Throughout Florida, many communities feature lakes that improve their property’s aesthetic appeal and offer recreational opportunities to the residents. In addition to ensuring that these lakes remain clean and functional, it is also important to maintain the shoreline and lake bank in good shape for safety purposes. Most lake banks are required to have slopes that are not steeper than four feet horizontal to one foot vertical. However, the natural erosion of these lake banks is inevitable.
What Are the 4 Main Causes of Erosion in Lakes?
Erosion in lakes and other water bodies can be caused for many reasons, ranging from natural causes to climate change and deforestation. Some causes cannot be controlled, but these are generally natural causes that happen slowly over time. Other causes of erosion stem from human activities and tend to cause an acceleration of lake soil erosion. Understanding all of these causes helps in creating a comprehensive plan for remediation.
Natural Causes of Lake Soil Erosion
Water itself can be incredibly destructive. We can see this on a grand scale, as rivers have carved out canyons and move mountains. We also see this on a much smaller scale as the water of lakes and ponds routinely brushes up against their shorelines. Even on a calm day, wave action can move soil into the water.
When it rains, raindrops can move even more soil from the shoreline of lakes and ponds into the water. Bank erosion is the main cause of shoreline damage. Over time, it wears away the underlying soil, causing the entire bank to slide into the water.
Depending on where you live, the natural causes of soil erosion include:
- Splash erosion–when precipitation and stormwater hit loose soil, it causes displacement depending on the bank’s slope.
- Wave erosion–whether due to natural causes or boat wakes, waves can displace any loose soil in places where natural vegetation has been removed.
- Stormwater erosion–as stormwater runoff moves over soil that is loose, layers of that soil are displaced or removed in “sheets,” a phenomenon known as “Sheet Erosion.”
These natural forms of lake soil erosion happen over time, and in normal conditions, may not be of concern and can be easily managed.
1. Climate Change and Lake Soil Erosion
Climate changes such as more frequent and more intense rain events can cause erosion to increase and result in more sediment washing into rivers, lakes, and streams.
Stronger storms, faster stream velocity, and higher river levels all increase erosion, which results in increased suspended sediment in water bodies. These conditions also affect the normal distribution of sediment along the beds of rivers, lakes, and streams. These climate impacts can make it challenging to maintain water quality and require significant erosion and sediment management efforts.
In addition, excessive levels of suspended stream sediment or a change in the distribution of sediment that often occurs when storms are more frequent and intense can negatively impact ecosystem health. The impacts from these changing levels of erosion and sedimentation threaten invertebrates, fish, and especially aquatic vegetation.
Unchecked increase in sediment and erosion in lakes, streams, and rivers can also have an effect on water quality and the availability of drinking water sources. For instance, increased sedimentation can have a negative effect on the storage capacity in reservoirs and increase the need for treatment by water utilities.
2. Human Causes of Lake Soil Erosion
Human activity is a significant cause of lake soil erosion. When human actions such as construction, logging, gardening, and more disturb the soil, the result is a weakening of the topsoil of the earth, which leads to excessive erosion. Effects of human-caused soil erosion include:
- Level control structures – this can raise lake levels to an unnaturally high point on the shoreline where the soil is less able to withstand lake wave action.
- Clear-cutting natural vegetation – homeowners often remove vegetation in order to create better views or gain access to the water. This destroys wildlife habitats and eliminates the protection provided by erosion-preventing root structures of plants, trees, and shrubs.
- Stormwater runoff – when too much earth is paved over, these impervious surfaces around lakes collect and deliver precipitation over land rather than letting it infiltrate into the soil.
3. Loss of Vegetation and Trees
The potential for lake soil erosion increases when the soil has little to no vegetative plant cover. Plants help bind the soil together with their root systems, which means they’re able to serve as a protective layer that can help prevent soil erosion in several ways.
Plant cover protects the soil from raindrop impact and splash by forming a protective canopy over the soil. Plants can work as a mechanical obstruction to the movement of runoff water and allows excess surface water to be absorbed into the soil, reducing its erosive potential.
The plant roots help build a better structure. In addition, firm plant placement works to slow water flow as the stems create think barriers. Once the protective vegetative cover is gone, land erosion happens faster.
The effectiveness of plants for reducing erosion depends on the type, extent, and quantity of cover they provide. Vegetation that completely covers the soil and intercepts all falling raindrops on or near the surface are the most efficient at slowing or controlling soil erosion.
4. Topography, Tectonic Activity, and Lake Soil Erosion
The topography of the land can also contribute to lake soil erosion. In steeper areas, runoff moves at a higher intensity and increased speed. This means even heavier and larger sediment particles can easily be carried by the moving water. Because of this, hilly areas face more soil erosion. The longer and steeper the slope of a lake or pond bank, the higher the erosion risk is. As the slope length increases and aids the accumulation of runoff water, soil erosion also increases.
Tectonic activity molds the shape of the landscape itself, thus influencing how erosion affects an area. For example, tectonic uplift may cause one part of the landscape to be higher than other parts of the landscape. This process generally happens over time. It took about 5 million years for tectonic uplift to cause the Colorado River to cut increasingly into the Colorado Plateau and eventually form the Grand Canyon.
Lake & Pond Shoreline Restoration in Florida
Shoreline erosion affects homeowner associations, commercial properties, and other developments throughout Florida. We provide an eco-friendly solution to soil erosion and shoreline restoration in lakes and ponds. Call Lake & Wetland Management at 855-888-5253 or contact us online for a free on-site inspection and proposal.