Evaluating the Rice Crop Water Productivity of Irrigation Schemes Practicing Continuous Flooding Irrigation Regime: A Case Study of Ahero Irrigation Scheme in Kenya

The growing scarcity of freshwater resources presents a major challenge to rice production particularly in irrigation systems that rely on limited freshwater supplies. Enhancing the water use efficiency has therefore become essential for sustainable rice cultivation. This study evaluated the rice crop water productivity under continuous flooding irrigation regime using the Ahero Irrigation Scheme in Kenya as a case study. The rice crop water productivity was determined as the ratio of the total mass of rice production to the total volume of water supplied for irrigation. The rice crop water productivity for the scheme was measured and found to be 0.3406 kgm<sup>-3</sup>. The measured value was lower than what is commonly achieved under improved irrigation regimes such as intermittent irrigation. The low water productivity was mainly attributed to conveyance losses along the earthen canals and application losses due to inefficient irrigation practices. Improving the water productivity requires several interventions; lining and maintenances of canals to reduce conveyance losses, adopting intermittent irrigation to use less irrigation water resource, training farmers on proper land preparation techniques to enhance leveling in the irrigation basins thereby reducing excessive irrigation water application in unleveled basins, and strengthening the capacity of Irrigation Water Users Associations to monitor and enforce proper irrigation water usage.