Microcatchments are mainly used for growing trees or bushes. The plum-sized fruits are delicious and a rich source of vitamins. Therefore for dams of 70 cm height, the VI should theoretically be 70 cm. Negarim microcatchments have been developed in Israel for the production of fruit trees, but even there the returns on investment are not always positive. Stone bunds for crop production can be used under the following conditions: Rainfall: 200 mm - 750 mm; from arid to semi-arid areas. 28.2 Types of Water Harvesting. Negarim microcatchments are appropriate both in village afforestation blocks, or around homesteads where a few open-ended "V" shaped microcatchments provide shade or support amenity trees. The simplicity of design and construction and the minimum maintenance required are the main advantages of this technique. Design "b", with larger and wider spaced bunds, is more suitable for drier areas, and does not need such even topography. It is particularly important to pack the small stones well at the lower levels to increase the rate of siltation. This is particularly important in the arid and semi-arid regions of Africa and may help to explain the failure of so many projects that did not take into account the people's priorities. Rain Water Harvesting in India: Need, Methods and other Details! There are three method of harvesting and recycling of runoff water. The reduced rainfall in the Sahelian zones over the last two decades has left much of the land in this area barren and encrusted with a hard surface cap. Trapezoidal bunds are used to enclose larger areas (up to 1 ha) and to impound larger quantities of runoff which is harvested from an external or "long slope" catchment. Stone bunds in West Africa are often used for rehabilitation of | infertile and degraded land. Having selected the starting point (A) at the upslope end of the bund system, it is marked with a peg. 5.6.3 Layout and construction These pits, which are usually about 0.9 m apart, are up to 0.15 m deep and 0.30 m in diameter. Size of microcatchments (per unit) normally range between 10 m2 and 100 m2 depending on the specie of tree to be planted but larger sizes are also feasible, particularly when more than one tree will be grown within one unit. PROFILE: Permeable Rock Dams on the Central Plateau of Burkina Faso. By 1987 about 150 trapezoidal bunds had been constructed for the production of quick maturing food crops including sorghum and cowpeas. Furthermore, stone bunds require much less maintenance. This results in recommendation of a maximum C:CA ratio of 10:1, although ratios of up to 30:1 are sometimes used. Construction of a set of trapezoidal bunds must start with the row furthest upslope. Transport of stone increases this figure considerably. 5.2.3 Layout and construction Another useful technique is to plant curcurbits like gourds or watermelons on the bottom bund if water ponds deeply. 5.5.4 Maintenance New Techniques There are two main techniques of Water Harvesting 1. 5.2.4 Maintenance Some mechanical measures to increase runoff        can be adopted such as land surface smoothening reducing surface depressions compacting the soil surface by rollers of spreading the clay blanket before rolling in sandy soils. We use water for drinking, irrigation, industry, transport and for the production of hydro-electricity. Rainwater Harvesting: Rainwater harvesting is defined as the method for inducing, collecting, storing and conserving local surface runoff for agriculture in arid and semi-arid regions. The centre points of the bunds, for example, in the second row should coincide with the middle of the gaps between bunds in the first row and so forth. This technique is appropriate for small-scale tree planting in any area which has a moisture deficit. A common error is to use only large stones, which allow runoff to flow freely through the gaps in-between. The diversion ditch is aligned on a 0.25% slope and a common dimension is 50 cm deep and 1 - 1.5 m wide, with the soil piled downslope. Stone bunds follow the contour, or the approximate contour, across fields or grazing land. 5.7.2 Technical details Demonstration and motivation are therefore very important. In the driest areas planting is sometimes delayed until a runoff event has saturated the soil within the bund, and germination/establishment is guaranteed. 5.3.5 Husbandry Trapezoidal bunds can be used for growing crops, trees and grass. At point 3 (4) distances of 2.90 m either side and perpendicular to the wingbunds centreline (line 1-3, 2-4) are measured and marked. 5.4.1 Background Trapezoidal bunds were designed for Turkana District when a widespread food relief operation was underway in 1984. Conservation techniques conserve water within the biomass and the soil by reducing run-off and keeping the water where it falls, as much as possible. Design "a" as described here has a C:CA ratio of only 1.4:1, and does not require provision for overflow. Examples of its application come from Baringo District, Kenya. At this point, the plants have a greater depth of top soil. Spacing of rock dams (Source: Berton 1989). The Central Arid Zone Research Institute (CAZRI) at Jodhpur, Rajasthan, has carried-out experiments to investigate the effect of microcatchments on fruit production. Labour rates for stoneworks: Typical labour rates achieved are 0.5 m3 per person/day for construction. 1- Roof top harvesting - This is the most popular technique among all the rainwater harvesting techniques which are used by people at home to collect the rainwater. A recently established project, PATECORE, at Kongoussi specializes in permeable rock dams, or "filtering floodwater spreaders" as the project calls them. The size of microcatchment per tree is estimated in the same way as for Negarim microcatchments. The apexes of the bunds of the upper row will be the tips for the second row and the corresponding apexed will be found according to Step 3. Therefore, it may be difficult to motivate the population to invest voluntarily, in the time and effort required for implementing and maintaining such a water harvesting system. Gram – 65 – 70 Days – pod development stage. Using a line or water level and, if necessary, a tape, point B is pegged on the contour 100 m away from A. Contour ridges: layout technique. The space in between the ridges can be several metres (for strip collectors, the space is usually between 2-5 metres). Where permeable rock dams are constructed in wide, relatively flat valley floors, they are sometimes made straight across - in contrast to the usual design where the spreader bunds arch back from the centre to follow the contour. Storage of rain water on surface for future use The storage of rainwater on surface is a traditional technique and structure used in underground tanks, ponds 11. This should be built up gradually following the required sideslope, and the centre packed with smaller stones. The points D and E should be pegged and mark the centreline of the second bund. However in practice this may not be practicable due to the amount of stone and labour involved. As with design "a", the bunds must be arranged in a staggered configuration. Soil excavated from the ditch is used to construct an embankment on the downslope side, which also assists in diverting runoff from the bunds. Material for fill should not be excavated adjacent to the bunds on their downslope side, as this promotes gullying and bund failure. Under low rainfall situations to increase the runoff from catchments area the soil surface is treated with sodium salt betonies clay hydrophobic compounds like sodium ciliolate sodium rosinate etc. At each side of the block, a lateral bund of 25 - 30 cm height is built to prevent loss of runoff out of the system. 5.8.2 Technical Details QUANTITIES OF EARTHWORKS FOR TRAPEZOIDAL BUND. A … The principles of water harvesting are not new. On a 5% slope the size could be reduced to 54 m2 because of the increased runoff. 5.3 Contour bunds for trees In most cases, however, it will be more appropriate to re-seed with seed from outside. The implementation of permeable rock dams raises several important socio-economic issues. techniques except for lnter-row water harvesting technique are shown in Figure 4 with their recommended parameter ranges. This technique is limited to low ground slopes. For the wingbunds, the demarcation of the earthworks limits is slightly more complicated. The radius of the semi-circle is 20 metres. Good soil is nothing without water! Small earth ties in the furrow are provided every few metres to ensure an even storage of runoff. After setting out, bund construction is started with excavation of a small trench inside the bund. Surprisingly, this technique has never been used traditionally. The exact size of each microcatchment is thus defined. The earth should be deposited upslope and the trench filled with gravel or small stones. Over the years, though, many of these tanks have gone out of use. The skill of construction is in the use of large stones (preferably of 30 cm diameter or more) for the casing of the wall. One important advantage of contour bunds for tree establishment is that oxen or mechanized cultivation can take place between the bunds, allowing crops or fodder to be produced before the trees become productive. Water harvesting is one way that farmers can deal with climate-change induced water scarcity in Ethiopia. Point C is 50 m downslope from point B and can be established by marking of a right angle perpendicular to AB, using a wooden triangular right angle frame (sides: 100 cm, 60 cm, 80 cm) and a tape. Applications of stored water to the crops. The approximate contour, or overtops during peak flows a short slope catchment system, it is a of! Every 50 metres contribute to water harvesting techniques for many different designs for water harvesting 11 surveying such. Line ED a distance of 2 metres 4 structures required per hectare –Seepage evaporation... 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