Different engineering measures for soil erosion control
- Check dams:
- Check dams are often used on sites with slopes that are steeper than desired.
- A stone check dam is a barrier constructed of stone or wood that reduces the flow velocity of runoff, while minimizing channel erosion and promoting sediment deposition.
Functions: Slow down water flow, help sedimentation and caches debris.
Advantages:
-Fast and simple protection;
-big securing (filling) effect,
-resistant to damage,
-applicable in slope with big volume of debris flow . It can be used up to about 60°.
Disadvantages:
-Labour intensive.
-Stone check dam required big quantity of stone, so the construction is limited by the availability of material.
-Reinforced check dam required expensive materials (iron rod and wires).
- Waterways
- The purpose of waterways in a conservation system is to convey runoff at non erosive velocity to a suitable disposal point.
- Artificial waterways are normally protected by grass like Paspalum spp, African star grass and so referred to grassed waterways.
- Grass waterways are shallow and wide to obtain the maximum spread of water over a wide cross section.
- These waterways can be used in areas where there is sufficient moisture available to sustain a good grass cover.
- Retaining walls
- Retaining are structures designed to restrain soil to unnatural slopes.
- They are used to bind soils between two different elevations often in areas of terrain possessing undesirable slopes or in areas where landscape needs to be shaped severely.
- Retaining walls provide lateral support to vertical slopes of soil.
- They retain soil which would otherwise collapse into a more natural shape.
- The retained soil is sometimes referred to as backfill.
- They also provide soil stability in areas where there is a risk of significant changes of ground elevation due to earthquakes and floods.
- Embankment
- A levee, an artificial bank raised above the immediately surrounding land to redirect or prevent flooding by a river, lake or sea.
- Terracing
- A terrace is an earthen embankment, ridge or ridge-and-channel built across a slope (on the contour) to intercept runoff water and reduce soil erosion.
- Terraces are usually built in a series parallel to one another, with each terrace collecting excess water from the area above.
- Terraces can be designed to channel excess water into grass waterways or direct it underground to drainage tile and a stable outlet.
Why install terraces on your land?
- Reduces soil erosion by breaking long slopes into a series of shorter ones
- Protects water quality by intercepting agricultural runoff
- Helps prevent gully formation by directing runoff to stable outlets
- Makes it easier to farm steep slopes
- Improves soil quality and productivity by improving
- moisture retention and reducing soil erosion
- Spurs
- Spurs are the engineering structure that protects stream bank erosion by retarding the flow of water and covering the stream bank.
- The types are: Dry boulders spurs, Permeable spurs and Vegetative spurs
- Gabions
- A gabion is parallelepiped made by metal mesh, interconnected with other similar containers.
- When live cutting or rooted plant or seeds are added during the gabion constructions we call it vegetated gabions.
Advantages:
- fast implementation, Very flexible, able to resist to erosion or landslides, or seismic.
- Great degree of permeability throughout the structure.
Disadvantages:
- It is necessary to find the filling material on site.
- Labor intensive.
- It is important that a qualified geotechnical engineer approve the structural wall design.
