What is in news : The State government of Karnataka is promoting construction of new generation multiple arch buttress check  dams across natural streams, rivulets and other waterbodies under the MGNREGA

What are Multiple Arch Buttress dams :

• Multiple arch dam contains series of arches and in this case arch slabs are provided at the upstream face of the dam. These slabs are supported by buttresses. The buttress wall is constructed as single stiffened wall or double hollow wall.
• This type of dam can be preferred for larger heights about more than 50 meters. As compared to deck slab type buttress dams, multiple arch buttress dams are more flexible and stable.
• The main disadvantage in this case is the adjacent buttress units depends on each other. So, if one unit gets affected then it causes severe problems for the whole series of arches. To overcome this good foundation for each of buttresses wall should be provided.
• The thickness of arch provided varies in case of larger spans and constant in the case of shorter spans. The central angle of arch should be in between 180 degrees to 150 degrees.
• The space between buttresses should be in between 15 to 21 meters. However, larger spacing can also be provided by taking some consideration.

MAHITI FOR PRELIMS – MNREGA

• The scheme was introduced as a social measure that guarantees “the right to work”. The key tenet of this social measure and labour law is that the local government will have to legally provide at least 100 days of wage employment in rural India to enhance their quality of life.
• Key objectives:
  • Generation of paid rural employment of not less than 100 days for each worker who volunteers for unskilled labour.
  • Proactively ensuring social inclusion by strengthening livelihood base of rural poor.
  • Creation of durable assets in rural areas such as wells, ponds, roads and canals.
  • Reduce urban migration from rural areas.
  • Create rural infrastructure by using untapped rural labour.
  • The Ministry of Rural Development (MRD), Govt of India is monitoring the entire implementation of this scheme in association with state governments.