Soil erosion is often a very slow process, so slow that it happens without anyone noticing. However, sometimes it can happen at an alarming rate. Soil erosion can negatively affect water quality and the aesthetic appeal of lakes and ponds. Soil erosion can cause lakes and ponds to be damaged or develop too much sediment. This can damage the land surrounding lakes and ponds as well as the organisms and wildlife that live in them.
Types of Soil Erosion
In Florida there are three main causes of soil erosion: water, wind, and anthropogenic soil erosion. Water and wind erosion cause the majority of all land degradation, however, in many cases, human activities have exposed the land to these forces.
Rainfall & Surface Runoff
Rainfall and surface runoff due to rainfall can cause a lot of soil erosion. The four common types of soil erosion caused by surface runoff include splash, sheet, rill, and gully.
Splash erosion is caused by raindrops falling on top the soil, causing it to break into tiny, individual particles. The particles then detach from the soil and form a crust on top. This crust easily runs off when it is rainy or windy.
The second type of erosion, called sheet erosion, happens when a thin upper portion of the soil is displaced, usually due to heavy rain or water runoff. During this process, nutrients and organic matter are lost. This kind of soil erosion is gradual and often goes unnoticed until large portions of soil are lost. If the vegetation cover has been lost, the soil will erode at a much faster rate.
Knowing the signs of erosion can help you prevent it from happening. Signs to look out for include:
- Puddles of water that emerge after rain
- Bare patches in the soil
- Visible roots of grass and trees
If this happens, you can protect the soil from erosion by planting native plants to help hold the soil.
Rills are shallow drainage lines that measure about 30 cm or just under 12 inches deep. Surface water begins to collect on the soil and make depression that begins to erode the soil. It forms rills that can become hills and make the land more prone to erosion.
This type of erosion is common in areas where there is loose or bare soil. You can reduce the likelihood of rill erosion by creating grassed waterways, mulching, and contour drains. If not remediated, these rills may turn into gullies.
The worst type of soil erosion, gully erosion, wears more than 30 cm (just under 12 inches) into the soil. Soil conservation can’t happen through cultivation practices. It often occurs when runoff flows strongly and is concentrated in one location. In some cases, the water flow is strong enough to detach and take soil particles with it.
For instance, a small waterfall or spring may form. The runoff flows downward and starts to pick up energy as it goes over the gully head. As the water splashes, it can erode the subsoil, and the gully eats away the topsoil on the slope. This type of soil erosion is very visible and damaging. It often has a drastic effect on the productivity of the soil and can make the land unusable.
Gullies can range from 2 m (just under 79 inches) to 10-15 m (under 393-590.5 in) in depth. Gullies are caused by many different things, such as:
- Cultivation and grazing
- Increased runoff due to the clearing of trees
- Improper waterway design, construction, and maintenance
- Deforestation or removal of vegetation
- Gradual seepage over time
- Drainage lines diversion
Water flowing along a pathway can cause erosion that can deepen valleys or extend them into the hillside. As the water flows, it creates head cuts or steep banks.
In the beginning, the erosion is mainly vertical, creating valleys with a v-shape. The gradient becomes really steep, and when the water reaches the bottom, the erosion switches to a lateral direction. This may widen the floor of the valley and shrink the floodplain.
Tunnel erosion removes soil from the subsoil layer as water runs through a small hole or crack where plant and tree roots have decayed. The soil begins to be carried away with the flowing water, creating a small tunnel.
Initially, the surface soil structure remains untouched, but as the water flows through overtime, the tunnel gets larger. The top of the tunnel eventually collapses and creates a gully. This process speeds up as the inner layer gets more exposed to the water flow. The mix of clay, silt, and sand can start to shift, which results in sediment loss.
When the banks of rivers or ponds wear away, it is called bank erosion. Flooding can make bank erosion worse and cause the soil on the bank to be removed entirely. One of the biggest causes of bank erosion is the removal of vegetation along the edges. Bank erosion can also be caused by:
- Vehicle or human traffic on the bank
- Lowering of the water level in lakes and ponds
- Flooding of the soils along the bank
- Waves caused by boats or wind
- Rapid water flow
Bank erosion can be very critical in some areas and may even cause human displacement.
Ways to Prevent Soil Erosion in Lakes & Ponds
If you have a lake or pond on your property, its beauty and utility are probably a highlight of where you live. But your enjoyment of it might be temporary if you don’t prevent soil erosion. To keep that from happening, here are some ways to help control lake and pond erosion including lake erosion solutions.
Reinforce the Shore
Reinforcing the shoreline of lakes and ponds can help mitigate further erosion. Rocks can be used to protect and hold the shoreline in a pattern known as rip trap. Alternatively, bioengineered living shorelines can be installed and then planted over to give an all-natural look.
Install Native Plants and Vegetation
Planting native plant species along the shoreline helps keep the soil in place. Native plants tend to do well with very little attention and create a natural habitat for wildlife and fish species within lakes and ponds. Choose plants with deep root systems that will hold the soil and are hard to uproot during storms and other weather events.
Bulkheads and Retaining walls
Bulkheads and retaining walls are often used to control erosion in lakes and ponds that have banks with steep slopes. These are often expensive construction projects that require easements and rights-of-way from adjoining properties. They are often considered a last resort option.
Benefits of Professional Soil Erosion Control
When looking for ways to control erosion in lakes and ponds, your best bet is to use a professional service that can install native plants or a bioengineered solution to hold the shoreline. These are not do-it-yourself projects. Trained professionals will know the best method for mitigation and control of all types of soil erosion, keeping lakes and ponds healthy and aesthetically pleasing for the communities surrounding them.