Landslides pose a significant risk to life and infrastructure in Papua New Guinea (PNG). The combination of rugged topography and high seismicity makes PNG highly susceptible to large-volume, earthquake-induced landslides, while the climate encourages widespread rainfall-induced landslides. Of the two triggering mechanisms, rainfall offers the best opportunities for the development of early warning/forecasting systems, as meteorological models continue to improve in skill and resolution. To understand the relationships between rainfall and landslides, studies have conventionally looked to develop landslide-triggering rainfall event thresholds. Such thresholds can form the basis for early warning/forecasting systems. In this thesis, satellite-based precipitation estimates from the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) are used to examine characteristics and relationships between rainfall and landslides. These data, in conjunction with Bayesian statistical approaches, were then used to develop landslide probabilities based on rainfall events of varying duration and magnitude. Understanding the landslide triggers is only one aspect of slope instability. Environmental control factors, such as slope or curvature, can enhance or reduce the likelihood of slopes to fail. Therefore, multispectral imagery and high resolution GeoSAR (synthetic aperture radar) digital elevation models have been exploited to verify and map landslide scars in different regions of PNG. These data also support the development of landslide susceptibility maps, providing detailed information on the terrain and structures important for slope instability. Using fuzzy relation-based assessments these data were used to produce landslide susceptibility maps which differentiate areas of low/no susceptibility from those with high susceptibility. Overall, the satellite and airborne techniques have provided the tools to understand landslide occurrence relative to changes in rainfall and susceptibility, which can form the basis of early warning/forecasting models.

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This thesis focuses on the use of Terrestrial LiDAR Scanning (TLS) for the monitoring of active slopes. Research into this area has developed an innovative methodological framework of spatial analysis approaches for the characterisation and monitoring of active slope instability sites. Methods implemented include monitoring using TLS derived Digital Terrain Models (DTMs) with scans conducted approximately every two months. Temporal responses of morphological parameters to slope instability and deformation were assessed. A pioneering assessment of TLS deviations over a scanning period of one day was utilised to identify the implications systematic errors have for temporal monitoring analysis. An evaluation of standard and robust statistics, statistics which are not affected by outliers, is presented for the applicability of TLS with implications for terrain evolution and error assessment. In addition to TLS monitoring, Aerial LiDAR (ALS) was assessed for the application of the morphological characterisation on a larger scale from selected sites around the world including the United Kingdom (UK) and Canada. This thesis presents the temporal, statistical and morphological responses of slope deformation over a monitoring period of two years. Rates of movement were found to vary with greatest magnitude occurring during Winter and Spring. Evaluation of error over the one day period identified limited deviation in the acquisition of successive point clouds. The implications for this error assessment illustrated the potential use of robust statistical measures. Temporal morphological assessment resulted in the identification of pre-and post-failure characterisation of slope instability. This resulted in the development of a quasi-empirical model of failure for the selected slopes. Spatial analysis results were validated using Aerial LiDAR and TLS datasets. The overarching impact of this thesis is that it has provided insight into the real world application of TLS monitoring of slope deformation and the benefits of such investigation for partner organisations and their key remits to governmental bodies.

This thesis investigates sediment transport by slow mass movement within a small upland catchment area near Stanhope in Wearable, N. England. In the field, emphasis is placed on measurements of the rate and spatial distribution of mass movement; in the laboratory, a possible mechanism for slow movement has been investigated in several controlled experiments. A review of the literature on slow mass movement processes indicates that there is considerable confusion over terminology. Terms such as creep, slow mass flow and soil slip imply that the mechanism of movement is known, whereas they are usually intended to be descriptive. An alternative classification of movement is suggested which separates description, knowledge of mechanism and knowledge of the domain in which a process operates. The term slow mass movement (S.M.M.) is used throughout this thesis to refer to downslope displacement of soil particles at a rate expressed in mm^/yr but whose mechanism of movement is not necessarily known. A fieldwork programme was established to measure superficial slow mass movement rates in an upland catchment area for a period of two years. Data were recorded from seventy 1m(^2) measurement plots at monthly intervals. Each plot contained four instruments recording mass movement, thus allowing comparison within as well as between plots. The experimental design allows analysis of the effects of slope angle, vegetation type and soil texture on movement patterns and rates. The general aim is to develop an understanding of how S.M.M. relates to physical and ecological variables in an upland catchment area and to assess its importance as an erosional process. The instruments used ai-e techniques, or modifications of techniques which have been described and used successfully by several previous researchers. These include Anderson's Tubes, Anderson's Inclinometer Pegs and Young's Pits. Measurements were also taken of water table levels and of the shear strength of soils at all plots at regular intervals in order to assess how the mechanical properties of soils may change in situ, over short time periods. These changes are related to the temporal patterns of S.M.M. Associated with rapid mass movements such as landslides and mud-flows are slowly deforming soil masses. Several slopes within the catchment area appear to be exhibiting slow deformation. The mechanism of this process has been analysed by simulating the normal and shear forces imposed upon the soil mass in a stress-controlled, undrained, direct shear test. Prom this test the value of the yield stress of the soil can be derived: this is the rnaximum shear stress the soil can withstand without undergoing continuous deformation. By comparing the yield stress with the predicted shear stress occurring in a natural slope it is possible to determine, according to a slope stability equation, whether continuous deformation could occur and at what rate it could proceed. The apparatus was used to determine the contribution that the natural soil structure and plant rootlets make towards strength during slow deformation. Previous analyses have measured either root tensile strength or root permeated soil shear strength. Neither of these techniques is suitable because in the former case the frictional and apparent cohesive strengths of the soil are ignored and in the latter case the forces imposed during testing far exceed those actually encountered in the field. The creep-shear tests allows the tensile and shear components of strength to be combined with realistic shear stresses because the slow rates of strain which occur during testing allow roots to stretch along the zone of failure causing a tensile stress to build up in the roots, thus increasing the apparent cohesion of the soil. The research described in this thesis concentrates on substantiating and amending previous ideas on the rate of slow mass movement, its temporal persistence and on variables which control its action. The investigation is based upon both empirical and theoretical methods with field observations being compared with the results from laboratory experiments and also with theoretical ideas being analysed using data collected from a field experiment.

Problems concerned with the utilization of soil and water are worldwide in scope, but are particularly distinctive in arid zones where high temperatures and dryness can create soil salinity, soil alkalinity, and deficits in the water balance of plants. As a part of the semi-arid zone, the Eastern Jordan Valley suffers from such problems, which are reflected in crop yields and output, and hence in real incomes. During the last twenty years the impetus for the agricultural development in the area has largely come from successive waves of Palestinian settlers. These new immigrants have brought about revolutionary changes in the Agricultural Geography of the region. The increasing pressure of population on natural resources is the most important factor which has led to the search for additional utilization of available irrigation water. Execution of the East Ghor Irrigation Project in the nineteen sixties has aimed at transforming the economic and social life of the inhabitants of the valley. Thus, the present decade represents a transitional period leading to the proper development in the valley. The water resources of the area are discussed, with particular attention being paid to their qualities and quantities, their problems and potentials. The characteristics and distribution of the various soil types are analysed, and particular attention has been given to soil management problems, i.e. salinity, alkalinity and erosion, especially where these problems integrate with the problems of water use. The transformation of the land use pattern and management practices during the last ten years is considered in relation to the capability of lands in the valley, and the new problems which have arisen from recent development are discussed. These considerations lead to an assessment of past and present land evaluation in the study area, and suggest lines for future research and development.

Reactive transport modelling of contaminants in the environment is being increasingly relied upon for a wide range of tasks associated with risk-based decision making, such as interpretation of historical contamination data, optimisation of attenuation and remediation methods, and monitoring of changes resulting from an implemented remediation scheme. However, in the area of contaminant fate and behaviour in bed-sediments, reactive transport modelling has until now stopped short of integration of various mechanistic models to a single modelling environment that would allow a cohesive understanding and prediction of contaminant profiles. This study has developed CoReTranS, a predictive modelling environment that simulates one-dimensional organic contaminant reaction and transport in bed- sediments, using an object-oriented modelling approach. The CoReTranS model has been verified and benchmarked by comparing numerical results of simplified problems with their analytical solutions. The following simulations were undertaken to validate the CoReTranS model: 1. Simulation of the dataset from a diffusion-controlled laboratory experiment for the transport and distribution of selected trace level organic contaminants in a riverine environment gave new numerical results to improve on predicted modelling approach. 2. Simulation of the dataset from a study of marsh sediments contaminated with petroleum-derived hydrocarbons from Wild Harbour, West Falmouth, MA and Kitimat Arm, Douglas Channel, British Columbia resulted in an excellent agreement between the numerical results of the transport model in CoReTranS and the numerical results and data of the original study. The CoReTranS model was also used to interpret results from the following field studies in order to explain key processes that controlled the fate and transport of PAHs and PCBs in bed-sediments: 1. Simulation of the dataset from Kitimat fjord system near Kitimat, British Columbia, wherein PAHs in sediments were purported to be derived from atmospheric particle emissions, wastewater discharges and accidental spillages from a nearby duminium smelter provided a better understanding of the post-depositional reactive transport of PAHs in the fjord system. 2. Simulation of the dataset from a study on the natural recovery of PCB-contaminated sediments at the Sangamo-Weston/Twelvemile Creek/Lake Hartwell Superfund Site in the US showed that it would take nearly 30 years to achieve the 1 mg/kg clean-up goal for total PCB in the chosen transect sites, and 20 years more than the predicted time in the original study. The CoReTrans model was also used to predict the effect of capping contaminated sediments as a remedial strategy. Results from the various simulation scenarios using the CoReTranS model showed that sediment capping as a remedial strategy in managing contaminated sediments can effectively reduce contaminant flux to the overlying water through interaction with the sediment cap matrix and by increasing the dissolved contaminants' transport lengths (i.e., cap thickness). Comparing the results obtained from laboratory experiments or field monitoring studies of bed-sediment systems with different accumulation, degradation and release mechanisms, with the results from the CoReTranS model was critical in identifying the key processes that drive the fate and transport of organic contaminants in bed-sediments. The information derived from the use of the CoReTranS model highlighted recommendations to guide future experiments, field monitoring and model extension which include other relevant transport mechanisms such as colloid- enhanced transport, rate-limited reaction processes and the effect of sediment consolidation to contaminant fate and transport. This information will further enable practical application of such information by engineers to site-specific risk assessment and remediation, as well as continued research and technology development.

Following a review ofthe Mediterranean environment and its development during the late Quaternary, eleven published papers, one paper in preparation, a book (which accompanies the thesis volume) and as yet unpublished data are presented on seven areas of the Mediterranean (in s Portugal, Sicily and Greece). The aims of the research are to consider methodologies in the study of .soils in relation to archaeology (including the relationships between soils, geomorphology and archaeology), and to consider questions of relevance to such research, including a number which have been raised, but not satisfactorily answered, in the wider literature on the Mediterranean. The research comes within the area of geoarchaeology. The studies presented cover a range of spatial scales: single soil profile and archaeological excavation context - the hillslope - river catchmentand broader region. General conclusions in respect of the questions raised include the following. 1. Significant differences in environment and soils occur between the Mediterranean and neighbouring regions arising particularly from climate, but also from other aspects of the environment and human history. Distinctively Mediterranean soils began forming in the Pleistocene or earlier; Holocene soils tend to be weakly de~eloped and similar to soils of cool temperate regions. 2. Geomorphological changes in the physical landscape during the Holocene are generally well defined, if not always well dated. 3. Evidence from much of the Mediterranean points to environmental resilience (an ability to recover from disturbance) rather than 'degradation', though some 20th and 21 st century land use pressures have caused changes that are probably significantly faster and possibly more severe than any during the Holocene. 4. The 'paradox' ofthe Mediterranean - much diversity within elements of strong regional conformity - may result in local factors in environmental change overriding major regional. In many cases, data are not available to permit more than speculation as to the relative importance of anthropogenic versus natural triggers of change during the last five millennia. Intensive, local studies are required to test assertions about major regional effects. 5. For its impact on the archaeological record, 'erosion' must be defined in terms of precise processes and their potential effects in the context of detailed conditions on the hillslope; analysis of valley alluvial sediments, though invaluable in the study of erosion history, cannot fully address these questions. 6. Geoarchaeological analysis requires close integration of archaeological, geomorphological and pedological analyses. Research applying soil information to archaeological diagnosis of excavation contexts also requires a closely integrated, multidisciplinary approach to sampling and analysis, and to intensive computer processing and advanced statistical methods of data analysis.

It is current practice to investigate surficial seafloor sediments by the acoustic technique of vertical-incidence reflexion profiling whether the investigation is done for the purposes of foundation engineering, of underwater sound propagation or pure sedimentological research. Such a technique gives no information about the variation with depth of such properties of the seabed materials as the acoustic velocity and attenuation. Gross changes in these properties can be expected if sediments are gasified or ice-bonded. Comprehensive reviews of what is known about these phenomena are given. Briefer summaries are included of the significance to the fields of engineering and of underwater acoustics, of the acoustic properties of seabed materials. The long-established seismic techniques for measuring velocities on the basis of travel time measurements can be applied to seabed sediments, but require adaptation, particularly in deeper water. The necessary amendments to field equipment and data-reduction technique are described, with results from areas of Maritime Canada and from Lake Erie. A description is given of equipment built to gather 12-channel acoustic data on a scale suitable for the investigation of surficial sediments and results are presented from the Beaufort Sea (Arctic Canada). Application of synthetic seismogramme modelling to these records shows that the acoustic technique when analysed in this way is capable of discovering properties of seabed sediments which are not revealed by either the vertical incidence profile or the travel-time methods of velocity analysis. In particular, a substantially different velocity profile results from this analysis. Suggestions are made for optimising the future gathering of field data for treatment in this way.

It is clear when looking at a gravel-bed river that the flow turbulence is not random: eddies and boils can be seen at the surface. Understanding the behaviour of gravel-bed rivers is limited until the flow structures are described and their origins explained. This work uses a combination of point monitoring of velocity and visualisation of flows over gravel beds in both the field and flume to describe and explain the structure of the boundary layer and the generation mechanisms of flow structures within it. The boundary layer over fluvial gravel beds can be split into two main flow zones. The inner zone consists of eddies developing and shedding off relatively large obstacles clasts and more confused eddying in the inter-obstacle wake zone. There is some evidence to suggest that flow directly above the inner zone is characterised by the domination of negative Reynolds stress associated with the upwards ejection of eddies at higher than average streamwise velocity. The visualisations show that the eddy shedding becomes more confused as the flow rate is increased, and is best described as intermittent. Above the obstacle crests is the outer flow zone in which there are larger flow structures. Visualisations of the vertical streamwise plane and simultaneous logging of velocity at three points suggest that the larger structures consist of inverted wedges of high-speed fluid which move at more than the mean streamwise velocity as "sweep-like" structures. Low-speed fluid is ejected away from the bed after a high-speed front has passed. These structures become increasingly dominant as the flow rate is increased. The high-speed zones appear to be associated with the passage of the front slopes of water surface waves, although this cannot explain some of those monitored in the field. The flow structures are observed to exhibit a crudely intermittent behaviour in the visualisations. Attempts to quantify the intermittency both from the vistlalisations and by time series analysis of both velocity and stress does not produce the clear quasi-periodic velocity signatures that some other workers have found. There is some agreement between the periods of dominant peaks in the spectra of Reynolds stress and calculated burst periods. This is interpreted as meaning that a similar bursting process occurs over mixed gravel beds as that reported over the smooth and uniformly rough surfaces. There is no evidence that eddy shedding produces a periodic signature in either the velocity or stress series. A mechanistic model is proposed which involves the coupling of eddy shedding with the outer flow wedges. In conditions of high relative roughness (or low flow). eddy shedding is predominantly responsible for the generation of turbulent structures in the boundary layer. whereas at low relative roughness (or high flow conditions). the outer zone wedges dominate. This allows the interpretation of flow structure in gravel bed rivers to be made with respect to that observed in sand bed rivers and in tidal flows over gravels. Observations of gravel entrainment in the visualisation experiments suggest that there are two modes of entrainment. At marginal transport conditions. fines are entrained from the wake zones of the larger obstacle clasts by vertical velocity fluctuations. At higher flow conditions, the high speed "sweep-like" structures are responsible for entraining the larger clasts, although the timescale of entrainment is greater that that of an individual flow structure.

The study begins with an examination of the literature, as a result of which it is concluded that the most significant impediment to further progress in the study of sediment transport is ignorance of grain dynamics. A simplified analysis is performed of the trajectory of a grain after dislodgement based on the assumption that the lift it experiences is due to circulation. The resulting grain path represents observed saltation paths with fidelity both in horizontal and inclined flow, but its utility is impaired by high sensitivity to the velocity gradient at the boundary, a quantity which can neither be calculated nor measured with great accuracy. To test the saltation model in an objective way, measurements of bed-load transport rate were made in a closed duct at a variety of angles of inclination and using four different materials. The results are compared with predictions made using the saltation analysis and a theoretical study of limiting equilibrium in the inclined duct. In view of the success of the comparison it is concluded that both the saltation analysis and the study of limiting equilibrium are probably correct in principle. The alternative, namely that both are wrong but that by coincidence they combine to give a reasonable, answer seems unlikely both inherently and by virtue of the observed fidelity of the saltation model. The validity of the study of equilibrium enables conclusions to be drawn about the manner of grain dislodgement. The bed-load transport rates measured in the duct are also-compared with partially theoretical treatments by earlier writers. These comparisons required that shear stress over the mobile bed be measured and this -was done with indifferent success. It is demonstrated that local shear, stress can be measured with a stagnation probe over the bed at the degree of grain mobility studied here. If the instrument-is placed at a nominated multiple of the grain diameter above a bed of uniform grains, then a "universal" calibration can be achieved in the plane Inadequate length of the experimental duct prevented a good calibration being achieved, in the study, yet even the curve obtained in these circumstances may improve on methods of estimating used hitherto. Those results for which direct comparison with earlier work was justified, agreed well with Yalin's prediction and, as might be expected from other work, showed greater bed mobility than would be predicted by Einstein. Little evidence was found that either.bed shear .stress or stream power is clearly to be preferred over the other .as independent parameter in sediment studies. Finally, it is suggested that further studies are needed of the lift force on a grain, of the interplay of this force with diffusion and of dislodgement. The strategies which might be adopted in such studies are outlined.