Engagement with farmers and landowners is often undertaken by the research community to obtain information relating to typical land, livestock and enterprise management and generally centres on responses to questionnaire surveys. Farmers and land managers are constituted as expert observers of ground-level processes and provide diverse information on farming practices, enterprise economics and underpinning attitudes towards risk. Research projects designed to inform policy and practice may rely on such data to understand better on-the-ground decisions that can impact on environmental quality and the rural economy. Such approaches to eliciting local-level expert knowledge can generate large quantities of data from which to formulate rules relating to farm enterprise types. In turn, this can help to inform the structure of Decision Support Systems (DSS) and risk-based tools to determine farming practices likely to impact on environmental quality. However, in this paper we advocate the need for integrated farmer participation throughout the whole research process – from project inception through to community qualitative validation and legitimation - and thus not just for the elicitation of questionnaire responses. With farm questionnaire surveys being adopted widely by the research community, it is an opportune time to highlight a recent case study of the Taw catchment, Devon, UK. This serves as an example of co-construction of a DSS via a co-ordinated and integrated approach to expert elicitation with a farmer questionnaire survey as a central methodology. The aim of the paper is to detail the core aspects of an iterative cycle of participatory environmental management and DSS development for water quality protection and consider the multiple benefits of co-ordinated programmes of engagement with the farming community in this process.