Backswamp Development’s Effects on Water Management System of Tidal Swamp Irrigation Palingkau SP1 SP2 SP3, Kalimantan, Indonesia

Abstract

The Palingkau SP1 SP2 SP3 swamp irrigation is an expansion of handil’s agricultural area, which is influenced by tides from the Kapuas River on the left and the Kapuas Murung river on the right. The new area that exploits backswamp and the buffer zone upstream of Handil, gives an additional burden of dispersion of toxic materials resulting from the oxidation of acid sulfate soils and the loss of fresh water supply from backswamp. The actual leaching process is indicated by the water pH value in the collector and primary channels ranging from 2.58 ~ 3.6. Meanwhile, the water quality of Handil, Kapuas and Kapuas Murung rivers is better, ranging from 3.7 ~ 5.34. The confluence of tidal from two opposite sides has resulted in the disruption of pollutant discharge. Instead of discharged into rivers, its flow to Handil’s agricultural area and reduce agricultural productivity. The HEC RAS software simulation model is used to evaluate the optimal water management system. One-way flow system is introduced hydraulic structures for regulating the flow of freshwater water at high tide from the left handil into the new irrigation area and regulating the drainage at low tide through the right handil.