Gravity-fed irrigation for small-scale vegetable farming in mountainous areas
Lwasso is geographically close to the major urban center Mbale, but its location high on the slope above the town makes access difficult especially during rainy periods.
Because of very high population density in this area, vegetable plots are very small. Many men go for work in Mbale, and women are most often responsible for crops. Vegetables are a major contributor to incomes, as they are highly valuable per unit of growing area and prices are relatively good because of the proximity to town.
Most farmers in the area use a shallow valley in the hillside for dry season production. Farmers have traditionally used wash basins to throw water from small channels to adjacent plots, which is very labor intensive and requires doing twice per day to meet most crop water needs. Our project has constructed a head tank roughly 40 meters upslope from the plots, providing pressurized water throughout the valley.
Lwasso is located in Bugisu Subregion on the mid-slope of Wanale, one of the foothills of Mt. Elgon. With cool temperatures, high population density, and small plot sizes, it is typical of the mid-altitude Elgon region.
Major crops in the region include bananas, Arabica coffee, vegetables, beans, and Solanum potatoes in the higher altitudes.
Soils are volcanic nitisols with very good structure, heavy in clay and high in nutrients and organic matter. Slopes tend to be steep, with small areas of mild slopes. The area has a large percent of tree cover, both natural and cultivated.
Site and Community Characteristics
Landscape and Water
Site occupies a shallow elevated valley, approximately 10 hectares in size, in the Mt. Elgon foothills above the town of Mbale
Average plot size is less than 1/10 hectare
Valley is bordered by a near vertical cliff to the east and an irregular slope descending to the north, west, and south
A cliff-side waterfall supplies a small spring at the uppermost fringe of the valley
Valley is mostly fallow during rainy season to due waterlogging, and intensively cultivated in dry seasons
Tillage: hand hoe
Chemical application: Knapsack sprayer
Weeding: Small hand hoe
Planting: Hand hoe
The Farmers and Community
Valley supports approximately 200 farmers who comprise the Maalo Women Farmers Association, including members from 10 smaller farmer groups and some independent individuals
Horticulture irrigation group includes approximately 20 active members, and additional individuals who participate in occasional events, trainings, and meetings
Mbale draws many men from the community for employment, leaving a majority of women responsible for irrigated vegetable production
Crops Grown Here
Small scale vegetable production in valley: cabbages, collard greens, tomatoes, onions, taro
Staple crop production in uplands: bananas, coffee, beans
Innovations for irrigated horticulture in Lwasso
Natural rock head tank
Our project worked with farmers to construct a water tank using natural rockfall rather than traditional construction materials. In many situations this would be significantly cheaper than a traditional cement head tank. This was the case in Lwasso, where it is difficult to transport construction materials to the hard-to-read reach areas where water can be diverted. This technology is suitable for areas where there is a natural stream that can be diverted into the tank, which serves as a head tank for a piped gravity flow scheme.
Gridded drag hose
This system sets a grid of buried pipes with taps throughout an area with many small irrigation plots. At each tap, a hosepipe is connected which an individual farmer uses to hand-water their plot. The hosepipe is long enough to cover the entire area between taps, to ensure all plots in the area are irrigable. With a drag hose, the farmer can accurately apply water to the whole plot but not outside of it. The system is well suited to gravity flow schemes, but also can be used with small engine pumps.