Do awareness-focussed approaches to mitigating diffuse pollution work? A case study using behavioural and water quality evidence.

Efforts to tackle diffuse water pollution from agriculture are increasingly focusing on improving farmers' awareness under the expectation that this would contribute to adoption of best management practices (BMPs) and, in turn, result in water quality improvements. To date, however, no study has explored the full awareness-behaviour-water quality pathway; with previous studies having mostly addressed the awareness-behaviour link relying on disciplinary approaches. Using an interdisciplinary approach, we investigate whether awareness-focussed approaches to mitigating diffuse water pollution from agriculture indeed result in water quality improvement, addressing the pathway in full. We worked with Dŵr Cymru Welsh Water (a water and waste utility company in the UK) on a pesticide pollution intervention programme, referred to as "weed wiper trial". The main goal of the trial was to raise farmers' awareness regarding pesticide management practices and to promote uptake of BMPs to tackle the rising concentrations of the pesticide MCPA (2-methyl-4-chlorophenoxyacetic acid) in raw water in three catchments in Wales. Using factorial analysis of variance, we analysed MCPA concentrations from 2006 to 2019 in the three targeted catchments and in three control catchments. This was followed by semi-structured in-depth interviews with institutional stakeholders and farmers with varying degrees of exposure to the weed wiper trial. Results show that MCPA concentration for both targeted and control catchments had reduced after the implementation of the weed wiper trial. However, the decline was significantly larger (F(1) = 6.551, p < 0.05, n = 3077, Partial eta-squared (ηp) = 0.002) for the targeted catchments (mean = 45.2%) compared to the control catchments (mean = 10.9%). Results from the stakeholder interviews indicate that improved awareness contributed to changes in farmers' behaviour and that these can be related to the water quality improvements reflected by the decline in MCPA concentration. Alongside awareness, other psychosocial, economic, agronomic factors, catchment and weather conditions also influenced farmer's ability to implement BMPs and thus overall water quality improvements.