Microcatchment Rainwater Harvesting

Land Use: Annual cropland with cereals (sorghum, millet, maize), leguminous grains / pulses (cowpeas, pigeon peas etc.), vegetables (tomatoes, onion, potatoes, etc.). Often used for the cultivation of tree crops, sometimes also for fodder bushes and forest trees.

Water Use: To increase water availability in the root zone and hence plant production. The combination of planting pits with stone bunds is used in West Africa to rehabilitate degraded and crusted lands and bring them into cultivation. These technologies should be combined with technologies which reduce runoff and evaporation loss (through soil cover, shade and wind protection and weed control) and enhance soil fertility (such as manuring and microdosing with fertilizers) to further increase yields.

Climate: Mainly applied in semi-arid regions with 250 – 750 mm annual rainfall. In addition, these practices can sometimes also be found in sub-humid to humid areas. Vegetative strips perform better in more humid climate. Terrain: MicroWH practices can be applied on steep slopes as well as in flat areas, as long as there is adequate runoff available. While the different types of pits are applied in flat areas, cross-slope barriers including bunds, trenches and terraces are more commonly used on sloping land.

Scale: Water is collected from small catchment areas, usually 10 – 500 m2, within the boundaries of individual farms and within the agricultural land.

Level of mechanisation: Usually manually constructed, though in the case of Vallerani micro-basins, mechanized. Land ownership and land / water use rights: MicroWH practices are often applied by individual land users especially for crop production, however sometimes also on state owned or communal land e.g. in the case of afforestation. The small catchment areas can be easily controlled by individual land users, which makes the systems easy to adapt and replicate. Since water is stored in the soil and has its source / origin in-field, each land user can apply the system without a community being involved or conflicts with neighbours over the water use.

Skill / knowledge requirements: While the implementation of MicroWH practices requires little knowledge by the land users, agricultural advisors need to have a medium level of know-how.

Labour requirements: Medium to high labour requirements: pitting systems especially require sufficient labour availability as they have to be re-dug every cropping season. However compared to land preparation of the entire area without microcatchments the overall workload and labour input is concentrated onto the area where plants are effectively growing.