Saturday Aug 18, 2018

Genaveh

 

A number of detailed study sites have been selected for each phase of the MONITOR SB&B project.  Sediment transport patterns and rates will be investigated in detail at the selected sites.  Three sites were selected for the third phase, which are: 1) Bushehr Bay area and Bushehr Port, 2) Genaveh Port, and 3) Reeg Port.  Selection was based on the importance of the site from economic and/or environmental point of view, existing problems that need to be addressed and future economic potential.  The selected sites cover a wide range of conditions within the Phase III study areas from the perspective of geomorphic conditions and forcing functions (waves and currents).

Genaveh and Reegharbours are two neighbouring ports with an approximately 15 km distance between them. Despite their different sedimentary conditions, they are located within the same littoral cell with Reeg Port being located in the downdrift side of Genaveh Port.  Therefore, considering their relative proximity and their relative dependency from sediment budget point of view, the two sites are investigated together.

In this report, MIKE21 is applied to the entire Genaveh- Reeg area and overall conditions of nearshore waves, hydrodynamics and sediment transport processes in the study area are discussed.  Our methodology in the present study is to employ numerical modeling together with GIS analysis of historic shoreline changes and engineering judgment to define a sediment budget including sand supply sources, transport patterns, sediment sinks, and sand transport rates. 

2DH hydrodynamic and sediment transport modellingcoupled with nearshorespectral wave transformation was conducted to calculate wave field and depth averaged flows in two horizontal dimensions. The driving forces considered behind the movement of sediments in the nearshore are the wave-induced orbital motion and the longshore current system including longshore and circulation currents.  Wind-driven currents are not considered because their contribution to the transport of sand in coastal areas is usually insignificant. The Danish Hydraulic Institute’s (DHI) MIKE21 modeling package (coupled model FM) was applied to the analysis of the conditions of waves, nearshore currents and sediment transport at the selected sites.  This advanced software employs improved computer simulation techniques to model waves, hydrodynamic processes and sediment transport processes.

Figure 1 Position of WW3 predicted offshore wave data at Reeg-Genaveh. 

Figure 1 Position of WW3 predicted offshore wave data at Reeg-Genaveh.

Figure 2.WW3 predicted wave height point rose offshore Reeg-Genaveh.  

Figure 2.WW3 predicted wave height point rose offshore Reeg-Genaveh.

Genavehand Reeg areasare two special study sites for Phase III of Monitor SB&B Project.

All of effective waves for LST Genaveh and Reeg area are from North-West and the 10 most effective wave conditions which make 79% of total LST are from North-West direction.
Annual net LST along the shoreline between Genaveh and Reeg was estimated to be in the range of 20,000 to 30,000 m3/year.  Littoral transport occurs mainly inshore of the -2 m contour and there is no sand on the bed beyond this contour.
Outgoing tidal current at the entrance to Arash estuary block the southward transport of sediment and keep the entrance open.