Changes

Water Portal / Rainwater Harvesting / Groundwater recharge / Bunds

1,247 bytes added, 23:11, 29 March 2012

→‎Construction, operations and maintenance

* Trapezoidal bunds work well in high rainfall intensity areas, and spillways around the edge worked better than spillways in the centre of the bund where erosional forces were concentrated. Even stone-faced spillways (as per Israeli design) were not always robust. Therefore type of bund has to be applicable to the local conditions. The exact shape of the trapezoidal bund varies in shape according to the terrain.

* A few tips for construction of trapezoidal bunds: leveling the cultivated area within a bunded area is a good thing to do since it spreads flood depth evenly; a cut-off drain uphill of the bund allows high flows to be diverted if necessary, protecting the bund; trapezoidal bunds should be reinforced with stonework to counter erosive forces as this is the edge of the spillway in these bunds; low-tech leveling devices help uneducated people to be trained in designing their own bunds.

* Bunds should be adequately compacted. If animals are used to create the bunds, they can help to compact the soil with their hooves. It also seems best to make bunds in the middle of the dry season so that they can settle under impact of human and livestock movement, in order to make them sturdy enough for the rainy season. Access to finance therefore seems to be important in allowing farmers to implement bunds. Due to the uncertain nature of flood events, it is important to plant drought-resistant (local) crop varieties in the fields which give better results.

* In the site-specific case of artificial glaciers, the following methods are used: before the onset of winter, water is channelled from existing streams through 1.5” GI pipes into shadow areas of mountains close to villages. The water is made to flow out onto a sloping hill face where at regular intervals along the mountain slope, small stone embankments are situated to impede the flow of water which helps to create shallow pools. These pools freeze rather than infiltrate, but water is later released for crop irrigation prior to the usual time when snow melts on mountain tops. In this way, water is available more reliably for crops during a very short sowing season.

• ← Older edit
• Newer edit →

Winona

Akvopedia-spade, akvouser, bureaucrat, emailconfirmed, staff, susana-working-group-1, susana-working-group-10, susana-working-group-11, susana-working-group-12, susana-working-group-2, susana-working-group-3, susana-working-group-4, susana-working-group-5, susana-working-group-6, susana-working-group-7, susana-working-group-8, susana-working-group-9, susana-working-group-susana-member, administrator, widget editor

30,949

edits