Last year, we published an article questioning the anticipated cost of the North Bexhill Access Road (NBAR). According to funder the South East Local Enterprise Partnership (SELEP), the road was going to cost a total of £16.7m.

We thought this seemed a little low. The NBAR is 2.4km long, giving a per km cost of around £7m. By contrast, the Bexhill Hastings Link Road, at 5.6km and £125m, has cost (so far: there may yet be more increases) £22.4m/km, or over three times the per km cost of the NBAR. Even allowing for the engineering challenges of building a road across a flood plain (and in fact, the NBAR will also cross a floodplain), this discrepancy seemed excessive.

Cost downplayed to secure funding?

Members of Combe Haven Defenders (CHD) questioned the seemingly very low cost of the road at the NBAR ‘consultation’  in 2015, suggesting that the real cost – based on the per km cost of the Link Road – was likely to be closer to £50m. They were scoffed at by the engineer present, who said that if the road were going to cost that much, it would never be built.

Combe Haven Defenders were suspicious that the real cost of the road had been downplayed, in order to secure funding, and that at a date where the project could not be stopped, SeaChange would ask for more money. CHD set up a petition to SELEP, demanding that no more funds be spent on the NBAR. No response was forthcoming.

Bridge replaced with culvert

Now, however, it would appear that funds may be getting a little tight. In April, road developer SeaChange Sussex put in a planning application to replace the planned bridge over the Combe Haven stream (just to the west of the proposed roundabout at Buckholt Lane) with a culvert (basically a concrete structure channelling the stream into a pipe or – in this case – a square ‘box’ culvert under the road).

Map of culvert location

Map showing location of bridge to be replaced by culvert, just off Buckholt Lane

According to the report prepared by their engineers as part of the planning application:

‘Significant thicknesses of  peat bearing alluvium were encountered and following a detailed geotechnical assessment of the area around the Combe Haven stream, the proposed  Scheme seeks to introduce a crossing structure with a geotechnical solution more appropriate to the scale of the overall NBAR scheme.’

‘Value engineering’

We’re not engineers, and can’t argue with this. However, East Sussex County Council (ESCC) has a different view on the reason for replacing the bridge with a culvert. In a July 2017 report on the Local Growth Fund (the central government money being used by SELEP to fund the NBAR), it states that:

‘Changes to the design of NBAR as part of a value engineering exercise have meant delays due to seeking amendments to the extant planning permission. Should the change be accepted by the local planning authority then the new design will include a culvert through an embankment for the Combe Haven rather than requiring the construction of a bridge.’ (italics added)

So according to ESCC, it’s not a ‘geotechnical solution’ but ‘value engineering’. This can be defined as ‘the process of reducing the cost of producing a product without reducing its quality or how effective it is’. Which rather begs the question: if a culvert is just as good, and is likely to be cheaper (see below), why did the original application specify a bridge? There must have been some reason why it was considered superior to a culvert at that point.

You might say that there’s nothing wrong with reducing costs without reducing quality, and we’d agree. However, is this ‘value engineering’ or is it straight cost-cutting? Will a culvert be as good as a bridge?

Culvert under construction. Photo John and Elaine Chesterton, flickr

A culvert (not on NBAR) under construction. Photo John and Elaine Chesterton, flickr

Not so good for pedestrians, cyclists and horseriders…

Well, if you’re a pedestrian, cyclist or horserider, the answer must be no. The road design includes a ‘greenway’ which was to run under the proposed bridge, so non-motorists didn’t have to cross the road. Now, you’ll be forced off the greenway and have to cross a busy road instead (the report by the planning officer says that an ‘at grade crossing’ will be provided but gives no details of whether this will be an actual pedestrian crossing with lights). The loss of the underpass is described in the report as ‘disappointing’.

Not so great for wildlife…

It’s not so great for wildlife, either. The bridge was designed to allow space for planting of a continuous belt of scrub underneath, providing an important route for mammals whose territories will be divided in half by the road. The culvert instead will have a ‘shelf’ for larger mammals, and a dormouse ‘bridge’ (a thick rope). For bats, there will be a ‘severance of continuous woodland/scrubland belt, which may have been used as bat flyway’.

Whilst all these issues are considered in the engineer’s report to be of no significance, the Environment Agency is not so sanguine about culverts, stating that culverting ‘can destroy wildlife habitats, damage a natural amenity and interrupt the continuity of the linear habitat of a watercourse’. In addition, the Agency says, ‘Culverts can be impassable to riverine fauna and can create barriers to the movement of fish’, and ‘Culverting results in the loss of natural in-stream and bankside habitats through direct removal and loss of daylight.’

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Approximate site of culvert – Combe Haven stream runs along treeline

Flooding?
The Combe Haven stream is classified as a flood zone 3b, which is to say a floodplain. According to the Environment Agency, ‘Culverting can increase the risk of flooding’ (because a culvert, unlike a river, is easily blocked).

And whilst the Environment Agency has not objected to this particular application, their overall view of culverting is very clear: ‘No watercourse should be culverted unless there is an overriding need to do so’ (italics added).

Overriding need to cut costs?

Whether there is an overriding need to substitute a culvert for a bridge in this case, is not at all clear. What is pretty clear, however, is that culverts are cheaper to install than bridges (see here, here, here and here ). We suspect that’s the real reason for this redesign, and that before the NBAR is finished, we’re likely to see either more ‘value engineering’, or SeaChange going back to SELEP to ask for more money.