Erosion: A Two-Sided Story
Shoreline erosion is a common problem faced by thousands of waterfront property owners. Many of whom view erosion issues as an inevitable consequence of living near the water. However, it is important to recognize that human actions can significantly contribute to and exacerbate erosion, and that there are steps we can take to prevent or reduce it. Our shorelines serve as the conversion zone between land and water. This is an extremely tough and very important job. With the many forces acting on them, our shores need to be maintained for the health of our natural systems and the security of our infrastructure.
The problem is that these forces are relentless. Wave action in the summer and ice push in the winter both nick away soil along the water’s edge. Run-off from streets and the upheaving frost action degrade shorelines from the land side. All while the wind erodes the ground from both sides. In general, lakes are considered depositional features, and rivers as erosional features. There are some differences between these classifications but both mean that a great deal of energy is acting on your shoreline every moment. Erosional forces already push coasts to their structural limit. Then we as humans come along and intensify those forces to the detriment of both parties.
Impactful Human Activities
Unfortunately, many of the activities we partake in as humans make conditions worse for our water features. We do not set out to intentionally harm these systems, rather the impacts are a by-product of other pursuits.
Reducing the Amount of Shoreline Vegetation
For one reason or another, many waterfront property owners like to clear the vegetation along their shoreline. Terrestrial plants (those on land) get torn out to create a clear view of the water and provide direct access to the shore. Then aquatic plants (those in the water) are removed to open up areas for docks and swimming. This essentially removes a large portion of the soil’s structural support system.
If you think of the soil as concrete, the root systems of plants are comparable to the rebar latticework placed by masons to reinforce the cement. Take all that away, and you open up your shoreline to erosional forces and even collapse. Not a good situation.
Increasing the Amount of Impervious Surfaces
The copious amounts of water are another serious issue. Increased development around bodies of water has led to a considerable spike in the number of impervious surfaces. These areas, such as paved driveways, parking lots, and roads, do not allow water to seep into the ground during storm events. Instead, mass amounts of water combine and run off into the water, carrying soil with it.
System-Wide Effects
Shoreline degradation is harmful to landowners, the water, and the plants and animals that occupy these areas. Increases in soil erosion cause a dramatic influx of minerals and nutrients into waterways. Now you might be thinking this is a good thing. Pedialyte for the plants to grow big and strong, right? While some nutrients in this runoff promote plant growth, the issue lies in volumes being emptied into the water.
Eutrophication
Plants and other photosynthesizing organisms are limited by certain chemicals, namely nitrogen and phosphorus. Accelerated runoff introduces these chemicals at an unnatural rate. Once this happens, a process known as eutrophication is sure to follow.
The immediate release of nutrients in runoff allows plants and algae to grow prolifically. Large sheets of algae then cover the entire surface of the water. Since this prevents the sun’s rays from penetrating the surface, most submergent plants cannot photosynthesize. Over time, the plants produce less and less oxygen. This leads to a poor supply of dissolved oxygen available for aquatic invertebrates and fish.
Increased Turbidity
Even when eutrophication does not occur, the rapidly eroding soil makes the water more turbid (cloudy). This increase in suspended particles blocks the sun’s rays from getting to aquatic plants under the water. The same negative result as before.
Common Solutions
Spend any amount of time on a developed lake, and you will get an idea of how many waterfront property owners choose to protect their shorelines. Rip-rap and seawalls.
These two methods are often promoted heavily by contractors as the only available option to protect your shoreline. Both of these approaches do have some applicability in some situations. However, it would be in your and your ecosystem’s best interest to consider these options only as a last resort.
Rip-Rap
Riprap is a technique that uses loose angular rock to stabilize slopes and protect shorelines from wave action. Rip-rap removes and prevents most plant life at the initial 10 to 20 feet of your shoreline. This functionally eliminates all the quality habitats for fish, wildlife, and invertebrates in this range.
Seawalls
Seawalls are large barriers, typically constructed of concrete, positioned between the shore and the water to block waves from contacting the coast. Seawalls likewise remove essential habitats but have additional impacts.
In many cases, seawalls actually increase the amount of erosion. When waves hit the wall, they are generally reflected laterally and downward. This movement causes the scouring of sediment in front of the seawall and also pushes water towards surrounding properties. Essentially, seawalls only protect the shoreline immediately behind them. Which is not a viable solution when thinking about shorelines along an entire water system.
Natural Solutions
If we want to preserve the biological integrity and health of our aquatic systems, we need to re-think how we build along our shorelines. The best way to begin is to picture how an undeveloped shoreline would look…
Plants sprawled from the water’s edge to above the high water mark on the shore. The uneven structure of vegetation and fallen branches almost make it appear messy. Damselflies, turtles, and frogs abound. Fish darting from shady log to shady log. — That’s the goal.
So you might be wondering, can I mimic a natural shoreline while maintaining a good aesthetic? Yes, you definitely can! Let us discuss the solutions of how to protect your shoreline naturally.
Solution #1: Use Native Plants to Improve Shoreline Integrity
Using native plants to act as a buffer between land and water is an excellent method to help reduce erosional forces and pollution. The key to making these plants effective is placing them in suitable areas and arrangements.
Take some time to research how each species grows and how deep its roots typically go. Look for plants that will establish while fully saturated and some that will do well along the bank. Like other native plantings, shoreline plants will generally take 1-5 years to fully mature and form a stable root arrangement.
Solution #2: Install Coir Logs to Encourage Plant Establishment
Coir, a biodegradable fiber made from the outer husks of coconuts, makes an excellent material to use near and in water. Placing natural coir logs along your shoreline protects the sediment from wave action. Coir logs are strong enough to stand up against years of wave action and the occasional storm if installed correctly. There is no risk of potential chemical contamination, and the fiber will break down after just 2 to 5 years.
Solution #3: Place Erosion Control Fabric to Stabilize Bank
Erosion control fabric is a type of geotextile material that is used to stabilize soil and prevent erosion on slopes and banks. These sheets of fabric are made of natural materials, such as coconut fiber or jute, and are designed to hold the soil in place while allowing water to pass through.
Erosion control fabric comes into play when dealing with any slope of the bank. This is usually slopes of at least 3:1 (3 feet of horizontal distance for every 1 foot of vertical drop). You should also consider the type of soil and vegetation that are present at the site, as well as the climate and weather conditions.
To install erosion control fabric, you will need to clear any taller vegetation or debris from the site and lay the fabric over the slope. The fabric should be secured to the ground using stakes or grass plugs, which will help to anchor it in place. You can then plant grass or other vegetation on top of the fabric to help hold it in place and provide additional structure to the soil.
Erosion control fabric is a simple and effective solution for stabilizing banks and preventing erosion. It is durable and long-lasting, and can help to protect your property from the damaging effects of water and wind erosion.
Solution #4: Slow Down Water Flow Using Rain Gardens
Rain gardens are designed to mimic the natural hydrology of a site and can be an effective tool for slowing down the flow of water and reducing soil erosion. They work by collecting and temporarily storing excess rainwater, allowing it to infiltrate into the soil rather than running off the surface. Rain gardens can be used to manage runoff from a variety of sources, including roofs, driveways, and sidewalks.
To create a rain garden, you will need to select a site that is located in a low-lying area of your yard and has good drainage. The garden should be at least 10 feet away from the foundation of your home and any other structures. The size and shape of the garden will depend on the amount of runoff that you are trying to manage and the slope of the site. You should also choose plants that are well-suited to your region and don’t mind having their roots intermittently wet.
Rain gardens can provide a number of benefits in addition to slowing down water flow and reducing soil erosion. They can also help to improve water quality by filtering pollutants from runoff, provide habitat for wildlife, and add beauty to your yard. Overall, rain gardens can be an effective and sustainable solution for managing water runoff and protecting your yard from erosion.
Final Thoughts
The techniques I mentioned above are best when used in concert with one another. Together they form a healthy and resilient shoreline that looks beautiful. If you have some waterfront property, please consider using some of these methods to protect your shore.
In some locations, there might also be cost-share programs through local soil and water conservation entities you can take advantage of.
Until next time, Ben
Note: This post was originally written for The Conservation Companion, but is now archived here.
Citation
@online{tjepkes2022,
author = {Tjepkes, Benjamin},
title = {Naturally {Protecting} {Shores} {From} {Erosion}},
date = {2022-10-16},
url = {https://btjepkes.github.io/posts/can-you-naturally-protect-shores-from-erosion},
langid = {en},
abstract = {In this blog post, we will explore the causes of shoreline
erosion and discuss some effective ways to prevent it. By
understanding this issue and taking action, we can protect our
waterfront properties and preserve the natural integrity of the
surrounding ecosystem.}
}