STUDY OF RAPID SEDIMENTATION AT PARESAR INTAKE BASIN, CASPIAN SEA, DUE TO LARGE WRACK PARTICLES AND WIND-INDUCED CURRENTS

Mina Rashvand,Amir Masoud Moattar Kharrazi,Mohsen Soltanpour

doi:10.9753/icce.v36v.papers.4

Abstract

The rapid sedimentation at the entrance of Paresar intake basin is studied, in which unnatural wrack accumulation at the coast, combined with the existing sand, resulted in a major increase in the actual Longshore Sediment Transport (LST) rate. Considering the volume of updrift fillet at the northwest of main breakwater and the estimated LST rate, the advancement of updrift shoreline was highly unexpected. Sands and vegetative wracks were observed only 3 years after constructing the rubble mound breakwaters, resulting in water depth decrease at the entrance. Employing field measurements and numerical modeling, it is revealed that general wind-induced currents in Caspian Sea, which were ignored in the design, have a small effect on increasing LST rate. The unusual sedimentation can be mainly related to the high percentage of wrack particles at updrift coast.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/UNNnjDHL41k

Highlights

The construction of coastal structures, such as groins and breakwaters, generally results in an extensive shoreline change
It is observed that the variations in particle size, porosity, density, and shields parameter significantly affect the sediment transport rate
It is observed that the contribution of wrack particles significantly increases the bypassing in a long time

Summary

Introduction

The construction of coastal structures, such as groins and breakwaters, generally results in an extensive shoreline change. The blockage of Longshore Sediment Transport (LST), i.e. the cumulative movement of nearshore sand parallel to the shore, is the common reason of shoreline advancement and retreat at updrift and downdrift sides of coastal structures, respectively.

Results

Conclusion