Rainwater harvesting is an agricultural technique of collecting and storing rainwater or runoff in tanks or natural reservoirs. This practice is mostly practiced in arid or semi-arid areas with temporal and spatial variability of rainfall mostly lost as surface runoff or evaporation. Runoff is harvested and utilised as a preventative measure for soil erosion, as well as a water management strategy for irrigating crops and for livestock water. This technique enables farmers to capture and store rainwater during times of plenty for use during times of scarcity. Rainwater harvesting is a technology that maximises the use of existing freshwater resources and is a useful technology for water resource planners and managers in both governmental and non-governmental organisations, institutions and communities.
To effectively implement Rainwater Harvesting practices:
- Step 1: Create a water collection zone connected to a gutter system.
- Step 2: Install filters to the water collection zone.
- Step 3: Connect a hose pipe for easy distribution of irrigation water.
- Step 4: If a farmer intends to use water for human consumption other than flushing toilets, etc, water quality must be frequently tested using reliable and low-cost/low-tech solutions.
- Step 5: Use of filters can be considered to reduce particulate and other pollutants but should be thoroughly investigated – as a separate subject – by the extension officer and the farmer, otherwise it could lead to illness. It is recommended that farms utilise harvested rainwater for irrigation and other farming activities only.
- Die Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, 2018. How to Protect Our Water Resources from Climate Change.
- The Food and Agriculture Organisation (FAO), 1985. Role of forestry in combating desertification. Germany. Rome, Italy.
- The Food and Agriculture Organisation (FAO), 2016. Strengthening agricultural water efficiency and productivity on the African and global level. Rome, Italy.
Benefits
- Rainwater harvesting acts as a source of water at a point where it is needed, usually stored in a tank.
- Works as an alternative water source in cases of drought or irrigation system breakdown.
- Rooftop rainwater catchment construction is simple.
- Success in rainwater harvesting depends on frequency and amount of rainfall.
Drawbacks
- Asphalt, tar and wood roofs may contaminate the water making it unsafe for direct human consumption.
- For potable water collection, lead containing gutters should not be used.
- Harvested water may be contaminated by animal waste.
