The greening of St.Helens' Stanley Bank Triangle as part of the creation of the Blackbrook link road has been calculated to be worth £15m to the borough. The scheme was showcased earlier this year as an example of best practice at an international conference in Toronto.
In recent years a wide range of partners including St.Helens Council and The Mersey Forest have worked to improve the important green area - including a Site of Special Scientific Interest (SSSI) - through which the new Black Brook diversion passes.
20,000 trees have been planted, grassland and woodland habitats have been brought into management, and a sustainable drainage system has been put in place.
The project has also helped people visit and enjoy the local wildlife, with 1,500 metres of new paths created, and facilities at the Sankey Valley Visitor Centre upgraded. Local people have also been involved in community archaeology at the area's iron-slitting mill to bring further educational benefits.
The road scheme has won both Public Project of the Year (Builder and Engineer Awards) and Green Construction Civil Engineering Project of the Year (Construction News Awards).
Site inspector Brian Williams commented: "In eight years and 1,500 site visits as a Considerate Constructors' Scheme Monitor, this is by far the best highways project I have ever seen."
Using the prototype Green Infrastructure Valuation Toolkit developed by the Natural Economy Northwest project and other partners including Defra, the benefits of the greening project (which received £1.6m of initial investment) have been valued at £15.2m.
More than 75% of this comes from the health and wellbeing benefits that the project will bring to local communities. This includes reducing health bills by helping people to do more walking and cycling, and avoided costs for air pollution control measures, with the area's new greenery absorbing airborne pollutants naturally.
Other valuable benefits of the project include the boost that it will give to local land and property values, and the premium that people attach to living in an area that is rich in wildlife. Other contributing factors include reduced water management costs and savings made on heating bills for nearby buildings sheltered by the 'wind break' provided by the area's new trees.
The results from the use of the toolkit on the Stanley Bank Triangle were presented by The Mersey Forest at the international Greenbelts Conference in Toronto in March 2011. The conference was attended by environment specialists from all over the world, including Brazil, Germany and Australia, as well as key UK figures including Chair of the Forestry Commission, Pam Warhurst.
The Stanley Bank road and greening project has received funding from a range of sources including the Heritage Lottery Fund, an EU Objective One Mersey Forest grant, and the Department for Transport.