Ahmad Sana

In order to improve the accuracy of the original full-range equation for wave boundary layer thickness, with special reference to increasing its applicability to tsunami-scale waves, a theoretical investigation is carried out to derive a dimensionless expression which is valid under both smooth and rough turbulent regimes. A coefficient in the equation is determined through a comparison with k-ω  model computation results for tsunami-waves along with laboratory scale oscillatory flow experiments. Thus, the improved full-range equation for wave boundary layer thickness enables us to cover a wide range of wave periods from wind-wave to tsunami.

A College of Arts, Sultan Qaboos University, PO Box 42, Al-Khod PC 123, Oman; email: hatrushi@squ.edu.om; buloshis@squ.edu.om B Remote Sensing and GIS Center, Sultan Qaboos University, PO Box 33, Al-Khod PC 123, Oman; email: kwarteng@squ.edu.om; ...

The transitional flow regime of the bottom boundary layer under hypothetical shoaling tsunamis is investigated in the entire region from the tsunami source to the shallow sea area. In order to calculate the shoaling process of a tsunami, an analytical method based on Green’s law and the linear long wave theory are employed, and flow regime criteria for the wave boundary layer proposed by one of the authors are applied. It is found that the bottom boundary layer in a tsunami source area is located in the laminar regime. Subsequently, transition occurs to the smooth turbulence during the shoaling process, with a transition from the smooth to the rough turbulent region in the shallow area. For precise evaluation of bottom friction acting on the sea bed and the resulting energy dissipation beneath the tsunami, it is highly necessary to include such transitional behavior in sea bottom boundary layers.

A number of studies on bottom boundary layers under sinusoidal and cnoidal waves were carried out in the past owing to the role of bottom shear stress on coastal sediment movement. In recent years, the bottom boundary layers under long waves have attracted considerable attention due to the occurrence of huge tsunamis and corresponding sediment movement. In the present study two-equation turbulent models proposed by Menter(1994) have been applied to a bottom boundary layer under solitary waves. A comparison has been made for cross-stream velocity profile and other turbulence properties in x-direction.

The Makran coastal belt is over 1000 km long stretching from Iran to east of Karachi in Pakistan. A major active subduction zone known as Makran subduction zone defi ned by the under thrusting of the Arabian plate beneath the Eurasian plate runs parallel to the coastline. The subduction zone is associated with a thick accretionary sedimentary wedge deposited in an active fore-arc basin containing very thick detrital sediments contributed by the accretion of the subducting plate since Late Eocene time. The sediments in the fore-arc basin are fi ne-grained usually of clay size fraction deposited in highly fl uidized conditions trapping methane gas. The fl uidized mud diapirically moves upward along weak zones as mud volcanoes due to high sedimentation rates and escaping gas pressure piercing through the overlying sediment layers. The development of mud volcanoes shows a close relationship between the sedimentation rates, gas escape from sediments and tectonic activity. Mud volcanoes are found in abundance both onshore and offshore of the Makran Coast. Most of the onshore mud volcanoes are associated with active fault zones and are believed to be triggered by tectonic activity. Located in the hanging wall of an active subduction zone, the region is seismically highly active and occur

A College of Arts, Sultan Qaboos University, PO Box 42, Al-Khod PC 123, Oman; email: hatrushi@squ.edu.om; buloshis@squ.edu.om B Remote Sensing and GIS Center, Sultan Qaboos University, PO Box 33, Al-Khod PC 123, Oman; email: kwarteng@squ.edu.om; ...

The coastal plain aquifers in Sultanate of Oman are suffering from seawater intrusion due to huge water deficit in the coastal communities thereby seriously deteriorating the groundwater quality. Among other options in arid countries like The Sultanate, one of the viable one is the use of treated wastewater to recharge the coastal aquifers. This option is viable because of the availability of tertiary treated wastewater from the treatment plants managed by Haya Wastewater Company, Oman. In the present study MODFLOW for groundwater flow is implemented and calibrated in one of the most important coastal plain aquifers in Al-Batinah region, Sultanate of Oman. The calibrated model is then used to study the effect of treated wastewater injection into the aquifer on groundwater levels. It was ascertained that the available treated wastewater could be used as an effective option to defy seawater intrusion into this region by raising groundwater table.

Al Batinah coastal area has been experiencing rapid development over the past three decades including the construction of major engineering infrastructures such as harbors, corniches, roads, etc. The project aimed to access the status of coastal erosion in Al Batinah using a series of integrated studies and to suggest solutions. A multidisciplinary approach was adopted in order to address the issue of beach erosion along Al Batinah coast as holistically as possible. Accordingly, the study included the following sections: (1) Literature review of existing knowledge, (2) Survey of the needs, problems and perceptions of local communities concerning sandy beaches, (3) Use of aerial photos and satellite imagery to consider large scale changes to this whole section of coast, (4) Regular surveys of beach profiles at selected locations to initiate a monitoring system and to obtain measurements on a finer scale (temporal and spatial) of changes, (5) Analysis of grain sizes and mineralogy of ...

ABSTRACT Salalah in the southern region of the Sultanate of Oman is the only region in Arabian Peninsula to receive monsoon rainfalls during summer. This region is also suffering from the seawater intrusion due to extensive pumping. Tertiary treated wastewater can be used to combat seawater intrusion in coastal aquifers. In order to study the technical feasibility of replenishing the groundwater using treated wastewater, MODFLOW and MT3DMS are used in the present study. First, a conceptual model for Salalah coastal plain aquifers was developed based on available hydrogeological data. The conceptual model was implemented in Groundwater Modeling System (GMS). The model consists of several coverages for input data of various hydrogeological parameters. Then, the calibration of the model was done using the data from wells scattered over the whole study area. After a good agreement between computed results and measurements the model was applied to consider various scenarios of artificial recharge by treated wastewater to mitigate seawater intrusion and effective management of groundwater resources. It was found that the calibrated model could satisfactorily simulate groundwater levels and salinity intrusion. This model could be used as an effective management tool by the concerned authorities.

【摘要】：正Existing experimental data of sediment movement due to waves and current coexistent motion, or pulsatile motion,are collected to investigate the modes of sediment transport.The data set analyzed in this study covers very wide range of experimental ...