ANALYSIS OF FLOW AROUND BARRAGE STRUCTURES USING HEC-RAS

Abstract

In the last few decades, powerful computing techniques have improved the performance of hydraulic models drastically. This has further been enhanced with the use of Geographic Information System (GIS), remote sensing and radar system to provide accurate input data. One such software which can simulate complex flow systems and model 1-D and 2-D Steady and Unsteady flow conditions is HEC-RAS. In the present study, the performance of HEC-RAS to model and simulate 1-Dimensional Steady Flow around Barrage Structure proposed on the Saryu River in Ayodhya has been analyzed. Digital Elevation Model of the river system in ArcGIS has been integrated with HEC-RAS to generate accurate input parameters of river geometry. The set-up of the HEC-RAS model and input data requirements such as river centerline, cross-sections, and empirical coefficients have been highlighted and summarized. The Water Surface Profile obtained in the HEC-RAS model, before the construction of barrage, was compared and conforms well to the site data available with a Mean Absolute Percentage Error (MAPE) of 0.3% and Coefficient of Determination (R²) value of 0.79. For examining the simulated flow around the proposed barrage, the HEC-RAS model was compared with the physical model of the river system in the laboratory. Results of the study indicate that simulations of the HEC-RAS model in predicting flow for barrage are quite consistent and effective. HEC-RAS acts an effective tool to simulate 1-Dimensional Steady Flow around Barrage Structures.