Field Study of Longshore Sediment Transport Rate Estimation over the Newly-Developed Coastline of Northern Oman Sea

Abstract

Estimations of sediment transport rate is the prerequisite of coastal development and management studies, as accretion and erosion are among main controlling considerations for port planning. The Iranian coastline of the Oman Sea, which is so-called Makran Coastline, has a complex morpho-dynamic behavior and should be considered from both scientific importance and its high potential for development in the next decade. It is while morpho-dynamic perspective of the area is not well studied so far. On the other hand, the wave climate of the area is affected by different regimes: monsoon waves, normal seas, swells coming from the Indian Ocean and tropical cyclones. There are limited researches on the contribution of each regime on the longshore sediment transport with considering the sensitivity to deep water wave direction variability. This study aims to put different pieces of knowledge together, including field measurements, numerical modeling and Geographic Information System-based (GIS-based) analysis of multi-year cross-shore profile data, to obtain a more realistic estimation of Longshore Sediment Transport (LST) rate along the undeveloped Makran Coastline. The focus of this paper is mostly on the accurate wave and sediment transport modeling, verified against available field data and morphological evidences. The major challenge in this regard has been the lack of long-term data availability, as the coastline has been remained undeveloped. This has been overcome by adopting satellite imagery as a complementary source to the available periodic hydrography data, as well as data science methods for improving wave data accuracy. A numerical model is applied for simulating the transportation process of sediments along Makran Coastline. The existing extracted shoreline changes around Makran Coastline through GIS analysis of satellite images were used to assess the general morphological changes in the study area. All the simulation and coastline change analysis results are adopted for obtaining an integrated conclusion in Zarabad Port as the case study of this research. The obtained results were in fair agreement with observations and this is why the model setup and study methodology can be applied for LST rate estimations over Makran Coastline.