ANALYSIS OF PACINAN RIVER NORMALIZATION CONSIDERING RIVER MOUTH CONSTRICTION USING HEC-RAS SOFTWARE

Abstract

The Pacinan River in the Veteran Road area, spanning 1,392 meters, plays a crucial role as the main drainage channel. However, over time, it has encountered issues such as pollution, siltation from sedimentation, and narrowing due to construction. The reduced capacity of the river has caused rainwater not to flow improperly, leading to flooding around roads and residential areas. This study aims to analyze the normalization of the Pacinan River to prevent overflow using HEC-RAS software. The analysis includes hydrological aspects, such as rainfall frequency analysis and planned flood discharge using rational method for recurrence intervals of 2, 5, 10, and 25 years, as well as hydraulic analysis covering river cross-sections and dredging volumes through 1D Unsteady Flow simulations. The research results indicate that the planned flood discharge values for recurrence intervals of 2, 5, 10, and 25 years at the Pacinan River range from 1,28 m³/s to 2,15 m³/s. Based on HEC-RAS simulations, the depth of the Pacinan River before normalization ranged from 0,89 to 1,7 meters, with a cross-sectional width between 2,8 and 27,8 meters. After normalization was performed without changing the river's cross-sectional width, the river depth increased to between 1,83 and 1,86 meters.

Keywords: River Normalization, Estuary Narrowing, HEC-RAS, Pacinan River