Optimasi Pemanfaatan Air Irigasi Di Daerah Irigasi Widas Kabupaten Nganjuk (Studi Kasus Daerah Irigasi Ngudikan Kanan)

The Ngudikan Kanan Irrigation Area is one of the main pillars of the agricultural sector in Nganjuk Regency, serving a paddy field area of 1,418 hectares, with water supply sourced from the Bening Reservoir. Despite having significant agricultural potential, water availability in this area is highly vulnerable to hydrological fluctuations during the dry season. This condition triggers shortages and unequal distribution of irrigation water, which directly impacts the decline in the quality and quantity of crop yields. Considering that existing water management evaluations have not yet produced a quantitatively optimal allocation scenario, this study aims to develop an optimization scenario for water allocation and planting schedules to maximize the utilization of water resources in the Ngudikan Kanan Irrigation Area. In this study, an optimization technique known as dynamic programming was utilized to calculate the water distribution to be channeled to various tapping structures within the irrigation system. Dynamic programming is a method used to maximize the decision-making process involving various stages, which is divided into two types: deterministic and stochastic. In this research, the applied method is deterministic dynamic programming. Based on the optimization results using deterministic dynamic programming, the profit from agricultural productivity based on the channeled discharge shows a linear relationship, where an increase in water flow efficiency results in an increase in crop yields and farmers' income. With the optimal allocation pattern, the total agricultural profit increases, with the total profit of water provision for each stage or irrigation structure amounting to Rp.56.467.681.684,27. This indicates a 5% increase compared to the pre-optimization profit of Rp.53.546.370.437,40. Therefore, it can be concluded that the deterministic dynamic programming optimization has successfully increased the profit obtainable by farmers, with a profit margin difference of Rp.2.921.311.246,87 compared to the conditions before optimization.