Detailed Project Report - Commissionerate of Rural Development ...

District Watershed Development Unit - Jamnagar
1. Boulder Checks
Boulder checks or gully plugs are loose rock dams made on small drainage lines or seasonal streams which have a catchment area of less
than 50 ha. It is adopted where the water velocity is high and where basically stone available with in radius of 100-150 m from the site. The main aim of
constructing loose boulder checks is to reduce the velocity of water flowing through the drainage line. By reducing the velocity of runoff, boulder checks
help in:
1. Reducing soil erosion;
2. Trapping silt which slows the rate of siltation in water harvesting structures in the lower reaches of the watershed.
3. Creating a hydraulic head locally which enhances infiltration of surface runoff into the groundwater system; and
4. Increasing the duration of flow in the drainage line. Therefore, the capacity of the water harvesting structures created downstream on the drainage line
is utilized more fully as they get many more refills.
2. Gabions
Gabion structures are rock and wire dams constructed across drainage lines with a catchment area of 50-500 ha. They are also constructed to reinforce
highly erodible stream embankments. The main aim of constructing gabion structures is to reduce the velocity of water flowing through the drainage
line. By reducing the velocity of runoff, gabion structures help in
1. Reduction in soil erosion
2. Trapping silt, which reduces the rate of siltation in water harvesting structures in the lower reaches of the watershed.
3. Increasing recharge of groundwater and
4. Increasing the duration of flow in the drainage line. Therefore, the capacity of the water harvesting structures created downstream on the
drainage line is utilized more fully as they get many more refills.
Drainage line Treatment and water harvesting:
The second tier treatment is the slope treatment. This is generally agricultural land or waste lands. These are generally water conservation or
surface water storage structures. These being highly labour intensive will involve more of manual labour so schemes like National Rural
Detailed Project Report – IWMP-1 (Patan )