This study covered the review, further development and trial of the assessment methodology used to identify the benefits of mine water treatment schemes. Specifically, the study aimed to:
- Review and update the methodology for assessing the benefits of treating coal mine discharges; and
- Review and update the methodology to ensure that it is appropriate for assessing the benefits of treating metal mine discharges, given that visual impacts may not always be apparent.
The study identified new or updated benefit transfer values, as well as additional categories that should be included within the methodology. The Environment Agency’s (2013) Water Appraisal Guidance was also reviewed to ensure that the revised methodology followed a consistent approach.
Face-to-face and telephone interviews with representatives from sectors such as heritage, biodiversity, angling, abstraction and water use were undertaken to obtain views and opinions on the impacts of mine water discharges. Local authorities and estate agents were also consulted to gain additional views on the public perception of discharges and to explore the potential benefits of mine water treatment for property and regeneration.
The information gathered from the literature review and consultation was used to develop two methodology documents: one covering coal mine discharges and the other covering non-coal mine discharges. These documents built on the Environment Agency’s (2003) Benefits Assessment Guidance. They outlined the assessment process, following a category by category approach to determine the overall benefits. They additionally included suggestions on how to apportion benefits between treatment measures, the use of scenarios to deal with uncertainty in treatment outcomes, and the identification of ecosystem services and beneficiaries should a ‘Payments for Ecosystem Services’ (PES) approach be considered.
The methodology documents were subsequently trialled on two sites (one coal mine discharge and one non-coal discharge) to ensure that they were fit for purpose.