Assessment of Reservoir and Canals Revitalization to Improve The Reclamation Process at Unit Tamban Tidal Irrigation Area, Central Kalimantan

Abstract

The Unit Tamban is one of the tidal irrigation areas in the Central Kalimantan Mega Rice Project (MRP). The Unit Tamban is an irrigation system consisting of three primary canals with a settling pond or reservoir at each end. After being developed in 1970 by the Tidal Rice Field Development Project (P4S), the three reservoirs no longer function because they are full of sediment. Sedimentation also occurs in primary and secondary canals, impacting tidal attenuation and decreasing canal capacity. The reservoir at the end of the primary canal assists water regulation for irrigation purposes and leaching acid sulfate water. Three scenarios can be used to increase the capacity of the irrigation system, namely reservoir revitalization, secondary canals normalization, and combining two previous scenarios. The performance of both options was assessed by hydraulic simulation modeling using the HEC-RAS software. The hydraulic simulations show that reservoir revitalization can increase the volume of incoming water during high tide by about 90% more than without a reservoir. If the secondary canal normalization is carried out, the fresh water volume entering the secondary canal exceeds 19% before normalization.