Sedimentation Processes at the Navigation Channel of the Liquefied Natural Gas (LNG) Port, Nile Delta, Egypt

Essam Abd El-Halim Mohamed Deabes

doi:10.4236/ijg.2010.11002

Abstract

Liquefied Natural Gas (LNG) port is located at Abu Qir Bay on the northwestern coast of the Nile delta, Egypt. The port was constructed in 2004 to export liquefied natural gas worldwide. The offshore basins of this port including the turning and berthing areas (15-m depth) are connected to the deep water by a 15-m depth dredged channel that extends 4 km offshore. However, the navigation channel and its contiguous basins have experienced problematic shoaling that might affect the navigation activities of gas tankers. Sedimentation processes have been investigated by analyses of waves, currents, bathymetry, grain size of seabed and channel dimensions. Sedimentation rates are estimated using a developed numerical model. Sedimentation rate fluctuates between 0.048 × 106 m3/month and 0.388 × 106 m3/month, with an annual sedimentation rate of 1.977 × 106 m3/yr. The variance in the sedimentation rates between winter and summer resulted in increasing of current speed and direction flowing towards offshore. The sedimentation process is influenced by the temporal variability in the direction and intensity of the predominant waves, currents, orientation of navigation channel, basin breakwaters, seafloor morphology and sediment sources. Due to the geographic location of LNG port it lays within a sediment sink for sediments supplied from different alternating directions by several pathways, flowing towards the N-W, S-W, N-E, and S-E quadrants. Most of these currents components are substantially effective in transporting fine-grained sediment towards the navigation channel axis and contiguous basins. Together with these currents, the predominant NW and SE waves acting to agitate and stirrup sediments in the vicinity of the port, and thereby accelerating sedimentation rates.

Highlights

During the last three decades, there have been a large number of harbors built along the Nile delta coast as a result of the increasing development of this valuable region
Liquefied Natural Gas (LNG) port is located at Abu Qir Bay on the northwestern coast of the Nile delta, Egypt
Characterization of waves and currents is necessary to understand their role in inducing shoreline changes and sedimentation process in channels and waterways

Summary

Introduction

During the last three decades, there have been a large number of harbors built along the Nile delta coast as a result of the increasing development of this valuable region. Most of these harbors are experiencing frequent sedimentation and siltation in their access channels due to the higher littoral drift rate and sedimentation imbalance [1]. The turning and berthing basins (15 m depth) are connected to the deep water by means of dredged channel-entrance of 4 km length (Figure 1). This navigation channel is oriented in the NW direction (~1350 from the north) and attaining about 15-m depth and 245 m width. The port basins are protected from the N-W waves by a breakwater of ~900 m length which is roughly parallel to the shoreline

Objectives

Methods

Results

Conclusion