Design of a community Irrigation scheme to serve five small holder farmers

Abstract

There is unreliability of food security in Uganda caused by over reliance on rain fed agriculture by the biggest percentage (97%) of households in Uganda. Prolonged droughts always lead to food scarcity in the country. Irrigation is the solution this problem. However, farmers have not engaged in irrigation majorly because of the financial requirements. The major aim of this project therefore, was to design a community irrigation scheme to serve small holder farmers. A case study area was chosen to be Galiraya in Kayunga district where five farmers were growing upland rice on 4acres of land each, totaling to 20acres. Information on the climate, soil, topology, water availability, solar irradiance and wind was collected to aid in the design. Measurements of head, area, distance from the water source as well as coordinates of the place were also taken. Considerations were made on different types of irrigation and the manual hose pipe type was found most eligible because of its low costs involved. The irrigation water requirement for the rice was calculated by subtracting the total effective rainfall from the total rice water requirement and this was found to be 26.7m3/day. Total head(26m) was calculated by summing up the head of the area(16m) as measured by a hand held GPS, the head loss in the pipes(5m) and the dynamic head required by the nozzle(5m). A tank was designed to accommodate 30,000litres a day. The main pipe was also designed with diameter of 1.5inc, total length of 600m and was of flexible PVC material. The pump was designed by calculating the pump power from the flow rate and total head required. A suitable pump was chosen from available pumps and it had 550watts, maximum head of 52m and maximum discharge of 4m3/hr. the number of solar panels for the pump was determined from the pump power required and these were 6 In number. With this design, a topomap was created from the coordinates showing the design. A prototype was then set up in the area. Analysis was done to see the financial benefits of this system and it was discovered that through this, every farmer earns Shs 5,400,000 more per season with this system than when without it. It was concluded that setting up these kinds of irrigation schemes would increase food availability as well as increase the financial benefits of the farmers.