Sustainable engineering

The days are gone when a would-be developer could buy up any old plot of land and build whatever he wanted with scant regard for the surroundings. Many schemes have been disastrous in terms of their impact on the local natural and human environment, compounding traffic problems, increasing the risk of flooding and reducing habitat for endangered species of plants and animals.

The prospect of obtaining consent for development on most available sites is now influenced by a host of
environmental and regulatory issues. Engineering design for developments is increasingly about much more than structures, roads and drains. And the modern building engineer needs to embrace sustainable development as closely as he or she understands bending moments, fluid mechanics and materials.

“When environmental issues first began to make their presence felt in development, they were seen by many as obstacles to be overcome,” says Richard Bettridge, managing director of Bettridge Turner & Partners. “This attitude often led to developers adding expensive environmental mitigation to conventional engineering designs.”

Things have changed fundamentally: “It is no longer acceptable to address environmental issues by merely providing a bolt-on report appended to a planning application,” he says. “Sustainability is a principle that is fundamental to every project, to be applied to the earliest concepts and embodied throughout the design and construction stages, as well as in the operation of the completed development. Accepting this reality can save time, and often produces solutions which have less environmental impact at lower development cost.”

Building on past lessons

When evaluating developments, the project’s interaction with the surrounding environments need to be carefully considered from conception through to completion. Failure to give proper consideration to sustainability can lead to lengthy, frustrating and costly conflicts between developers and planning authorities and/or local communities.

Adding retrospective environmental mitigation measures to conventional schemes can be expensive, and often produces inelegant solutions – both functionally and environmentally. This is why the sector is increasingly moving on to a much broader and more sustainable approach.

“Developers who persist in treating sustainability as an impediment to be challenged or overcome with gimmicks or embellishments to otherwise conventional designs are likely to be frustrated,” argues Ed King, of BT&P subsidiary King Environmental. “They will do better if they treat sustainability as an ally and an opportunity rather than as an hindrance.”

Systems thinking

A common thread running through sustainability is ‘systems thinking’ – the concept that the real world is a complex interdependent system. The traditional approach of reducing assessment of a particular development to single unconnected specialist issues is often shortsighted and seldom results in a sustainable solution.

A fully integrated approach can save time and money, and it is likely to produce solutions which are superior from both an environmental and functional perspective.
A multidisciplinary approach
By taking account of all the issues surrounding a potential development right from the outset, proposals can be developed which address the full range of design requirements and are cheaper than retrospective mitigation.

A multidisciplinary consultancy can achieve this while reducing the client’s time absorbed in managing different specialists with conflicting agendas. But it is no longer sufficient to have environmental and sustainability specialists in the back room, available when the authorities get tough.

Companies such as Bettridge Turner and Partners are going a stage further, having introduced sustainability training for all staff and offering sustainable advice from the outset.

An integrated approach

The benefits of this integration can be seen in the project to build a relief road serving Bolnore Village, Sussex, where BT&P was retained to provide development consultancy and project management services on behalf of developer Crest Nicholson (South). “The route of the new road passes through some of the most sensitive countryside in the south east of England,” BT&P’s Brian Gooch says.

The project included environmental and engineering support from the planning stage through detailed design and technical approval, to contract administration and site supervision. It has also seen the first UK commercial application of a Matière arch, bridging Foundry Brook.

The 10m span of the structure is sufficient to accommodate a safe wildlife route along the banks of the watercourse beneath the carriageway. Combined with badger fencing along both sides of the road, the structure will reduce the risk of road death to mammals such as local badgers and otters returning to the headwaters of the river Ouse.

The principal alternative – an open span bridge – would have been three times the width and four times the cost, with substantial foundations at either end. The Matière system is the ideal all-round solution, according to Andrew Yeardley of Crest Nicholson: “The Matière bridge meets our functional requirements and satisfies the Environment Agency’s conservation objectives at a reasonable build cost.”

On previous sections of the road, BT&P has designed wildlife mitigation measures including otter ledges, badger tunnels, amphibian tunnels, permanent newt fencing and rope bridges linking the canopies of adjacent trees. Specially created for this road, the rope bridges are intended to provide an aerial link for the local dormouse population.

Allies or adversaries?

With some justification, there will always be concerns from ecologists and residents about proposed changes to land use. On this crowded island, builders will inevitably come into conflict with the environment. But developers still have an important job to do, providing the homes, business premises, leisure amenities and transportation required.

The integration of environmental and civil engineering consultancy is the industry’s response to the challenges it faces. “This is spawning a new generation of multi-disciplinary engineer, for whom sustainability is a central feature of their art,” asserts Richard Bettridge.

Some developers may attempt to bury their heads in the sand and ignore or defeat the environmental consequences of their work. But Bettridge says: “Firms which embrace these considerations and make sustainability their ally are likely to make faster progress and be more successful. They will also have the satisfaction of bequeathing to subsequent generations a better balance between the natural and built environment.”