Hydrological regime of the Rhône Delta and dynamics of its coastline

Specific features of the hydrological regime of the Rhône River and the nearshore zone of its mouth are discussed. The processes of seawater intrusion into the delta branches are described. The information on the history of the delta evolution and development is presented along with the reconstruction of the Holocene evolution of the Rhône Delta and analysis of formation peculiarities of the present-day delta. Channel processes in the Rhône Delta and the dynamics of the delta coastline are described; characteristics of the deep-water fan are discussed, and the data on sediment balance are given.     

The bedrock topography of the botany basin,New South Wales

The bedrock topography of the Botany Basin has been determined from seismic‐sparker records made in Botany Bay and Bate Bay, and from seismic‐refraction and gravity measurements on the Kurnell Peninsula. Supplementary information has been obtained from boreholes both on land and in the sea.

The Cooks and Georges Rivers formerly constituted the main drainage of the Basin and flowed generally southeastwards (beneath the present Kurnell Peninsula) and joined the Port Hacking River east of Cronulla. The depth of the bedrock channel of the former Georges River is 75–80 m b.s.l. at Taren Point, 90–95 m beneath the Kurnell Peninsula and 110–115 m at its junction with the Port Hacking River channel. The bedrock channel of the former Cooks River is about 30 m b.s.l. at Kyeemagh, its present entrance to Botany Bay, and it joined the Georges River at a location now 90 m b.s.l. beneath the Kurnell Peninsula.

A second drainage system existed in the north and east of Botany Bay and generated the present mouth beneath which the bedrock is now 110 m b.s.l. This channel followed a southeasterly course parallel to the present northern shore of Botany Bay and was separated from that of the ‘Cooks and Georges Rivers’ by a bedrock ridge which extended from beneath Sydney Airport to the northern extremity of the Kurnell Peninsula. Over much of its length this divide had a depth of about 30 m b.s.l.

The formation of the Kurnell Peninsula tombolo led to the diversion of the ‘Cooks/Georges River’ through the mouth of Botany Bay and subsequently led to the development of the bay. This change in the drainage system occurred when the sea was less than 30 m below the present sea level.     

Challenges associated with pre-border management of biofouling on oil rigs

The potential for oil rigs to transport diverse, reef-like communities around the globe makes them high risk vectors for the inadvertent spread of non-indigenous species (NIS). This paper describes two case studies where a suite of pre-border management approaches was applied to semi-submersible drilling rigs. In the first case study, a drilling rig was defouled in-water prior to departure from New Zealand to Australia. Risk mitigation measures were successful in reducing biosecurity risks to the recipient region, but they resulted in the unintentional introduction of the non-indigenous brown mussel (Perna perna) to New Zealand when the rig was defouled in-water by divers. In the second case study, lessons learned from this high-profile incursion resulted in a more structured approach to pre-border management, and this serves as a useful template for future rig transfers.     

Coastal processes and cliff recession between Gabicce and Pesaro (northern Adriatic Sea): a case history

Cliff recession on the high rocky coast between Gabicce and Pesaro Adriatic sea causes a wide range of mass movement processes on the whole slope, affecting both the bedrock and the overburden. The outcropping late Miocene rock formations are represented by marls, marly limestones, dark laminated mudstones and bedded sandstones and marls. Mass movements are common because of stratification and discontinuities in the rocks that, together with the presence of groundwater and weathering processes, reduce the overall strength of the slopes. A model for the evolution of this coastal area is proposed, which involves cyclic basal erosion, followed by mass movement that favours debris accumulation at the base of the cliff. The longshore currents have to then remove the material before a new cycle can begin.     

Discontinuity controlled probabilistic slope failure risk maps of the Altindag (settlement) region in Turkey

The evaluation of potential rock slope problems using stereographic projection techniques known as kinematic analysis is one of the most important parts of a slope stability investigation to be carried out in jointed rock media. In conventional stereoprojection techniques for the assessment of possible rock slope failures, the peak orientations of joints together with the slope geometry and the friction angle of the weakness planes are used. Other possible joint orientations which may be encountered in the rock media are ignored, although they belong to the group of joint peak orientations. In this study, nearly vertical jointed andesites cropped out at the Altindag settlement region in Ankara were studied in order to evaluate the relevance of this ignored discontinuity orientation data on slope stability. As a result, probabilistic risk maps for planar, toppling and wedge failures were produced using the kinematic rules and digital elevation model of the study area. The comparison of the distribution of the actual failures in the area and the probabilistic risk maps prepared for the study area revealed that all of the identified failures are found to be located in the higher risk zones on the probabilistic risk maps.     

Precise photorealistic visualization for restoration of historic buildings based on tacheometry data

This paper puts forward a 3D reconstruction methodology applied to the restoration of historic buildings taking advantage of the speed, range and accuracy of a total geodetic station. The measurements representing geo-referenced points produced an interactive and photorealistic geometric mesh of a monument named ‘Neoria.’ ‘Neoria’ is a Venetian building located by the old harbor at Chania, Crete, Greece. The integration of tacheometry acquisition and computer graphics puts forward a novel integrated software framework for the accurate 3D reconstruction of a historical building. The main technical challenge of this work was the production of a precise 3D mesh based on a sufficient number of tacheometry measurements acquired fast and at low cost, employing a combination of surface reconstruction and processing methods. A fully interactive application based on game engine technologies was developed. The user can visualize and walk through the monument and the area around it as well as photorealistically view it at different times of day and night. Advanced interactive functionalities are offered to the user in relation to identifying restoration areas and visualizing the outcome of such works. The user could visualize the coordinates of the points measured, calculate distances and navigate through the complete 3D mesh of the monument. The geographical data are stored in a database connected with the application. Features referencing and associating the database with the monument are developed. The goal was to utilize a small number of acquired data points and present a fully interactive visualization of a geo-referenced 3D model.     

Evaluation of hydrogeochemical processes and groundwater quality for suitability of drinking and irrigation purposes: a case study in the Aosta Valley region,Italy

The present study aims to discuss the hydrogeochemical processes in the Aosta Valley region and assess the quality of its groundwater for suitability of drinking and irrigation purposes. One hundred twenty-two samples were collected from the Aosta Valley region in the years 2007 and 2008 (61 per year), and analysed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, major cations and anions. The pH of the samples in both years indicated a near-neutral to alkaline nature of the groundwater. The cation and anion chemistry showed the general ionic abundance as: Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃ ^?>SO₄ ^2?>Cl^?>NO₃ ^?>F^? in both years. Ca²⁺-Mg²⁺-HCO₃ ^? and Ca²⁺-Mg²⁺-Cl^?-SO₄ ^2? were the dominant hydrogeochemical facies. The computed saturation indices demonstrated that the groundwater was supersaturated with respect to dolomite and calcite in both years. The groundwater chemistry of the study area was mainly controlled by the dissolution of carbonate, sulphate and silicate minerals, as well as ion exchange processes. A comparison of the groundwater quality in relation to drinking water standards showed that most of the water samples were suitable for drinking and domestic uses. The computed water quality index (WQI) values of the study area groundwater ranged from 24 to 84 in the year 2007 and from 22 to 82 in the year 2008, and all the location fell under the Excellent to Good category. Quality assessment for irrigation uses revealed that the groundwater was good to permissible quality for irrigation; however, locally higher salinity, residual sodium carbonate (RSC) and magnesium hazard (MH) restricted its suitability for irrigation at a few sites. These results will be useful in implementing future measures in groundwater resource management at regional and national level.     

Application of time-frequency transforms to processing of full waveforms from acoustic logs

The paper deals with the application of time-frequency methods, Continuous Wavelet Transform (CWT) and Matching Pursuit algorithm (MP), to acoustic full waveform processing. The goal of the research is to present possible ways of application of these methods, particularly for the precise identification of selected acoustic waves, waveform decomposition into separate waves, and determination of zones of different elastic parameters in the geological profiles. The simulations, developed methodology, and results of each method are discussed in detail. The Continuous Wavelet Transform is used to improve qualitative interpretation. Time-depth-frequency plots for a given frequency are constructed to distinguish the waves and identify gas-bearing zones. The Matching Pursuit has a better resolution in time-frequency space than CWT; thus, it is used to extract individual waves from the whole acoustic waveform, i.e., decompose the signal. For the extracted waves, the slowness is calculated. Results from MP methods are compared with their counterpart parameters obtained from the original waveforms. Additionally, time-frequency decompositions are used for the determination of the frequency content of each wave packet to get unique information about formation in situ.