- 13th October 2017
- Posted by: Sophie Bunker
- Category: Projects
In a world of restricted budgets and projects competing for limited funds, the ability to demonstrate that your project costs are outweighed by the benefits, in addition to achieving the stated aims and wider benefits, is becoming ever more important. Whilst there are a multitude of techniques available to consider and qualify the project aims and any wider social/environmental benefits, the failure to quantify the monetary benefits of restoration projects can risk underselling a business case.
We were asked by the Forestry Commission to assess the flood alleviation benefits of woodland planting at an upland site in Southwell, Nottinghamshire. A key aspect of this project was the comparison on typical flood benefits (using Flood Hazard Research Centre’s Multi-Coloured Manual) against the wider environmental benefits that may be gained from the woodland.
In addition to calculating standard flood damage to properties, we undertook a review of academic and grey literature. This was combined with value transfer approaches to help assign monetary benefits to the carbon sequestration of woodland, amenity and recreational benefits, biodiversity and habitat gains and economic employment benefits.
Further to the benefit assessment, whole life costs for the project were calculated using data provided by the Forestry Commission, plus allowances for future maintenance of the woodland, compensation payments and grants. The costs and benefits were compared in the usual way to determine the potential cost effectiveness of the proposals.
Incorporating the impacts of woodland into hydraulic models enabled us to model the physical impacts of planting on flood levels and therefore to estimate the economic value of associated flood relief benefits. The research showed that the inclusion of environmental benefits significantly helped to justify the proposals and were essential when land compensation costs were included within the analysis.
The analysis suggests that for all scales of planting and the three cost scenarios (low, medium and high), flood benefits outweigh the planting costs with a benefit-costs range between 1.0 to 8.3. This is the same for the environmental benefits (excluding flooding) with a benefit-cost range between 4.8 and 40.3.
While uncertainties exist in terms of availability of grant and land opportunity costs, the analysis suggest that woodland creation can provide, in this case, small but cost-effective reductions in damages from flooding. They could play a key role as part of a wider Working with Natural Processes (WWNP) or traditional scheme for appropriate catchments.