Development of New Monks Farm for 600 homes and an IKEA could affect ‘fragile’ Lancing and exacerbate historic flooding issues, residents fear.
Flooded roads and gardens and sewer back up have caused misery across the area during wet winters.
New Monks Farm, west of Shoreham Airport, is key to ensuring Lancing remains above water, with drainage ditches and culverts running through the site.
New Monks Farm Development Limited – a subsidiary of Brighton and Hove Albion – believes its plans will address flood risk.
But long-term flood campaigners have employed professional help to scrutinise their plans. Bill Freeman, chairman of Adur Floodwatch, said there were ‘issues’ with the proposals but declined to comment in detail while advice was being taken.
But pointing to Lancing’s long-term flooding woes, he said: “I know the grief and problems it causes with the sewer inundation and people with water lapping at their doors. It is not a nice experience. It is a great concern.”
Mr Freeman said the village was ‘fragile’, mainly because of groundwater in extreme weather. The only way for it to drain into the River Adur was through the Lancing Brooks ditch network, which runs through New Monks Farm, he explained.
“This is why we are concerned about in-filling with concrete 30 hectares of New Monks Farm,” he said.
“It can only accelerate water into those ditches which will cause problems. It is risky business.”
West Sussex County Council, together with consultants CH2M, produced the Lancing Surface Water Management Plan in 2015, to highlight a long-term strategy for the village.
Even with a range of suggested long-term measures, the report claimed Lancing would ‘still be at risk of flooding during more extreme weather events’.
It stated: “This is because drainage systems and any other flood risk infrastructure will become overwhelmed during extreme weather events. In addition, Lancing is highly vulnerable to groundwater flooding which is significantly more technically and economically challenging to manage.”
Plans for New Monks Farm include the upgrade and long-term maintenance of the ditch network. Development director Martin Perry said a full flood risk assessment had been submitted, with regular meetings held with the likes of the county council throughout the planning process. Plans will be considered by Adur councillors later this year.
How Albion hopes to tackle flood risk
Developers hoping to build on New Monks Farm will have to demonstrate they can address flood risk from a range of sources.
Fluvial or tidal flooding, groundwater and surface water all pose a threat which will need to be managed.
Perhaps the simplest of the risks relates to flooding as a result of the River Adur, which lies to the east of the site.
The Environment Agency has begun construction of the £25million Adur Tidal Walls river defence scheme, which New Monks Farm Development Limited director Martin Perry said would mean the site was ‘not at risk’ of fluvial or tidal flooding. A bund along the western boundary of the site will also be constructed.
Plans to deal with groundwater and surface water, meanwhile, are more complex.
New Monks Farm Development Limited installed a series of monitoring systems in 2016, including 121 bore holes, to analyse water flows throughout the site.
They claimed this research showed in times of higher rainfall and rising groundwater, water flowed via the Lancing Ditches into the watercourse south of the railway line.
Director Martin Perry said the existing watercourse would be enlarged, together with the creation of a new watercourse along the northern boundary of the site.
“This new watercourse will effectively flow along the spring line on the south side of Old Shoreham Road, relieving the pressure of groundwater as it emerges above the level of the bed of the watercourse,” Mr Perry argued.
A culvert beneath the northern section of Mash Barn Lane will be replaced with a larger culvert, while a pumping station will release water from the northern outfall into the river.
Mr Perry said the northern outfall was currently tide-locked for long periods but the pumping station would create a ‘continuous outlet’ and increase capacity in the drainage system.
A management company will be set up to ensure regular maintenance of the watercourses, which Mr Perry said had been an issue in the past. He said IKEA and Brighton and Hove Albion, whose training ground lies to the south, had a ‘vested interest’ in ensuring they were maintained.
Bill Freeman, of Adur Floodwatch, said funds should be set aside in case the management company folded in future – but the developers argued this was not needed because of the major parties’ interest in the site. Mr Freeman said even football clubs could experience financial difficulty, hence the need for an instant access performance bond.