The Value of Green Infrastructure

Green Square Group

Background

The Triangle is a high-quality, sustainable 42-home development from Hab Oakus; a joint venture between the Green Square Group and Kevin McCloud’s development company, Hab. The approach takes account of both the housing and surrounding landscape in creating a place that is ecologically and socially sustainable.

The designs are informed by Hab Oakus’ principles of a strong sense of community, a belief in the importance of public space, respect for cyclists and pedestrians, and a commitment to sustainable lifestyles.

Green space at the Triangle

The development occupies a 0.8 hectare site of which approximately 25% is green space. At the centre of the Triangle is a communal green space overlooked by every household which provides a focal point for the community, encouraging social interaction and recreation. There are two kitchen garden areas for food growing, a swale to contribute to the management of surface water run-off and 80 new trees were incorporated into the scheme of which 75% were dwarf or trained espalier fruit trees. These were combined with fruit bushes (blackcurrants, gooseberries, redcurrants and raspberries) to create an edible landscape.

Visit the Haboakus website to find out more about this and other projects, all of which aim to respect and where possible enhance the biodiversity of the existing area.

Valuing the landscape

Using the Green Infrastructure Valuation Toolkit to assess the potential economic benefits of green infrastructure investment made at the Triangle, there is a return on investment estimated at between £230,000 and £400,000 for less that two hectares of soft landscape. These benefits are realised across five main areas:

Climate change

The combination of grass, trees, bushes and climbing plants exhibit a significant cooling effect. The peak surface temperatures are expected to be 8C degrees lower than they were when the site was undeveloped. The benefit, although uncosted, will enhance residents' comfort, particularly during the summer months.

In addition, the benefit from the value of stored carbon in trees (0.3 tonnes of CO2 per year) is calculated at £1,470 at present value. This does not account for carbon stored and sequestered in other forms of vegetation.

Recreation

The homezone and central green with natural play provision provide an important opportunity for play and recreation. Where people have access to good quality green space, they are 24% more likely to be physically active. It is estimated that tending to and harvesting the edible landscape has the potential to draw 20% of the adults living at the scheme.

Land products

The kitchen gardens and fruit trees and bushes have the potential to yield a harvest estimated to be 900kg - 1,800kg of fruit and vegetables per year. The present value of the crop is estimated to be in the range of £14,000 to £25,000. These figures do not account for the value of carbon emissions avoided.

Water management

Incorporating permeable, water absorbent landscape reduces the amount of water entering the local combined sewer system by over 600 cubic metres per year. This in turn reduces the need for water treatment lowering associated operational costs, energy consumption and carbon emission. The present value of these benefits was calculated to be £4,300.

The soft landscape areas of the scheme were designed to manage and infiltrate on site all the surface water run-off. As a result, the Triangle's residents will be eligible for a rebate on their water drainage service charge. The present value of this saving was estimated at £17,500.

Property values 

Good quality parks and green spaces are proven to enhance property values in the neighbourhood. Using a model developed by the Royal Institute of Chartered Surveyors (RICS), it is estimated that the uplift from amenity green spaces at the Triangle would range between 3% and 6% having a positive impact on the value of the properties. The total value of this was estimated to be between £190,000 and £400,000 at present value. More detailed market analysis would be needed to make a more precise estimate.