Introduction
The report on the potential technical options for a solution to the ‘Langstone Millpond issue’, commissioned by Chichester Harbour Conservancy, has now been published and is available for all to read. The report was put together by Royal HaskoningDHV and presents the background to the issues, highlights a number of possible solution options and documents a preferred recommendation which reflects the viewpoint of the Chichester Harbour Conservancy.
The document is well set out and should be read in depth before drawing your own conclusions. (You can open the report directly by clicking the image below. If you are viewing this post on a PC or tablet, the report will open in a separate browser tab alongside this post for ease of reference.)
The report’s primary focus is on environmental and coastal engineering matters, perhaps unsurprising given its sponsorship and authorship. That said, there are three key areas which need to be explored fully before options can be ratified and a balanced recommendation made:
The first is an assessment of the impact on local heritage and amenity value, the second is an appraisal of the site in the context of its location at the interface between the various administrative boundaries and the third is engagement with the affected landowners. The report sets out to draw ‘independent’ conclusions without such third party engagement and agreement, an approach which calls into question the viability of its findings without additional elapsed time and effort being spent on completing the picture.
The options
The report itself sets out four distinct options, one of which has three variants. The first option is the self-explanatory ‘Do Nothing‘ scenario in which the existing wall failure at the eastern end of the pond, close by the end of Wade Lane, is left to fail in much the same manner as the earlier failure at Southmoor.
The second option is termed ‘Maintain‘ and would see the coastal defences repaired and maintained to the currently-designed standard of protection, prolonging the life of the seawall while guarding against a breach. In this option the wall would not be increased in height or width. The repairs identified and costed include rebuilding the failed sections of the wall, repointing the mortar joints along its entire length, securing of any loose bricks, repairing the path at the southern end and rebuilding the pondside retaining wall. Removing unwanted vegetation and restoring and servicing the sluice gate would complete the scope of work.
There are three variants of the third option, ‘Improve‘. The first variant replaces the existing brick structures with a concrete seawall. The second is effectively the same as for the ‘Maintain’ option, but allows for the addition of an ‘upstand’ wall in a future phase to add protection against future sea level rise. The third variant replaces the entire dam and wall by a wider and taller embankment on the same plan but with a wider footprint than the existing dam.
The fourth option, the one selected as the report’s recommendation, is a ‘Managed Realignment‘. In this option, the existing failed part of the wall would be removed, allowing the tidal flood plain to move inland ‘in a controlled manner’. Assuming the lessons from Southmoor have been learned and the necessary level of management can be secured, the report suggests different options to manage or compensate for the inevitable loss of freshwater habitat. These include an option to develop a new freshwater lake, fed by the Lymbourne stream situated on Langstone Meadow.
Observations
The Executive Summary at page x, reflects the Chichester Harbour Conservancy’s desired outcome expressed in disappointingly inaccurate language. This is of concern since this may be the only section read by many who will be called upon to ratify recommendations and make decisions on the way forward. The following paragraph, in particular the sentence highlighted in bold, contains unevidenced assertions which seem to drive the whole report to the inevitable conclusion:
“Maintain and Improve options are not considered viable due to high costs and planning considerations, especially considering that any investment will be offset by the fact that the sea wall will be overtopped more frequently in future leading to a habitat transition in the mill pond anyway. The improve option could delay this transition but it is not sustainable or environmentally responsible to create a “freshwater island” within a coastal zone. The Do Nothing option is a high risk strategy as there will be no control on the timing and location of breaching which would cut off the footpath and coastal access, but also shock the habitats by not allowing them the time to transition gradually.“
We assume that the misuse of the geographical term ‘freshwater island’ is intended to define a feature which is an exclusive body of fresh water within an otherwise saline coastal environment. The Havant community fully understand that the millpond is not currently a freshwater body, nor will it be at any time in the future. The pond’s unique habitat is naturally brackish due to regular overtopping with seawater from the harbour, and has a variable salinity which will increase over time with increased overtopping from the south and variable freshwater inflow from the north.
Turning to the report ‘Options’:
The ‘Do Nothing‘ option is rightly discounted within a couple of pages. Rather than document it as an ‘option’, the report should simply have stated the obvious, that doing nothing is not an option. After the experience at Southmoor, where a planned ‘Managed Realignment‘ was overtaken by an unplanned storm breach before any planned construction work was carried out, there is understandable concern that without timely action, the same fate will befall the millpond. The prevailing view within the Havant borough community is one of frustration with the inability of ‘the authorities’ to enable the undertaking of repairs. With another winter setting in, the unsatisfactory outcome at Southmoor provides an object lesson for the Langstone millpond and also indicates that much greater urgency should be applied to the delivery of a pragmatic solution without recourse to continued protracted debate.
The ‘Maintain‘ option – more accurately ‘repair and maintain’ – clearly outlines the solution which has been sought by the borough residents from the outset and it is frustrating to see it raised and discounted as an option in this report. Like a game of Chinese whispers, the interpretation of that simple request now appears in this report to have been over-complicated and overwhelmed by unnecessary bureaucracy. It would be helpful here to bring the focus back to the original request.
The local residents, supported by Havant Borough Council, simply want the existing structure repaired and maintained as it is, keeping the walking route unchanged. The sea wall is in its current state because of the lack of routine maintenance over the last forty years. Had the responsibility been ‘owned’ and maintained by ‘some body’ after the local authorities funded the previous repairs back in the 1980s, a regular annual summer ‘check and essential maintenance’ regime should have warded off decline at reasonable cost. The estimate for the repair and ‘maintain’ option is set out in the report as £144,000, which appears to be a reasonable sum, albeit with an additional, un-costed, ongoing annual maintenance component.
Table 5 and Figure 9 in the report show that it would only be necessary to raise the sea wall by 23cm to limit overtopping events to one per year up until 2050. (Using pessimistic sea level predictions.) This could be achieved with a parapet only four bricks high. There is no need for a fancy scheme such as illustrated in Figure 20 and accordingly the cost of Option 7.2 should be much less than quoted.
All the ‘Improve‘ options include the statement that “Gaining planning permission for this option will be challenging, as it does not align with the environmental and conservation objectives of the regulatory bodies.” This is situating the appreciation. The purpose of the report is to recommend solutions, not proceed from an acceptance that bureaucratic obstacles are insurmountable.
Having discounted the ‘Do Nothing’ and ‘Maintain’ options, the ‘Improve’ options appear to have been included simply to steer the reader towards accepting the preferred recommendation for ‘Managed Realignment’.
Without engagement with the landowners, it is hard to see how the ‘Managed Realignment‘ option came to be considered as a recommendation, though the sceptical reader might conclude that this particular recommendation had actually been the starting point for the report. The optional creation of a new freshwater habitat within Langstone Meadows suggested in the recommendation is particularly curious, considering constraints in the title deed for the land.
The brief heritage summary in the report at Section 3 (pages 17, 18), appears to be more for background interest than as a key input to the options and recommendation. The heritage value associated with the Langstone mills is significant to the local Havant borough community. When considered in association with the local Billy Track, the regional walking and cycling routes and the national coast path, the amenity value to the general public and the value to tourism in the borough should not be ignored.
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 is 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.
Rerouting the path
The walking route around the millpond forms an integral part of the Wayfarer’s Way, the Solent Way and is the currently planned route for the King Charles III National Coast Path. The Langstone Village section, with its two waterside inns and the tranquillity of the millpond has amenity value recognised world-wide, thanks to the long history of businesses in Havant with global workforces. With the proximity to the Billy Trail route for cyclists and pedestrians from Havant station to South Hayling, the environs of the millpond are one of Havant Borough’s most important destination sites for leisure and tourism.
Rather than taking the unnecessary step of rerouting the path inland via some currently undetermined boardwalk, walkers simply need to appreciate that at some states of the tide, coastal walks may be temporarily cut off as currently happens to the east of Wade Lane on Spring tides. As the frequency of inundation increases in the medium to long time frame, there might be justification in considering a secondary alternative inland route, perhaps a cycle path, once the relationship with the landowners is established. However the rush to replace the current walking route with an inland ‘boardwalk’ is premature.
The acceptance of natural change
The Havant community fully accept the inevitability of sea level rise and the need for climate change adaptation. In the main, they also accept the reality that there is little justification and no ready source of funds for the building of future-proof sea defences of greater height at the millpond. The gradual increase in the frequency and extent of overtopping is understood to be inevitable, as is the consequent increase in salinity of the pond habitat. Maintaining the historic footprint of the pond at its current height during this gradual change in sea level would allow a natural transition alongside other local environmental change over the same timescales.
It’s not surprising that Managed Realignment has been selected as the recommendation since the primary goal of managed realignment is the creation of a new habitat, specifically a saltmarsh habitat, inland of the sea wall. The report concludes that the Managed Realignment option enables “space [to] be created to allow the saltmarsh to adapt naturally to changing environmental pressures reducing the effect of coastal squeeze.”
Like all good citizens, the Havant borough community share concerns for the health of both Langstone and Chichester harbours and the “continued loss of seaward intertidal habitats”. However, rather than place blame for the historic loss of seagrass on 200 metres of sea wall at the very margin of the AONB, Chichester Harbour Conservancy and the Environment Agency should perhaps place greater focus on the excessive nitrate and phosphate laden discharges which have been entering the water body for years at the Thornham, Nutbourne, Chichester and Lavant combined sewer overflows.
In summary
The report presents and reflects the viewpoint of the Chichester Harbour Conservancy. In order to arrive at a balanced outcome, the Havant borough community needs to ensure that the missing arguments are properly presented. Time is of the essence and continued protracted delays in arriving at an acceptable solution appear only to enable the Conservancy’s wishes, by default. The unfortunate result of the lack of engagement with landowners is that the proverbial can has just been kicked down the road again.
To move forward, we have to recognise the value of the broader heritage and amenity asset of which the millpond is an integral part, linked to Havant and Hayling via the Billy track. The document lays out a summary of the ‘history’, but fails to link that with ‘heritage’ and ‘amenity’ and completely ignores it in its recommendation.
The report indicates (at sections 2.9 and 7.4.5) that some of the land areas of interest are of unknown ownership. In reality however, the ownership is not in question, even if there may be uncertainty over the maintenance responsibility for the features fronting the shoreline. Given the ease with which simple Land Registry checks can be made, it is surprising that the authors of the report did not engage with the affected local landowners at an early stage before deciding on the direction taken.
In the second part of this two-part post, we look in more detail at the history, the land ownership and the interfaces between the administrative boundaries, drawing attention to the importance of keeping a sense of scale and context.
Havant Civic Society 