Water

Abstracts from the 36th Flood and Coastal Management Conference (2001)

Please see the main Conference page for details of ordering Conference proceedings or individual papers. Unfortunately the full proceedings for this conference are no longer available. Please note that the views expressed in Conference papers are those of the speaker and do not necessarily represent Defra views or Government policy.

Session 01: ENVIRONMENTAL IMPACTS AND APPRAISAL

01-01: Implementation of the Habitats Regulations – A Case Study at Pett Level, Sussex

By: Rachel Fowler HALCROW GROUP LIMITED

The Habitats Regulations have introduced a major change in the planning and implementation of coastal defences around the UK coastline. Achieving compliance can be expensive and time-consuming. It is therefore essential for issues relating to European nature conservation sites to be identified at an early stage of strategy and project planning, since there may be fundamental implications for the way in which projects are designed and implemented. Both the studies required to demonstrate compliance with the Regulations and the mitigation or compensation measures that may be needed to achieve compliance are likely to add significantly to the time scale and budget required for preparing projects and securing consent.

01-02: Restoration of the Pevensey Levels SSSI

By: Richard Hull ENVIRONMENT AGENCY

The Pevensey Levels SSSI and Ramsar site, one of the largest lowland wet grassland systems in the south is a prime example of a nationally important conservation site where interest has declined due to historic land drainage and flood defence activities. This paper describes the approach taken by the Environment Agency in funding a collaborative project aimed at restoring the conservation value of the site to preserve its designation. The project has been integrated into English Nature's Wildlife Enhancement Scheme and is intended to provide a simple solution for landowners wanting to enter land into management agreements where this will benefit the key species protected by the designation.

01-03: The Application of Environmental Valuation in Flood and Coastal Defence Decision-Making

By: Paul Murby THE WILDLIFE TRUSTS

Environmental economics offers two broad approaches to dealing with environmental problems: 1) market correction and 2) market constraints or standards. The European Habitats Directive and UK Biodiversity Action Plan are conceptually based in the latter. This has implications for environmental valuation in flood and coastal defence planning and investment. The establishment of a minimum standard of no net loss disposes of the reason for deriving proxy monetary valuations of the features to which the standard pertains. The cost of measures necessary to meet standards remain germane to the decision making process. However, this should be established by compliance cost assessment - a far more straightforward technique proxy monetary valuation, which does not require the in put of controversial monetary valuations for environmental assets. The Treasury's Green Book provides clear guidance on this matter but MAFF's Flood and Coastal defence Project Guidance is somewhat less clear.

01-04: International Habitat Management, Creation and Restoration Experience Relevant to Flood and Coastal Defence

By: Jan Brooke ENVIRONMENTAL CONSULTANT

Many flood and coastal defence schemes incorporate an associated habitat restoration, improvement or creation initiative, especially where designated nature conservation sites will be affected by the construction or operation of the defence. The 1994 Conservation (Natural Habitats, &c.) Regulations (the "Habitats Regulations") set out the requirements for habitat mitigation or compensation where European sites are likely to be detrimentally affected. Two forthcoming reports prepared by the International Navigation Association (PIANC) are likely to be of interest to those involved in designing such habitat mitigation or compensation measures. The PIANC Environmental Commission's Working Group 2 is due to publish a report later this year providing international guidance on the management of bird habitats, and Working Group 7 is completing a technical report describing best practice with respect to the creation and restoration of wetland habitats.

01-05: Porlock Shingle Ridge and Marsh: 5 Years On

By: Nick Stevens ENVIRONMENT AGENCY

Porlock Bay and shingle ridge is located on the north coast of Somerset some 9 kilometres to the west of Minehead. The coast in this area is generally formed by cliffs fronting hills, which rise steeply to 400 meters on Exmoor. At Porlock the hills are set back from the coast between Gore Point to the west and Hurlstone Point to the east, a distance of some 5 kilometers. Between these points Porlock Bay has formed with a shingle ridge to the landward edge which provides some protection to the property at Porlock Weir and the low-lying land of Porlock Marsh. Over many years, dating back to the early nineteenth century various authorities and landowners have worked to actively maintain the ridge as a sea defence against the flooding of Porlock Marsh. The work was in part successful with both agricultural and recreational use of the marsh occurring during much of this period. There have however been several breaches of the ridge leading to significant flooding on each occasion, each requiring a more extensive restoration than the previous. Following a lengthy consultation period the Local Flood Defence Committee decided to cease maintaining the ridge and to allow natural processes to prevail. On 28 October 1996 the remnants of Hurricane Lily reached the British Isles and the storms that ensued caused the ridge to be breached with consequent loss of its function as a sea defence. This paper briefly outlines the administrative process that led to the decision to cease maintaining the ridge and summarises the changes that have occurred to the natural environment in the Bay.

Session 2: PUBLIC CONSULTATION AND DISSEMINATION

02-01. The Consultation Process - Purpose and Practice

By: Peter Barham ENVIRONMENT AGENCY

The background to many aspects of public works is that, by and large, decisions about them were taken by people in positions where the authority to carry out work was part of the job. Associated with this was a general understanding that without specialist knowledge the general public could offer no valuable contribution. It could also be argued that even with appropriate knowwledge, contribution from those outside the decision making process was not sought or welcomed. Linked to this was a general understandin that those in aythority knew what ther were doing and were acting in the public interest. In recent years this is no longer the case. There are a number of possible reasons for this and it is worth examining them because to do so gives good pointers to mechanisms for resolving them. …………. Through describing the consultation process and case studies of its application, this paper sets out to show that consultation is not only essential, but if handled well can add real value to the appraisal process.

02-02. Participatory Planning in Coastal Defence: A Pilot Study from the Baltic Sea Coast of Germany

By: Dr Jacobus Hofstede SCHLESWIG-HOLSTEIN STATE MINISTRY FOR THE RURAL AREAS, STATE REGIONAL PLANNING, AGRICULTURE AND TOURISM

Modern society increasingly demands for a more comprehensive and active participation of the (affected) public to planning and decision making procedures (FÜRST et al. 1998). The existing methods and regulations for the establishment of public plans already include procedures to consider private (and other non-governmental) interests. These are, however, all of a more reactive nature. The responsible authority creates a plan on which affected private persons as well as certified ngo´s may comment. No formalised instruments exist for private persons to actively contribute to the development of public plans. As a consequence, reactions are often negative. A time-consuming and costly adaptation of the original plan may become necessary. In response to this demand, new planning methods are developed by the scientific community that aim at optimising public participation (FÜRST et al. 1998). Participatory planning seeks to consider and integrate all relevant interests in the planning procedure. This active co-operation leads to engagement and shared responsibility of the involved persons, contributes to the recognition of the real problems, and may result in acceptable solutions (EUROPEAN COMMISSION 1999). The coastal defence administration in schleswig-holstein faces the challenge to safeguard the inhabitants of the coastal lowlands against catastrophic flooding during storm surges and land loss by coastal erosion. Partly different from great britain, the authorities have the legal obligation to, e.g., Build and maintain sea walls that are in the public interest, and protect settled (built-up) coastlines against irreversible land loss. Owners of protected land may be summoned to the costs for building and maintenance according to their benefits. In all, about 345,000 people and economic assets of 46 thousand million euros are concentrated in the flood-prone lowlands along the about 1,200 km long baltic sea and north sea coasts of schleswig-holstein (HOFSTEDE AND HAMANN 2000). As in other public sectors, the demand for active participation in the planning of measures is increasingly being forwarded to the coastal defence authorities. In response, they financed a pilot study in which a new method to actively involve private persons in the development of plans was tested.

02-03. The Geology and Geomorphology at Birling Gap, East Sussex: The Scientific Case Against Coastal Defence

By: Roger Moore HALCROW GROUP LTD

In July 2000, a public inquiry was held to consider two applications for coastal protection works at birling gap, east sussex. The first application was an appeal and the second was called-in by the secretary of state on account of the apparent contravention with the statutory local development plan, shoreline management plan and national planning policy guidance. The schemes proposed conflict with an array of national and local designations, aimed at protecting the conservation and scientific interests at the site. The case raises important issues regarding human rights and the management of private defences on coastlines designated for their outstanding natural beauty. Birling gap is a palaeo-dry valley truncated at the coast by marine erosion. The valley is situated between high chalk cliffs on either side that form part of the 'seven sisters', a nationally and internationally recognised coastal landform. The paper focuses on the scientific importance of the site with regard to the potential impacts that either scheme would have on the geology and geomorphology at the site and on the adjacent coastline. An overview of coastal processes is supported by an assessment of historical coastal change at birling gap to evaluate the potential direct and indirect impacts that the proposed works would have on the natural development of the coastline. The harm that would be caused to the geological and geomorphological interests at the site is addressed.

02-04. Coastal Collaboration (Working Together for Coastal Defence)

By: Nicholas Pettitt POSFORD DUVIVIER

Legislation in the uk today provides a framework for the protection of the coastline. The water resources act, land drainage act and environment act created the environment agency and defined its tasks; the coast protection act does likewise for coast protection authorities. In recent years the european habitats directive and subsequent uk habitat regulations have provided further legislation with which operating authorities must work, and the champs initiative will also soon take effect. By rigidly defining roles, legislation greatly influences the fluidity of the coastal management and defence approach. At last year's maff conference there were several calls for more legislation, to help the coastal managers - an avenue which maff were keen to avoid. Alternatively, less legislation but more guidance may allow the development of freer, lateral thinking, and innovative solutions. This paper considers the case study of felixstowe ferry on the suffolk coastline, where the combined problems of flooding and erosion bring together the above legislation. It discusses a number of specific issues that have been encountered during the process of applying this legislation, and suggests a way forward for the regulators of flood and coastal defence.

02-05. R&D Introductory Note: Policy Development Theme

By: Mike Child R&D THEME LEADER

The policy development (pd) theme covers a very wide area of interest and is summarised in the following statements:

Summary objective To undertake wide-ranging research into policy development issues (organisation and management; people and communication; land use and development; economic appraisal and environment and biodiversity).

Key customer purpose To facilitate the adoption and implementation of' policy' measures, which improve understanding, reduce risks and costs, and, most importantly, improve decision making resulting in better value for money.

The pd theme covers many non-traditional areas of research and development, such as organisation, management, communication and people. The importance of such areas is being increasingly recognised: flooding is about people not water and protection is about managing the risk not just building new defences.

It includes many topical areas for action identified in recent reports: for example, in the lessons learned: autumn 2000 flood report, consistency in defence standards, greater awareness and participation by communities and the public, and consideration of health and social impacts not just benefit/cost ratios in scheme appraisal.

There are many other 'drivers for change' in addition to the lessons learned report: the national audit office report on inland flooding and the funding review (september 2001) to name just two. The challenge for the pd theme will be to keep abreast of these 'drivers' and to develop a real user-lead work plan and programme of projects.

Session 3: CLIMATE CHANGE - PREDICTING AND MONITORING THE EFFECTS

03-01. Climate Change: State of the Art of Global and Regional Modelling

By: Jonathan Gregory HADLEY CENTRE, THE MET OFFICE

Climate change due to the enhanced greenhouse effect is one of the most significant global environmental issues facing the world today. Predictions of such changes depend principally on the use of computer models of the global and regional climate system. The aim of this paper is briefly to describe the capabilities of these models and to show some relevant results from the Hadley Centre. Increases to the probability of heavy precipitation events and extreme storm surges may lead to increased risk of severe flooding. This is among the important impacts of climate change on society.

03-02. The UKCIP02 Climate Change Scenarios: Contents and Application

By: Iain Brown UK CLIMATE IMPACTS PROGRAMME

The UK Climate Impacts Programme (UKCIP) has a remit from DETR to provide decision makers with the information they need to plan for climate change. This paper provides the context for future climate variation by linking it to the evidence for changes occurring now. Then it introduces the technical advances featured in the new UKCIP02 scenarios. Spatial and temporal resolution have been considerably improved compared to the UKCIP98 scenarios, making the new scenarios more suited to local impact assessments. The enhanced resolution also means that more information is available on changes in extreme events and climate variability. The latter topic has been neglected in most impact assessments to date, and it is proposed that for coastal and river catchment impacts this deserves more attention, using full scenario ensembles. Developing effective strategies for adapting to climate change also needs transparent declaration of the chain of uncertainties involved in the impact assessment. This requires a move towards more probabilistic risk analysis using climate change scenarios.

03-03. Climate Change and Region-Specific Changes in Storm Depth and Frequency: Impacts on Flood Alleviation Scheme Design

By: Murray Dale THE MET OFFICE

It is generally accepted that the British climate is changing and that there has been an increase in the proportion of winter rainfall and intense storms. This trend is set to continue in the 21st Century. However, predicted precipitation changes differ from region to region in the UK and there are predicted to be variations in the intensity and frequency of storms. Met Office research carried out recently for one of the larger UK water companies showed that the magnitude of 24 hour rainfall events was set to increase by 15 to 20% by 2080 whereas the 1 hour rainfall events were predicted to increase by 20 to 40% in 2080, for the company's region. Such predictions are the result of increased carbon dioxide emissions alone: changes in rainfall and flooding in the future are also likely to be influenced by natural forces in the atmosphere and changes in the antecedent condition of catchments. With such variations in future rainfall coming to light, it is important that engineers have access to region-specific rainfall information to be able to design effective and robust flood alleviation schemes for the future.

03-04. Integrated Effects of Climate Change on Coastal Extreme Sea Levels

By: Roger Flather PROUDMAN OCEANOGRAPHIC LABORATORY

The possibility that future climate change could have other impacts, e.g. from changing "storminess" - the frequency, duration and severity of storms - was mentioned, but it was not considered possible to quantify its effects for routine application. The general assumption is therefore that trends in extreme sea levels will be the same as those in MSL. Clearly, there may be substantial cost implications if this assumption is not correct. Guidance on and quantitative estimates of changes in extreme sea level round UK coasts resulting from climate change, including indications of uncertainty, would therefore be valuable. The work described here aims to derive guidance on changes / trends in extreme sea levels from existing information.

03-05. GPS Monitoring of Changes in Groud Level for Flood and Coastal Defence

By: Richard Bingley IESSG, University of Nottingham

The development of GPS techniques for monitoring changes in ground level have been on-going at the IESSG since 1990, based on research funded by both MAFF and the Environment Agency. On a national scale, GPS is being used to monitor changes in ground level at coastal tide gauges in order to obtain improved estimates of long term changes in sea level. On a more regional scale, GPS is being used for monitoring changes in ground level in relation to the flood defences of the Thames Estuary.

03-06. Coastal Defence Vulnerability 2075

By: James Sutherland HR WALLINGFORD LTD The Coastal Defence Vulnerability 2075 (CDV2075) project has produced methodologies that allow the assessment of the likely change to coastal flood and erosion risk over a 75 year timescale. This is intended to inform the future planning of defence needs and any adaptation strategies. The methodology has been applied to five example sites and its use is demonstrated at one site here. The relative effects of increased mean sea level, future wave climates, raising the crest height of a seawall and coastal steepening are demonstrated. This paper reports on ongoing work that is intended to influence MAFF's long-term view of the possible changes to coastal defence vulnerability. The method is, however, driven by only one realisation of one climate change scenario from one model and conclusions are restricted to the site and climate scenario used.

03-07. A Short Introduction to the R&D Programme in Risk Issues

By: Ian Meadowcroft R&D THEME LEADER

This short paper provides an introduction to R&D to be carried out in Theme 5 of the combined MAFF / Agency Programme. The Theme, 'Risk Evaluation and Understanding of Uncertainty' (REUU) is centred on assessing risk and making decisions. It will include development and implementation of a range of approaches for identifying and assessing risks, accounting for uncertainty, and arriving at appropriate decisions.

The Theme is divided into four Sub-Themes:

  •  5.1 Risk and Uncertainty
  •  5.2 Climate Change
  •  5.3 Data and Information
  •  5.4 Performance Evaluation

Risk assessment and management is gaining higher prominence in government. Departments and non-departmental bodies publish their approaches to risk and are sharing information on best practice in risk management.

Session 4: CLIMATE CHANGE - ESTIMATING THE IMPACTS

04-01. Combined MAFF/EA Flood and Coastal Defence R&D Programme: Broad Scale Modelling Theme

By: Edward Evans R&D THEME LEADER

Numerical models are used throughout the full spectrum of activity in flood and coastal defence, supporting both policy development and the planning and design of defence solutions. In recent years such models have become progressively larger and more complex in the number of parameters and facets they are able to deal with. This overview describes the subject areas that are covered by the Broad Scale Modelling (BSM) Theme within the combined MAFF/EA Flood & Coastal Defence Research and Development (R&D) Programme, based on the Report of the Advisory Committee on Research and Development: Penning-Rowsell Report (referred to hereafter as the P-RR).

This Paper covers the period up to April 2001. It includes theme development and the formulation and approval of the New Starts R&D programme for 2001-02. An important Workshop covering the whole theme, supported by five review papers on Whole Catchment Modelling (WCM), Estuaries, Coastal, Socio-economic and Eco-system BSM was held on 30 January 2001. In recent months the joint MAFF/EA programme of Catchment Flood Management Plans (CFMPs) has come to the fore. In order to support this the WCM 'demo project' included in the New Starts has been accelerated and widened with the help of additional funds from the CFMP programme. This provides an exciting opportunity for the research community to make a direct key contribution to an important national initiative.

04-02. A National Economic Appraisal of the Impacts of Flooding and Coastal Erosion Considering the Potential Impacts of Climate Change

By: Robert Deakin HALCROW GROUP LTD

Research commissioned by MAFF has examined different scenarios of defence standard provision at a national level. This work has been used to assist in policy formulation with regard to defining Government spending levels on the provision of flood and coast defence. The MAFF report "National Appraisal of Assets at Risk from Flooding and Coastal Erosion" (MAFF, 2000) details the findings of this research. A second phase of research has now been commissioned to refine the analysis techniques employed, improve our knowledge of actual standards of service and to examine the potential influence of climate change on the economic impacts of flood and erosion damage. By being able to better spatially resolve areas susceptible to greatest economic loss the research is intended to better inform decisions taken on investment in defences. This paper sets out details of the methods introduced to assess the economic impacts under climate change scenarios and those used to examine the economic impacts on agriculture. Preliminary results are presented for the calculated economic impacts of climate change on built property damages, and of those to agriculture in respect of foregone production under a "Do Nothing" flood defence management strategy. Further information will be made available at the conference and in the succeeding paper.

04-03. Predicted Implications of Climate Change to Future Levels of Protection Offered by Fluvial and Coastal Flood Alleviation Schemes in Scotland

By: David Price BABTIE GROUP

This paper reports upon a project commissioned by the Scottish Executive to investigate the likely implications of climate change projections on the levels of flood protection offered by both coastal and fluvial flood alleviation schemes. Climate change projections of the key flood related factors are reviewed and set in the context of observed trends. Analyses on projected future fluvial and coastal flood risks for Scotland are presented. In general fluvial floods that are presently likely to occur with an annual probability of 1% are projected to become more frequent in the future with equivalent flood flows having annual likelihood of about 1.4% - 1.7% by the 2050s, and 2% by the 2080s. Coastal water extreme levels that were evaluated in 1990s as having a 1% annual likelihood of occurring are projected on average to become 5 to 10 times more likely by the 2050s. The uncertainties and assumptions that underlie these provisional estimates are discussed and highlighted.

04-04. The Regional Impact Study (RegIS)

By: Robert Nicholls FLOOD HAZARD RESEARCH CENTRE

The objective of the Regional Impact Study (RegIS) was an holistic, stakeholder-led evaluation of the potential impacts of climate change, by developing and applying an integrated methodology for agricultural, hydrological, biodiversity and coastal-zone sectors (Holman and Loveland, 2001). The methodology was applied to two contrasting regions: (1) East Anglia (Cambridgeshire, Norfolk and Suffolk) and (2) North West England (Cheshire, Greater Manchester, Merseyside, Lancashire and Cumbria). The implications of the UKCIP98 climate change scenarios and two contrasting socio-economic storylines developed within RegIS were analysed for the 2050s. This paper focuses on one component of RegIS: the impacts of climate change in terms of increased flooding along coasts and rivers and possible changes in the distribution of coastal ecosystems (saltmarsh and coastal grazing marsh) (see Figure 1). For more details see Chapter 5 in Holman and Loveland (2001). For each scenario combination, standard impact models were used to evaluate the potential impacts without any human adaptation to determine the worst-case impacts. The potential for adaptation to counter the identified impacts is also evaluated in a more qualitative manner. This includes considering the benefits of existing project appraisal guidance for climate change (MAFF, 1999). Finally, the implications for long-term flood and coastal management and future research needs are considered.

04-05. Assessing the Impacts of Climate Change on the SCOPAC Coast

By: Adam Hosking HALCROW GROUP LTD

The anticipated implications of climate change and sea level rise present a significant challenge to future coastal management to address increased levels of risk to many coastal assets. This paper describes the first stage of a study, commissioned by SCOPAC, to inform coastal managers, along the central south coast of England, of the likely impacts, and their implications for future management. The paper considers the impact of changes in sea level, nearshore wave climates and effective rainfall as predicted in published climate change scenarios. These are applied to the Geomorphological characteristics of this length of coast and examples are provided of the possible impacts on coastal behaviour and potential for coastal change. The final output from this first stage of the study will form a series of generic coastal impacts of climate change based on the Coastal Behavioural System types identified in the SCOPAC region. These will be developed for example sites to define the exact nature of potential climate change impacts and will provide input to the second stage of the study.

04-06. Towards a Design Winter - Design Dilemmas

By: Taquir Ishaq WS ATKINS CONSULTANTS LTD

Currently, statistical design for river and coastal engineering cannot easily be addressed within a risk based philosophy as it concerns a non-stationary dataset with limited historical data. There is also an inconsistent and unscientific approach as to the use of safety margins and where and how these can be most effectively applied. Before we can explore some of the processes required to determine a 'design event' or indeed a 'design winter' it is necessary to examine the philosophy of design and the weaknesses in the design process within the context of climate and climatic change. We can then consider extending our understanding of 'design storms' to accommodate a series of events over an extended period. This time frame could be several months but could be a number of storms over a few weeks or days. This paper explores these issues using comparisons with structural design philosophies and examines the difficulties in the pure statistical approach currently adopted. Risk assessment procedures require all relevant items to be identified and valued but in the case of river and coastal engineering, it is difficult to assign a value to the uncertainty of existing and future climate regimes and how representative past datasets are in this regard.

04-07. Modelling Environmental Change Impacts on River Flow

By: John Packman CEH WALLINGFORD

Widespread floods during the autumn and winter of 2000/2001 heightened public awareness of the concept of climate and land use change affecting river flow. Many words appeared in the national and local press, and images on the television, linking global warming with an increase in flood frequency and several theories were expounded concerning the possible impacts of changes in agricultural practices on runoff processes. The climate is continually changing and has always varied over a range of temporal and spatial scales. However the evidence, from statistical and model based evidence, is that the human element of climate change is now detectable and becoming more important relative to natural climatic variation. This paper considers for one catchment, The Thames, the impacts of possible future climate and land use change and how these changes relate to changes over the previous 100 years.

Session 5: STRATEGIC APPROACH TO COASTAL ISSUES

05-01. The Fluvial, Estuarine and Coastal Processes Theme: The Way Forward

By: John Pos R&D THEME LEADER

The underlying objective of research in the Fluvial, Estuarine and Coastal Processes Theme is to be able to describe and quantify all the important processes that contribute to the evolution of fluvial, estuarine and coastal systems. This is required in order to enable the development of technically feasible, and environmentally acceptable, flood and coastal defence schemes and operations, which are sustainable in the long term. The Theme aims and objectives have been described in more detail in the MAFF Flood and Coastal Defence Newsletter No 12 of January 2001. This newsletter also lists the Processes Theme Advisory Group (TAG) members. The TAG performs a very important function in guiding the development of the Processes Theme R&D programme.

05-02. Strategic Monitoring of the Coastal Zone - Towards a Regional Approach

By: Andrew Bradbury NEW FOREST DISTRICT COUNCIL

Recommendations from shoreline management plans and coastal strategy studies have consistently identified a requirement for development of coastal monitoring programmes. The current approach to coastal monitoring is generally adhoc, both within individual Coastal Groups, and on a wider regional basis; it is recognised that some extremely good local monitoring programmes are in place, however. Although there are a few existing regional monitoring initiatives, these need to be co-ordinated and integrated within a cohesive regional framework, to maximise use of data and to provide best value. This paper summarises the principle findings of a scoping study based upon current practice within the Southeast of England, to discuss proposals for an integrated regional approach to coastal monitoring; it also indicates how Coastal Groups are taking the proposals forward.

05-03. Making the Link Between Strategies and Shoreline Management Plans

By: Ben Hamer HALCROW GROUP LTD

Following work on numerous Strategy Plans, the authors have encountered several issues that are considered to be of value to inform the review of Shoreline Management Plans, shortly to commence for the majority of the coastline of England and Wales. A lack of consistency has been identified in the definition of boundaries for strategic studies, which can lead to overlapping, or conflicting studies of coastal processes. In some cases, the definition of strategy boundaries may lead to a change in the preferred management option that is identified. In one case study on the south coast of England, substantial savings to the public purse may be identified through co-ordination of several Strategy Plans with a strong process link. The paper picks up the theme set down in FCDPAG2, which states that: "They {Strategy Plans} are a vital link in the feedback chain, which should ensure that the benefit of expertise and knowledge gained is actively used in the development of future strategic planning including large scale plan reviews (eg SMPs)." Recommendations are provided for consideration by client groups, when undertaking the scoping stage of Shoreline Management Plan reviews.

05-04. The "Legal" Impacts on Coastal Structures

By: Roger Maddrell HALCROW MARITIME

Many significant Coastal and River Structures have been built in Britain in the last 2,000 years. They have ranged from relatively small wooden pile structures and the earth embankments that reclaimed salt marshes in the Middle Ages, to the major ports and coastal structures that we see today. In terms of coastal engineering perhaps the structures that had the most impact were those built in the Victorian Period and soon after. These structures were built at a time when man thought that he could control the environment and the structures were simply aimed at withstanding nature. We are now being forced to live with that legacy. Their designs were in part trial and error, although with significant safety factors in many cases, which is why they are still standing. In the second half of the last century there was a gradual realisation that the more you fought against nature, the higher your costs and the greater the adverse impacts and risks. This does not mean, however, that modern structures do not impact on the environment, but their design must be a balance of benefits against potential adverse effects. This paper is based on the experience gained during a case presented to the Lands Tribunal in October 1998 (LCA/143/95).

05-05. Shingle Bypassing - Solving an Erosion Problem

By: Tony Vaughan SHOREHAM PORT AUTHORITY

In 1987, Shoreham Port Authority took over responsibility for the maintenance of two kilometres of beaches along the port's frontage. These beaches, located downdrift of the harbour entrance breakwaters, had suffered a considerable reduction in shingle volumes and were severely eroded. In addition the timber groynes and sea wall were in poor condition. Following a Coastal Management Study carried out in 1990, the Port Authority adopted a strategy of a phased replacement of the timber groynes with a series of rock groynes, and with infilling of the groyne bays using dredged shingle. To counter the effects of erosion downdrift of the entrance breakwaters, a programme of shingle bypassing was commenced. In this operation, shingle is excavated from the west side of the entrance and transported and placed on the east side. The paper will describe the shingle bypassing process and the powers available to Shoreham Port Authority to undertake such an operation. Additionally, it will discuss transportation options for the shingle, the effects on the updrift and downdrift beaches and the arrangements for liaison with other authorities and the public.

Session 6: RIVER ENGINEERING

06-01. Engineering Theme, Flood and Coastal Defence R&D Programme

By: Mervyn Bramley R&D THEME LEADER

The overall objective of research in the Engineering Theme is to develop improvements in the design, construction and management process for flood and coastal defences, as well as approaches to the removal, realignment or adaptation of existing defences and improvements in the flood-resistance of buildings. We aim in particular to improve understanding of both the performance and the whole-life costs of defences, and of the interaction between defence systems (and their component parts) and their local environment. The Theme objectives and its structure within the five Topic Areas of:

  • River and Catchment-related Performance and Design  
  • Estuary and Coastal Performance and Design
  • Operation and Maintenance
  • Delivering the Construction Product

Structures, Materials and other Cross-cutting Aspects are described in the Coastal & Flood Defence Newsletter published in January 2001 (see "research programme" under MAFF Web Site http://www.defra.gov.uk/environ/fcd/default.htm). This newsletter also lists the Theme Advisory Group (TAG) members who, like both the Research Advisory Committee (R&D Review Report, 1998) and myself, are determined that the Engineering programme will deliver relevant and useful outputs to coastal and flood defence practitioners.

06-02. Here Today Gone Tomorrow - The Case for Temporary Defences

By: Roy Stokes ENVIRONMENT AGENCY

Capital Flood Defence Schemes in England and Wales have traditionally consisted of permanent structures constructed from concrete and steel or earth embankments. The demand for more versatile defences, which retain the character of riverside towns, may see the introduction of a number of schemes, which include the use of removable barriers. There are advantages and disadvantages to using temporary barriers and defences, both as first line and secondary means of protection. A new approach is required to reduce the dependence upon sand bags which appear to be the last line of defence utilised by all Emergency Services. The ongoing flood events of October/November 2000 have further highlighted the problems associated with the use of sand bags. The improved Flood Warning System now offered by the Environment Agency provides an opportunity to look to more specialist equipment to establish well planned flood management systems.

06-03. Generalised River Flood Frequency Estimation Using Continuous Simulation

By: Ann Calver CEH WALLINGFORD

Flood frequency estimation is addressed by the modelling of catchment runoff on a continuous time basis. A sample of British catchments has been used to develop relationships between model parameters and properties of river catchments. This has enabled the methodology to be spatially generalised for use at sites without flow records. The method can be extended in time by the use of generated rainfall data to allow estimation of high recurrence interval floods. Aspects of climate change can also be incorporated into the methodology. The paper describes principles of the generalised methodology and results of spatially-generalised flood frequency estimates in Great Britain.

06-04. Comparison of FEH and FSR Estimates of Design Flood Magnitudes in Scotland

By: Alistair Cargill BABTIE GROUP

The approaches of the new Flood Estimation Handbook do not guarantee that estimates of design floods will conveniently agree with those derived by previous techniques. Differences may have major implications upon the design costs of new schemes or shed new light upon the perceived levels of protection offered by existing schemes. This paper aims to investigate, in a Scottish context, the scale of differences that can result when FEH pooling-group estimates are compared to ones based on the methods advocated in the Flood Studies Report. The paper also aims to provide some explanation as to why the potential for obtaining different flood estimates for the same problem, exists. Relative differences in flood estimates will be set in the context of flood management, and the implications to the industry discussed.

06-05. Understanding Rivers - Two Examples of the Application of Fluvial Geomorphology as a Tool in River Engineering and Management

By: Will McBain ARUP WATER Heritage University of Salford; Alexander Obodovsky, Kiev State University

The key to any robust river engineering or management solution is to develop a clear understanding of the true nature of the problem. This paper outlines an approach incorporating fluvial geomorphology as a key tool in developing a framework of understanding through which sustainable solutions to river engineering and management problems can be developed. This approach is the focus of the recently published Environment Agency (EA) Guidance Note 18. An overview is provided of the geomorphological issues relevant to river engineering and a technique for assessing stable river channel dimensions is described. Two case studies are briefly outlined which illustrate the application of a geomorphological approach to different scales of river management problem. The first case study relates to a siltation problem in Forge Valley National Nature Reserve on the River Derwent in North Yorkshire, an issue identified in the EA's Local Environment Action Plan (LEAP) document. The second case study relates to the development of a flood management strategy on the River Tisza in the Carpathian Mountains of Western Ukraine, resulting from a review of a major flood event that affected over 33,000 people.

Session 7: COASTAL MANAGEMENT

07-01. COAST 3D - Influencing an EC Research Programme to Deliver Practical Outputs

By: Jane Rawson ENVIRONMENT AGENCY

The three-year COAST3D project involved extensive field campaigns at two sites (Egmond, NL and Teignmouth, UK) where dense morphodynamic and hydrodynamic data sets were collected. These were analysed by researchers to improve our understanding of coastal processes and used by modellers to test the performance of a selection of numerical models. The involvement of national agencies ensured that there was an emphasis on producing results of practical use to end-users. Summary results of research findings are presented, with a description of the processes involved in formulating guidelines for the use of Coastal Zone Management Tools.

07-02. The Effects of the Segmented Shore - Parallel Breakwaters at Sea Palling on the Longshore Transport of Sand

By: Frank Thomalla SCHOOL OF ENVIRONMENTAL SCIENCES, UNIVERSITY OF EAST ANGLIA

The segmented shore-parallel breakwaters were constructed to provide long-term protection for Sea Palling and its hinterland against inundation by providing a wide, high beach in front of the existing sea-wall and dunes. In association with periodic nourishment programmes they have been locally successful, but the breakwaters almost totally block the south-eastward littoral drift and effects on the beaches, both down- and up-drift, have been considerable. In this paper the effects of the first four breakwaters on the beaches, during the period from 1995-8, are discussed and the results of numerical modelling the wave-induced circulation around the breakwaters are shown. There are a number impacts of these breakwaters that are unexpected and which may be important for the design of future strategies for shoreline management. 1) Existing empirical relationships for predicting shoreline response provide conflicting with McCormick (1993) performing best, but generic design criteria for locations with large tidal range and strong littoral transport are needed. A new set of criteria needs to be developed UK guidelines. 2) Up-drift erosion should be expected whenever the littoral drift is variable in direction. 3) When breakwaters block the longshore sand transport path the sand recharge necessary to maintain the beaches is likely to be considerably greater than the littoral transport measured in the absence of the breakwaters. 4) Within the embayments between the breakwaters, wave driven currents move sand counter to that intuitively expected and jet-like flows carry the sand offshore.

07-03. The UK Estuaries Research Programme - Phase 1

By: Richard Soulsby HR WALLINGFORD LTD

The morphology of an estuary (its shape and underwater contours) affects, and is in turn affected by, issues relating to flood defence, water quality, conservation and navigation. The UK Estuaries Research Programme aims to provide answers to some of the key questions that face those concerned with such issues: estuary managers, stakeholders and interest groups. The programme is planned in three phases, over an approximately ten-year period. Phase 1 of the research was undertaken by the EMPHASYS consortium, which comprised 13 partners including practitioners and researchers with widely varying and complementary areas of expertise. Links were made between the understanding and prediction of changes in estuarine morphology and the resulting changes in the ecology and water quality that are subject to legislative constraints, policy and directives.

07-04. Integrating Reliable Flood Modelling with Probabilistic Analysis in Practice

By: Paul Sayers HR WALLINGFORD

In recent years there have been a number of advances in modelling flood events. This has been matched by simultaneous advances in probabilistic techniques to evaluate loading and response. The reliability of a flood risk assessment, however, remains constrained by the ability to determine the likelihood of defence failure and test multiple failure and load scenarios. In addition, conventional analysis has difficulty resolving flood risk resulting from multiple breach/failure locations and load combinations. Therefore, it often remains focused on the impact of a breach on discrete areas of the flood plain; rather than considering the potential damage resulting from a broader perspective of multiple failures arising in any given 'system' of defences. As a result, the improvements in flood inundation modelling and probabilistic analysis techniques have been largely incompatible in practice. For 'simple' flood plains protected by a limited number of discrete defences subjective techniques based on expert judgement supported by limited modelling and sensitivity analysis offer robust and appropriate solutions to determining flood risk. However, in complex situations, a more advanced 'physically-based' approach is required. Therefore, to improve decision making in these complex situations and achieve reliable flood risk mapping, a probabilistic systems based approach that integrates flood inundation modelling with defence performance and economic analysis is presently under development. The methodology is being developed in tandem with a number of Coastal and Tidal Defence Strategy Studies and combines large quantities of synthetic data from joint probability analysis with 'system' thinking on defence performance, to enable economic damages to be directly and consistently assessed. The outline procedure presented in this paper is generic and could be applied to many situations to provide a consistent evaluation of different options. However, this level of analysis would not be appropriate in cases where the risk and investment levels are low or where decisions are clear cut.

07-05. Pevensey Coastal Defences P.P.P. 'The Contractor's Perspective'

By: Guy Hardacre PENTIUM COASTAL DEFENCE LTD

The Pevensey Bay Sea Defences Contract is the first Public Private Partnership flood defence scheme to be let in the U.K. and, as a pathfinder project, it's success or failure is likely to be significant in future flood defence procurement policy. The £30m contract started on 1st June 2000 and runs for 25 years. The central principle of the Public Private Partnership (PPP) method of procurement is that the public sector client pays the private sector supplier to provide a service over a long period of time. This is radically different from the traditional contractual arrangement, in which the private sector constructs an asset which the public sector then takes ownership of and manages. In this case the service to be provided is the prevention of flooding, so the Environment Agency is actually paying Pentium to ensure that something does not happen. This further complicates an already unfamiliar contractual situation. The use of the PPP principles, however, also brings many advantages which can, for the right projects, enable better value for money for the public purse to be achieved. This paper sets out to briefly explain the background to PPP and the Pevensey Scheme and to address some of the issues encountered during the bidding process and the execution of the project so far.

Session 8: FLOOD APPRAISAL AND MANAGEMENT

08-01. Flood Management of the Yangtze River: The Lessons of Economic Appraisal

By: Colin Green FLOOD HAZARD RESEARCH CENTRE

The Yangtze is one of the two main rivers in China. It is has a very flat gradient, the base of the Three Gorges Dam being only 75 metres above datum. The flood season is from July to September and floods are the result of rainfall, the rain fronts moving from east to west. Whilst it follows that the coincidence of flooding from the tributaries has a significant effect on the flood peak on the main river, flood flows are dominated in the middle section by flows from the main stem. Floods are, however, characterised by multiple peaks; eight in the 1998 flood (Daoxi and Siping 1999).

08-02. Implementation of MAFF 'Project Appraisal Guidance' in Complex River Systems

By: David Webb HALCROW GROUP

A primary consideration in the assessment of scheme design, is the need to show that the most cost-effective option has been selected and that 'taxpayer's' money is being put to best use. In recent years, MAFF has published guidance documents reflecting the development and refinement of the guiding principles and procedures:- 1985; Investment Appraisal of Arterial Drainage, Flood Protection and Sea Defence Schemes: Guidance for Drainage Authorities (1) 1993; Flood and Coastal Defence Project Appraisal Guidance Notes (PAGN) (2) 1999; Flood and Coastal Defence Project Appraisal Guidance Economic Appraisal FCDPAG3 (3) FCDPAG3 identifies methods for valuing costs and impacts in monetary terms and also sets out recommended decision process, based on economic values, which requires a robust and comprehensive evaluation of scheme options. In complex river systems, this can require a detailed appraisal of the river hydraulics under a range of conditions, evaluation of flood limits/depths, and calculation of flood damages. It has become vital, therefore, to develop accurate flood prediction and damage assessment techniques that are both repeatable and efficient in order that a number of design options can be evaluated cost effectively.

08-03. 50 Years of BRE Studies of Flood Embankment Behaviour

By: Tony Butcher CENTRE FOR GROUND ENGINEERING AND REMEDIATION

The behaviour of earth embankments for flood defence is highly complex particularly in tidal estuaries where the banks are usually founded on soft estuarine deposits. The continuing rise in sea level, the construction of tidal barriers, the changes in predicted flows in rivers during storms and greater than expected settlements have all meant that embankment heights need to be constantly monitored and raised to maintain flood protection. Over the past 50 years the Building Research Establishment (BRE) has been continuously involved with research and consultancy into the behaviour of flood embankments. Much of this work has been on the Thames estuary (Marsland 1986) where the soft alluvial soil, which contains layers of peat, suffers significant short and long term compression. The alluvial soil is underlain by Thames gravel that allows seepage and uplift on the landward side. This paper summarises work on overtopping, trials to failure, tidal loading instability and seepage and uplift. New work includes the long term (almost 20 years) behaviour of a working flood embankment, the surprising effect on stability of re-profiling, and the use of deep soil mixing in soft organic soils to increase soil strength and reduce settlements.

08-04. Dike Failures in the Last 200 Years in Hungary

By: Sandor Toth NATIONAL WATER AUTHORITY, BUDAPEST

Hungary is situated in the part of Europe drained by the Danube, in the deepest part of the hydrographic unit called the Carpathian Basin. Her territory covers 96,000 km2 and represents 11.4 % of the 817,000 km2 large Danube catchment. The Carpathian Basin is bounded to the west by the 2000 3000 high ranges of the Alps, to the north and east by the Carpathian Range the peaks of which rise to over 1000 2000 m above sea level (a.s.l.). In contrast, 70% of the territory is plains below 200 m, while only about 1% consists of hills higher than 500 m a.s.l. The eastern parts of the country are the deepest, the lowlands here being between 80 100 m a.s.l. only. Owing to this topography, an area of round 21,200 km2, that is 23% of the territory of Hungary is below the flood level of the rivers. This fact alone presents flood defence problems which are unique in Europe and comparable in order of magnitude perhaps to those in the Netherlands alone (Tóth 1993).

08-05. Flood Hazards and Flood Prevention Measures in China

By: Yongqiang Zong DEPT OF GEOGRAPHY, UNIVERSITY OF DURHAM

China has a long history of suffering from flood hazards. Strongly influenced by the monsoon climate, China faces severe flood problems almost on an annual basis. This paper provides a general introduction to the nature of flood hazards and references to emergency measures and flood-prevention policies developed and implemented in China. The main points being argued in this paper include: Floods have become more and more severe and frequent, despite the gradual reduction in flood-season floodwater discharge from the upper Yangtze basin. Flood defences have restricted floodwater from spreading over the floodplain, resulting in a net rise in water level in the middle reach of the Yangtze. Recent development of monitoring and warning systems has helped improve emergency planning and emergency decision-making. The centralised command systems for emergency management have been effective, resulting in a sharp reduction of fatalities. The long-term solutions to flood problems seem sound, but there are considerable obstructions towards implementation. Some aspects of the flood problems in China may be unique, but some lessons from China's experience may be relevant to Britain.

Session 9: CURRENT POLICY ISSUES

09-01. The Flood and Coastal Defence Funding Review

By: Jim Park, FLOOD MANAGEMENT DIVISION, DEFRA

The Flood and Coastal Defence Funding Review is focused on whether the sources of funds should and could be redistributed so that more responsibility for funding falls on those directly benefiting from the expenditure and on whether the identification of priorities is sufficiently coherent. The overall aim is to produce an effective and sustainable system. A number of official reports on flood and coastal defence have been produced in 2001 and a number of other reviews are underway in parallel with the funding review. Recommendations and conclusions resulting from all these activities will need to be taken into account in implementing any changes to the funding arrangements and in considering any necessary longer-term changes to institutional arrangements. This paper places the funding review in context by describing the flood and coastal defence issues which have been, or are currently, under scrutiny and which will all have to be taken into consideration in the funding review and in any consequential recommendations about institutional arrangements.

09-02. Prioritisation of Flood and Coastal Defence Investment

By: David Richardson, FLOOD MANAGEMENT DIVISION, DEFRA

This paper aims to summarise the situation with regard to the review of prioritisation currently being carried out by DEFRA. Prioritisation is necessary if the best use is to be made of available funds for capital works and they are to maximise the benefits of defence provision. However, the system must be seen to be reasonable, equitable and transparent without imposing undue additional administrative burdens. The alternatives put forward for consideration in the final round of consultation, as a result of feedback and developments in the early summer, are summarised but the final system will depend on the results of this consultation in Autumn 2001.

09-03. FUTURECOAST: Assessing Future Coastal Evolution

By: Kevin Burgess HALCROW GROUP

An examination of the first generation Shoreline Management Plans (SMPs) was commissioned by MAFF in 1999 (MAFF, 2000) to review best practice, identify lessons learned, and produce guidelines for future revisions. A key recommendation from this review was the need to 'utilise an improved understanding of both coastal processes and coastal morphology information (including long-term predicted evolution, and the implications of future sea level rise and climate change) to identify sustainable shoreline management policies'. The review also concluded that there was relatively little "vision" presented in the existing SMPs of how the coast is likely to evolve over the longer timeframe (e.g. 50 to 100 years). The need for research to address this, based on a longer-term and wider scale framework, was identified, to provide a national consistency of approach with detail at the sediment cell or sub-cell scale. In response to this, MAFF commissioned the current research project to improve understanding of the major natural influences upon evolution over the next century for the open coastline of England and Wales. This will deliver an improved understanding of coastal behaviour and the factors that are influencing shoreline evolution, upon which the second round of SMPs can build. This paper presents the work being undertaken to achieve this, which was defined from the first stage of this research concluded in February 2001.

Session 10: YEAR 2000 FLOODS

10-01. The Wake Up Call

By: Gary Lane ENVIRONMENT AGENCY

The Deputy Prime Minister John Prescott MP described the severe weather and flooding that dramatically disrupted parts of the country in the autumn of 2000 as a wake up call to the impacts of climate change. The country saw its road, rail, air and sea transport infrastructure severely disrupted. Flooding became widespread and prolonged and many communities were both devastated and traumatised as their homes and personal possessions were inundated and in some cases destroyed by floodwater. The Agency produced the "Lessons Learned" report in response to a request from the Minister for Fisheries and the Countryside Elliot Morley MP. Its recommendations are a challenge to the Government, Flood Defence Committees, the Agency and all its professional partners to respond to that wake up call.

10-02. Seamless and Integrated

By: David Rooke ENVIRONMENT AGENCY

A notable feature of the response to the floods of October and November 2000 was the tremendous collaborative effort of all the agencies involved including the relevant Local Authority, Police, Fire, Ambulance, Military, utility companies, private sector and the Environment Agency. This was achieved primarily through the establishment by the police and Local Authorities at various times of Gold 'Strategic', Silver 'Tactical' and Bronze 'Operational' level Controls. In the North East Region of the Agency there were 5 Gold and 8 Silver Controls plus a number of Bronze. The Agency maintained a presence at most of these groups. This paper draws on the experience gained across the Region and in particular at the Silver Control in Selby, North Yorkshire and looks at two key issues :- Organisation and co-ordination of the multi-agency response. Was the emergency work effective? The paper brings out issues on the economic, social and environmental aspects of responding to a series of major incidents across catchment and political boundaries. It also covers the health, safety and welfare of those involved and those benefiting from the service provided. It addresses the competence of people required in an emergency where competence is that unique mix of knowledge, skill and behaviour. The political considerations and political involvement are discussed. The paper highlights best practice and draws attention to areas for improvement and lessons learned.

10-03. The Silent Saviour

By: Andrew Pearce ENVIRONMENT AGENCY

The autumn 2000 floods caused devastation and trauma to many communities. But the successful operation of flood defences saved many thousands of properties from the impact of the floodwaters such that many property owners were oblivious to the threat. The flood storage reservoir on the River Medway upstream of Tonbridge built after devastating floods in the 1960s protected some 800 properties from flooding and yet some media reports ignored this and wrongly blamed it for causing flooding elsewhere. The barrier performed well in excess of its design capabilities but the quiet success of its operation by Agency staff was obscured by misinformation in the press and public confusion. If the Agency and its professional partners are to deliver a "seamless and integrated service of flood forecasting, warning and response", management of information for the media and the public is a key element.

10-04. Whose Role is it Anyway?

By: Geoff Bayliss ENVIRONMENT AGENCY

This paper describes the role of the Environment Agency in managing flood events particularly by reference to its flood warning responsibilities. It illustrates where areas of responsibility are either blurred or where others have the primary role. It also raises the issue of public expectation particularly with regard to the issue of flood warnings (and the accuracy thereof) and their perception of the efficiency of sandbags. It contrasts this pattern of behaviour with the reluctance of people to leave their property when there is an imminent threat of flooding to their property and threat to life. During the Autumn 2000 flood event there is evidence that the public were confused by the split responsibilities between various operating bodies for different sources of flooding such as surface water sewers, streams, and major rivers. They were confused and angered by the differing policies for example concerning the issue of sandbags, yet in the few cases where evacuation was urged upon them by the emergency services there were examples where they steadfastly refused to move preferring 'to go down with the ship'. So whose role is it anyway?!

10-05. In at the Deep End - Handling a Major Flood Emergency

By: Lindsay Frost LEWES DISTRICT COUNCIL

This paper describes the major flood emergency which affected Lewes, East Sussex, in October 2000 from the viewpoint of a District Council Emergency Co-ordinator who helped run a Incident Command Post throughout the event. It will cover a brief background to the flood event; flood warning and emergency response arrangements; cleaning up and long term recovery. It will conclude by trying to draw some wider lessons on management of flood emergencies and the long term recovery process.

10-06. Flood Warning and Forecasting Theme: Introductory Notes

By: Jim Haywood R&D THEME LEADER

Fluvial and tidal flood forecasting and warning play a vital role in minimising the impact of flooding. Predicting flood events provides valuable lead-time that allows the deployment of mitigation works and, in severe events, evacuation of the public and mobilisation of the appropriate emergency response. Even where vulnerable settlements are protected by flood defences, these are constructed to a finite design standard. Particularly in the case of raised defences, flood forecasting is required to allow warning of overtopping, a situation which has the potential for significant loss of life. The provision of accurate forecasts is of no benefit if a warning is not received or acted upon, or if actions taken are ineffective. Post-event surveys indicate that many of those affected receive no warning, or are warned too late for action. There is also a need to raise public awareness and understanding of flood risk and improve the preparedness and effectiveness of response actions.

Session 11: CATCHMENT PLANNING 1

11-01. The European River Flood Occurrence and Total Risk Assessment System (EUROTAS)

By: Paul Samuels HR WALLINGFORD

The EUROTAS project has taken a catchment scale view of flood management through linking hydrological and hydrodynamic models of flood propagation with a GIS and database to economic and land-use data to provide a perspective on both flood hazard and flood vulnerability. Through the use of an Integrated Catchment Model (ICM) the change in risk can be identified for river management and flood defence strategies and interventions. This approach facilitates dialogue between government organisations, industry and other stakeholders in the use and management of the flood plain and assists with the development of sustainable solutions to unacceptable flood risks. The project was executed as a set of ten main tasks including five pilot catchments studies using the ICM, the development of procedures for flood risk assessment and a prototype Decision Support System. The EUROTAS project was funded by the European Commission between 1998 and 2000 and was a major initiative in the European research programme on hydrological risks. This paper describes some of the key issues including, the catchment-scale consequences of land use change, flood risk and uncertainty assessment, climate change impacts and assessing the effects of river engineering measures. The project was coordinated by HR Wallingford with 14 partners from 8 countries.

11-02. Practical Applications of SUDS in the West Midlands

By: Ian Baird ENVIRONMENT AGENCY

With major flooding experienced across the majority of the country during recent years the need for sustainable urban drainage systems has never been more evident. Surface water drainage methods that take account of quantity, quality and amenity issues are collectively referred to as Sustainable Urban Drainage Systems (SUDS). This urban drainage "triangle" of quality, quantity and amenity balances the adverse impact of urban surface water runoff on the environment. In the West Midlands this has been achieved at several sites, notably Newhall Valley and Blythe Valley Park. These and other sites are discussed in the paper and the paper details the practical application of SUDS with emphasis upon planning, construction and maintenance (including adoption) issues together with various environmental benefits that can accrue. Results will be presented as to the effectiveness of SUDS at particular sites. The case studies presented will demonstrate how SUDS techniques work in the same way as natural processes and thus provide a successful practical engineering solution to increased surface water run-off which can additionally reduce pollution and provide landscape and amenity habitats.

11-03. Getting Wise on Inland Flood Management

By: Sarah Fowler RSPB

The recent floods resulted in hundreds of millions of pounds worth of damage as well as emotional trauma for many people. It brought into question the current approaches to flood defence planning. There are undoubtedly lessons to be learnt from these floods. The response must not just result in a piecemeal knee-jerk reaction of building defences higher and wider. There is a growing recognition that the current management of water and land, and the isolation of rivers from their floodplain, compounds the problems of floods and also increases the risk of summer droughts. The RSPB is leading an EU Life Environment funded project looking at tools and techniques for restoring the link between floodplains and their rivers to improve flood management and implement the Water Framework Directive. The Government has announced an additional £51 million spending over four years including the development of Catchment Flood Management Plans. What should these plans look like; should flood defences be planned strategically; and should landowners be paid for providing flood defence benefits? This paper looks at changes needed in planning and funding for flood defence works to take account of new legislation, climatic pressures and policy developments.

11-04. Integrated River Flood Defence

By: David Ramsbottom HR WALLINGFORD

The extensive river floods of Autumn 2000 have demonstrated the vulnerability of many parts of the country to flooding in spite of the considerable investments in flood protection works over the years. It is estimated that 10,000 properties were flooded at over 700 locations, 58% of which had no flood defences. However it is also estimated that 280,000 properties were protected from flooding by flood defences, indicating the vital importance of flood defence work (Environment Agency, 2001). Present indications are that climatic conditions and weather patterns will change, leading to an increase in rainfall and flooding. Flood defences designed for a particular standard of protection based on historic data are likely to fail more frequently in the future, and defences will require enhancement to maintain the present standards. The impacts of flooding are also likely to get worse if the level of investment in flood defences is not considerably increased, and construction in flood risk areas continues.

Session 12: CATCHMENT PLANNING 2

12-01. Flood Risk Assessment for Development Control

By: David Rylands ENVIRONMENT AGENCY

In order to mitigate future flood damage, development control decisions and building design in flood risk areas should take into account the uncertainties of flood risk assessment and the consequences of flooding in events larger than the '100 year flood'. Development is generally permanent and so a very long term view should be taken when assessing flood risk, taking into account possible changes in land use, channel maintenance, flood plain and climate. Assessments should be made on the precautionary principle - restrictions can always be relaxed when better information is available. Moving to a risk based approach should reduce flood damage, but will be more complicated than the current system based primarily on a best estimate of the 100 year flood outline in current conditions. Therefore to be effective, development control teams must be adequately resourced and supported by expert flood risk analysts. Any additional costs associated with building more safely in flood risk areas should be absorbed by reduced values of development land in flood risk areas. Suggestions are made on some of the information that would need to be produced in order to achieve effective and consistent flood risk assessments.

12-02. Flood Risk Reduction Through Active Reservoir Management

By: Kermen Mok DRAINAGE SERVICES DEPARTMENT, GOVERNMENT OF HKSAR

The Kowloon Reservoirs Group comprises four interconnecting reservoirs upstream of a densely populated urban area in Hong Kong. A quantitative risk assessment has indicated the possibility of large overflows from the reservoirs during severe rainstorms. Recent developments in the urban area and its hinterland have resulted in the existing drainage systems being unable to cope with such large inflows thus posing a high risk to life and properties from the ensuing floods. To reduce the flood risk in the interim period before the completion of a tunnel project to divert the potential overflows from the reservoirs to the nearest sea outfall, a scheme to turn the reservoirs into dual-use is pursued that would allow active management of the flood storage in them. This paper describes the setting up of hydrological and hydraulic models to simulate the routing of the flows through the reservoirs and assessing the hydraulic performance of the trunk drainage system. The existing draw-off capacity of the reservoirs group was established and extra draw-off facility implemented. Continuous refinement of the rainfall-runoff relationship and monitoring of the effectiveness of the scheme are achieved by real-time rainfall and water level measurements.

12-03. Sustainability Assessment of Flood Alleviation Schemes in the UK

By: Janine Franklin OVE ARUP & PARTNERS INTERNATIONAL LTD

The UK Strategy for Sustainable Construction 'Building a Better Quality of Life' (DETR, 2000) recognises the significant contribution large construction projects can make to quality of life through sustainable development. An assessment method based on this ideal has been developed by Arup to identify opportunities for improving the sustainability of flood alleviation schemes. Arup have applied a sustainability assessment matrix, using SPeARTM, to the design and construction of five flood alleviation schemes, carried out under a design and build contract for the Environment Agency. This has contributed to ensuring that sustainability is a central theme running through the projects. The five flood alleviation schemes range from city centre and urban locations, to environmentally sensitive estuarine locations. The issues associated with individual schemes are diverse and the sustainability assessments highlight the very different approaches required to achieve sustainable flood defence solutions. The new method uses a computer application to assess the sustainability of schemes and also to identify opportunities for improvement. Sustainability indicators for flood defence are identified using current Best Practice guidance. The assessments show both positive and negative results and are completed at key development stages to show the opportunities for improvement in sustainability through careful design and considerate construction. Application of this methodology optimises environmental, social and economic performance of flood alleviation schemes and can lead to opportunities for significant project cost savings.

12-04. Research to Determine the Impact of Severe Weather: A Project Overview

By: Stewart Wass THE MET OFFICE

The United Kingdom has recently been affected by a number of severe weather events that have caused widespread disruption and economic loss. In March 2001 much of the country received heavy snow that caused loss of power to thousands of homes, severe delays to the already beleaguered rail system and road closures. In October 2000 extremely high winds affected the whole of the British Isles, again causing loss of power to thousands of homes, millions of pounds worth of physical damage to properties and travel disruption. The nations' media has been awash with reports of flooding, with graphic pictures highlighting both the monetary loss and misery that these events can bestow. It is immediately clear that we are very susceptible to the effects of severe weather, with average economic losses alone of approximately £2Billion per year. The Met Office is responsible for the forecasting of these events and has a National Severe Weather Warning Service (NSWWS) to disseminate specific information to the relevant authorities. Bodies such as the emergency services, council emergency planning officers and the media receive these warnings in the hope that mitigating actions can be taken to reduce the impacts of severe events. Aside from insurance claims and dramatic media reports there is little wide-scale appreciation of the impact of these events. This is mainly due to their infrequent occurrence and the widespread nature of the impacts which affect unrelated public and private institutions as well as individuals. This has highlighted a need to understand the influences of severe weather at a government level in order that measures can be put in hand to reduce the impacts, thus avoiding loss to 'UKPLC'. This paper presents the development of a system to define the impact of severe weather on the United Kingdom and to determine ways in which the impact can be reduced through the effective use of forecasting and mitigation.

12-05. Methodology and Results from a Regional Flood Risk Assessment Programme: The Flemish Approach

By: Bridget Woods Ballard HR WALLINGFORD

Over the last decade, Flanders has suffered repeated major flooding events. During the winters of '93/'94 and '94/'95, August '96, September '98 and December '99, wide areas of the region were inundated causing significant damage to infrastructure and distress to the local population. AMINAL performs in Flanders many of the functions that in the United Kingdom (UK) lie within the remit of the Environment Agency, it being the Flemish administration responsible for all environmental resources and land/water management processes. Groundwater and surface water fall within the remit of their Water division (created in 1995), and this department thus has duties relating to both flood risk management and flood alleviation.


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Department for Environment, Food and Rural Affairs