Langstone Millpond – The urgent need to balance habitat, heritage and amenity

[Updated 17-5-23]

In response to concerns that there may be a ‘catastrophic’ failure of the dam in the near future, on May 15 Coastal Partners commented that “Un-maintained, the risk of further collapse of the wall … is anticipated to erode similar to the section which has already failed. Rapid and dramatic breach is unexpected, there are already defects present in the wall. Should the noted defects collapse we expect the rate of erosion will vary year to year depending upon the severity of the winter, but would estimate approximately 0.1m per year.”] This offers some encouragement that there is adequate time for further detailed assessment to be undertaken.

The campaign team is encouraged by the news that on 15 May, Chichester Harbour Conservancy issued a tender to seek quotations from external consultants for “A feasibility study relating to Land at Langstone, Chichester Harbour”. (Click the link to view the comprehensive specification prepared by CHC)

Section 5 updated to correct comments re the potential availability of an Environment Agency grant to HBC for carrying out work.

Why you should read this

Do you take your children or grandchildren to the millpond at Langstone to feed the ducks, or enjoy a walk or a cycle ride down the Billy Track to Hayling, perhaps stopping off at The Royal Oak or The Ship on the way? Well, without urgent action by the relevant authorities, the path will be gone and the millpond abandoned to become a tidal swamp, changing the shoreline forever and destroying this unique environment.

We cover the essential detail below so please read the rest of this post to understand the background and the current state. If you share our concerns, then please write to your MP, lobby your Councillors, sign the petition and get involved with the campaign to save this much-loved part of our local heritage.

  1. Langstone’s millpond
  2. The structure of the dam
  3. Why should you be concerned?
  4. Designated habitats
  5. Ownership and responsibility
  6. The actions needed
  7. Sign the petition
  8. Further reading
  9. An aerial view

Langstone’s millpond

It is, without question, the most sketched, painted and photographed corner of the borough of Havant. The Royal Oak and Langstone Mill have been significant local sites for the past three hundred years and, thanks to the many overseas staff who worked in the borough during Havant’s manufacturing heyday, framed memories of this scene can be found in homes around the world.

The term Langstone Mill is probably seen by many as a singular reference to the old black structure of the windmill. Less obvious is that Langstone is possibly unique with its combination of both a windmill and a tide mill on the same site.

Built around 1800, the tide mill operated two ten foot wheels, one set higher than the other to make full use of the stream feed and the tide, which was kept back behind tide gates. The more distinctive black windmill is an earlier structure, dating from 1720 – 1740. The Historic England listing record describes “a close group of three parts, comprising a water mill (tide mill) and a mill store (now a dwelling) attached to a windmill (part of the dwelling). Early 19th century. The water mill is built across a creek and is associated with a sea-wall with sluices.” 

Tucked away behind the mill is the millpond, a destination well known to bird watchers, local families and the many passing hikers on the England Coast Path. It is a peaceful and beautiful haven which in recent years has become home to the largest colony of little egrets on the south coast of England, recently joined by nesting pairs of cattle egrets.

The structure of the dam

The millpond is contained by a simple earthen dam which also forms the foundation of the walk Havant residents have enjoyed for the past couple of hundred years. On the millpond side, a clay coating prevents the pond water from permeating the dam while on the seaward side the Victorian brick structure protects the earth dam from erosion by high-tide wave action.

The integrity of the whole depends on each of those components since failure on either side will significantly weaken the structure. The pressure of water behind the dam would ensure that any uncontrolled breach could be rapid and dramatic.

Why should you be concerned?

Look behind the tranquillity of the scene and all is not well. The Victorian sea wall which serves as the boundary between the chalk-stream fed millpond and the shore of Chichester Harbour is now in a precarious state as these images from 3 May 2023 demonstrate.

Seen from above, the 200 metre sea wall, stretching between the old water mill building on the left and the southern end of Wade Lane on the right, is the retaining structure which maintains the level of water in the millpond. The Lymbourne Stream enters the pond from the north, draining via the tide gate under the old watermill building and the sluice midway along the wall.

Increasing intensity of seasonal storms and the inevitability of the rising sea-level leaves the dam and sea wall between the mill and the bottom of Wade Lane at risk of collapse. Only last year, a memorial bench placed as a testament to happier days had to be removed from the most immediately vulnerable section close to the bottom of Wade Lane.

After years of wear and tear with no coordinated programme of maintenance, if the wall is now allowed to fail, then the damage to the currently stable environment of the millpond will be unrecoverable. At the date of this article, the whole length of the sea wall fronting the millpond is in a serious state of disrepair.

Without urgent action, the wall is likely to emulate the failure of the wall at Southmoor, a few hundred metres away to the west of Langstone bridge. Take a look at the image below which shows the millpond on the far right and the field at Southmoor on the left. Click through the arrows or swipe left on the image to see the impact of the September 2020 Southmoor sea wall breach, noting the dates at the bottom left.

The result of that breach can be seen in the RSPB drone image below, taken at high water in October 2022, just two years after the breach occurred.

Aerial view of the Southmoor site, 11 October 2022 (RSPB)

The poor condition of the Southmoor wall had been recognised well in advance of the breach and the Environment Agency had developed plans for its ‘managed realignment’ in 2017. In the design of that project, a planned breach would have been made at the weakest point on the wall to create a new coastal wetland. This was the point at which the tide eventually broke though during storms in October 2021. The planned ‘managed realignment’ had not been progressed due to concerns about the underground utility services to Hayling Island that run across the site but within the space of four winters, nature had taken its course.  (For further information, see the ABPMer ‘OMReg’ website.)

Taking a positive view, the new Southmoor lagoon will in time mature into a new biodiverse wetland which should also add value to the local amenity. The coast path is yet to be re-established with a temporary diversion only possible via the road.

In contrast, the adoption, by default, of a policy of ‘No Active Intervention’ – in reality, ‘unmanaged realignment’ – for the Langstone millpond will destroy an existing established environmental asset, leaving a mess which will take many years to stabilise. If the wall is left to breach, estimates suggest that 15,000 tons of water and silt will be spilled rapidly into the Chichester Harbour SSSI, leaving behind a tidal environment in which the level of the former millpond would drop by well over a metre at each low tide.

Designated habitats

A recent Chichester Harbour Conservancy ecology report notes that the Langstone millpond and paddock have been designated as a Sites of Importance for Nature Conservation (SINC) while some of the woodland to the north, Wade Court Park, is a separate SINC. Three components of these sites are listed under Natural England‘s priority habitat inventory‘, the woodland as ‘deciduous woodland’, part of the reedbed area as ‘reedbed’, and the entire paddock as ‘floodplain and coastal grazing marsh’. These important local sites lay adjacent to the Chichester Harbour Site of Special Scientific Interest (SSSI), Chichester and Langstone Harbour Special Protection Area (SPA) /Ramsar and Solent Maritime Special Area for Conservation (SAC).

The current millpond is a 2.9 acre natural reserve for wildlife.  The sea wall fronts a dam with the footpath set on top of an earth bank backed by a clay membrane retaining the pond water. Its unique environmental feature is that its waters occasionally become saline when some combination of Spring tides, low pressure, and south-easterly storms cause the dam wall to be overtopped. The pond is subsequently refreshed with fresh water from the Lymbourne Stream making this a large and highly unusual intertidal habitat.  Usually such intertidal habitats are found on the fringes of estuaries and drain on every tide whereas the sea wall at Langstone millpond permanently retains the pond water, occasionally becoming saline but regularly refreshed by the incoming, chalk-fed spring water from the Lymbourne Stream. This unusual phenomenon provides a habitat which is rare in the UK.  Its size and seclusion make it an attractive nursery for a wide range of bird species, and yet this public amenity is also readily accessible, free of charge, to local people.

The inclusion of the millpond and paddock in HBC’s Langstone Conservation Area, recognises the importance of the mills, the millpond, the dam and sea wall as an integral part of this important heritage site.

Ownership and responsibility

The sea wall is not registered as the property of the owners of the mill, nor is it an asset registered to the Chichester Harbour Conservancy, whose responsibility includes the intertidal zone in front of it.

Extract from the Land Registry title plan showing the boundary of the mill

Since there are no homes at risk of flooding behind the sea wall, the Environment Agency and Natural England, both non-departmental public bodies sponsored by Defra, have neither responsibility nor legal obligation for the maintenance. Significantly, they also deny any justification for the use of ‘Flood Defence Grant in Aid’ funds for this purpose. (It is that aid program which is underwriting the massive sea defence work seen around Portsea Island.)

Hampshire County Council is responsible for the management of the public’s right to access and use the public footpath, but has no legal responsibility for maintenance of the sea wall.

A Langstone Flood and Coastal Erosion Risk Management (FCERM) Scheme is currently being developed by Coastal Partners to reduce the flood and erosion risk to the community, important heritage assets and the A3023, the single road access to/from Hayling Island. Following extensive option, environmental and economic appraisal, replacement of the defences fronting the millpond were deemed not financially viable and therefore are not part of the proposed scheme at Langstone.

Havant Borough Council has permissive powers under the Coast Protection Act 1949 to undertake “any coast protection work, whether within or outside their area, which appears to the authority to be necessary or expedient for the protection of any land in their area.” However, it appears that the current approach by HBC and HCC is to cover only land on which home or business properties are at risk, ignoring the obvious potential for loss of heritage, amenity and locally designated habitat. The local authorities appear also to be suggesting that no central funding can be made available to protect against such a risk, whereas it appears that the Environment Agency may be able to make grants available to local authorities for such work under the Flood and Water Management Act 2010, with conditions as to repayment.

The local authorities have seized on a blanket high-level argument by the Secretary of State responsible for Defra that “It is more likely than not that the opportunity to rollback would produce a healthier saltmarsh of more variable composition, which would enhance the quality of the protected sites”. That argument is undoubtedly true in the overall context of the 86 km shoreline of Chichester Harbour, where 25 km is already free to rollback, but it’s hardly a convincing argument for abandoning the 200 metre stretch of sea wall which protects the millpond and the paddock. An argument should be made that the unmanaged realignment at Southmoor has already added three times that length of coastline in mitigation.

The overriding fact is surely that the millpond is a fundamental part of one of Havant borough’s premier heritage and outdoor amenity assets – free of charge to all. It’s an asset which punches well above its weight to a world-wide audience. As a natural branch from the Billy Track and an integral section of the Wayfarer’s Walk, the dam and the sea wall form a well-known and well-trodden coast path which the families of local residents and visitors have enjoyed for generations.

Allowing the wall to fail will result in the failure of two ecologically interdependent SINCs; the pond and the paddock. Placing a recycled plastic boardwalk over the muddy wreckage is surely not the best solution that can be found for such a much-loved public amenity.

The actions needed

Faced with conflicting priorities for already inadequate funding, the local authorities seem content to play a waiting game in the hope that the force of nature will eventually take the issue off the immediate agenda as it did with Southmoor. To defend political positions, the various national and international environmental and ecological designations are being played like cards in a game of Top Trumps. The local authorities, Havant Borough Council and Hampshire County Council, seem more concerned with bowing to generic guidance from Natural England rather than challenging Defra and putting the specific case for their own locally designated environments. HBC and HCC appear to accept that EU and national designations at the Chichester Harbour level should trump local designations such as the millpond and the paddock, a position which is overly simplistic and not supported by local residents.

Stuck in the middle, while some at very local levels might disagree, Coastal Partners are doing a solid job of ensuring that the right coastal engineering solutions are being delivered for the areas within the priorities set by Defra for funding. With so much of the Solent shoreline at risk from sea level rise, sacrifices will inevitably have to be made and that’s where HBC need to step up, with the support of the borough’s MP, to fight the case for the millpond. That fight will only be won when the heritage and amenity cards are played together with the local habitat card.

As far as climate change is concerned, the main coastal defence designations for stretches of coastline are ‘Hold the line‘ (maintain the existing coastline), ‘Advance the line‘ ( build new defences out from the shore) ‘Managed realignment‘ (enable controlled rollback) and ‘No active intervention‘, (do nothing). The North Solent Shoreline Management Plan (2010, last updated 2022) shows the millpond included within an ‘Important Heritage Site’ and designated the entire coastline between Wade Lane and Southmoor Lane (Policy ref. 5A18) as ‘Hold the Line‘, noting that “further detailed studies are required which consider whether ‘Managed Realignment’ may occur at Southmoor”.

The opinion previously put forward by HBC representatives that the ‘advice from Natural England is clear’, effectively that ‘do nothing’ is the only option, in our opinion is wrong. That would condemn one of the borough’s most important environmental, public amenity and industrial heritage assets to the history books, taking with it a locally important, globally appreciated tourist site. If that sentence doesn’t cause Havant Borough Council and our local Member of Parliament to join forces, stand up and fight the case with central government, then the public will likely express its opinion at next year’s elections.

These are complex arguments and with constraints on funding there seems a lack of will on the part of the authorities to fight for a long term solution which will preserves Langstone’s heritage, habitat and amenity in balance. We would encourage concerned residents to write to our member of parliament, Alan Mak MP, copying Cllr. Alex Rennie as the leader of Havant Borough Council and your local ward councillors, calling for a concerted effort to push back against the Secretary of State for Defra and argue the wider case for investment in a properly thought out solution.

If all else fails, then there are local precedents for community-driven sea defence work. You only need to look a little further round the same shoreline to see the work undertaken by the ‘Friends of Norebarn Woods’. The problem they needed to solve was rather more straightforward and the ownership of the land was not in dispute – it was Havant Borough Council. Times and scientific thinking have now moved forward and with a necessary focus on the effect of sea level rise on the entire coastline, any local ‘small scale’ project would need to take into account its relationship with the land and the shoreline on either side of it.

Immediately east of Wade Lane, the England Coast Path follows the shore – already inaccessible at high water spring tides – and the only sea defence there is provided by a line of vertically-stacked railway sleepers recycled from the Hayling Billy line. Since the current Environment Agency coastal erosion risk map shows the strategic direction for that section as ‘Hold the line’, perhaps that would be a better use for the ‘recycled plastic boardwalk’.

Sign the petition

Last year, hundreds of people signed a petition launched by Margaret Tait to address the subject of the millpond. The petition is still open, so please, if nothing else, add your voice to the campaign.

Click the image to sign the petition

Further reading

Coastal Partners – Langstone to Wade Lane damage status
Langstone Long List Options report – Aecom, 2018
Chichester Harbour Conservancy – Langstone Millpond ecology report – December 2022
Condition review of Chichester Harbour sites: intertidal, subtidal and bird features – Natural England (Feb 2021)
North Solent Shoreline Management Plan (Southmoor to Wade Lane)
The Southern Coastal Group (SCG) and Standing Conference on Problems Associated with the Coastline (SCOPAC)
Friends of Norebarn Woods
Defra MAGIC map tool
EA Coastal Squeeze webinar
Flood and coastal erosion risk management report
EA coastal erosion risk map
Coast Protection Act – 1949
Chichester Harbour – Facts and figures
Chichester Harbour Conservancy – Langstone Feasibility Study specification – 15 May 2023
Langstone Village Association – Article in the Hayling Herald, Gemma Nash
The tide mill institute
Earth dams – Types, construction and failure

An aerial view

Drone view of Langstone, with the millpond prominently on show.

Courtesy of ‘Drone Local’, aka Paul Minay, whose terrific local drone videos can be found here on Facebook.