Basics of Natural Shoreline Erosion Control
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Prevention:  
Preventing erosion is the easiest and least expensive approach to maintaining a healthy shoreline.  Here are some ideas especially if you have not built on your lot yet or are planning to remodel. 
  • Site your house a minimum of 100 feet from the lake.
  • Keep as many trees, shrubs and native plants as possible.
  • Limit turf grass especially at the lake edge. 
  • Minimize impervious surfaces. 
  • Share the shore with aquatic plants. ​
Photo: Jane Herbert
Photo: Julia Kirkwood

What to do instead of seawalls when shorelines are eroding?

Soft-Armoring or Bio-engineering
There are situations where eroding shorelines will need some help to become stabilized. But a seawall is not the only option!​  Techniques called "soft-armoring or "bio-engineering" can solve shoreline erosion in a way that supports the lake ecosystem and protects lakefront property.  Bio-engineering is not an exact science.  Bio-engineered shoreline erosion control is usually applied as a system of applications that provide upland stabilization, bank toe stabilization and bank toe protection.  All of these methods require the reintroduction of deep-rooted native plants to create a system that mimics naturally stable shorelines.  
Photo: Jane Herbert
How do I know if bio-engineering will work for my site?
​Although not every site is suitable for bio-engineering most are! Solutions range from very simple and inexpensive to complex and more costly.  The more challenging the site the more complex the solution is going to be.  A site must be properly assessed by a knowledgeable professional to determine the solution.  Many factors such as site conditions, space availability, where buildings are located, lake levels (natural or lake level controlled), lake shape, water depth and the erosive energy at the site including boat wave energy should be included in the assessment.  
Yes - bio-engineering requires a permit! 

What types of materials are used?

Each solution is a system of different materials and design concepts. Below is a basic introduction about some of the materials that might be used in many different designs.  There are many different types of materials and design concepts.
Native Plants
Vegetation native to Michigan is a critical component of ALL bio-engineered shoreline erosion control solution.  The MNSP has created a list of plants to help find the "Right Plant for the Right Place".   Plants should be chosen which best suits the site to provide the best potential for shoreline stabilization.  They should be a mix of flowers, grasses, sedges and even trees and shrubs. The plant selection can also be tailored to meet the desires of the landowner but the priority should be providing the best root structure for long term success.  Planting options come in plugs, pots and live stakes. 
Photo: Jane Herbert
Coir (Coconut fiber) Logs
Coir logs are rolled coconut fiber logs held together with twine woven from coconut material.  They come in a variety of lengths, sizes and densities.  They are typically placed at the toe of the shoreline but can be used in other parts of a stabilization technique as well.    The goal is to have plants grow into the logs and create a strong root system that can withstand the erosive forces at the shoreline.  The coconut fiber logs will eventually biodegrade after a few years. As the plants grow, their root structures naturally stabilize the shoreline.  Conditions need to be suitable for plants to grow to be able to colonize the coir logs. This means adequate soil, sunlight and water for the plants that have been chosen.  One limitation is that they cannot withstand excessive erosive energy and ice push without some extra toe protection.  Some design techniques may include both coir logs and appropriately sized and placed rock. And always remember the plants!
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Photo: Julia Kirkwood
Erosion Control Blankets 
Erosion control blankets such as jute, coir (coconut husk fiber) and wood-fiber blankets can be a product used in natural shoreline projects.  These are useful on slopes for holding the soil in place until plants become established.  Ideally, they should be fully bio-degradable. These products are staked over an area and allow plants to grow through the fibers. Plug plantings are planted through the open woven fabrics or through slits made in the fabric of denser products. Manufactures of these products will typically provide information on applications based on various site conditions. These types of products should not be used alone on really steep slopes!  Other techniques should be used to ensure the slope is properly stabilized.
 Showing erosion control blankets being used at a site before planting. ​Photo: Jane Herbert
Rocks
Rock (also known as rip rap) can be used in bio-engineered shoreline erosion control techniques.  This approach requires appropriately sized and placed rock based on site conditions.  Rock can provide the extra toe protection needed to protect coir logs to help plants become established.  In many situations if designed appropriately the rock will become hidden creating an aesthetically pleasing shoreline and still providing erosion control.  As with all techniques plants should be used.  
Using rock to protect the toe of the shoreline. 
Photo: Jennifer Buchanan
While the use of rip rap can be better than a vertical concrete or steel wall, improperly sized and placed rock can also create barriers for wildlife and tend to look ugly.  In this picture the rock was not sized or placed correctly in order to be called a "bio-engineered" solution.    And there are no plants!
Watch a bio-engineering installation training day!

What can I expect for costs?

The costs vary by what solution is needed.  The more complex the higher the cost.  A homeowner can expect to spend an estimated $45 - $70 per linear foot on materials. Example for pricing of native plants:  A 38 cell plug flat of native plants costs about $60.  Planting recommendations is usually about 1 square foot per plant.  However, if a site is challenging to access or the solution requires the use of rock materials will cost more. 

*Permit fees, design and installation fees are not included in the estimate.

 Solving shoreline erosion requires proper:

1. Diagnosis of lake conditions and understanding lake processes.
2. Assessment of what is happening on the land.
3. Proper construction of erosion control systems. 
4. Maintenance of erosion control systems.
5. Landscape practices that are healthy for the lake.  ​
Know Your Cause of Erosion:  
  1. Terrestrial (Land based) forces
  2. Aquatic (Water based) forces
  3. Human activities.​
Know Your Eroded materials
Every lake and every shoreline is different however there are two primary types of materials that are found near the shoreline: consolidated and unconsolidated materials.  
  • Consolidated materials are basically bedrock and will not usually have drastic erosion problems.  
  • Unconsolidated materials include sand, gravel and clay and are loosely held together which makes them much more susceptible to erosion.​
Calculating Erosion Energy

There are many different factors that go into calculating an estimated erosion energy at a given site. Engineers have determined that, of the factors that cause bank erosion, wind-driven waves are the main factor in determining the severity of erosion. This determination uses the longest fetch (distance that wind can blow waves across the lake to a site), the average depth along the fetch (depth determines the height waves can reach before breaking), and storm wind speed.   The MNSP Certified Natural Shoreline Professionals are trained in how to calculate the erosion energy at your shoreline.  
Graphic illustrating determining the fetch for a specific site.
​The longest unobstructed distance. 

Wisconsin has created an on-line erosion energy calculator.  This is a good first step for a property owner to get a general idea of the typical amount of wave energy at their site.  However, when doing a design a much more intensive review and calculation of the erosive energy must be done.  Each site is very different and there are differences even within each site.  Human caused waves should also be factored into the erosive energy calculation.
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Wisconsin Online Erosion Energy Calculator

Shoreline Maintenance

Natural shorelines are living shorelines!  

They do need some observation and care.  The first year of the project is very important.  The plants need to establish a good root system and then need to be protected from wildlife such as geese.  

Use the 3 W's of Care: WATCH WATER and WEED
  • Watch:  Watch what happens throughout the different seasons and different storm events to make sure everything is still in place.  Property owners should discuss any potential problems with their contractor and any follow up action up front.  
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  • Water:  Choosing the right plants for the right place is important but they do still need to be watered until their root systems have become established.  

  • Weed:   As with any landscape property owners should expect to do some weeding.  How much?  That will depend on the owner and what is happening.  Non-native invasive species such as purple loosestrife should be controlled.   Other plants such as jewel-weed and mint can creep in and take over the site.

What if I already have a seawall?

Even if you already have a seawall there are things you can do to help lessen the negative impacts seawalls have on lakes.

1)  Where practical and feasible replace an old and failing seawall with more natural
     solutions. 
2)  Place rip-rap in front of a seawall which helps to reduce the wave energy thus     
     reducing wave flanking and scour.  Rip-rap can also create a slope for allowing     
​     animals to access the land and provide places for aquatic insects and plants to grow.  
3)  Plant into the rip rap.
4)  Reduce your lawn and add native vegetation on the land. ​
Any construction at the shoreline including placing rip rap in front of a seawall does require a permit from the Michigan Department of Environment Great Lakes and Energy (EGLE)
 
​The photo to the right is illustrating an example of rip rap in front of a seawall to help absorb wave energy and create a softer slope.  Plants were then added to the rock to provide root structure for stabilization and habitat - the butterflies are especially happy!  The plants will eventually hide most of the rip rap.
Photo: Mary Blickendorfer

Want more information?

Library 

Check out the many resources on our Library page to learn more about bio-engineering and what you can do on your property. 

Demonstration Sites

The MNSP uses public locations to train professionals on how to properly install basic bio-engineering erosion control practices.  See some pictures of different techniques. 

Find a Contractor

The MNSP maintains a list of professionals that have gone through the Certified Natural Shoreline Professional Training.  We do not provide specific recommendations though.