PERFORMANCE OF CONTINUOUS AND STAGGERED TRAINING WORKS IN TIDAL REGIMES UNDER OBLIQUELY INCIDENT CURRENT

Abstract

ABSTRACT The use of training works in the form of spurs/guide bunds and training jetties/breakwaters are common in river/estuarine environment to maintain the course of river or natural depths in navigational channel at inlets. However use of training works in the regions near the mouth of creek in the gulfs requires thorough understanding of flow/morphological processes, since flow conditions are more complicated due to presence of large regions, dynamic shoals and natural channels. The mathematical model studies to examine flow hydrodynamics around 1000 m long solid continuous and staggered training work under obliquely incident current at 90°, 60° and 45° orientation with the flow were carried out by setting up a sufficiently wide test channel with training work at its center. The studies carried out revealed that effect of continuous/staggered training work on flow regime is prominent up to a distance of about half the length of training work on up-flow side, while up to one and half times the length on down-flow side of it. The staggered training work with current/flow at 90° to it revealed that it helps in reducing flow/sediment carrying capacity behind training work compared to solid continuous training work. Also staggered training work at 45° orientations would be suitable for reducing flow/sediment carrying capacity in navigational channel on down flow side. Planning and constructing such training works at a distance of about one and half times its length on up-flow side of navigational channel would be beneficial to reduce siltation in navigational channel in complex tidal regimes like gulfs and creek confluence.