Abstract

This paper deals with how best the underutilized resource of treated sewage water can be utilized productively for nearby hillside irrigation with drip irrigation avoiding environmental degradation. Design analysis was performed to adopt the offset and split manifold designs for drip irrigation system in different land slopes to achieve better uniformity of application. For land with slopes of 5, 8, 10 and 12 percent, the offset manifold design is recommended for having uniform manifold diameter. Split manifold design is feasible up to 5 percent land slope with manifold mainline junction at the centre and beyond this slope the junction should be located other than midpoint. Rainfall analysis, crop water demand and sewage water availability reveal exciting opportunities for water productivity enhancements in rainfed agriculture by integrating components of water management within the context of rainfed farming through sewage water harvesting and supplemental irrigation for dry spell mitigation.

Keywords

Crop water, Drip irrigation, Hill side irrigation, Manifold design, Rainfall, Sewage water, Sewage Treatment Plant, Semi-arid regions, Lake Hawassa, Chelelaka wetland, Sewage treatment plant, Friction coefficient, Equivalent lateral length, Multiple outlets Coefficient, Split manifold design