Hazel P. Faulkner

Developing a translational discourse to communicate uncertainty in flood risk between science and the practitioner

Abstract The language and tools of risk and uncertainty estimation in flood risk management (FRM) are rarely optimized for the extant communication challenge. This paper develops the rationale for a pragmatic semiotics of risk communication between scientists developing flood models and forecasts and those professional groups who are the receptors for flood risk estimates and warnings in the UK. The current barriers to effective communication and the constraints involved in the formation of a communication language are explored, focusing on the role of the professionals agenda or “mission” in creating or reducing those constraints. The tools available for the development of this discourse, for both flood warnings in real time and generalized FRM communications, are outlined. It is argued that the contested ownership of the articulation of uncertainties embedded in flood risk communications could be reduced by the development of a formally structured translational discourse between science and professionals in FRM, through which process “codes of practice” for uncertainty estimation in different application areas can be developed. Ways in which this might take place in an institutional context are considered.

The role of some site geochemical processes in the development and stabilisation of three badland sites in Almerı́a, Southern Spain

Samples of both surface and subsurface soils were collected on various surfaces in three badland areas of differing ages (Tabernas, Vera and Mocatan), in Almeria province, southern Spain. Data were explored with the aim of identifying any diagnostic geochemical relationships between site EC, pH, sediment size and SAR, which might constitute typical ‘signatures’ for site materials, with some success. Data for the three sites are further used to explore the hypothesis that changes in site geochemistry through time are involved in badland stabilisation. It was found that: (1) the physico-chemical properties of the three sites can be differentiated by the functional relationship between EC and SAR, and this may represent a useful tool in characterising sites where piping predominates; (2) there is some (equivocal) evidence that sediment size distribution may play an additional role in site diagnosis and evolution; and (3) surfaces appear to lose sodium over time, the suggestion being that sodium is either progressively buffered by calcium during leaching, or exchanges with hydrogen on the cation exchange sites under a vegetation cover. Since other research suggests that smectite can also relocate down the profile on some marl sites, reducing hydraulic conductivity and suppressing pipes, we argue that the surface at Tabernas may be capable of long-term autostabilisation in which piping intensity progressively reduces. However, this possibility really applies only to fine-grained, densely structured materials, and evidence from the silty Triassic-rich unit in the Mocatan basin suggests that without a high clay content, piping may be expected to increase through time. From this standpoint, contemporary badland morphology at Mocatan does not represent an early stage of the forms seen in Vera and Tabernas.

Changes to the dispersive characteristics of soils along an evolutionary slope sequence in the Vera badlands, southeast Spain: implications for site stabilisation

In dispersive marls near Vera, badland gullies are eroding into a previously stable matorralcovered landscape. This relatively recent activity was probably triggered by minor climatic or landuse change. In this landscape, Calvo-Cases and Harvey [Earth Surface Processes and Landforms 21 (1996) 725] argued that new gully-head slopes with differing aspect represent a sequence of progressive erosion. Using this interpretation as a basis, slope surface materials were explored for evidence of material (chemical) stabilisation by sampling along profiles positioned centrally on those slopes. The extent to which the inferred geomorphic sequence is paralleled by progressive changes in site geochemistry is considered. Crusts and subsoils differ significantly in terms of pH and Sodium Adsorption Ratio (SAR), but not calcium content. The crust is thus distinctive but not calcic, rather the pH differences suggest a process involving an organic agent, probably algae. Slope position was an important discriminant; taking SAR alone, differences between crusts and subsoils were not significant at the slope base but increased in significance with distance up the profile. Considering differences between the three profiles, the ‘middle’ profile had significantly higher SAR values both in the crust and at depth, than the other profiles, whereas ‘late’ slope subsoils and crusts taken alone are not dispersive (SAR<10), nor are the soils at the base of the other two profiles. Whilst pH increases systematically with SAR up all the profiles, crust pH vs. SAR ‘signatures’ progressively bunch when compared to those of the

Risk communication in emergency response to a simulated extreme flood

Abstract Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties.

Environmental hazards and risk communication

Between April 19 and 21, 2006, a conference on this theme was organised by Middlesex Universitys Flood Hazard Research Centre (FHRC) in collaboration with Middlesexs Centre for Decision Analysis and Risk Management (DARM). This volume represents the conference proceedings of the meeting, which sought to explore the state of risk communication in the context of environmental hazards. The event was sponsored by the Flood Risk Management Research Consortium (FRMRC), a UK-based interdisciplinary research consortium investigating the prediction, prevention and mitigation of flooding. The Consortiums activities are supported by the UK Governments Engineering and Physical Sciences Research Council (EPSRC), in collaboration with the UK Governments Department for Environment, Food and Rural Affairs (Defra), and by England and Wales’ Environment Agency (EA), particularly the Joint Research and Development Programme on Flood and Coastal Defence. The UKs Water Industry Research Group (UKWIR), and the Natural Environment Research Council (NERC) also support the research, which is in two phases. This research has emerged from the FRMRCs phase 1 activities under the Stakeholder and Policy theme.

Comparison of three cation extraction methods and their use in determination of sodium adsorption ratios of some sodic soils.

Cation concentrations are extensively used in soil science to determine a soils potential for dispersion. A number of extraction methods were compared using either ammonium acetate or various ratios of soil:water. The ammonium acetate method extracted the largest quantities of all the cations compared with water extractions and this was especially true for calcium. However, it was concluded that this extraction technique is not appropriate for dispersion studies since it is lengthy and does not mimic field conditions. The water extraction methods were rapid and simple. However, inconsistency was found in the results and subsequent sodium adsorption rate (SAR) calculations where these were expressed using water concentrations that had not been corrected for soil mass. The concentration of cations extracted also changed as the volume of water extractant increased which in turn had a significant effect on SAR. The variation in extraction however was not incremental or linear and diminished above a 1:10 soil:water ratio. It was concluded that for dispersion studies, extraction results should be expressed in terms of concentration per mass of soil, and that extraction ratios of at least 1:10 soil:water should be used.

Spatial and temporal variation of sediment processes in the alpine semi-arid basin of Alkali Creek, Colorado, USA.

This paper develops a simple method of predicting sediment removal during snowmelt and flashfloods in Alkali Creek watershed, western Colorado. The method links successful runoff simulations to field-monitored sediment relationships to predict site yield. The yield data are differenced to derive an index of “scour and fill”, from which it is possible to infer the patterns of erosion and deposition that the stimulated events might produce across the watershed. Site sediment yield patterns produced suggest that even for a basin with this south-facing orientation, the summer storms are geomorphologically ineffective when compared to the amount of sediment transport potentially associated with the melt flows from a stimulated snowpack. Predicted patterns of “scour and fill” are spatially and temporally variable, and are dependent on sediment supply laterally to the network. Scour is extensive at tributary junctions, explaining the overall network concavity. These patterns conform generally with monitored channel change in the network over a 13 year period, and can be contrasted with patterns of sediment yield documented for other climatic types. It is concluded that in this alpine semi-arid environment, the sediment-rich debris removal associated with the decay of a considerable snowpack in the spring months is the most important geomorphic process, and that tributary junctions appear likely to be the most active sites of change. Implications for threshold behaviour in these environments are also explored.

Moderating accurate topographic EDM survey with expert-derived planimetric geomorphological information: a case study mapping soil pipes, Mocatán, SE Spain

Abstract Please click here to download the map associated with this article. This paper describes the mix of methods involved in the development of a detailed geomorphology map designed to facilitate the analysis and interpretation of an area of rapidly eroding soil pipe badlands in the Mocatán basin near Sorbas in SE Spain. Accurate EDM survey data was moderated by inclusion of expert-derived planimetric geomorphological information to produced as accurate as possible a map of the complicated pipe and channel landscape. It is argued here that although the spacing of the topographic data was close, the spline algorithm that generates the topographic contours between pipes can be improved by hand-mapping topography whilst in the field. Whilst the primary aim of the expert was to add in the vegetation cover distribution, fan pipe exits and the 175 entrances, pipe roof-collapse features, and the position of roads, quarry and breaks of slope, the process also adds value to topographic information. Combining the old and new geomorphological tools resulted in a useful and detailed expertly-adjusted map tailored to the needs of the project.

Causes and impacts of serious foulwater contamination: Pymme's brook, North London

The downstream deterioration in macroinvertebrate scores and in levels of key determinands at both low and high flow on Pymmess Brook over a period of 7 years can be related to the pattern of SSO entry and SSO catchment (track‐back surveys). Although the macroinvertebrate scores and other data support the NRA designated 2B class in the headwaters, sudden quality deterioration occurs downstream which in this paper is related to problems of foulwater contamination at one particular SSO during the surveyed period. Escherichia Coli surveys in the middle part of the basin are shown to be primarily related to this foulwater overflow, and the situation is shown to have slightly deteriorated since 1985. Data collected during sample storms suggest, however, that the “first flush” phenomena is responsible for a wide temporal variability in determinand concentration as well as E. Coli count, the latter increasing even further during storms. Proposals to improve the situation via provision of an East Barnet low leve...

The use of the slope-area function to analyse process domains in complex badland landscapes: Process domains in complex badland landscape

This paper explores the effectiveness of the widely-used functional relationship between drainage area (A in m) and slope (S in m/m) to identify local process domains and aid interpretation of process interactions in a complex badland landscape. In order to perform this investigation, a series of sub-basins tributary to the Formone River in the Orcia catchment (central Italy) were selected as a suitable study area within which to explore our questions, given these basins’ general representativeness of local terrain, the availability of a high resolution digital terrain model and previous extensive geomorphological research. Eroding basins containing both calanchi and landslides are common in the sub-humid badland landscape of central Italy, where field observation identifies a complex pattern of erosive processes associated with a history of uplift, despite which parts of the local landscape appear disconnected. Results reveal that the shape of all S–A curves (plotted using S data binned on log A) is comparable with that described in the literature, although sub-basins containing calanchi generally plot with higher S values than non-calanchi ones, except in the ‘fluvial’ section of the plots. Second, when viewed on total data (non-binned) S–A plots, landslide source area domains and calanchi domains are entirely coincident in all basins, supporting a cause–effect relationship. Additional plotting of the frequency characteristics of the raw data in a new way supports the interpretation that calanchi frequently initiate in landslide scars. In general though, although the S–A plots can contribute to the disentanglement of geomorphological behaviour in some complex erosional landscapes, it became apparent that in this landscape, process domains do not separate out with clarity along the A axis as suggested by theory. Despite this, an alternative, broader-scale morphoevolutive model can be proposed for the development of within-landslide calanchi, driven by changes to basin connectivity to the base channel.