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Circulation: Members Date: 13.12.2013 Ref: Version 2 - Revised notes on recovery on pages 5-7. Contact: Ian Moodie Tel: 024 7685 8650

December 2013 tidal surge floods – Agricultural impact

The tidal surge experience between Thursday 5 and Saturday 7 December 2013 was the most serious in over 60 years.

An area of low pressure caused a large tidal surge, with gale force northerly winds and large waves coincided with spring tides peaking. The shape of the coasts around the North Sea acts as a funnel, squeezing the water into an ever narrowing gap. This combination of factors resulted in significant coastal flooding to Rhyl and Denbigshire in North Wales and isolated parts of Northwest from midday on Thursday before the storm surge began to track down the East Coast of England from Thursday afternoon and through the night into Friday. Higher than average tides continued into Saturday although largely these only affected areas where defences had previously been damaged from the day before.

In places waters were higher than those seen during the devastating floods of January 1953, waters in Hull rose by 5.8metres and at the Thames Barrier it was the highest tide seen since its completion in 1984. The Environment Agency has reported that the Figure 1: (Environment Agency) Severe Flood Warnings (Red) and Flood Warnings (Orange) around England and Wales as surge resulted in the flooding of around 1,400 at 17.30 on Thursday 5 December 2013. properties, with 18,000 people evacuated and 64 severe flood warnings issued.

Official estimates have not yet been provided for the area of agricultural land flooded. However, anecdotally it is estimated that in excess of 2,000ha of farmland has been flooded, over 1,000ha of which were around the Estuary and River Ouse. Estimates have not been made for the Norfolk coast, Broadlands or lower Trent Valley. NFU Mutual has said that it is dealing with more than 300 claims for storm damage to property.

For those farmers affected the focus is now on draining any land still underwater, clearing rubbish debris and silt from fields and drainage channels, and recovering the condition of land as well as repairs and recovery of buildings, homes and machinery. Freshwater reservoirs may also have become contaminated by salt water. At the end of the briefing (page 5) are some notes on recovering agricultural land following salt water flooding. Information about SPS following flooding events is available for members here (you need to log in).

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Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge

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The Environment Agency has said that they are assessing flood defences in those areas where breaches and overtopping has occurred. Breaches aside, a common concern from farmers affected are where the surge has overtopped defences resulting in scouring and cracking of the landward face, particularly for stretches where vegetation on coastal embankments is not managed, or is less frequently mowed or grazed. There are calls for urgent repairs to be undertaken by the Environment Agency before any further winter storms and the next very high tides which are scheduled at the beginning of January 2014.

Figure 2: Typical damage to a coastal Guidance for those whose homes and properties have been embankment, East (James affected by the floods is available from the Environment Agency Copeland) website.

BBC Farming Today (12.12.2013) included a feature on the damages as a result of the storm surge. Reporting from , Yorkshire they spoke with arable farmer Paul Martinson and James Copeland, NFU North East Regional Environment Adviser. Listen again here (available until Thursday 19 December 2013).

How has the flooding affected your farm business? The NFU would like to hear from members affected by flooding as a result of the storm surge in order to get an estimate of the impact on the agricultural sector. If you were affected and would like to share any photographs or information about the flooding please drop our Flood Risk Adviser Ian Moodie an email at [email protected].

The following summarises the impact to agricultural in each NFU region, it does not try to repeat information available elsewhere regarding damage to people and property. The briefing is gathered from accounts from members, regional advisers and the media.

North East Approximately 1,000 hectares of agricultural land have flooded around the Humber.

Along the North Bank of the Humber pumping operations by the Ouse & Humber Internal Drainage Board, Environment Agency and Council were continuing to remove standing water from roads and fields in the , and Yokefleet area (~650 ha flooded) into this week. Land here flooded to a depth of around 3ft, water travelling over half a mile inland and taking 3 to 4 days to be drained/pumped Figure 3: Flooded farmland (~650ha) at Yokefleet, North Bank off. of the Humber (James Copeland)

On the South Bank of the Humber near a length of the coastal defence bank which is 9 inches lower than surrounding defences overtopped spilling through the village and onto agricultural land (~250ha). This has since drained, but the rate of the flood has caused scouring damage to drainage channels in the area.

On the Peninsula approximately 400ha had flooded near Welwick, Sunk Island, Weeton, and Skeffling. Elsewhere there was flooding to land around between the Rivers Ouse and Aire (~50ha) and at Bridge (~50ha).

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Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge

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East Riding of Yorkshire Council has confirmed that assistance can be applied for under the council’s local welfare assistance scheme, which provides emergency loans or support grants to residents and businesses.

Image: Yokefleet Video: Blacktoft, Faxfleet and Yokefleet from the air (Humberside Police) Image Welwick

East Midlands The South Bank of the Humber was perhaps worst affected with the village of South Ferriby and surrounding land, including a poultry farm, almost entirely submerged. Around 700,000 broiler chickens were drowned by the surge waters on the Thursday night. The extent of the flooding here is as yet unquantified but certainly runs into hundreds of hectares. As with other parts along the south bank these areas flooded rapidly but also drained away relatively quickly too. The surge has left widespread damage to the South Humber bank defences where cracks, gaps and slumping has occurred.

Floodwaters overtopped banks along the in and around the Isle of Axholme including the villages of Susworth, Goxhill Barrow, Butterwick, and Keadby.

On the Lincolnshire coast Jubilee Bank north of Boston broke in two places and the reclaimed outer marsh flooded approximately 200ha from the South as far as Sea Lane at Friskney. Flood water will remain until the gaps are sealed and the water is pumped out. Jubilee Bank is a privately owned flood bank and the outer line of defence, whilst the primary defence sits approximately half a kilometre inland.

South of Boston a breach in sea defences resulted in a substantial pumping operation by Black Sluice IDB where close to 200 million litres of sea water was pumped back into the Haven over two days at Wyberton Marsh Pumping Station which serves a mixture of agricultural land, Wyberton village and South Boston.

The Environment Agency are holding drop in sessions for the public to discuss the flooding in Boston:  Wednesday 11 December Boston Market (11am-3pm)  Thursday 12 December Boston Crafts Day, near St Botolph’s church (10am-3pm)  Friday 13 December Asda, Lister Street (11am-3pm)

North Lincolnshire Council has created a £100,000 relief fund to help people across North Lincolnshire who have been affected by the severe flooding.

Image: North Lincolnshire from the air (Humberside Police) Video: South Ferriby, North Lincolnshire from the air (Humberside Police) Image: Poultry units at South Ferriby

East Anglia In Norfolk there are likely to be some cliff top arable land losses, but no estimates yet. At Burnham Deepdale in North Norfolk breaches in flood bank has resulted in flooding to around 200ha of farmland. The land flooded to around 4ft in depth and water has remained on land for several days after the event.

The Environment Agency is asking people to avoid walking on flood defences which have footpath closure orders on them due to damage by the recent storm surge. In a number of coastal locations in Norfolk the flood banks have been weakened or damaged by the tide making them unstable and unsafe to walk on. The main locations of concern at the moment are: Brancaster, Burnham Deepdale, Blakeney, Cley Beach Road. Alternative routes are being signposted to walkers.

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Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge

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Around 7 breaches in Suffolk have resulted in flooding to low-mid hundreds of hectares of agricultural land. Farmers are concerned about contamination of fresh water irrigation reservoirs with salt water. Repairs are being undertaken by EA and others to coastal defences. Cliff collapses at Benacre and elsewhere in north Suffolk have resulted in possibly as much as 20 acres of lost arable land. For land around the Rivers Alde and Ore a more detailed summary is available here - http://www.coastalscene24.co.uk/news/alde_and_ore_group_reflects_on_damage_caused_by_flood_1 _3091157?utm_source=CoastalScene

In Essex 11 farms flooded by overtopping to ~150ha of farmland but all have drained away effectively. The surge peaked at 2 metres in Suffolk and 1.3 metres in Essex.

In Kent there was limited overtopping of defences around Sandwich and the Romney Marshes with the surge peaking at around 1.1 metres. There has however been scouring to the landward face of embankments during Figure 4: Flooded farmland alongside River Colne, overtopping where vegetation control has been less Essex (C N Cock) frequent.

Image: Breach in flood bank at Burnham Deepdale

The voice of British farming

Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge

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Recovering agricultural land following salt water flooding

Steps to follows once flood waters have receded/been drained: 1. Clear land of debris and rubbish and ensure good conveyance of field/land drainage systems/channels. The aim here is to maximise the flushing of salt water from areas that have been inundated. 2. Aeration of soil, so sub-soiling and related techniques may be relevant, if soil structure is lost. Flood waters a couple of feet deep can apply tons of pressure onto the land. Reintroducing air and permeability helps with flushing salt from the soil. 3. Test soil for salt content. 4. Irrigation can be used to wash salt out of the soil, but the quantities of water necessary may be prohibitive and given we’re now in winter rainfall may itself be sufficient. 5. Spreading gypsum to replace sodium within soil structure can be effective. However, if the gypsum to be used is from waste sources it is important to follow Environment Agency guidance on land spreading and receive the necessary spreading permit and deployment note.

The following notes have been adapted from Soil Code - The 1998 Code of Good Agricultural Practice for the Protection of Soil (PB0617)1. Please note any legislation and regulations quoted in the Soil Code may have changed.

When sea flooding occurs, it is important that the water on the soil surface drains back to the sea or river as quickly as possible in order to minimise residues of sodium and chloride in the soil. High residues can restrict crop growth and damage soil structure. The sooner surplus water is removed, the sooner the recovery process can start.

In freely draining soils, average winter rainfall in England and Wales can remove most of the chloride left in the soil in one winter. If flooding occurs in late winter or spring, the chloride may not be removed until the end of the next winter.

On soils that are not so well drained, washing out the excess chloride may take two or three winters. If the soil is very poorly drained, with little or no water moving through the soil, the soil may remain contaminated. This is a particular problem if the soil is very dry at the time of flooding, so that salt water penetrates deep into the soil. However, the soil is usually already wet when it is flooded and in this condition the salt water will not penetrate so deeply into the soil.

Soils with pipe drainage will recover naturally as long as the system is working properly. The number of winters needed to leach the excess chloride will depend on rainfall, the structure of the soil and the effectiveness of the leaching process.

If soils contain more than 1200 mg/litre of water-soluble chloride in the top 20 centimetres, more tolerant plants such as barley or ryegrass are more suitable than more sensitive species such as legumes or brassicas.

As water moves through the soil, the soil sodium concentration will be reduced by leaching. If sodium taken up by the clay particles is not replaced by calcium or magnesium, the clay particles will disperse and the soil will become very difficult to cultivate. Soils with a high silt or clay content are most at risk of deterioration. Peaty and coarse sandy soils are less prone to damage.

1Soil Code - The 1998 Code of Good Agricultural Practice for the Protection of Soil (PB0617) http://adlib.everysite.co.uk/adlib/defra/content.aspx?doc=4052&id=4096 The voice of British farming

Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge

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To maintain a satisfactory structure, the soil must contain a supply of calcium or magnesium. This may come from a high natural content of calcium carbonate or from added gypsum. Gypsum is calcium sulphate which is more soluble in water than lime (calcium carbonate). On cultivated soils which are susceptible to structural deterioration and have been flooded with seawater, applying finely ground gypsum at 5 tonne/ha should be undertaken once the soil has dried out. This is likely to improve the soil even if it already contains some calcium carbonate. Gypsum is most effective if it is left on or near the soil surface. You may need to make another application on clay soils which do not contain lime and which have been flooded for a long time.

Soils in grassland should only be treated with gypsum if they have a weak structure and contain no lime. There is little/no benefit in treating peaty and coarse sandy soils.

Use of waste gypsum in this way is subject to permitting regulations, see below.

For rapid recovery from flooding damage, do not carry out cultivations in wet conditions. Avoid sowing crops until the soil structure is fully restored.

Apply adequate fertiliser because any nutrient shortage will increase the problem. If there is a drought, irrigate the land with non-salty water where possible.

Spreading Gypsum Gypsum (calcium sulphate, CaSO4) can be used to restore or improve soils that were flooded with sea water. Gypsum replaces sodium cations with calcium cations in the layers of clay particles in the soil environment. These dynamic reactions are commonly referred to as cation exchange. Cation exchange is one of the most common and important soil reactions. It takes place on the negatively-charged surfaces of soil particles. The soil's capacity to exchange cations is used to determine the appropriate application rate. Lime (calcium carbonate, CaCO3) can also have the same affect but should be avoided as it will change (increase) the pH of the soil.

Agricultural (Non-Waste) Gypsum If the land treatment is required urgently then this practice of soil treatment can be achieved using agricultural (non-waste) gypsum without any need for a Standard Permit or prior approval of a deployment.

Agricultural Gypsum registered as a CE fertiliser grade gypsum can be obtained from certain suppliers (such as Formula Saint Gobain) where it has been obtained from naturally occurring mineral sources. It is used in a variety of agricultural applications including as a carrier for horticultural dressings, as a mushroom composting ingredient, as a soil improver and in land reclamation after salt water flooding.

Waste derived Gypsum However, if waste gypsum is used in this way a Standard permit is required to spread it (SR2010No4 Mobil plant for land spreading). This is most likely to occur if the gypsum is a waste derived from treatment of waste plasterboard. The permit fee is £700 http://www.environment- agency.gov.uk/business/topics/permitting/117161.aspx.

In addition prior to spreading waste gypsum a deployment note is also required. This costs £400 – £970 per application dependant on risk level of land being spread on. http://a0768b4a8a31e106d8b0- 50dc802554eb38a24458b98ff72d550b.r19.cf3.rackcdn.com/geho0911budi-e-e.pdf

It should be possible for operators to gain deployment approval as part of a managed plan to use gypsum on an affected field. Such a managed plan will need to take account of the wait until land is in a suitable condition for spreading and gypsum incorporation following waterlogging.

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Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge

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Note – When applying for such permits allow for at least 25 working days from the time an application is complete for the EA to make an assessment.

According to the EA’s How to comply with your land spreading permit guidance the following information is required to determine an appropriate application rate:  assess the soil's sulphur requirement,  calculate the cation exchange capacity (CEC) using the method in: The Specification for Topsoil, British Standard 3882, 1994, Annex D (normative), Extraction of exchange cations in soil.

Advice should be sought from a suitably trained agronomist before spreading gypsum.

If the options outlined above are not suitable and more rapid action is needed the Environment Agency have advised that farmers should contact their local Environment Agency Area office who will be able to consider the site specific issues and seek national advice.

The voice of British farming

Although every effort has been made to ensure accuracy, neither the NFU nor the author can accept liability for errors and or omissions. © NFU Policy Services/NFU Briefing/December 2013 Tidal Surge