GI-Val is The Mersey Forest's green infrastructure valuation toolkit
The current prototype is free and open source, and can be downloaded right here.
User guide Calculator
Supplementary notes on revised runoff tool (tool 2.1)

Creative Commons License

These resources are licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.

Recommended citation: The Mersey Forest, Natural Economy Northwest, CABE, Natural England, Yorkshire Forward, The Northern Way, Design for London, Defra, Tees Valley Unlimited, Pleasington Consulting Ltd, and Genecon LLP (2010). GI-Val: the green infrastructure valuation toolkit. Version 1.6 (updated in 2018).


Valuing our vital green infrastructure

Green infrastructure – the network of trees, parks, green spaces, canals and rivers that lies within and between our towns and cities – is our life support system. It also helps to underpin and drive our economy.  

Like other infrastructure, it sets the scene for recreation, tourism and investment and underpins physical and mental health and wellbeing. When it's lacking or removed, places can fail to thrive. Conversely, well designed, planned and managed green infrastructure can bring a wide range of benefits to local communities and places from reducing flood risk and tackling air pollution to attracting investment and encouraging tourism.

We need a common understanding across government, businesses and civil society on the importance of our shared green infrastructure. That means recognising it as a common good that brings tangible physical and emotional benefits to people; that protects, enhances and energises the economy of our towns and cities; and that is an essential part of the natural ecosystem that we all depend upon. To do that, we need to demonstrate clearly that the multiple and essential functions of green infrastructure give it a significant monetary value.


Why put a price tag on green infrastructure?

The role green infrastructure plays is finally becoming more widely understood. Even so, project managers, funders and client teams often need to provide robust evidence that environmental and economic development projects that include new green infrastructure deliver economic benefits.

Existing green infrastructure can also be under threat without an economic case for its preservation. Whilst the intrinsic value of a rare species, a cultural landscape or a tranquil area in the heart of a town or city may be considered as 'priceless', there is a danger that priceless can then lead to them effectively becoming 'valueless' in economic assessment terms.

There has been a great deal of work carried out to try to value the benefits of the natural environment using a wide range of techniques. Many of these are academic and not accessible to project managers who need to be able to rely on sound data from easily accessible sources to provide a robust valuation that they can employ as justification to funders and/or developers.

To enable such a valuation to be carried out, The Mersey Forest has developed GI-Val. The toolkit calculates monetary values for the social, economic and environmental benefits that green infrastructure provides.


History of the toolkit

The toolkit was orginally developed as part of a Natural Economy Northwest project, in conjunction with other regions across England and with national bodies such as Defra. A range of organisations pooled their expertise to aid the design of an easily accessible toolkit to enable green infrastructure valuation.

The toolkit has been released as a prototype, in a 'Creative Commons' format that means it can be used by all interested parties at no cost. It's not yet complete and still in active development, with a network of users who share information and ideas. Repeated use of the toolkit by The Mersey Forest and other organisations is helping us to refine and modify its contents to make it more suitable for analysing a wider range of projects. The aim is that over time the toolkit will become an increasingly robust model, recognised by decision makers and funders.


How does the toolkit work?

The toolkit provides a set of calculator tools, to help assess an existing green asset or proposed green investment. They are organised under eleven key benefits of green infrastructure:

The toolkit looks at how the range of green infrastructure benefits derived from an asset or investment can be shown:
  • in monetary terms – applying economic valuation techniques where possible
  • quantitatively – for example with reference to jobs, hectares of land, visitors
  • qualitatively – referencing case studies or important research where there appears to be a link between green infrastructure and economic, social or environmental benefit but where the scientific basis for quantification and/or monetisation is not yet sufficiently robust.
The toolkit uses standard valuation techniques to assess the potential benefits provided by green infrastructure within a defined project area. These benefits are assessed in terms of the functions that the green infrastructure may perform, support or encourage, depending upon the type of project.

For example, the diagram below shows how an urban tree planting scheme can result in improved air quality, carbon sequestration and reduced health costs, thereby illustrating green infrastructure function, benefit and potential monetisation.


Once data is entered into the toolkit, it generates financial values for many of the green infrastructure benefits. The toolkit identifies the marginal benefit , the additional value of the green infrastructure, and also tries to ensure that there is no 'double counting' of value.


Current limitations

The toolkit remains a prototype and this means there are some green infrastructure benefits for which it cannot calculate a direct financial value. While there is a rich body of evidence that illustrates and demonstrates the different types of benefits deriving from quality green infrastructure, robust valuation techniques do not yet exist for all benefits. Therefore some valuations come with detailed caveats as they are based on limited evidence at this stage.  

The toolkit's calculation is designed to be useful for initial, indicative project appraisal, providing a range of figures indicating the potential impact of a green infrastructure intervention or the value of an existing green infrastructure asset. The toolkit does not assess the quality of the design or detailed management requirements of green infrastructure. It does not replace a full cost benefit analysis, but it provides a basic valuation at a much lower cost.

Valuations such those made with a toolkit or cost benefit analysis also need to be seen as part of a much bigger picture. The valuation should not replace community engagement and local dialogue about what is valued about a place. Calculating economic value of green assets will always be a controversial technique and financial value should only be seen as one factor in decision-making.

The reported GVA values include transfers from one organisation to another, which means that although GVA increases for the beneficiaries, it may not increase for the study area as a whole.


Real examples of how the toolkit has been used

Alt Meadows green infrastructure assessment (2015)
A section of the River Alt was deculverted in 2014 by The Cass Foundation to create a new park called Alt Meadows. GI-Val was used to carry out a cost-benefit analysis.

Wirral Waters Indicative Economic Assessment (2011)
A quantification and valuation of the economic benefits of a proposed programme of improvements to the green infrastructure in the areas around the development at Wirral Waters

Stanley Bank Triangle Estimated Economic Valuation (2011)
A quantification and valuation of the estimated economic benefits of the programme of improvements at Stanley Bank funded through the Heritage Lottery Fund and the A570 improvement partnership

Greening the UK for greater dividends - The Triangle case study (2011)
A case study applying the Green Infrastructure Valuation Toolkit to a residential development in Swindon called The Triangle

Noisiel Park - Assessing returns on landscape management (2011)
A case study applying the Green Infrastructure Valuation Toolkit to a park in Paris

Northwich Business Improvement District Green Infrastructure Plan (2016)
GI-Val was used to estimate the benefits from a series of recommended interventions designed to increase footfall in the town centre

Stockport Town Centre Urban Green Infrastructure Enhancement Strategy (2015)
GI-Val was used to estimate the benefits from a series of recommended interventions

The Mersey Forest Delivery Plan (2014)
GI-Val was used to estimate the benefits that will accrue if we reach our tree planting and other targets

Green Infrastructure in the Liverpool City Region – a pipeline of commissionable projects (2015)
GI-Val was used to estimate the benefits from the proposed projects

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 730426

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