The problems of the area are exacerbated by limited infrastructure and geographic isolation. The nearest main road is 54 kilometers away; the village cluster has no modern communications. Koraro is one of the Earth Institutes Millennium Village clusters.
With funding from the The Ceil and Michael E. Pulitzer Foundation, the Columbia Water Center designed an innovative rainwater harvesting system designed to catch and store water in the landscape. The design includes an interconnected network of five microdams along with an infiltration trench system to recharge underground aquifers. The trench system promises to be a significant innovation over conventional water-storage schemes such as open-air ponds that have low infiltration and are subject to evaporation.
With the Columbia Water Center design, mountains and gullies act as a natural rainwater collection system, from which rainwater is diverted into a man-made level trench. Water then percolates into the soil on the slopes above Koraro. Over time the infiltrated water raises the water table for the areamaking more water available for plants, irrigation wells and household water use.
To date the CWC taskforce has implemented a pilot project consisting of a 1.2 kilometer, 3 by 3 meter trench, capable of retaining and percolating about 10,800 cubic meters of water per storm.
Results so far have been promising, suggesting that the trench has worked to recharge the groundwater around the village and had numerous other positive impacts:
- New wells dug above Koraro have reached groundwater at 2.5 to 3 meters; farmers have begun growing vegetables in small plots using these wells
- A small stream that used to dry up near the village now has flowing water for many more months (into February last year)
- Farmland erosion has been controlled
- A local conflict between farmers over water rights has been alleviated
- Some farmers have begun planting a dry-season crop with the irrigation water from a shallow aquifer that was previously unavailable
Going forward the team plans to further the development of infiltration infrastructure by:
- Conducting more thorough measurements of groundwater response through monitoring wells and channel flow measurement
- Assessing how groundwater recharge affects agricultural production
- Extending the trench an additional 3 kilometers following an assessment of the performance of existing infrastructure
In addition, the CWC team plans to:
- Complete a sand filtration and pipe water delivery system
- Develop a software toolkit and instruction manual for developing similar projects
Get more information about Koraro on the Millennium Village website. Read a blog post about water catchment in Koraro. Watch a short video about the Columbia Water Center project at the International Research Institute for Climate and Society website.