Strengths and Weaknesses of Rainwater Harvesting

A recent article by Yosef and Asmamaw (2015) highlights some of the many strengths and weaknesses associated with Rainwater Harvesting (RWH). As highlighted in the previous post, there are weaknesses but these do not apply to all localities and if there is scope for the community to mitigate or overcome these challenges, then RWH could be very beneficial in some areas.

Strengths 

• It is possible to cultivate crops twice or more a year (Getanehand Tsigae 2013) since individuals can grow crops outside of the rainy season
• RWH allows supplementary irrigation when rain stops early or when rainy seasons are short but intense.
• Increases rainwater productivity and there are minimal negative impacts on natural resources (Pachpute et al 2009)
• In situ RWH is low cost and can be practiced in almost all land use systems (Ngigi 2003)
• It doesn’t need to be near a stream or river. This way RWH can support distant subsistence farmers in remote areas.
• Where there is no surface water, or GW is inaccessible, Mupenzi et al (2011) argue that RWH is simple and inexpensive

Weaknesses

• There can be high water losses through seepage
• Losses through evaporation from strorage tanks or wells
• Labour intensive to irrigate fields by pumping water from the storage facility 
• It has to be site specific and so it requires research before it can be implemented

 However, in my opinion, the first two are not legitimate weaknesses since they can be mitigated by using silt traps to reduce seepage or the tanks can be covered to reduce evaporation.