| Modelling
of Rainwater Catchment and Utilization on Farmsteads in Sipili, Kenya Nicholas Kiggundu, R. K. Muni
Abstract Undependable and erratic rainfall patterns, with frequent rainless periods within the rainy season in Sipili location, a semiarid area in Kenya, is the primary natural limiting factor to the rain-fed agricultural production potential of the area. Although the average annual rainfall of 600 - 800 mm would appear sufficient for one or two good crops per year, at times, the harvest is poor or there would be a total crop failure due to poor rainfall distribution. The level of supplemental irrigation mainly for horticultural crops is inadequate since farmers lack guidance on how efficiently harvested rainwater could be utilized for maximum returns. A computer model was developed based on the mass balance equation to facilitate simulation of water utilization from different tank capacities meant to provide water for domestic use, watering two grade dairy cows and supplemental irrigation of a cabbage crop. The maximum cropped areas for different planting decades (10-day period) of the year up to crop maturity were determined for tank capacities of 50, 100, 150, 200, and 250 m3. The optimum cropped area for each tank capacity could be obtained when planting was done on the 14th decade. The maximum cropped area could be achieved when planting was done on the 2nd, 14th and 26th decades for 50, 100, and 150 m3 tanks and on the 1st, 13th and 25th decades for 200 and 250 m3 tanks. Such results would give farmers in Sipili and its environs an opportunity to strategize for the highest market prices of the cabbage crop or the highest crop yield. |
