River Enrick Emergency Flood Response Plan

Transcription

1 River Enrick Emergency Flood Response Plan May 2006 Jacobs Babtie 95 Bothwell Street, Glasgow G2 7HX Tel Fax No liability is accepted by Jacobs Babtie for any use of this report, other than for the purposes for which it was originally prepared and provided. Opinions and information provided in the report are on the basis of Jacobs Babtie using due skill, care and diligence in the preparation of the same and no explicit warranty is provided as to their accuracy. It should be noted and it is expressly stated that no independent verification of any of the documents or information supplied to Jacobs Babtie has been made.

2 Contents 1 Introduction Background Areas of responsibility Inverness Police Scottish Environment Protection Agency Highland Council Coastguard Fire Brigade Road Authority (BEAR Scotland) NHS Utility Providers; Water, Electricity, Gas and Telecommunications Voluntary Organisations Property Owners/Public Activation procedure Warning Levels Information Dissemination Warning Level Specifics and Review Emergency response Control and Command Strategic Command Tactical Command Operational Commands Incident Site Setup Evacuation Routes Trafficability Hazard Assessment Long-term response Prevention and Preparation Validation and review References i

3 APPENDICES Appendix A Appendix B Appendix C Appendix D Flood Warning Trigger Level Inundation Plots Severe Flood Warning Trigger Level Inundation Plots 0.1% Annual Probability Inundation Plots Drumnadrochit Flood Risk Plot ii

4 1 INTRODUCTION Jacobs Babtie was commissioned by the SAFER project through the Forestry Commission Scotland and The Highland Council to undertake the following: Part a) A flood risk assessment of the River Enrick, with particular focus on the village centre of Drumnadrochit, and to produce an Emergency Response Plan. Part b) To undertake a hydrological and geomorphological survey of the River Enrick for the purpose of providing baseline data for the SAFER erosion modelling programme. This report details the work undertaken under Part a) for the Emergency Response Plan. The full list of reports produced by Jacobs Babtie for the River Enrick SAFER project are given below: 1) Flood Risk Assessment of the River Enrick, (Jacobs Babtie, 2006a) 2), (Jacobs Babtie, 2006b) Together with two supplementary reports supporting the survey undertaken during Part b) of the project: 3) River Enrick Geomorphological Appraisal, (Jacobs Babtie, 2006c) 4) River Enrick Hydrological Assessment Hysim rainfall-runoff modelling, (Jacobs Babtie, 2006d) 1

5 2 BACKGROUND After the damaging consequences of the Easter 1998 flood in England an inquiry into the emergency that arose was conducted and its finding were published in a document known as the Bye Report Although this was not a Scottish inquiry it did serve to set the scene for emergency flood planning across the UK. Two leading recommendations from the report were; Through the emergency planning forum encourage local authorities and emergency services to develop effective response plans and to; Establish emergency response procedures within the catchment. An emergency plan, in summary, sets out what actions each organisation will undertake and how this will be co-ordinated in an overall manner. This includes the management and communication structures and the roles and responsibilities of each emergency and council service. Typically an emergency response plan considers all four aspects of emergency management, they are: Prevention: - This aspect encompasses measures which are adopted in advance of an emergency and which seek to prevent it occurring or to reduce its severity. In the case of a flood emergency, this would be the prevention of development in the floodplain and flood protection works reducing risk in areas prone to flooding. Preparedness: - This is the insurance policy considering the preparation involved in responding to flood events. Planning can be underpinned by training and exercises. Educating the community about the risk and appropriate response in the event of a flood is also vital to this aspect of the plan. Response: - The initial response is normally provided by the statutory emergency services supported as necessary by the appropriate local authorities, public and private agencies and voluntary organisations. The primary objectives of the response would be to; preserve life, property and environment, reduce to a minimum the harmful effects of the event, prevent its escalation, and, provide a rapid return to normal life. Recovery: - This encompasses those activities necessary to provide a return to normality for the community. 2

6 These aspects are mirrored by the Scottish Executive s National Flooding Framework where the 4 A s; Avoidance, Awareness, Alleviation and Assistance outline the method of flood management for Scotland. The objective of this report is to aid in the facilitation of an emergency response plan for the River Enrick and focuses primarily on the response to a flood emergency on the watercourse. It attempts to blend a suitable emergency response management model with specific catchment characteristics determined from the detailed hydraulic modelling of the River Enrick (Jacobs Babtie, 2006a). The development of a detailed emergency flood plan is beyond the scope of this project, rather this report intends to establish the foundation of an emergency response plan for the glen or aid the improvement of an existing plan. As such it identifies the structures and roles that are deemed necessary in a generic standard plan and these have been set within the context of Drumnadrochit and the flood characteristics of the River Enrick. However it is recognised that this first pass will need to be discussed and refined to ensure that a properly workable and effective system results. 3

7 3 AREAS OF RESPONSIBILITY The extent of response depends primarily on the severity of the flooding emergency, however, each service or agency responding to the flood emergency has its own role and functions. It is integral to the effective response to the flood that each organisation is aware of their and others responsibilities. Given below are the responsibilities of each organisation consistent with the control and command response model considered in this report. 3.1 Inverness Police The Northern Constabulary facilitate the policing of the Highlands and Islands of northern Scotland. Drumnadrochit is located within Inverness-shire and has a local police station located near the A82 bridge adjacent to the River Enrick. Due to the inconsistency of this post being occupied, the management of flood response is allocated to the Inverness Police Service. Their roles and responsibilities are defined below. Receive flood warnings from SEPA. Co-ordination of the overall response activities of other agencies responding to the incident. Control traffic within the immediate area of the flood. Site security and protection from sightseers, media intrusion and criminal elements. The responsibility for processing casualty information, identification of the deceased and removal of bodies from the scene. 3.2 Scottish Environment Protection Agency (SEPA) SEPA is the public body responsible for environmental protection in Scotland. Its main aim is to: "provide an efficient and integrated environmental protection system for Scotland that will both improve the environment and contribute to the Scottish Ministers' goal of sustainable development." This incorporates the monitoring of river levels, rainfall, tidal predictions and weather forecasts for all of Scotland enabling them to perform the following role in flood emergency response; Receive and record details of flooding incidents. Dissemination of the warnings to police. Operation of Floodline, a public information hotline. Monitor levels during the event and alert the appropriate organisations of the flood s progression (where possible). Prior to an event SEPA is responsible for advising local authorities on flood risk. 4

8 3.3 Highland Council In the event of an emergency the local authority s principle concerns are to support emergency services and the local community and coordination of the response from voluntary organisations. As time goes on and the emphasis switches to recovery, the local authority will take the lead role in rehabilitating the community and restoring normality. A summary of their responsibilities is listed below. Provide resources such as sandbags. Identify and operating reception-centres, including rest centres, friend and relative reception centres, survivor reception centres. Providing short and long-term accommodation. Maintain essential council services such as waste removal. If appropriate, facilitate a temporary mortuary. Co-ordinate the work of voluntary agencies and individuals. Providing counselling and support for those affected. Monitor and close, when appropriate, local roads. Co-ordinate the recovery operation, returning the community back to normality. 3.4 Coastguard Prior to the 2002 Elgin flood event (Figure 1), the coastguard was a minor agency providing boat and helicopter facilities when requested. As a result of the serve flood incident at Elgin, a trial has commenced to review the coastguard in northern Scotland as a major flood response agency for river and urban flooding. The trial has promoted further training for all coastguard voluntaries and established a specialists group to lead the agency in the event of a flood. The agency has additionally purchased inflatable boats and other equipment to facilitate their appropriate response to a civil flood emergency. For the past 11 years the coastguard has patrolled the waters of Loch Ness, providing a search and rescue lifeboat along the waterway. The boat is currently stationed at Drumnadrochit, the lifeboat operators are likely to have extensive local knowledge as well as a rapid response time to a flood event on the River Enrick. Still dependant on the results of the trail, the coastguard can potentially provide the following resources to a flood response at the River Enrick; Trained personnel Lifeboats at Loch Ness Inflatable, transportable rescue boats 5

9 Lifejackets Helicopters Emergency vehicles Figure 1: 2002 Elgin Flood (BBC, 2002); the flood event triggered the coastguard to consider adopting the role of a major flood response agency. 3.5 Fire Brigade Their first concerns are to rescue people and to prevent further escalation of the disaster. Additionally they should assist police and ambulance services with handling of casualties and recovery of any bodies. The fire service is also normally best placed to advise on the safety of personnel involved within the inner cordon. There is a fire station located within Drumnadrochit adjacent to the tourist information centre within the present 1% annual probability flood outline. The local station is not constantly manned and would require evacuation during major flood conditions. 3.6 Road Authority (BEAR Scotland) The River Enrick is crossed by the A82 trunk road, linking Fort William to Inverness. The road is managed by BEAR Scotland whom has the following responsibilities: Maintain safe conditions on the roads. Put flood warning signs on the highway. Organise road closures and traffic diversions. Clear blockages on highway drainage systems. 6

10 3.7 NHS The ambulance service provides the first NHS response at the scene. Immediate care for the injured and their evacuation to hospital are its tasks together with the mobilisation of further NHS resources required at the scene. 3.8 Utility providers; Water, Electricity, Gas and Telecommunications Utility providers such as electricity, gas, telecommunication and water companies are to provide specialised advice and potentially assistance regarding their installations. They are also responsible to act quickly during the recovery phase of the event to repair any facilities damaged during the event. 3.9 Voluntary organisations The voluntary sector in the UK is large and often well organised. Their primary concern is support to the emergency services and local authority by providing assistance with feeding, welfare, temporary accommodation, emergency communications systems and some clerical assistance Property owners/public The public should take some responsibility for at least their own safety, the following actions are advised: Move to a safe area if life is at risk Prevent water from entering property if possible Switch off electricity and gas supplies at mains Move valuable possessions above areas liable to be flooded If time permits, move livestock to higher ground Commonly during emergencies the community wish to be involved in the rescue operation, however this can often be inappropriate and increase the risk to others. Ideally any participation in the flood response is conducted through a voluntary organisation under the guidance of the police. 7

11 4 ACTIVATION PROCEDURE 4.1 Warning levels The primary role of SEPA is the dissemination of catchment status and associated flood warnings. Their staff continuously monitor rainfall, river levels and occasionally snow melt; using this information to forecast the probability and severity of flooding. SEPA utilise four codes to describe the conditions within the catchment: Flood Watch: - This level indicates whether flooding is probable in the 24 to 48 hours due to weather conditions, and instructs the public and community services to be aware and prepared. Flood Warning: - At this warning level flooding is expected to affect homes, businesses and main roads. This code should provoke property owners and occupants to move pets, vehicles, food, valuables and other items to safety and be prepared to turn off gas and electricity. Potentially additional flood protection should be sort from local councils in the form of sandbags or floodboards. Severe Flood Warning: - This is the highest flood warning and is triggered when a major flood is imminent. The trigger should provoke emergency services and local authorities to consider evacuation of certain sections of the community and closing transportation routes All Clear: - Issued when flood water levels have peaked and receded and flooding is considered unlikely to occur. 4.2 Information dissemination Each watercourse has a trigger level to activate the flood warning codes, when this level is exceeded a message is sent via a telemetry system to the base station at either SEPA s officers in Dingwall or Aberdeen. This flood warning is received by a flood system duty officer whom evaluates the signal for the both the authenticity and severity. Once these have been established, the Police headquarters in Inverness is contacted. Additionally this information is feed into SEPAs floodline telephone information system. Once receiving the flood warning and its associated code, the Inverness Police activate the response as required. The police initiate the response by contacting other flood emergency agencies including Highlands Council, the coastguard, and the fire brigade. Currently they additionally contact residents and businesses which have been identified by the local police officer as at risk of flooding. 8

12 A component of the SAFER project is the development of the Frontworks service along the River Enrick. This service provides an automated method of contacting those within the floodplain regarding potential risks predicted. Once established, the service will be activated by the Police, and a message will be sent via the internet and several modes of communication, including mobile and phone, SMS and . Frontworks allows continuous interaction, the list of contacts and their respective details can be readily updated via the internet. A pre-recorded message will be saved to the system ready for activation at the time of a flood. The message can be amended or additional messages can be added throughout the course of the event. The system allows emergency services to focus on coordination of the flood response of an informed public. Frontworks is currently being used in this manner by Scottish Borders, City of Edinburgh, Lothian and Moray councils within Scotland. However the system cannot be granted to be full proof. For example during the 2005 Carlisle flood events communications were severely disrupted as the town was virtually cut off by floodwater. About 70,000 properties experienced power cuts, telephone lines were down and only one mobile phone operator was functioning. When a message is sent from the Frontworks service an acknowledgement from the recipient is required. In the case where there is no response the message is repetitively sent until acknowledgement occurs. The police will be able to monitor the respondents and when appropriate mobilize resources to make visits to make contact. SEPA, in addition to disseminating the flood warning to the police, also place the information on their public flood information hotline Floodline. This service provides immediate practical advise on flood risk for the public and is available nationwide on: The quick dial service, activated whilst calling floodline provides the caller with information about the relevant catchment, for the River Enrick the specific catchment code is Information regarding road conditions can be sought from AA Road Watch by calling or mobiles on (this is a charging service), or Additionally weather and traffic services are available on teletext 160 or BBC2 Ceefax 437 & 438. National Driver Information and Control System (NADICS), established by the Scottish Executive, provides a co-ordinated traffic management service for Scotland s strategic road network and can be accessed via the web; Warning level specifics and review Within the River Enrick catchment the flood warning level is currently determined from the flow\level gauge (no.6008) located on the River Enrick at Mill of Tore (Balnain), and is verified by the rainfall gauge at Corrimony. As part of the SAFER project it is proposed 9

13 that additional river level gauges at - i) Corrimony and ii) on the neighbouring River Coiltie should be installed. At present there is no level trigger within the Enrick catchment for the SEPA Flood Watch code, this instead is determined from the conditions in the larger Ness catchment. The Enrick trigger levels for a Flood Warning and Severe Flood Warning are 2.3m (76 m 3 /s) and 2.6m (107 m 3 /s) respectively. These levels were established by SEPA from anecdotal evidence and in particular from the March 1997 flood extents. As the 1997 flood event was not an entirely typical flood event with some of the key downstream flooding occurring due to debris dams it is not an altogether appropriate event to establish relationships between flood extents and upstream gauge levels. Based on the design hydrology presented in the accompanying report on flood risk (Jacobs Babtie, 2006a), approximate flood probabilities were determined for each trigger level. A Flood Warning is approximately a 17% annual probability event (equivalent to a 1 in 6 year event) and a Severe Flood Warning is a 3.3% or 1 in 30 year return flood event. Flood extent plots associated with these two warning levels are provided in Appendix A and B. These plots provide an indication of the likely minimum flood inundation associated with each trigger level. Furthermore the flood modelling assumes that the river channel is running cleanly and has the same dimensions as were surveyed at the beginning of 2005, ie no debris blockages as in the March 1997 flood event. A brief analysis of the extents determined that during a flood watch event one property is potentially inundated and during a flood warning two properties. Both these properties are located in the Drumnadrochit, downstream of the gauge. An evaluation of the 0.1% annual probability (1 in 1000 year return flood event), Appendix C, considered an extreme flood event. It is estimated that approximately twenty five properties and a large extent of rural land would be inundated during such a flood event. Inundation of the A82 trunk road occurs in a 2% annual probability flood event. The local road A831 stretching almost the entire length of the River Enrick is predicted to inundate in the 20% annual probability. Although flood response time does vary for different duration and probability storm events, an assessment of major historical flood events determined that the shape and duration of the events were reasonably constant within the River Enrick catchment. It was this shape that was adopted as the critical event for this study and used to determined a general understanding of response times for flood peaks within the catchment: a peak at Mill of Tore gauge, just downstream of Loch Meiklie arrives half hour later in Drumnadrochit, whilst a peak at Corrimony, the location of the new gauge, arrives five hours later in Drumnadrochit. 10

14 In light of the detailed study into the flooding characteristic of the River Enrick it is recommended that the flood warning trigger levels be re-evaluated and possibly amended. Each level should represent an emergency response stage, for example, road closure or area evacuation. The levels selected should be additionally consistent with the warning information disseminated via Frontworks to the community. As part of this investigation the Forestry Commission has been provided with a list of properties identified to be within the 0.1% annual probability flood envelope, they have also been provided with the list of properties identified by the Northern Constabulary as at risk of flooding. 11

15 5 EMERGENCY RESPONSE 5.1 Control and command In most situations the on site management of flooding will suffice. In some situations however, either because of the scale and duration of the flooding, or because the emergency may be widespread covering several sites, it may be necessary to establish an emergency management system. The control and command emergency management model is actively used throughout the UK for a variety of emergency response situations, including flooding. This management system separates the organisation of a major incident into three levels Operational, Tactical, and Strategic. The requirement to implement one or more of these management levels will be dependent on the nature of the incident. Emergency Management Systems are ideal for catchments where several, predominately urban, areas require flood response. Within the River Enrick catchment, only Drumnadrochit has been identified as requiring assistance. However when the River Enrick is in flood condition it is highly likely that neighbouring catchment will also be experiencing flooding. Hence an Emergency Management System should be considered as it could provide an effective and efficient method to allocate resources within the region. Each level of responsibility views the incident from a different perspective. Clear lines of responsibility lead to a more effective and co-ordinated response Strategic Command Senior officers from the organisations involved will meet as a Strategic Command Team, they are responsible for the total response potentially on a regional level. They are also responsible for briefings, press and media releases. The Strategic Command is chaired by a senior officer from the lead organisation, in this case the Inverness Police. The Strategic Command Team will be located at the Incident Control Room, this does not need to be located within the vicinity of the flood. More importantly it should be in a facility that can be activated at short notice and is fully equipped with a full range of communication equipment and planning tools. The control centre will be the strategic hub of the response, coordinating all agencies involved. The headquarters of the Inverness Police is an ideal location for an Incident Control Room. 12

16 5.1.2 Tactical Command The main task of the Tactical Command is to translate the strategic view into actions to be taken on the ground. A number of organisations and groups will take on a tactical role. Most have their own co-ordination or emergency centres to assist them and will make extensive use of liaison officers to ensure that there is good communication between the agencies. The tactical level exists to determine priority in allocating resources, to plan and coordinate when a task will be undertaken and to obtain other resources as required. They are additionally responsible for; Staff deployment at the scene Health and safety of those at the scene The log of persons in and out of the outer cordon The tactical command is established at the incident control post within close proximity of the flood. An obvious location for the control post would be the local police office at Drumnadrochit, however as the facility is located within the floodplain, a location on higher ground further away from the watercourse is considered more appropriate. The new educational facility in Drumnadrochit, the Craigmonie Centre is considered a potentially suitable location Operational Command The operational level directly responds to the flood emergency, implementing the actions required, under the direction of the tactical command. They operate within the cordon, and primarily ensure the protection of life remains a priority. 5.2 Incident site setup In order to control the incident site the following areas (Table 1) are used to manage the response effectively and efficiently. The different site areas can be readily merged depending on the extent and duration of the flood event. Table 1 describes the different site areas and potential corresponding location for a flood incident on the River Enrick. Incident Site Area Inner Cordon: - The inner cordon surrounds the immediate scene and provides it with security. Incident site areas set in the Glen Urquhart context This area should be defined as the potential maximum extent, in this case the 0.1% annual probability flood envelope of the River Enrick will provide an appropriate designation. 13

17 Outer Cordon: - The outer cordon controls movement of unauthorised persons in an area surrounding the inner cordon. This is set up by the Police and often has traffic control functions. Ideally this would be defined by the diversion locations surrounding the incident. Due to the limited road network diversion locations are located a considerable distance from the inner cordon. Alternatively the northern boundary will include and be approximately parallel with the A831 and north section of the A82, whilst the south boundary will be located 200m metres south of the River Enrick bridge. Forward Control Point: - The operational control point nearest to the scene of the incident yet outside the flood extent. As it is predicted that emergency services will arrive to the site by both the north and south it will be appropriate to setup two points, at both diversions points located by the outer cordon. Incident control point: - The point from which the on scene management and co-ordination of the incident by the tactical command is carried out. The emergency services will deploy their command and control vehicles to the ICP. It is also the point of contact for other agencies with a part to play at the scene. An obvious location for the control post would be the local police office at Drumnadrochit, however as the facility is located within the floodplain and is identified as one of the first properties to experience flooding, a location on higher ground slightly further away from the watercourse is considered more appropriate. The Craigmonie Centre in Drumnadrochit is a candidate location as it is out of the floodplain, has several phone lines and \internet facilities; appropriate for a variety of emergency response purposes. Marshalling Area: - Area to which resources and personnel not immediately required at the scene or being held for further use can be directed to standby. Rendezvous Point: - Point to which all resources The building has a comprehensive ICT infrastructure, including video conferencing facilities. The Craigmonie Centre additionally can provide the emergency response agencies with a café and catering facilities. The Craigmonie Centre has vast grounds to accommodate personnel and flood response resources. The Centre contains the Glen Urquhart High School and numerous meeting rooms which can hold 10 to 80 people. Furthermore there is an all weather floodlit pitch suitable for storing sandbags and heavy vehicles. The abundant room and communication facilities 14

18 arriving at the outer cordon are directed for logging, briefing, equipment issue and deployment. have identified the Craigmonie Centre within Drumnadrochit as the ideal location for reception and distribution of resources. Survivor reception centre: - Temporary shelter established by the emergency services for the victims of a disaster to provide basic initial needs. The Highlands Council and voluntary organisations may be asked to assist in care of the evacuees. Friends and Relatives reception Centre: - Premises established to meet the needs of friends and relatives who travel to the scene. Rest Centre: - Premises established for the temporary accommodation of evacuees, able to provide facilities for feeding and sleeping. Evacuation Centre: - Premises established to provide temporary shelter for persons evacuated from their homes or places of work. Currently the Glen Urquhart Public Hall located to the south east of the town has been identified as the reception centre, however the small hall capacity and minimal communication and parking facilities brings several limitations. The Craigmonie Centre in Drumnadrochit is a suitable location for a reception centre and the organisational hub of the emergency response. Depending on the season accommodation maybe available locally in hotels and guest houses. During peak tourist season however this will not be an option and community facilities such as the Craigmonie Centre and the Glenurquhart Hall maybe appropriate Table 1: Description of incident site areas and these sites set within the Glen Urquhart context. The various centres that can be established often also have a role in the registration of survivors for the Police Casualty Bureau. This enables an accurate record to be made to help the authorities account for any missing persons and provide information for friends and relatives. Additionally the inundation plots presented in Appendix A, B and C suggest that more than one reception centre will be required. As the majority of emergency services are likely to arrive from the north, Inverness, and the identified centre is to the south of the incident site. 5.3 Evacuation Routes In conjunction with these centres the evacuation and mobility routes across the floodplain need to be established Trafficability An assessment of trafficability, the ability of vehicles to pass over inundated road surfaces, is required for identification of appropriate evacuation routes and diversion locations. 15

19 Previous studies indicate that 15cm of fast flowing water will knock adults off their feet and 60cm of water will float a car. German emergency services use the following guidance: cars and jeeps could pass through up to 0.5m, whilst trucks could pass through water up to 1.0m.. Three sets of flood inundation plots together with depths have been provided with this report, Appendix A, B and C. Two of these identify the minimum likely flooding associated with the two levels of flood warning. The third gives the indicative inundation of a 0.1% annual probability flood. This flood is very unlikely to occur, however it does establish a likely worst case scenario for flooding along the River Enrick. It is predicted that during a 0.1% annual probability event, approximately 0.7m of water will inundated the A82 just south of its crossing of the River Enrick. The 0.1% annual probability flood indicates several sections along the A831, in particular near Milton where depths are predicted to be approximately 0.8m. Diverting traffic away from the scene of the incident is a crucial aspect of emergency response. The road network in the region is such that diversion options are limited and are likely to be located some distance from the area of flooding. The A82 is the major transportation route from Fort William to Inverness, an alternate route identified by BEAR Scotland is the B862 which is located on the opposite bank of Loch Ness. Access to this diversion in the south is at Fort Augustus and to the north at Inverness. It is suggested that all suitable transportation be diverted along this road in times of flooding (assuming flood problems do not exist there as well), whilst local traffic is controlled closer to the cordon. As this route is a one lane roadway, and hence could be heavily congested during a flood event motorists should be advised to seek alternative plans. South-bound local traffic on the A82 can be diverted at Abriachan or close to the town depending on the destination. The River Coiltie is also likely to flood at the same time as the Enrick, and it may be necessary to limit all A82 northbound local traffic at Invermoriston depending on the hazard posed by the Coiltie. Warning of road closure of the A831 should be located upstream at Cannink, Corrimony, Balnain and Milton and to the north along the A833. Additionally the 30 km stretch between Fort Augustus to Lochend has been identified as an area of high hazard for landslides (Winter et al, 2005). During and following times of heavy rainfall this may pose an additional hazard and complication to any diversion network Hazard Assessment 16

20 Traditionally trafficability and the assessment of evacuation routes has only considered the depth of flooding, however flood hazard assessment advice from DEFRA (2003) suggest additional aspects of flooding behaviour be considered. There are several models of assessing flood hazard in an area, all considering a variety of different aspects. For this study, evacuation routes within the inner cordon are more accurately assessed for hazard based on a combination of velocity and depth. Hazard can be defined into four categories each considering different aspects of the depth and velocity. Figure 2 shows indicative levels of hazard for evacuation routes. Figure 2: - Estimation of hazard along evacuation routes (CSIRO, 2000) These hazard categories were applied to the region surrounding Drumnadrochit. The levels are established from the results of the 1% annual probability flood event and utilise the maximum predicted depth and velocity during the flood event. Appendix D indicates the level of hazard predicted. The fast flowing main channel of the River Enrick has a peak velocity predominately above 1.2m/s hence is considered high hazard. The A82 through Drumnadrochit is predicted to be medium hazard. 17

21 6 LONG-TERM RESPONSE Once the initial response to a major emergency has been completed and the source of the incident has been dealt with and the immediate effects mitigated, the emergency is by no means over. In most instances there will be medium and long term effects such as damage to infrastructure, communities and environment, which will need to be addressed in a co-ordinated and sensitive manner. Management and co-ordination of the recovery phase is also important and would to be managed by the Highland Council with the aid of emergency services and government departments as required. 18

22 7 PREVENTION AND PREPARATION Anyone involved in an emergency plan should be aware of their role and responsibilities. If their role involves participation in the operational command then it is crucial that some aspect of emergency response training occurs. Currently the police service receive a broad emergency response training whilst the trial occurring in the coastguard has permitted certain members to receive specialist flood emergency response training. Community awareness of flooding is vital to efficient flood response. Landowners and occupants within the 0.1% annual probability flood envelope should be aware of possible risks during flood conditions. For properties within the severe flood warning envelope, local resources such as sandbags or floodboards should be accessible and trained personal available. Blockages due to debris have been a key component in previous flood events. When blockages occur downstream of Loch Meiklie the gauging station levels can not necessarily provide guidance on any potential hazard. A potential mitigation to this scenario is the establishment of a contact number for the local community when excess debris is identified within the flow channel. This will notify the necessary authority prompting the removal of debris immediately, reducing the level of risk of future flood events. This study has identified several locations along the A82 and A831 where flood inundation during major events is predicted. At each of these locations, depth markers along the roadside would warn motorists of the depth of flooding. During times of dry weather the markers would achieve heightened awareness of potential hazards to locals and tourist alike. Furthermore the trafficability of the road for both motorists and emergency services can be easily identified. This simple measure is viewed as being of particular use. The Drumnadrochit area is a popular tourist destination during the summer months due to its prime location along the Loch Ness. The co-ordination of tourists will be conducted by the police, however information to tourists travelling to the area could be provided by the tourist information centre at the advice of the police. As the Information Centre is located within the 0.1% annual probability flood envelope, early evacuation of this area is advised. 19

23 8 VALIDATION AND REVIEW Plan preparation is not a stand alone process, it is part of a cycle of risk assessment, plan writing, consultation, testing, exercise, review and revision (Figure 3). Figure 3: - The Planning Cycle Any plan must be tested to ensure that it encompasses all the outcomes of known reasonably foreseeable risks and it would be effective in providing a sufficient and timely response. 20

24 9 REFERENCES BBC, website: Brown A.J. & Gosden J. D., Interim Guide to Quantitative Risk Assessment for UK Reservoirs, for KBR and Defra. Commonwealth Scientific Investigation and Research Organisation (CSIRO), 2002, Flood hazard assessment for flood emergency planning, Floodplain Management in Australia: Best Principles and Guidelines. SCARM Report 73. Defra/Environment Agency, Flood Risk to People Phase 1, R&D Technical Report FD2317, July Earth Science Australia, website: Environmental Agency (EA) Case Study: The climate is changing, time to get ready, EA Frontworks, website: Highlands Council Leaflet; Flood Alleviation in the Highlands Islington Council, website: Jacobs Babtie, 2006a. Flood Risk Assessment of the River Enrick (). Prepared within the SAFER project for the Forestry Commission Scotland\The Highland Council. Jacobs Babtie, 2006b. (). Prepared within the SAFER project for the Forestry Commission Scotland\The Highland Council. Jacobs Babtie, 2006c. River Enrick Geomorphological Appraisal (). Prepared within the SAFER project for the Forestry Commission Scotland\The Highland Council. Jacobs Babtie, 2006d. River Enrick Hydrological Assessment Hysim rainfall-runoff modelling (). Prepared within the SAFER project for the Forestry Commission Scotland\The Highland Council. 21

25 Office of first minister and deputy first minister, website: Oxfordshire County Council, website: Scottish Environment Protection Agency (SEPA), Policy No 34, Flood Warning Strategy, Version 1.1, June Scottish Environment Protection Agency (SEPA), Policy No. 22, Flood Risk Assessment Strategy, Version 1, April Scottish Environment Protection Agency (SEPA), website: Waltham Forest Council, website: Wandsworth Borough Council, website: gencyresponse/default.htm Winter MG, Macgregor F and Shackman L, Scottish road network landslides study. Report for the Scottish Executive. 22