Applicability and impact of floodwater harvesting
Land use: FloodWH is mainly used for annual or mixed crops, fruit trees, timber and firewood trees. It is also used for pasture or forestland. Annual crops grown under FloodWH include cereals (sorghum, pearl millet, wheat, and barley), pulses (green grams, chickpeas, and cluster beans), oilseed crops (castor, mustard, sesame, rapeseed) as well as cotton, cucurbits, tomatoes and other vegetables. Fruit trees include olives, almonds, figs, date palms, etc. In some areas, FloodWH is used to spread water for pasture or forestland.
Water use: Flood recession farming and recharge of shallow aquifers.
Climate: Arid to semi-arid with annual precipitation of 100 – 700 mm, where evapotranspiration greatly exceeds rainfall.
Terrain: Spate irrigation is often found where highland plains meet alluvial flat slopes on deep loams to silt loams; jessours are often used on loess soils, tabias on deep foot slope soils. Catchment areas are often steeper than the application / cropped area, which is situated on medium to flat slopes.
Scale: FloodWH systems operate at the watershed scale.
Level of mechanization: Mainly manual labor, sometimes animals or tractors are used (e.g. in Eritrea, Spain, Sudan).
Land ownership and land / water use rights: FloodWH systems are used by sharecroppers and tenants as well as by landowners. The land use rights under which FloodWH is implemented range from hereditary land rights (e.g. Pakistan), government-owned rights (e.g. Eritrea, Ethiopia, Sudan) to private ownership (e.g. Yemen). In the case of tabias land, ownership is often individual and titled.
Skill / knowledge requirements: Development of local regulations, and organization and cooperation at the community level are prerequisites for the successful management of FloodWH systems. For the appropriate design of the structures, the area of the catchment and potential application area must be calculated as well as hydrological aspects such as peak discharge. Highly skilled technical knowledge is needed – and local experience is a vital help. Advisors and project planners need good skills and close collaboration with local land and water users.
Labor requirements: Reconstruction of canals, intakes and diversion structures both before and after flood events is very labour intensive.
FloodWH has many positive effects and benefits. Here you can see a list of them.
(Mekdaschi & Liniger 2013)