How do rock dams help soil conservation?
Answers
Definition:
Small barriers or dams constructed of stone, bagged sand or gravel, or other durable material across a drainage way.
Purpose:
To reduce erosion in a drainage channel by restricting the velocity of flow in the channel.
Explanation:
Gully plugs, also called check dams, are mainly built to prevent erosion and to settle sediments and pollutants. Furthermore, it is possible to keep soil moisture due to infiltration. Depending on the topography, amount of precipitation, material and financial resources available, there are several methods to construct a gully plug. They have to be inspected regularly and any damages must be repaired.
ADVANTAGES
Water speed is slowed, which reduces erosion and prevents unwanted gully formation during a flood
No trench design required, just uses existing gully drainage pattern
Can assist recharge of shallow wells
Can reduce salinity in groundwater
Allows groundwater recharge and sediment to settle out (reduces sediment transport)
Cost effective – these dams can use locally available materials
DISADVANTAGES
They can silt up and will need maintenance
Levels of infiltration can be slow due to silt build-up
Unclear land tenure can result in ownership of the structure
If designed incorrectly, may block fish passage
When only focussing on gully plug construction, the main cause of gully development is missed.
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