About
278
Publications
82,755
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
24,106
Citations
Publications
Publications (278)
Natural flood management (NFM) is a method for reducing flooding by using a catchment‐based approach to managing flood risk. Understanding and quantifying the impact of implementing NFM at the catchment scale remains ambiguous with a clear need for robust empirical evidence. A combination of fieldwork, laboratory analysis and modelling was applied...
As the frequency and magnitude of storm events increase with climate change, understanding how season and management influence flood peaks is essential. The influence of season and management of grasslands on flood peak timing and magnitude was modelled for Swindale and Calderdale, two catchments in northern England. Spatially-Distributed TOPMODEL...
Management of upland land‐use has considerable potential for mitigating flood risk by increasing topsoil storage and slowing overland flow. Recent work has highlighted the potential for vegetation to impact the velocity of saturation‐excess overland flow. Woodland creation is widely proposed for Natural Flood Management (NFM), but data on saturatio...
Woodlands can reduce the risk of rainfall-generated flooding through increased interception, soil infiltration and available storage. Despite growing evidence, there is still low confidence in using woodlands as a flood mitigation method due to limited empirical data, particularly for broadleaf woodlands. We measured soil properties and streamflow...
The dominant direct physical processes responsible for desertification are water erosion, wind erosion and salinization. Other threats that degrade the soil include loss of biodiversity, loss of soil organic matter, fire, changing water resources, soil compaction, soil sealing and contamination. Soil management inevitably combines human and physica...
Less attention has been paid to runoff generation from semi-arid than from humid-temperate catchments. The SCS curve number approach is simple to apply and widely used, but lacks physical underpinning. Here output from a runoff generation models is compared with data from field measurements, making use of 11 years data from rainfall and runoff even...
The study of hillslopes has been dominated by the expansion of studies into process rates and mechanisms. Perhaps the greatest volume of work has been on the ‘wash’ processes of soil erosion, but there has also been significant work on the diffusive mass movements of linear and non-linear ‘creep’ that shape the convexity of hilltops, on more rapid...
Land‐use change acts as a potential moderator of flood risk, affecting vegetation and soil properties, and thus influencing the storage and flow of water across landscapes. This study, conducted in northwest England, investigated physical soil properties and their hydrological function using overland flow and soil moisture sensors, for five upland...
Output from a runoff generation models is compared here with information from field measurements, making use of 11 years data from rainfall and runoff events at the Sierra de Enguera Soil Erosion Experimental Station in Eastern Spain.. The model presented simulates overland storm flow on a sloping rough and unvegetated surface, representing an area...
The theory that forms the basis of TOPMODEL (a topography-based hydrological model) was first outlined by Mike Kirkby some 45 years ago. This paper recalls some of the early developments, the rejection of the first journal paper, the early days of digital terrain analysis, model calibration and validation, the various criticisms of the simplifying...
The increased frequency of flood events has motivated interest in natural flood management (NFM), in particular the potential for woodlands to reduce flooding. Woodlands can reduce the risk of rainfall-generated flooding through increased interception, soil infiltration, and available storage. Despite growing evidence, there is still low confidence...
The theory that forms the basis of Topmodel was first outlined by Mike Kirkby some 45 years ago. This paper recalls some of the early developments; the rejection of the first journal paper; the early days of digital terrain analysis; model calibration and validation; the various criticisms of the simplifying assumptions; and the relaxation of those...
The impacts of climate change on soil erosion are mainly caused by the changes in the amount and intensity of rainfall and rising temperature. The combination of rainfall and temperature change is likely to be accompanied by negative or positive variations in agricultural and forest management. Turkey contains vast fertile plains, high mountain cha...
There is considerable interest in how headwater management may influence downstream flood peaks in temperate humid regions. However, there is a dearth of data on flow velocities across headwater hillslopes and limited understanding of whether surface flow velocity is influenced by seasonal changes in roughness through vegetation cycles or managemen...
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, p...
Flood processes in catchments are driven by a combination of rainfall and landscape characteristics. Upland peatlands are source areas of flooding but there is lack of understanding of how different rainfall intensities and temporal patterns may interact with land-cover configurations to influence flood peaks. Using spatially distributed (SD-) TOPM...
A simplified soil model is presented for evolution of the mineral soil profile. The model provides a compromise between highly empirical models and highly mechanistic/geochemical models, and represents some of the main features of observed profiles, with features that can be identified with ‘A’, ‘B’ and ‘C’ horizons. The model is responsive to a ra...
Upland agricultural land management activities such as grazing, vegetation burning and bare ground restoration impact hydrological elements of headwater catchments, many of which may be important for downstream flood peaks (e.g. overland flow and soil water storage). However, there is poor understanding of how these management practices affect rive...
Earth is unique in the combination of abundant liquid water, plate
tectonics and life, providing the broad context within which the critical zone exists,
as the surface skin of the land. Global differences in the availability of
water provide a major control on the balance of processes operating in the
soil, allowing the development of environments...
Earth is unique in the combination of abundant liquid water, plate tectonics and life, providing the broad context within which the critical zone exists, as the surface skin of the land. Global differences in the availability of water provide a major control on the balance of processes operating in the soil, allowing the development of environments...
This paper presents the PESERA-DESMICE integrated model developed in the EU FP6 DESIRE project. PESERA-DESMICE combines a process-based erosion prediction model extended with process descriptions to evaluate the effects of measures to mitigate land degradation, and a spatially-explicit economic evaluation model to evaluate the financial viability o...
In headwater peatlands, saturation-excess overland flow is a dominant source of river discharge. Human modifications to headwater peatlands result in vegetation cover change but there is a lack of understanding about how the spatial distribution of such change impacts flood peaks. A fully distributed version of TOPMODEL with an overland flow veloci...
This chapter discusses the evolution of the framework programmes (FPs) and the key research issues and approaches that evolved through the successive projects that John Thornes was influential in planning and running. For the United Nations Convention to Combat Desertification (UNCCD), desertification means land degradation in arid, semi-arid and d...
The Mediterranean region is particularly prone to erosion. This is because it is subject to long dry periods followed by heavy bursts of erosive rainfall, falling on steep slopes with fragile soils, resulting in considerable amounts of erosion. In parts of the Mediterranean region, erosion has reached a stage of irreversibility and in some places e...
To celebrate World Soil Day 2014, this editorial summary and Special Issue draws together a number of the most significant contributions that have appeared in Earth Surface Processes and Landforms since 2010. As a group they show the increasing importance of interdisciplinary work in this area of overlap, and point to significant opportunities for...
Despite the importance of soil processes for global biogeochemical cycles,
our capability for predicting soil evolution over geological timescales is
poorly constrained. We attempt to probe our understanding and predictive
capability of this evolutionary process by developing a mechanistic soil
evolution model, based on an existing model framework,...
There is global concern about headwater management and associated impacts on river flow. In many wet temperate zones peatlands can be found covering headwater catchments. In the UK there is major concern about how environmental change, driven by human interventions, has altered the surface cover of headwater blanket peatlands. However, the impact o...
Both the rate and the vertical distribution of soil disturbance modify soil properties such as porosity, particle size, chemical composition and age structure; all of which play an important role in a soil's biogeochemical functioning. Whereas rates of mixing have been previously quantified, the nature of bioturbation's depth dependence remains poo...
The paper focusses on connectivity in the context of infiltration‐excess overland flow and its integrated response as slope‐base overland flow hydrographs. Overland flow is simulated on a sloping surface with some minor topographic expression and spatially differing infiltration rates. In each cell of a 128 × 128 grid, water from upslope is combine...
Despite the importance of soil processes for global biogeochemical cycles, our capability for predicting soil evolution over geological timescales is poorly constrained. We attempt to probe our understanding and predictive capability of this evolutionary process by developing a mechanistic soil evolution model, based on an existing model framework,...
The British Society for Geomorphology (BSG), established as the British Geomorphological Research Group (BGRG) in 1960, is considering how best to represent geomorphology and geomorphologists in the light of recent changes in the nature of communication. These changes provide the BSG and other academic societies with challenges and opportunities. S...
In semi-arid environments, the characteristics of the land surface determine how rainfall is transformed into surface runoff and influences how this runoff moves from the hillslopes into river channels. Whether or not water reaches the river channel is determined by the hydrological connectivity. This paper uses a numerical experiment-based approac...
In 2011, the European Council stressed the significance of water quality for sustainable development in Europe and emphasized the need for better integration of the water policy objectives into the Common Agriculture Policy reform in rural areas. Since 2000, the Water Framework Directive (WFD) has required the EU Member States to target good ecolog...
Soil erosion models allow mapping and quantifying rates of runoff depth
and soil redistribution in a wide variety of environments for different
land uses and climatic scenarios. Runoff generation, soil detachment,
sediment delivery and river dynamic are non-linear processes that depend
on many factors, and thus the development of accurate and broad...
From the earliest models for soil erosion, based on power laws relating
sediment discharge or yield to slope length and gradient, the
development of the Universal Soil Loss Equation was a natural step,
although one that has long continued to hinder the development of better
perceptual models for erosion processes. Key stumbling blocks have been:
1....
Although hydrological connectivity can be defined between any two
points, the aggregate response of a hillslope or catchment is often the
practical objective, representing the integral of connectivity between
the many points on which rain falls and the slope-base subset of points
that deliver water to a collector or natural channel. A growing numbe...
Since water resources are scarce across dryland areas, including
Mediterranean Europe and much of Africa, the sparseness of meteo and
hydrometric networks require the application of indirect methods to make
best use of existing resources, and to plan for future needs in a world
of changing climates. Although remote sensing methods may be among the...
This paper shows how, with the aid of computer models developed in close collaboration with decision makers and other stakeholders, it is possible to quantify and map how policy decisions are likely to affect multiple ecosystem services in future. In this way, potential trade-offs and complementarities between different ecosystem services can be id...
Huge potential exist in Africa for surface WH as well as groundwater recharge. Most of the study sites belong to areas with high potential. The teams have the tendency of adopting already existing WH techniques as they do not need extension efforts from the researchers. However, they are very reluctant about the introduction of new techniques from...
Wildfires represent an important agent of land degradation in temperate sub-humid ecosystems, including southern European Mediterranean countries. Identification of integrated conservation approaches that can reduce or prevent degradational impacts is the aim of the EU-funded DESIRE research program, part of which is concerned with quantifying the...
The 18 DESIRE study sites represent a very wide range of climatic
conditions, and the climate exerts the strongest single constraint on
what are appropriate remedial technologies. Under the various climatic
conditions, the greatest constraints on sustainable land use may be
through wind or water erosion, water scarcity, wildfires or frost
damage, a...
Although the concept of connectivity has been increasingly canvassed in
the last 10 years, there have been relatively few, and sometimes
contradictory operational definitions. Connectivity can be reasonably
associated with water flow, sediment transport and ecological habitats,
and either generally or along specific pathways, for example in
hyporhe...
Detailed flume work and field observations indicate that the efficiency
of a vegetated buffer strip is achieved by breaking the continuity or
connectivity of the bed-load. Without continuous bed material sediment
discharge is dependent on material in suspension. With total transport
rates reduced due to the existing vegetation matrix and regrowth t...
The DESIRE project has trialled a series of sustainable land management
(SLM) technologies. These technologies have been identified as being
beneficial in mitigating land degradation by local stakeholders from a
range of semi-arid study sites. The field results and the qualitative
WOCAT technology assessment ftom across the study sites have been us...
The Portuguese territory succumbs yearly to severe wildfires. The years
2003 and 2005 were particularly bad, with some of the worst wildfires
seen in decades. They led to accelerated soil losses in these temperate
sub-humid ecosystems. There is the danger that these wildfires can cause
land degradation. Consequently, there is an urgent need to deve...
Water balance calculations based on gridded monthly climate data offer a
tool for partitioning available precipitation between surface runoff,
soil water storage, evapotranspiration and recharge to groundwater.
Using a dynamic model in which vegetation biomass and soil organic
matter also respond to the availability of water, we can distinguish
reg...
The paper uses a simple water balance model that partitions the precipitation between actual evapotranspi-ration, quick flow and delayed flow, and has sufficient com-plexity to capture the essence of climate and vegetation con-trols on this partitioning. Using this model, monthly flow du-ration curves have been constructed from climate data across...
With only sparse long-term river records, particularly for semi-arid
areas, we have made use of the much better records for climate to
provide estimates of monthly flow from source areas. These have been
expressed in the form of flow duration curves, and the monthly
frequencies of relevant flow stages, focussing particularly on low flow
conditions...
Recently an increasing number of integrated land-use models have become available that support policy making. Inevitably, their model components represent processes that act on different scales and that use different levels of detail to represent those processes. Therefore, it is a challenge to integrate them properly. In this paper we analyse and...
Monthly duration curves have been constructed from climate data across Europe to help address the relative frequency of ecologically critical low flow stages in temporary rivers, when flow persists only in disconnected pools in the river bed. The hydrological model is based on a partitioning of precipitation to estimate water available for evapotra...
The paper uses a simple water balance model that partitions the precipitation between actual evapotranspiration, quick flow and delayed flow, and has sufficient complexity to capture the essence of climate and vegetation controls on this partitioning. Using this model, monthly flow duration curves have been constructed from climate data across Euro...
This commentary brings together, as a virtual Special Issue, a number of recent papers in Earth Surface Processes and Landforms that are all related to issues of scale in soil erosion. Empirical concepts that were developed in the 1940s are now in need of re-thinking, and papers are increasingly exploring, through modelling and measurement, appropr...
Erosion by water is among the most severe threats to soil in Europe. Moreover, delivery of eroded sediment to river channels causes many environmental problems including diffuse pollution, transport and storage of fine sediment and associated contaminants, degradation of aquatic ecosystems, and changes in flow conveyance capacity and flood frequenc...
The probability of sediment deposition per unit distance travelled, or its reciprocal, the mean travel distance, are concepts that help to introduce some rationality into discussions of the relationship between slope length and soil loss. Here we illustrate the complexity of this topic using two very simple sediment transport relationships under sp...
The original application of PESERA was at 1km resolution across Europe. As such PESERA was designed to adopt a pseudo daily time step derived from monthly climate statistics available at the continental scale. Although available at the continental scale some of the climate detail, significant to erosion estimates, was already smoothed. The daily re...
The Earth surface may be seen as the result of coupling a system with
long spatial tele-connections and mainly short response times (the
atmosphere) with a system with mainly short spatial connections and some
very long response times (the landscape). One of the challenges of
quantifying landscape response to climate change is to understand the
pro...
Although forecasting systems have a limited time horizon due to the impact of unforeseen events, a rationally based model is able to provide some insights into likely short term behaviour, taking account of the dynamic interactions between climate, physical processes and land use decisions. The biophysical model (PESERA) takes land use decisions as...
This synthetic review of gully morphology and genesis focuses on incised semi-permanent gully systems rather than on shallow ephemeral gullies. It examines the conditions for gully formation; a sharp step to initiate a headcut, a sufficiently low effective bedload fraction to evacuate eroded material, and the potential to maintain steep sidewalls,...
Climate variability in combination with socio-economic processes acting on the land may induce a reduction of resource potential and hence cause land degradation. Any forecasting attempt to increase societal early warning capacity has to take the interaction between climate and socio-economics on the land into account. The DeSurvey Integrated Asses...
The performance of the Pan-European Soil Erosion Risk Assessment (PESERA) model was evaluated by comparison with existing soil erosion data collected in plots under different land uses and climate conditions in Europe. In order to identify the most important sources of error, the PESERA model was evaluated by comparing model output with measured va...
Using rainfall data at high temporal resolution, runoff may be estimated for every bucket-tip, or for aggregated hourly or daily periods. Although there is no doubt that finer resolution gives substantially better estimates, many models make use of coarser time steps because these data are more widely available. This paper makes comparisons between...
Vegetation biomass evolves to reflect the prevailing climate and soil conditions. However, biomass can be influenced by grazing and agricultural pressure and the resulting equilibrium biomass varies from the potential. Biomass is influential in both runoff generation and subsequent overland flow. The hydrological model at the core of the coarse sca...
Overland flow is an important component of peatland hydrology. Some
peats are dominated by Sphagnum, others moorland grasses and others by
shrubs or bare areas. Management can change the vegetation structure on
the peat. This may influence runoff rates over peatland surfaces.
However, surprisingly little is known about overland flow velocities in
p...
The principles and theoretical background are presented for a new process-based model (PESERA) that is designed to estimate long-term average erosion rates at 1 km resolution and has, to date, been applied to most of Europe. The model is built around a partition of precipitation into components for overland flow (infiltration excess, saturation exc...
Overland flow is an important component of peatland hydrology. Hydrological models of peatlands are being developed that require estimates of flow velocity and its controls. However, surprisingly little is known about overland flow velocities in peatlands. Some peatlands have also been drained using open ditches, and these need to be incorporated i...
Models for the evolution of tectonically active steeplands are commonly constrained by two limitations, the dynamic interactions with valley floor width and the balance between supply and flux limited removal. This paper discusses the implications of using sediment travel distance to provide a transition between supply- and flux- limited models. Wh...
The modelling of complex, dynamic and uncertain socioenvironmental systems requires close collaboration between research disciplines and stakeholders at all levels, for if such models are representations of aspects of reality, how can it be possible to build them without inputs from people who interact with the systems in reality? This paper reflec...
Moorlands are unique environments found in uplands of the temperate zone including in the UK, New Zealand and Ireland, and in some high altitude tropical zones such as the Andean páramos. Many have been managed through grazing, burning or drainage practices. However, there are a number of other environmental and social factors that are likely to dr...
The concept of connectivity is increasingly being applied within a range of disciplines in the Earth and Environmental sciences as researchers recognize the need to move beyond the traditional view that runoff is generated by either Hortonian infiltration excess or by the variable source area model. In studies which focus on connectivity two key as...
Much attention has been given to the surface controls on the generation and transmission of runoff in semi-arid areas. However, the surface controls form only one part of the system; hence, it is important to consider the effect that the characteristics of the storm event have on the generation of runoff and the transmission of flow across the slop...
We are working to improve a hydrological model for prediction of runoff in medium-scale semi-arid catchments in SE Spain. The aim is to develop and improve understandings of runoff generation in semi-arid areas and to improve modelling of runoff. Objectives are to investigate the influence of geology, landuse and seasonality on infiltration rates a...
Discolouration in catchment waters is caused by the release through
oxidation, warming and biological decomposition of the soil. Catchments
that yield highly discoloured waters not only increase treatment and
sludge disposal costs but also risk compliance failures and increase the
potential for Trihalomethane (THM) production; an unwanted byproduct...
IntroductionDriving Mechanisms for Soil ErosionThe PESERA/RDI ModelEvidence of European Impacts from Models and DataConclusions for Impacts of Environmental Change on Soil ErosionReferences
IntroductionRegional Assessment MethodsResults of Pan-European Assessment Methods
DiscussionConclusions
References
SUMMARYA mathematical model for soil profile evolution is developed in three parts; respectively for the weathering profile, the organic profile and for the inorganic profile associated with nutrient cycling. Processes modelled are percolation, equilibrium solution, leaching, ionic diffusion, organic mixing, leaf fall, organic decomposition and mec...
Water, its movement, changes of state, and chemistry, is fundamental to the nature of planet Earth. It is involved in the most important processes near the surface and supports life as we know it. Hydrological sciences potentially address all aspects of water movement and transformation, although with major divisions between hydrology, which is ess...
Most work on simulating landscape evolution has been focused at scales of about 1 Ha, there are still limitations, particularly in understanding the links between hillslope process rates and climate, soils and channel initiation. However, the need for integration with GCM outputs and with Continental Geosystems now imposes an urgent need for scalin...
The Pan-European Soil Erosion Risk Assessment (pesera) model was evaluated using existing soil erosion data collected under various types of climate, vegetation, landscape and soil conditions. The data used represent a variety of typical Mediterranean land uses such as winter wheat, vines, olives and bare, stony land prevailing in hilly areas. Usin...
Nitrogen-saturation and river water N-chemistry is usually evaluated o