Evaluation of community-driven smallholder irrigation in dryland South Pare Mountains, Tanzania: A case study of Manoo micro dam

Water is the main limiting factor for crop production in semi-arid sub-Saharan Africa. This paper presents an evaluation of the effectiveness of community-driven smallholder irrigation schemes using micro dams under current operational practices. The research site is the semi-arid Vudee sub-catchment within the Makanya Catchment, which is part of the Pangani River Basin (Northern Tanzania). A micro dam is presented as a case study. Micro dams are popular in the study area they have water sharing system between upstream and downstream users put in place with minimum input from external agencies. The effectiveness of micro dams on dry spell mitigation is investigated. The significance of dam size, total water diverted per season, system losses and approximate amounts of water received by each farmer in a given season is analysed. Local smallholder farmers have put up the micro dams to address their need for extra water for agriculture. The capacities of the micro dams are very small but without them there is insufficient water to allocate to at least one irrigation event per farmer in a season, the dams serve a useful purpose when operated as night storage reservoirs. The study found out that the micro dam system, under current operational rules, is inefficient as the high system losses put to question the wisdom of irrigating over scattered sites as opposed to one common irrigation plot near the dam site where each participant would be allocated a small piece of land to irrigate.