Terraces primarily work by managing water flow on slopes to prevent erosion and conserve moisture.
Understanding Terrace Mechanics
Based on how they are constructed and function, terraces operate through a simple yet effective process:
- Terraces catch runoff water. When rain falls on a sloped area, the water flows downhill. Terraces are built as earthen ridges around the hillside, following the contour lines. These ridges act like barriers, trapping the water as it moves down the slope.
- They let the water soak into the ground. By holding the runoff water behind the ridges, terraces allow it more time to penetrate the soil. This is crucial for moisture conservation, especially in agricultural settings or areas prone to drought.
- They deliver the excess to a safe outlet. Not all the water caught by a terrace will soak in. The terraces are designed with a gentle slope or outlet system to guide the excess water slowly and safely away from the hillside. This controlled drainage prevents the water from pooling excessively and also keeps it from rushing downhill and causing damage. This function is much like down spouts on a house, which collect water from the roof and direct it away from the foundation.
Preventing Erosion with Terraces
A key benefit of terraces is their ability to combat soil erosion. This is achieved because the earthen ridges built around a hillside on the contour cut a long slope into shorter slopes.
By breaking up a single, long slope into a series of shorter, level or gently sloping steps, terraces significantly reduce the speed and volume of water flowing over any given section of the land. This prevent[s] water from building to a highly erosive force. Fast-moving water carries away valuable topsoil, but terraces slow it down, allowing the soil to stay in place.
Key Functions Summarized
Terraces perform several vital functions:
- Catch: Intercepting downhill water flow.
- Soak: Promoting water infiltration into the soil.
- Deliver: Safely guiding excess water away.
- Cut Slope: Dividing long slopes into shorter segments.
- Prevent Erosion: Reducing water velocity and preserving soil.
By implementing these functions, terraces transform sloped land into more stable and productive areas, protecting the environment from the damaging effects of uncontrolled water runoff.
