Accurate characterisation of the hydraulic environment is a key step in describing hydromorphology at an ecologically relevant scale which has relevance to several aspects of river management, including monitoring river health, designing environmental flows and evaluating river rehabilitation measures. However, current hydraulic habitat quantification methods oversimplify the spatial heterogeneity of the hydraulic environment and do not explain or interpret the spatial arrangement of different habitat units sufficiently or define the dynamics of these shifting patterns. This research applied a novel numerical classification method and a landscape ecology framework to quantify the composition and configuration hydraulic patches in three UK lowland river reaches at five different flows. Five spatially coherent hydraulic patches, defined by the joint distribution of depth-velocity, were optimally delineated from hydraulic point data at each reach using the Gustafson-Kessel fuzzy clustering algorithm. Transitional zones between hydraulic patches occupied between 18- 30% and represent an application of the ecotone concept to the instream environment. Hydraulic patch diversity increased with discharge, peaking at high flow (Q38-Q22), suggesting that the provision of high flows is important for maximising hydraulic heterogeneity. The dominance of shallow, slow patches at low flow was gradually replaced by faster, deeper hydraulic patches at high flow illustrating the effect of discharge on the availability of different hydraulic patch types. The spatial arrangement of patches, quantified using a range of spatial metrics from the field of landscape ecology at two spatial scales (class and reachscape), was relatively invariant to changes in discharge suggesting that the configuration of the hydraulic patch mosaic is determined by channel morphology and remains stable between channel forming discharges. The majority of hydraulic patch types occurred in relatively fixed locations in the channel, moving relatively small distances as discharge increased, associated with the gradual expansion or contraction of patch area. The results suggest that sub-bankfull flow variations will primarily affect the composition rather than the configuration of hydraulic patches, however large fluctuations are likely to result in high rates of patch turnover (change in location), with potential implications for instream biota. The hydraulic patch/transition zone model of the hydraulic environment provides a new approach for exploring the link between physical and biological heterogeneity in the instream environment, including the role of instream ecotones. Whilst the application of numerical classification is currently limited by the large hydraulic data requirement, future advances in remote-sensing technology and hydrodynamic modelling are likely to widen its iii applicability at a range of spatial scales. The results highlight the need for further research on the ecological significance of hydraulic patches and transition zones and ecological sensitivity to changes in hydraulic patch configuration. Wider application of the landscape ecology approach to hydraulic habitat assessment in different reach types is recommended to improve understanding of the links between geomorphic and hydraulic diversity.

A meandering river is one which exhibits a serpentine course, formed by a series of alternating bends connected by short, relatively straight reaches. Meandering behaviour has been found to be ubiquitous in alluvial streams and rivers. The tendency of the bends in meandering rivers to evolve and shift is a natural outcome of interactions between the flowing water, sediment in transport and the resistance to erosion of the boundary sediments. The resulting formation, evolution and shifting of bends is intrinsic to the morphological behaviour of meandering, alluvial streams. The need to understand and predict this behaviour stems not only from the desire to explain the morphodynamics of meandering rivers, but is also required to manage down the risks to property and infrastructure located along the course of meandering rivers, as well as the people who live, work or travel in the vicinity of alluvial streams with meandering planforms. In this context, the aim of this research is to develop an original, scientifically-based, and practical approach to the risk-based prediction of the hazard associated with bend migration that accounts for the uncertainty inherent to the morphological behaviour of rivers. A database compiled for the National Cooperative Highway Research Program (NCHRP) was used as the primary source of data. This includes data for 1,505 bends taken from 125 locations on 89 rivers spread across 24 States.in the USA The rivers were classified into nine categories of meandering, based on a modified Brice Typology. Bend geometry data in the database were measured from aerial photographs and maps representing the bends in the 1930/40s, 1950/60s and 1990s. It has long been recognised that the dimensionless rate of bend migration (M/W) is related to the stage of bend evolution (initiation, growth, translation, termination) and that this can be represented by the ratio of the bend radius of curvature to the channel width (R/W). It was decided to analyse bend migration based on these parameters and use the dimensionless form of the bend radius as the independent variable in the probabilistic analysis. Using normal conditional density functions fitted to the data, rates of meander migration were estimated corresponding to: 50%, 60%, 75%, 80%, 90%, 95%, 97%, 98%, and 99% probabilities of not being exceeded. The risk associated with a hazard depends not only on the probability that it will occur but also the consequences should it do so. In selecting the acceptable level of probability that the predicted rate of migration will not be exceeded, care should therefore be exercised by the user in considering all the possible consequences should this occur.

The potential factor of Mesolithic impact on the vegetation of south-west Scotland from c. 10 000 - 5000 b. p. was investigated by pollen and charcoal analysis of small peat-filled basins and blanket peat near to the sites of lithics and in the context of subsequent vegetational history (from c. 5000 b. p.). Attention focused on upland sites by Loch Doon and Loch Dee. Upland areas by Clatteringshaws Loch and a site at Palnure near the coast provided a late and relatively incomplete record respectively. Two cores were collected at each of Loch Doon and Loch Dee to enable comparison of microfossil stratigraphies. At Loch Doon several cores were analysed across the rise in Alnus. Preliminary counts were made from a core from Loch Doon itself. Radiocarbon dating gave additional confidence to the chronological framework. The availability of comparable pollen data enabled some distinction between local and more regional vegetational events. The charcoal profiles were more problematical to interpret, but the contrast between a very low level of charcoal prior to a rise in the early postglacial (Fl I) at both Loch Doon and Loch Dee may prove to be of regional significance. The strongest evidence for local Mesolithic disturbance came from Loch Dee. The results from the small-basin sites were contrasted with those previously recorded from larger mires and loch sediments.

An understanding of the longstream distribution of hydraulic processes is important for evaluating the mechanisms which control the catchment-scale variation of channel stability, sediment transport and siltation, flood generation and aquatic habitats. However, little attention has been given to quantifying the detailed spatial and temporal variability of channel hydraulic parameters, despite considerable attention to reach-scale processes. This study uses a combined field and modelling approach to define the distributions of channel hydraulic parameters between the source and the near-tidal limit of the River Severn, UK. Field measurements were made at 25 logarithmically-spaced sites along the Severn, under 3 flow conditions (low, medium and high) defined by exceedence frequencies. A flow event, occurring between 15-24 February 1989, was simulated by the 1-D hydraulic model, MIKE11. The simulated reach consists of cross sections spaced at 1 km intervals between 4 km and 254 km downstream from the source. Channel hydraulic parameters showed considerable variability in both space and time, reflecting cross section geometry variation downstream. Mean velocity increased with distance downstream from 0.23 m s\(^{-1}\) to 1.72 m s\(^{-1}\) under steady, bankfull flow conditions. However, unsteady flows simulated by MIKE11 demonstrated a longitudinal decline in the mean velocity of the wave peak associated with the rapid movement and minimal attenuation of the flood wave through the unconfined upper Severn. Flow resistance (Manning's n and Darcy-Weisbach f) decreased downstream from the source (0.32 - 0.06), although under low flow conditions it increased from 0.3 to 1.1 downstream to the non-alluvial - alluvial transition at Llanidloes; thereafter it exhibited a steady downstream decline. Reach mean shear stress and unit stream power peaked near the source (5-10 km downstream; drainage area < 50 km\(^2\)) at 120 N m\(^{-2}\) and 290 W m-2 and further downstream at the Ironbridge Gorge (170 km) (38 N m\(^{-2}\); 40 W m\(^{-2}\)) in response to the lithological controls on channel slope and valley width.

This research investigates what type of actors and organisations are involved in achieving the goal of providing more sustainable high quality urban regeneration in England. The research draws on three key strands of literature including sustainable urban development, development processes and governance. The research gap is where these three strands come together. The thesis explores these issues through the use of case studies in Hafencity (Hamburg) and 22@ (Barcelona) alongside consideration of major projects in England. The main findings of the research show that the continental case studies place stronger emphasis on proactive public sector management of projects (‘positive planning’) than would normally be the case in England. The public sector is able to lead the projects for reasons including land ownership, the planning system, skills in the planning department, use of a local development agency and a more positive and collaborative approach between the public and private sectors involving the appropriate use of power, partnerships and networks. This approach permits greater emphasis to be placed on long term / sustainability issues and helps to balance public interest and private sector gain, both of which could be of interest in the context of achieving more sustainable urban regeneration in England.

Studies of landscape development via primary successional processes are an important area of research for understanding how landscapes evolve into stable, diverse ecosystems. This research sought to assess how geomorphic and hydraulic complexity alter as streams develop following glacial recession. Investigations revealed that younger streams were dominated by fast flowing geomorphic units such as rapids and riffles with little hydraulic or landscape diversity. As stream age increased, however, slower flowing habitat units such as glides and pools became more dominant, resulting in increased geomorphic, hydraulic and riverscape diversity. Determination of these changes in hydromorphic complexity which occur as streams develop, twinned with an assessment of the role of coarse woody debris in creating such complexity at the reach and microscale levels revealed the importance of coarse woody debris in driving these changes. Coarse woody debris was found to influence the development of biocomplexity and interaction between stream, terrestrial and floodplain environments. These changes in geomorphic and hydraulic complexity result in the creation and maintenance of instream habitat which biota such as juvenile Pacific salmonids may utilise.

Glacial sediments, particularly diamicts, can be ambiguous to interpret. Fabric analyses, such as anisotropy of magnetic susceptibility (AMS), have been shown to provide specific information on the formation and subsequent deformation of glacial sediments. In this thesis, detailed investigations utilising the AMS technique have been combined with traditional sedimentological and structural techniques, to help resolve a number of current problems in glacial geology. At the same time, limitations of such uses of AMS have been established. In the modern environment (Tunabreen, Svalbard), magnetic lineations develop parallel to glacier flow and reveal dynamic behaviour during past surges. In a Quaternary glaciotectonite (Bacton Green Till Member, Norfolk, UK), AMS fabric develop in response to glacial deformation and reveal strain vectors that can be related to ice flow from contrasting directions. Finally in Neoproterozoic diamictites (Wilsonbreen Formation, Svalbard), despite local tectonic overprinting and diagenetic change, AMS can be used to reveal a dominant ice-flow to direction to the north. In combination with other sedimentological techniques, this has allowed the identification of glaciotectonic features and an ice-marginal, terrestrial and subaqueous model is proposed. These results support the use of AMS as a fast, objective and accurate technique that can facilitate the interpretation of cryptic glacial sediments.

Predicting contaminant movement in aquifers is essential for the protection of groundwater resources. Contaminant movement is strongly influenced by hydraulic property heterogeneity. The aim of this project has been to determine if hydraulic property values are correlated with geological structures, even if the aquifer is a cemented sandstone: if they are, the correlations could be used in gaining insight into, and quantitatively estimating, solute transport. Example Permo-Triassic sandstone lithofacies associations across England were examined in order to determine common lithofacies geometries. Several thousand measurements of permeability and several hundred measurements of porosity were determined on a core from northern England and two outcrops from the Midlands in order to examine correlations with lithofacies. Two types of synthetic fluvial multiple channel systems with flow a long and across channels were then numerically simulated to determine the significance of the correlations found. Results indicate that the Permo-Triassic sandstones have a wide range of lithologies and permeabilities, varying between and within sequences and regions. Permeability is generally greater for aeolian sandstone than for fluvial sandstone. The borehole core stud y shows that lithofacies correlate with porosity, permeability, and permeability to porosity ratio, though some significant overlaps occur for permeabilities of the three coarser lithofacies. Mudclasts can reduce sandstone permeability of the two coarser lithofacies by up to 6 % and 8% respectively. Markov chain analysis indicates that the sequences of lithofacies are structured, and hence the permeability is also similarly structured. The two outcrop studies confirm that permeability structures vary more between than within beds. Solute transport modelling indicates that differing solute breakthrough patterns will occur with different types of hydraulic property distributions based on lithofacies geometry. Thus lithofacies correlations can be used to help predict solute movement, but transverse dispersion, not explicitly studied here, also appears particularly important. Generally, the heterogeneous porous medium can be reasonably represented by an equivalent homogeneous medium for prediction purposes, however determining appropriate properties for the equivalent homogeneous medium is challenging.

Chalk streams are of high ecological value and are dependent upon groundwater discharge to support flows. This study investigates chalk stream-aquifer interaction, focusing on a near-natural catchment; the River Lambourn of the West Berkshire Downs. The topographic catchment of the Lambourn is 234km², principally underlain by Upper Chalk. The river has a perennial length of c.16km, and a 7.5km seasonal section. Temporal dynamics of the recharge-storage-discharge sequence are investigated using linear regression techniques to identify the lag between recharge and discharge. The effective maximum duration of groundwater flow is 9.1 months, which is used with regional hydraulic gradients to calculate a bulk (interfluve) hydraulic conductivity of 114m/d (using Sy=1%), suggesting that interfluve permeability has been historically underestimated. Spatial flow accretion on the Lambourn is defined from 12 reaches (each 1-2km long), exhibiting mean accretion rates between -0.019 and 0.211 cumecs/km. The accretion rate profile approximates a sinusoidal pattern (λ=12km) suggesting a catchment scale litho-structural control. However, local topography and lithology also exert influence. High accretion rate reaches are associated with major dry valley intersections and elevated valley floor permeability, whilst the presence of Chalk Rock at shallow depths restricts local accretion.

This study investigates the current impact of acid deposition on the structure and function of benthic communities in streams of contrasting pH in mid-Wales, UK, and examines barriers to biological recovery across the sites. The results of field surveys across 30 streams revealed sustained effects of acid stress on macroinvertebrate assemblages. Acid streams supported fewer grazers and filter-feeders than circumneutral waters but other functional groups were less affected by low pH. Field experiments tested the effects of acidification on two key processes in stream ecosystems, benthic algal grazing and leaf decomposition. Grazer impacts on algal abundance were generally feeble and largely unaffected by acid stress. Leaf litter decomposition was impaired by acidification, due largely to reduced microbial breakdown. Prospects for biological recovery in chemically restored streams are discussed, and field experiments were undertaken to test two hypotheses (biotic resistance and resource limitation) proposed to explain the observed delays in faunal recolonisation. A resident-colonist competition experiment revealed no evidence in support of biotic resistance as mediated through interspecific competition, whereas growth experiments revealed that the quality or palatability of algal resources in chemically ‘restored’ streams limits growth and survival of colonist mayfly nymphs (Baetis).