Measures to deal with flood risk have been challenged by a developer promoting land south of New Monks Farm.
Hyde, which owns land at New Salts Farm, has questioned details in New Monks Farm Development Limited’s flood risk assessment.
Hyde’s planning consultant Boyer raised concerns in an official representation as part of the ongoing consultation into plans for IKEA and 600 homes.
The two-page letter states Hyde is ‘not convinced’ about claims the development would reduce flood risk for homes south of the railway line.
New Monks Farm Development Limited director Martin Perry issued a lengthy rebuttal to Hyde’s representation when the Herald asked for comment.
The letter read: “We do believe that there are some positive aspects to the flood risk assessment and proposed drainage strategy for the New Monks Farm site.
“However... we are not satisfied that there is a sufficient level of detail to demonstrate that the flows into the southern outfall ditches, and beyond onto our client’s neighbouring site, would not be increased.”
Hyde challenged the planning application’s analysis of the water flows in the Lancing Ditches.
It said its data suggested flows were mostly south to north, while the plans stated the opposite.
Hyde said this could have a ‘significant impact’ on the conclusions of the flood risk assessment and more detailed modelling was needed.
In response, Mr Perry said numerous survey locations and bore holes had provided a ‘constant supply’ of data to evidence his firm’s claims.
He said: “The evidence collected clearly shows that the hydraulic gradient on the groundwater across the New Monks Farm site runs from north to south. There has never been a recorded occasion when the water in the watercourses south of the railway has flowed back into New Monks Farm through the culvert underneath the southern end of the hard airport runway.”
Another Hyde concern centred on the amount of data collected. It said relying on a year’s worth of information, rather than predicted risk, meant it was ‘very unlikely’ that a one in 100-year event would have occurred and was therefore not factored in.
Mr Perry said it was ‘clearly not reasonable’ to record data over a period of 100 years or wait until a one-in-100-year flood occurred.
He said the flood measures were capable of accommodating such an event, plus an allowance for climate change.