Smart management for irrigation by hydrodynamics analysis and investigation of sulfate distribution in South Kalimantan, Indonesia
摘要
Tidal irrigation systems in peat soil areas of South Kalimantan, Indonesia, face challenges such as water stagnation and acidity accumulation, especially in regions influenced by acid sulfate soil containing pyrite (FeS₂), which can negatively affect agricultural productivity. To address this issue, the study applied long-term smart water level monitoring to analyze sulfate and pH distribution and water flow patterns using field data and hydrodynamic modelling. Water samples were collected from multiple points along the primary, secondary, and tertiary irrigation channels to measure sulfate and pH. In parallel, water level observations were conducted using a simple water level gauge built from low-cost components and deployed from May to December 2024. The recorded tidal fluctuations served as boundary conditions for hydrodynamic modeling using the Hydrologic Engineering Center’s River Analysis System (HEC-RAS). The results showed that water velocity decreased with distance from the river mouth, leading to longer hydraulic retention times (13–66 h) in downstream channels. This stagnation contributed to high sulfate accumulation (> 100 mg/L) and low pH (< 4), particularly in the tertiary channels. These findings underscore the importance of integrating smart field monitoring and flow modeling to mitigate acidification risks and support more sustainable irrigation strategies in peatland environments.