HURSLEY PARISH COUNCIL

FLOOD PLAN

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Back to 10th November 2003 minutes

 

 

INTRODUCTION

 

1.    This aim of this plan is to provide a pre-meditated and co-ordinated response to increasing groundwater levels in the vicinity of Hursley with a view to maintaining a safe environment and protect householder’s property as far as is practicable in the circumstances.

 

2.    The plan is focused on the operational aspects of flooding, specifically protecting life and property, providing safe access to and from the village and maintaining essential services such as main drainage, water supplies and sewage disposal. 

 

3.    The actions of each organisation are listed but they may not necessarily be carried out as the result of a duty or responsibility.

 

4.    When the plan was prepared, the following external authorities were consulted:

 

Environment Agency

Hampshire County Council

Winchester City Council

Southern Water

 

 

FLOOD WARNINGS

 

5.    The Environment Agency’s Local Flood Warning Plan provides details of the flood warning arrangements for Hursley.

 

6.    There are four warning codes:      

 

Flood Watch

Flooding possible. Be aware! Be prepared! Watch out! 

Flood Warning

Flooding of homes, businesses and roads expected. Act now!

Severe Flood Warning

Severe flooding expected. Imminent danger to life and property. Act now!

All Clear

No Flood Watches or Flood Warnings currently in force in the area.

 

7.    Flood Watch is a general alert concerning flooding from the sea, estuaries, rivers, streams, ditches, watercourses and high groundwater levels. Flood Warnings and Severe Flood Warnings relate to specific Flood Warning Areas at risk of flooding from the sea and rivers. 

 

8.    The Environment Agency do not issue Flood Watch, Flood Warning and Severe Flood Warning for Groundwater flooding, but do issue Groundwater level information to Parish Councils and individual residents by e-mail. Hursley Parish Council (HPC) and a number of residents in Hursley are registered with the Environment Agency to receive this information.

 

9.    Property owners and/or occupiers in risk areas will be informed by personal call or note through letter box of the Groundwater situation by members of the HPC Flood Action Group (see paras 41 to 45). Also, Groundwater level information and situation reports will be posted on the HPC Notice Boards periodically.

 

 

FLOODING EVENT

 

10.  The main types of flooding event referred to in this plan are:-

 

TIDAL                                     (sea, estuaries)

FLUVIAL                                (rivers)

FLASH                                    (roads, ditches, watercourses)

GROUNDWATER                 (high water table)

SEWAGE                               (sewers, rising mains and pumping stations)

POTABLE WATER               (mains failure)

 

11.  Of the above flooding events, Flash and Groundwater are the most likely to effect Hursley. Flash flooding occurs on occasions during the year following periods of intense rainfall. In the main its effects are short lived, restricted to the A3090 and are only usually exacerbated by highway drainage system blockages caused by debris and silt progressively running down from adjacent fields. The most recent Groundwater flooding events in Hursley occurred in the winter months of 1994/95, 2000/01 and 2002/03 suggesting that the problem could occur every year depending on the rainfall pattern during the summer and autumn when normally the water table would be expected to be reducing to its usual pre-winter level. 

 

 

LEVEL OF RESPONSE

 

12.  The level of response from the authorities to a flooding incident will depend on what is flooded or is at risk of being flooded.  There are five priority categories:-

 

PRIORITY

FLOODING AFFECTING

RESPONSE

1

People

Action to protect life

2

Houses

Action to protect life and property

3

Roads

Action to protect life and property

4

Commercial Property

Action to protect property

5

Gardens/Agricultural Land

No action

 

13.  In any flood situation HPC will attempt to address problems as they arise, however, in the event of a conflict of interest, HPC will draw on the above guidance if there is a need to prioritise resources. There are other factors which may influence the level of response to flooding in Hursley.  Priority will be given to the old or infirm when assisting people, and to occupied property when protecting property. The classification of roads may be used by Hampshire County Council in prioritising responses to road flooding and the protection of commercial property may depend on the risk of environmental pollution from stored chemicals etc.   

 

14.  Hursley Parish Council cannot guarantee that assistance will be provided in property risk areas such as cellars where flooding is a frequent occurrence in high Groundwater situations . In such cases the owners and occupiers are strongly advised to make their own arrangements to protect their property from flooding, but without detriment to the public highway and main sewerage system (see para 37). A sample of the formal advice available to householders from the EA is at Annex A.

 

 

AUTHORITIES INVOLVED

 

The following organisations will be involved in direct specific action during a flooding event in Hursley. Property owners are also listed as they have responsibilities not least protecting their own property from flooding.

 

·         ENVIRONMENT AGENCY

·         HAMPSHIRE COUNTY COUNCIL

·         WINCHESTER CITY COUNCIL

·         HURSLEY PARISH COUNCIL

·         HAMPSHIRE FIRE AND RESCUE SERVICE

·         SOUTHERN WATER

·         ELECTRICITY, GAS AND TELECOMMUNICATIONS COMPANIES

·         INDIVIDUAL PROPERTY OWNERS AND/OR OCCUPIERS

 

 

ACTION LISTS

 

ENVIRONMENT AGENCY

 

15.  The principal actions of the Environment Agency (EA) are:

 

·         ISSUE GROUNDWATER LEVEL INFORMATION

·         RECEIVE AND RECORD DETAILS OF ALL FLOODING INCIDENTS

·         MONITOR THE SITUATION AND ADVISE OTHER ORGANISATIONS

·         DEAL WITH EMERGENCY REPAIRS AND BLOCKAGES ON MAIN RIVERS AND OWN STRUCTURES

·         RESPOND TO POLLUTION INCIDENTS

·         ADVISE ON WASTE DISPOSAL ISSUES

 

16.  One of the EA’s remote telemetry groundwater level monitoring facilities is situated close to the junction of the A3090 (Main Road) and Poles Lane. 

 

HAMPSHIRE COUNTY COUNCIL

 

17.  The principal actions of Hampshire County Council (HCC) are:

 

·         CO-ORDINATE EMERGENCY ARRANGEMENTS

·         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

·         TAKE ACTION TO PROTECT PROPERTY FROM FLOODING BY WATER FROM THE HIGHWAY WHERE THERE IS A FAILURE OF THE HIGHWAY DRAINAGE SYSTEM

 

18.  Both Flash and Groundwater flooding events in Hursley will place heavy demands on the highway drainage system; the main road may also become flooded in places. It is essential that the highway drainage system and the outfall down Poles Lane are maintained in peak condition; de facto they must be regularly inspected and serviced by HCC who will, where appropriate, require the riparian landowners to deal with those roadside ditches which are their responsibility.

 

19.  The regular maintenance of the highway drainage system between Standon and the south end of Hursley village, and the Poles Lane outfall is a critical element of this Flood Plan. Failure of the highway drainage system to perform correctly will result in damage to properties in Hursley.

 

20.  The high probability of floodwater on the main road through Hursley means that warning signs and diversions will be required; a quick response by HCC is essential to maintaining safe conditions on the roads and walkways. Freezing conditions are also likely to arise during periods of Groundwater flooding for which the provision of grit/salt will be necessary.

 

WINCHESTER CITY COUNCIL

 

21.  The principal actions of Winchester City Council (WCC) are:

 

·         ASSIST HCC IN THEIR CO-ORDINATING ROLE

·         FLOOD WARNING DISSEMINATION  (by local agreement with EA)

·         EMERGENCY ASSISTANCE  (S138 LGA 1972) - PROVIDE SANDBAGS

·         CLEAR BLOCKED WATERCOURSES ETC. (Land Drainage Act powers)

·         ENVIRONMENTAL HEALTH ISSUES - POLLUTION

·         BLOCKED ROAD CHANNELS & GULLY GRATINGS - STREET CLEANING

·         EMERGENCY PLANNING SUPPORT GROUPS

 

22.  As the demand for sandbags at times of flooding is high, WCC cannot be relied upon to provide sandbags for every eventuality. Also, because WCC will only supply sandbags once to a particular property, householders may have to make arrangements to purchase them from local builders’ merchants and DIY sources. If necessary, HPC will negotiate the provision of sandbags to protect the footpaths and walkways through the village, and investigate the bulk supply of materials to allow householders to make up their own.

 

HURSLEY PARISH COUNCIL

 

23.  The principal actions of Hursley Parish Council (HPC) are:

 

·         MONITOR THE CONDITION OF THE HIGHWAYS DRAINAGE SYSTEM

·         DISSEMINATION OF GROUNDWATER LEVEL INFORMATION

·         SITUATION MONITORING AND LOCAL AUTHORITY LIAISON

·         PROVISION OF ADVICE AND LOCAL ASSISTANCE CO-ORDINATION

 

HAMPSHIRE FIRE AND RESCUE SERVICE

 

24.  The principal actions of the Hampshire Fire and Rescue Service are:

 

RESCUE

RESPOND TO ALL EMERGENCY INCIDENTS AS REQUIRED

ASSIST THE POPULACE WHERE A NEED IS IDENTIFIED AND THE USE OF FIRE SERVICE PERSONNEL AND EQUIPMENT IS RELEVANT

 

SOUTHERN WATER

 

25.  The principal actions of Southern Water are:

 

·         EMERGENCY OVERPUMPING OR TANKERING AT PUMPING STATIONS

·         CLEARING BLOCKAGES IN PUBLIC SEWERS AND OUTFALL GRILLS

·         REPAIRING BURST SEWAGE AND WATER PUMPING MAINS

·         TAKE ACTION TO PROTECT PROPERTY FROM FLOODING BY WATER FROM THE PUBLIC WATER MAINS OR DISCHARGES FROM THE PUBLIC SEWERAGE SYSTEMS

·         PROVISION OF PORTABLE TOILETS WHERE NECESSARY

 

26.  In the normal course, Flash flood events are not expected to degrade in any significant way the mains and sewerage systems in the village.

 

27.  A Groundwater flooding event in Hursley will almost certainly cause the main sewerage system to become inoperable at the south end of the village and result in raw sewage overflowing through manhole covers. If nothing is done, some residents in Main Road Hursley will be unable to use their toilets and dispose of foul drains, and South End Close will become contaminated by raw sewage.

 

28.  Notwithstanding the importance of maintaining the sewerage system in peak condition, the natural and unavoidable ingress of surface water into the system means that in the event of Groundwater flooding, the sewerage system is most likely to fail at the south end of Hursley village. Experience has shown that the only way this situation can be avoided is to control the excess groundwater by placing a portable pump on the corner of South End Close and Main Road, taking a suction on the main sewer and discharging into the highway drain. This procedure is of course subject to the necessary legal agreements with the EA being in place.

 

29.  On receipt of information from the EA that high Groundwater levels are to be expected in Hursley or the Groundwater level reaching 42 metres AOD, as recorded by the EA’s remote telemetry groundwater level monitoring facility in Hursley, Southern Water have stated that they will endeavour to place on standby a suitable portable pump. The flow in the sewers will be monitored and if it threatens to cause wastewater flooding of property or restricted use of sanitation facilities, Southern Water will advise the EA that a pump is to be brought on site and an emergency discharge of dilute wastewater is likely to be required to protect property. The operation of the pump will be subject to the prevalent conditions and meeting the requirements of the Regional Protocol and Guidance Note on Surcharging Sewers, jointly agreed by the Environment Agency and Southern Water in September 2002. 

 

30.  The provision of a portable pump to mitigate the effects of a Groundwater flood in Hursley is a critical element of this Flood Plan. Failure of the sewerage system to perform correctly will deprive residents of toilet and wastewater facilities in Main Road, and result in raw sewage contamination in South End Close.

 

ELECTRICITY, GAS AND TELECOMMUNICATION COMPANIES

 

31.  The principal actions of the electricity, gas and telecommunications companies are:

 

·         ATTEND TO EMERGENCIES RELATING TO THEIR SERVICE AT PROPERTIES WHICH PUT LIFE AT RISK AS A RESULT OF FLOODING

·         ATTEND TO FLOODING EMERGENCIES AT THEIR OWN SERVICE INSTALLATIONS

 

32.  Aside from normal domestic considerations (lighting, heating, cooking, telephones etc) the principal effect of a loss of electrical power will be on those householders pumping cellars. Prolonged loss of supplies at times of high Groundwater levels will almost certainly result in water entering properties. 

 

INDIVIDUAL PROPERTY OWNERS AND/OR OCCUPIERS

 

33.  The principal actions of owners and/or occupiers of property at risk of flooding or which is flooded are:     

 

·         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 FLOOR AREAS LIABLE TO BE FLOODED

 

34.  It is unlikely that Flash flooding will result in damage to property in Hursley, however, some water ingress may be experienced in the cellars of some properties.

 

35.  In the event of Groundwater flooding, those properties having cellars will almost certainly experience cellar flooding. In Serious Groundwater flooding events, the degree of flooding could threaten the ground floor rooms of properties. For those properties having cellars, controlling the level of groundwater ingress into the cellar by pumping could prevent the flooding of ground floor rooms. It should be noted however that during pumping there is a risk that cellar walls could be damaged if the water Level (pressure) outside exceeds that on the inside by more than a small amount. For those properties without cellars, sandbags and other means of preventing water ingress through doors etc. will likely be the only defence against Groundwater. It may also be appropriate for properties without cellars to install sump pumps, by constructing a sump beneath floor level within or immediately outside the property. In any event, caution should be exercised when pumping for long periods as such action could lead to the degradation of the foundations of properties. 

 

36.  The pumping of water from private properties onto the highway and into the main sewerage system is illegal on grounds of safety, however, HCC have stated that they would offer no objection to householders discharging Groundwater from cellars direct into the highways drainage system. Pumping floodwater into wastewater drains and sewers is likely to cause polluted water to escape lower down the catchment and lead to further problems for other residents.

 

 

POINTS OF CONTACTS AND COMMUNICATIONS

 

37.  Local Authority points of contact, their telephone numbers and e-mail addresses, and other useful information can be found in Annex B.

 

 

FLOOD RISK AREAS

 

The following are the Flash flooding risk areas in Hursley:

 

Main Road

 

Highway and cellar flooding.

 

The following are the Groundwater flooding risk areas in Hursley:

 

Main Road (North End), Port Lane and Collins Lane

 

Cellar flooding; threat to ground floor rooms.

 

Main  Road (South End)

 

Cellar flooding; threat to ground floor rooms; toilet and wastewater problems.

 

South End Close

 

Garden flooding; sewage contamination.

 

 

LOCAL CO-ORDINATION

 

38.  On receipt of a high Groundwater level information, the HPC will appoint a small Flood Action Group (FAG) to co-ordinate activities in the Village and provide the essential communications links with the EA, HCC, WCC and Southern Water. The Chairman of the HPC will act as the Flood Action Co-ordinator (FAC).

 

39.  The FAG will consist of the following people:

 

·         Mr Martin Waldron                  Chairman of HPC                   01962-775309

·         Mr John Brooks                      Clerk to the HPC                    01962-775552

·         Mr Steve Stevenson               Main Road                              01962-775544

·         Mr Ken Day                            South End Close                     01962-775319

 

40.  If the situation demands, an emergency centre will be established in the Village Hall and parishioners co-opted on a voluntary basis to assist with the manning of the centre.

 

 

·        ROLE OF THE FLOOD ACTION GROUP

 

41.  During and after a flooding incident, the following actions will require to be taken by the FAG appointed by HPC:

 

·         ESTABLISH COMMUNICATION LINKS WITH AND PROVIDE INFORMATION TO THE ENVIROMENT AGENCY, HAMPSHIRE COUNTY COUNCIL, WINCHESTER CITY COUNCIL AND SOUTHERN WATER EMERGENCY SUPPORT GROUPS TO ENABLE THEM TO ADVISE AND ASSIST AFFECTED PROPERTY OWNERS

·         MONITOR THE EFFECTS OF RISING GROUNDWATER LEVELS ON ESSENTIAL SERVICES (HIGHWAY ACCESS AND DRAINAGE, ELECTRICITY, GAS, TELECOMMUNICATIONS, WATER AND SEWAGE) AND PROPERTIES IN THE VILLAGE

·         MAINTAIN A CLOSE WATCH ON ELDERLY AND INFIRM RESIDENTS IN THE HIGH RISK AREAS OF THE VILLAGE