Sinah Lane: Deputation Rosie Law

Rosie Law: Deputation DMC 29th October 2020 APP/18/00724

Brent Geese

A major issue with this application is the protection of Brent Geese and Waders.

This 12.4ha of land is designated as a Primary Support Site, yet only 5.7ha of land will be kept

as an onsite refuge.

To mitigate completely for land lost to this development, and also the Oysters, another larger

proposed refuge at E26 (now IN1K) needs to run alongside.

It is stated in the Officers Report (Item 3) that E26 is adjacent to the onsite refuge. This is not

the case.

E26 is separated from this site by a Salt Marsh causing fragmentation in the Brent Geese

network.

E26 itself, lies within Flood Zone 3, and just like the North West boundary of this development,

is already being rapidly degraded by coastal erosion.

The Hayling Billy Trail was even to be moved inland to avoid this erosion.

What this means in practice, is that the land that is set aside to mitigate land lost for

development, is already decreasing in size – something that will be further exacerbated by the

effects of climate change.

It is therefore not sustainable now and certainly not for the lifetime of the development.

Furthermore, the proposed refuges need to actually be proven to work prior to development.

As seen in the Officer’s Report, there is still no clear evidence of an obligatory binding

agreement for the future management of these refuges.

“Page 15, Public Reports Pack 29102020 AKA. The Officer’s Report”

Currently, crop rotation is used on this land which reduces the amount of fertiliser and pesticides

required. Changing the land-use to a bird refuge will require mono cropping and increased use

of fertiliser and pesticides. The structure of the soil will also deteriorate, making nutrient runoff

into Langstone Harbour much worse.

Drainage

The Flood Risk Assessment (FRA), only published in March this year, raises many alarming

issues.

Not only does it confirm Southern Water has rejected any future involvement in the SuDS, it

also shows that Langstone Harbour will now be the final destination of water drained from this

site - 2 key revelations that really do cast doubt on the sustainability of this proposed drainage

system.

It should be noted that instead of Langstone Harbour, the FRA states ‘Sinah Lake’. This should

not be confused with the ‘Sinah Lake’ south of the site, the FRA is referring to a lesser known

channel that’s wholly within Langstone Harbour!

Underground fresh water is proven to lie very close to the surface of this site, as close as 45cm

below ground level in some areas.

The site has a less permeable clay layer just below the surface which currently separates

surface water from the groundwater. This layer will be compromised by the development.

The clay layer will be punctured by man-made structures, such as housing foundations, which

go deeper than 1m, creating a link between the groundwater and surface water.

Once the clay layer is compromised, attempting to drain this surface water, by pumping, will also

result in pumping up an endless supply of groundwater beneath the field that also rises and falls

with the tide.

This calls into question the feasibility of this drainage technique for this site.

Continual pumping, disturbance and extraction of groundwater from beneath a clay layer is a

known cause of subsidence. This will result in a serious issue with not only this development but

also existing houses.

Currently, the site floods with a vast volume of surface water, particularly in winter months. Once

the proposed attenuation pond reaches capacity, something very likely in winter, the SuDS will

need to move water offsite at the same rate and volume generated by precipitation (winter

storms etc.).

The rate and volume of this overflow will overwhelm any filtration system, so overflow leaving

the site will contain decades of farming fertiliser along with pollutants and nutrients from

households and building processes.

It is absolutely unacceptable that not only will this contaminated water be purposely directed into

offsite habitats such as the Saltmarsh and ancient natural ponds, but will end up draining out

into Langstone Harbour.

This is similar to what happens to Southern Water’s raw sewage after heavy rainfall in what

some describe as a ‘licensed discharge’, others would describe this as a reasonably

foreseeable failure of planning and insufficient infrastructure capacity - certainly not a starting

point for development.

This proposal is clearly not a sustainable development. The drainage plan represents a threat to

the surrounding offsite environment, including the adjacent dwellings, and the mitigation for

ecology and the transport network will not prevent a severe impact from this development.