shoreline access to humans and wildlife
• Allows stairway securing and installation
• Allows deck or boat house installation
• Allows installation of overtopping barriers if needed
• Can be installed without removing existing tree lines or vegetated slopes
• Allows the establishment of optimum 2 to 1 slope for re-vegetation
• No protrusions and pile caps allow traverse of rubber tired or tracked equipment
• Reduces lake erosion filling which contributes to high water level