Flood Investigation Report- Winter 2012 / 2013

Revision Schedule

East Riding of Council Flood Investigation Report Burton Fleming Winter 2012 / 2013

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Rev Date Details Author Checked and Approved By 0.2 01/10/13 Initial Draft PCT 0.3 11/10/13 Revised Draft GP/AMM

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Flood Investigation Report- Burton Fleming Winter 2012 / 2013

Copyright Notice

Maps in this report are reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of Her Majesty’s Stationery Office Crown copyright 2008.

Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Council 100023383.

Records of the public sewer system included are a facsimile of the statutory record provided by Yorkshire Water Services. For the purposes of this report minor sewers and other non- relevant data have been omitted from the plans for clarity. The statutory public sewer record is held by Yorkshire Water Services Ltd.

Acknowledgements

East Riding of Yorkshire Council would like to thank the following for their co-operation and assistance throughout this investigation.

Mr Keith Wells, Chair of Burton Fleming Parish Council, assisted throughout and acted as liaison between emergency services / East Riding of Yorkshire Council and residents. His input was vital to the whole recovery process.

Burton Fleming Parish Council. For use of the Village Hall facilities throughout, enabling ERYC/HFRS/Police/ residents to hold meetings and provide shelter and cooking facilities for crews working on site.

St Cuthbert’s Church and the local vicar, Revd Barbara Hodgson, for facilitating public meetings.

Mr Robert Linley for the use of his farm as storage of pumps and sandbags and also for assistance with sandbag removal.

Mr Steve Bramble for allowing East Riding of Yorkshire Council to set up level monitoring equipment on his property.

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Flood Investigation Report- Burton Fleming Winter 2012 / 2013

Table of Contents Page

Lead Local Flood Authority and Responsibilities ...... 4 Relevant Flood Risk Management Authorities ...... 4 Abbreviations ...... 6 1. Executive Summary ...... 7 1.1 Location of Flooding ...... 8 2. The Drainage System ...... 10 2.1 Geology of the Area ...... 10 2.2 The Land Drainage System ...... 10 2.3 Flooding History...... 10 3. The Flooding Event ...... 11 3.1 Conditions before the event...... 11 3.2 The Event ...... 12 4. Causes and Investigation Findings ...... 17 5. Conclusions ...... 18 6. Recommendations ...... 19 Useful Links and Contact Details: ...... 20 Appendices: ...... 21 Appendix 1 Monthly rainfall and groundwater levels ...... 22 Appendix 2 Burton Fleming village ...... 23 Appendix 3 Possible routes for alleviation works...... 24

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Flood Investigation Report- Burton Fleming Winter 2012 / 2013

Lead Local Flood Authority and Responsibilities

East Riding of Yorkshire Council, as the Lead Local Flood Authority (LLFA), has a responsibility under Section 19 of the Flood and Water Management Act 2010 to investigate significant flood incidents in its area. Section 19 states:

(1) On becoming aware of a flood in its area, a lead local flood authority must, to the extent that it considers it necessary or appropriate, investigate —

(a) Which risk management authorities have relevant flood risk management functions, and

(b) Whether each of those risk management authorities has exercised, or is proposing to exercise, those functions in response to the flood.

(2) Where an authority carries out an investigation under subsection (1) it must—

(a) Publish the results of its investigation, and

(b) Notify any relevant risk management authorities.

(3) The LLFA has lead responsibility for managing the risk of flooding from surface water, groundwater and ordinary water courses.

This report has been prepared by East Riding of Yorkshire Council in its role as LLFA in response to extensive flooding which affected properties in Burton Fleming during the winter of 2012 / 2013.

This report provides details and an overview of flooding that has occurred, describes the conditions which led to the flooding, considers the response to the flooding thus far and makes technical recommendations for the flood risk authorities concerned.

Relevant Flood Risk Management Authorities The risk management authorities that have relevant flood risk management functions are:

East Riding of Yorkshire Council ERYC is the Lead Local Flood Authority responsible for managing flood risk from surface runoff, groundwater and ordinary watercourses, development of a Local Flood Risk Strategy, Asset Plans and Investigations under the Flood & Water Management Act 2010. ERYC is also the Highway Authority with responsibility for highway drainage under the Highways Act 1980.

Environment Agency Responsible for managing the flood risk from main rivers, the sea and reservoirs including coastal erosion risk management, permissive powers to maintain Main Rivers, Strategic Overview over all forms of flooding and development of a national Flood Risk Strategy.

Yorkshire Water Yorkshire Water Services is the statutory sewerage undertaker for the Yorkshire region with a duty to effectually drain sewers pursuant to the Water Industries Act 1991.

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In addition:

Riparian Landowners

Riparian landowners are those who own land adjoining a watercourse and have certain responsibilities, including the following:

 They must maintain the bed and banks of an open watercourse, and also the trees and shrubs growing on the banks.  They must clear any debris, even if it did not originate from their land, this debris may be natural or man-made.  They must keep any structures that they own clear of debris. These structures include culverts, trash screens, weirs and mill gates.

If they do not carry out their responsibilities, they could face legal action under the Land Drainage Act 1991. Details of a riparian landowners responsibilities can be found in “Living on the Edge” published by the Environment Agency.

Photo 1: Garden waste inappropriately disposed of in the bed of the - September 2013. Riparian owners are responsible for clearing such debris.

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Abbreviations

AOD Above Ordnance Datum

Dia. Diameter

EA Environment Agency

ERYC East Riding of Yorkshire Council

GWL Ground Water Level

HFRS Fire and Rescue Service

HVP High Volume Pump

LLFA Lead Local Flood Authority

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Flood Investigation Report- Burton Fleming Winter 2012 / 2013

1. Executive Summary

The flooding over the winter of 2012/2013 in Burton Fleming was unusual in that it was not as a result of a single rainfall event but due to the cumulative effect of rainfall over a prolonged period.

During 2012, persistent wet weather (second wettest year on record in , see Appendix 1) resulted in exceptionally high water levels in the whole area and in particular the Gypsey Race catchment which includes the Burton Fleming area.

Elevated groundwater levels in the chalk combined with high water levels in the Gypsey Race meant the groundwater was not able to drain away and so remained at elevated levels for some time. This also led to many seasonal springs rising across the area, exceptionally high flows in many watercourses on the chalk Wolds with surface and property flooding in many places including parts of Burton Fleming, and the inundation of the foul sewer system. Significant areas of farmland were also flooded in the upper catchment area.

The Gypsey Race is a largely open watercourse through Burton Fleming draining a large catchment area to the north of in an area known as the . The Race is reportedly often dry for much of the year, in common with other such streams on the chalk Wolds.

The exceptionally high flows in the Gypsey Race in Burton Fleming during late 2012 and early 2013 led to flooding in the village itself, an event not witnessed for many years.

Various options to reduce flood risk are considered in this report’s recommendations.

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1.1 Location of Flooding Burton Fleming is situated in the far north of East Riding of Yorkshire Council’s area, approximately 6 miles north west of and 1 mile south of the boundary with in the Great Wold Valley

Location plan for Burton Fleming

An open watercourse known as the Gypsey Race, drains agricultural land to the west of Burton Fleming, with its head being at Wharram Percy approximately 15 miles west of Burton Fleming and discharging into the in Bridlington, approximately 10 miles to the east

Area flooding occurred near the cross roads of South Street and Thwing Road in the centre of the village. Waters were flowing out of the Race onto Thwing Road and ponding at the junction due to a rise in the carriageway level along South Street.

Burton Fleming showing the path of the Gypsey Race.

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Photo 2: Burton Fleming looking west at the cross roads

Photo 3: Farmland to the West of Burton Fleming

Photo 4: Groundwater emerging from a disused borehole near Burton Fleming

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2. The Drainage System

2.1 Geology of the Area

The Great Wold Valley contains the Gypsey Race, the only, albeit intermittent, surface stream on the high Wolds. Although there are many springs and other smaller streams within the overall area, these are principally concentrated around the edges of the Wolds, where the chalk meets the clay of the surrounding lowlands - as in the --Eastburn-Driffield area.

The chalk of the Wolds is generally highly permeable, the water migrating principally through the fissure system and being stored mainly in this system. It is not a single aquifer but a complex system due to the fractured nature of the rock. The fact that this takes place underground makes modelling of the flow through the ground very difficult.

As a result of the chalk resting upon the underlying clay formation any water that enters the chalk is trapped in the aquifer until it reaches ground level, either at a spring or through the bed/bank of a watercourse, such as the Gypsey Race.

The geology of the chalk Wolds

2.2 The Land Drainage System

Burton Fleming is within the Gypsey Race & catchment. The land drainage from the chalk Wolds to the west of the village drains into the North Sea via the Gypsey Race through Burton Fleming, , Boynton and Bridlington.

The Gypsey Race is a typical chalk stream in that water is only seen to flow in the bed of the stream following wet weather, mainly during the winter, and is known to be dry in the summer months. Although groundwater will still be flowing underground towards the river system/North Sea.

2.3 Flooding History

Following conversations with local residents, it is thought that the Gypsey Race tends to burst its banks approximately every 50-60 years

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3. The Flooding Event

3.1 Conditions before the event

Appendix 1: Monthly rainfall and groundwater levels

mm

Groundwater levels January 2012 to April 2013, ground level is 12.

m

The above data shows the delay in response as the rainfall percolates through the ground and then drains away slowly, and the cumulative effect of the rainfall on groundwater levels.

Following an exceptionally dry winter and spring in 2012 which gave rise to drought orders being drafted in parts of England, the wet summer was followed by persistent heavy rainfall in late November and early December. Reportedly, the second wettest year on record in England, this resulted in exceptionally high water levels in the whole of the East Riding.

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With elevated ground water levels, combined with sustained high water levels in the , the groundwater was not able to drain away into the North Sea and so levels remained elevated for some time. This also led to many springs appearing across the area and exceptionally high flows in various watercourses on the chalk Wolds and surface flooding on agricultural land in various locations. The elevated groundwater levels were the major contributing factor to the flooding which occurred.

Photo 5: Showing the ERYC 200mm diameter Pump on South Street 30 January 2013

3.2 The Event

The water levels in the Gypsey Race rose throughout December 2012; this is not an unusual situation following wet weather.

The water level in the Gypsey Race started to rise at on 13 December. The water level jumped from 40.7m AOD at 6.45 am on 13 December to 41.5m AOD at 19.15 on 14 December.

The rise then slowed, reaching 41.65m AOD at midnight of the 19/20 December. On 20 December the level again rose steeply to 41.8m AOD by 07.30 on 21 December.

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The level peaked on the 30/31 December at 42.04m AOD. It remained fairly constant with fluctuations between 41.8m AOD and 41.2m AOD until early February, the levels then started steadily falling until a rapid drop off occurred between the 1 and 5 of June 2013, some six months later.

Photo 6: South Street looking west, 27 December 2013

21 December - Sandbags started to be deployed by ERYC to protect the buildings by trying to keep the flow of the Gypsey Race in channel and away from properties.

23 December - HFRS were initially called to the village with their high volume pump (HVP).

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Photo 7: HFRS High Volume Pump (Courtesy of HFRS)

27 December - The EA attended, along with ERYC to deploy pumps and further sandbags. EA supplied 3No. pumps (2No. 150mm dia. and 1No. 200mm dia.)

28 December – HFRS pulled out, but left hoses until 2nd of January.

2 January - The EA pumps are moved by ERYC from Rudston Road into the village.

11 January - ERYC 300mm dia. pump installed and EA 200mm dia. removed.

7 February - ERYC installed further 2No. 150mm dia. pumps and 2No. 150mm dia. EA pumps removed.

11 March – Pumping operations cease, ERYC’s 300mm dia. and 2No. 150mm dia. pumps removed.

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Photo 8: Pumping operations on South Street, 15th January 2013

ERYC has built up a telemetry system with various sensors around the East Riding. These sensors are able to monitor the levels in various streams and ditches and feed this information back to the Flood and Coastal Risk Management team.

ERYC has a remote water level monitoring station on the Gypsey Race at Willy Howe, adjacent to the bridge to the west of the village. As there had been no previous flooding events with this telemetry system in place there were no specific alarm levels set, only alarms to inform ERYC that the levels were increasing.

Following the events over the winter, ERYC now has a set of reliable levels with which the telemetry can be programmed to provide alarm points that will provide an effective warning in the event of any future flooding. This information is vital in informing ERYC of any impending future flooding to Burton Fleming

With regards to the telemetry system that is covering the upper Gypsey Race catchment and specifically the village of Burton Fleming, ERYC would like to include a level of redundancy protection for the existing equipment.

This would involve the doubling up of the critical components of the telemetry system and the building of a chamber to place the equipment in to help to protect it from vandalism.

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Photo 9: Gypsey Race 24 July 2013, showing the normal summer condition, and the restrictions to flow at the bridge.

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4. Causes and Investigation Findings

Appendix 1 shows rainfall and groundwater levels which demonstrate that the conditions were extreme following the second wettest year on record in England with the rainfall concentrated into the latter part of the year, giving very high groundwater levels in the area.

Once the flow in the Race exceeded the capacity of the open watercourse in Burton Fleming, the water started to flow over the surface along Thwing Road and South Street, causing flooding to The Burton Arms and properties in the village.

From the corner of Thwing Road and along South Street, there are up to eight crossings over the Gypsey Race. During times of high flows in the watercourse their respective cross sectional areas act as a restriction to the passage of water. This, in turn, results in water overtopping the bank of the channel and flowing onto the adjacent highways and properties.

A computer model was developed after the event to simulate the effect of these crossings in order to better inform the future decision-making process. The model demonstrated that the existing watercourse even without the bridge crossings is unable to allow exceptionally high flows through the system without overtopping the banks. Once the bridge structures are added, the modelled top water levels rise due to the increased throttling effect of the structures. According to the model, increasing the width of the structures would have little impact upon the floodwater levels within the village. In order to accommodate high flows the model shows that the entire stretch of watercourse would require re-profiling and the bridge cross sectional areas would need to be increased.

Various ideas have been proposed as a solution to the flooding, some of which have been discounted as impractical. These include schemes to store the water to the west of Burton Fleming which would require the construction of an extremely large storage area due to the volumes of water involved. This could result in further problems, such as the water from the storage area being forced into the chalk aquifer only to rise in springs elsewhere.

Another idea, which has been discounted, was the creation of a flow exceedance channel along South Street which would be created by lowering the carriageway. This solution would present numerous practical issues, such as access to adjacent properties and buried utilities apparatus. An alternative route for a channel was considered from the west of Penny Bridge along South Lane joining into the Race at the junction of Rudston Road, but this was impractical due to issues with the topography.

Other options considered were the construction of bypass pipework to help prevent water ponding behind the hump in South Street, and the removal of the highway drainage that currently flows into the Race. This option and others will be further considered.

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5. Conclusions

ERYC, as LLFA has investigated the flooding at Burton Fleming during December 2012 and January 2013 using its powers under Section 19 of the Flood and Water Management Act 2010 and has concluded the following:

The overriding cause of the flooding was the prolonged exceptional rainfall during the period leading up to the flooding, giving rise to exceptional groundwater levels, rising springs and high levels in watercourses, particularly the Gypsey Race.

It is concluded that the elevated groundwater levels were the major cause of the flooding, with restrictions along the open watercourse a contributing factor.

The investigation has identified a number of measures that could increase flood resilience and these are set out in the following recommendations.

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6. Recommendations

The investigation has identified a number of measures that could improve flood resilience and these are set out in the following recommendations:

Recommendation 1

The impediments to the flow of the Gypsey Race within Burton Fleming village to be further investigated by ERYC to identify, if and where, improvements can be made. These works will be carried out as part of a detailed study outlined in Recommendation 3.

Recommendation 2

Riparian landowners will be reminded of their responsibilities in accordance with the Land Drainage Act 1991 and of their need to discharge them.

Recommendation 3

A detailed feasibility study is undertaken to establish if an engineered solution to flooding can be implemented. This study will assess a number of options that will include flood flow exceedance routing as well as traditional drainage solutions. Although ERYC have made funding available to carry out these feasibility works, before construction can commence a technical and financial case must be made to external funders such as Defra.

Recommendation 4

The accumulated silt in the bed of the Gypsey Race within Burton Fleming village will be removed. This will be undertaken by ERYC on a one-off Without Prejudice basis as enabling works associated with Recommendation 3.

Recommendation 5

Subject to satisfactory surveys being undertaken ERYC will install a ground-water monitoring station capable of sending readings to ERYC engineers in real time. This will compliment the existing watercourse level monitor situated to the west of the village. This technology will be used to better warn and inform the authorities and the public of future flooding

Recommendation 6

The ERYC response to future flooding will be based on continuous monitoring of rainfall, ground water and water levels in critical watercourses with plans in place to deploy available flood defence measures including ERYC mobile pumps as required. ERYC and the parish council will co-operate to implement operational procedures to be in line with the parish council’s local emergency plan. The parish council has reviewed its Local Emergency Plan, with a view to providing improved response to residents in the case of further flooding events in the future.

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Useful Links and Contact Details:

Lead Local Flood 01482 887700 www.eastriding.gov.uk Authority East Riding of Yorkshire [email protected] Council County Hall East Riding of Yorkshire HU17 9BA

Statutory Sewerage 0845 1242424 www.yorkshirewater.co.uk Undertaker Yorkshire Water Services Ltd Western House Halifax Road Bradford BD6 2SZ

Environment Agency General Enquiries www.environment-agency.gov.uk Dales Area Office 0870 850 6506 Coverdale House (Mon-Fri, 8am -6pm) Amy Johnson Way Clifton Moor Incident Hotline York 0800 807060 YO30 4UZ (24hrs)

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Appendices:

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Appendix 1 - Monthly rainfall and groundwater levels

mm

Groundwater levels, Tancred Pit, Kilham, January 2012 to April 2013. The ground level is 12m.

m

The above data shows the delay in response as the rainfall percolates through the ground and then drains away slowly, and the cumulative effect of the rainfall on groundwater levels.

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Appendix 2 - Burton Fleming village

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Appendix 3 - Possible routes for alleviation works

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