Author(s): Tatas. , Muhammad Hafiizh Imaaduddiin, Dimas P. Dibiantara
Linked Author(s): Tatas Tatas
Keywords: Stilling basin, weirs remedy, weir structure damage
Abstract:
Good irrigation system is an essential requirement of farmland. Agricultural infrastructure will be damaged if it is not maintained regularly. Weir as one of the agricultural infrastructures is part of the upstream irrigation systems to raise the water level and then distributing water to agricultural areas through the intake. As an agricultural island in Indonesia planted with tobacco and paddy, Madura is very dependent on good irrigation weir. The purposes of this paper are identification of dominant defects in the irrigation weirs and proposing a structural solution that can be applied to reduce the damage without replacing the irrigation weirs. Moreover, this paper writes about the proposal of repairing water structures, which is a topic with very limited reviews by other authors. The method used to identify the damage is to conduct a survey on several weirs in the Madura Island and to propose technical solutions to reduce further damage of the weir. To make repairs, the hydrological components are first calculated such as return period of rainfall with the Log Pearson III Method, time of concentration by Kirpich's Equation, Mononobe's Rain Intensity and Peak Discharge of Rational Method. To repair the weir structure design, the Lane's Equation and uplift pressure are used. For case study of the Grudjugan Weir, the remedy to the structural damage is proposed by cutting off the ruins of the stilling basin. Hydrologic analysis results show that the flood discharge is 56.2 m3 /s and water level on weir crest is 1.5 meter. A minimum length of weir structure is 9.25 meters, while the thickness of the stilling basin floor is at least 30 cm. Improvements recommended are by replacing the stilling basin floor with masonry and covered with 20 cm thick reinforced concrete, which is connected by anchor to the structure of masonry and old spillway. (2618, 66, 293)
Year: 2017