Revitalization of Irrigation Area Based on Optimization and Risk of Land Failure

Water availability significantly impacts rice cultivation in paddy fields, especially during land preparation when irrigation demand is the highest. Imbalances between water supply and demand can result in technical and social challenges. Hence, revitalizing irrigation areas is critical for improving agricultural productivity and profitability. This study was performed in the Cimulu Irrigation area, Tasikmalaya, West Java, Indonesia. The research employed the Land Failure Risk Assessment (LFRA) to determine the optimal irrigation area based on the water balance (k-factor), representing the ratio of available irrigation water to demand. Discharge data from 1984 to 2073, representing an 80% dependable discharge, were used as a reference for water availability. This was compared with existing data under the same discharge conditions. Linear programming (LP) optimization of irrigation areas often prioritizes "safety", potentially leading to suboptimal benefits. However, higher risks may yield more significant profit potential. This study integrated LP and LFRA to maximize benefits. The results indicated good discharge validity. LP optimization revealed that the highest profit was achieved with early cropping on Nov-1, generating Rp 61.96 billion with an 80% existing and IDR 67.24 billion with a Q80% generation. Utilizing the LFRA Model at the same cropping time resulted in profits of IDR 71.24 billion (k = 0.62) and IDR 96.16 billion (k = 0.72). Recommendations include modifying the cropping pattern to incorporate paddy-paddy-palawija in one cropping season, potentially generating a substantial profit of IDR 71.11 billion. This practice also allows for a "cropping break period" for soil health and risk mitigation.