Water pollution is an urgent and complex problem worldwide, with many dire consequences for ecosystems, human health and economic development. Although policy measures in OECD countries have helped to reduce point source pollution, the situation is set to worsen: population growth and climate change are placing increasing pressures on the ability of water bodies to process wastewater, nutrients and contaminants [1].

For future generations to maintain a sufficient supply of clean drinking water and to retain a vital level of biodiversity, it is critical to involve the general public in dealing with the problems of water quality and water pollution. One specifically important and increasingly prominent way for the general public to get acquainted with water quality issues is through participation in research projects. All around the world numerous citizen science (CS) projects take place in the field of (drinking) water quality, hydrology, groundwater levels, and water biology [2]. In most cases these projects are motivated by the enormous potential volunteering citizens have to increase the temporal and spatial data availability. We argue that the value of many CS projects lies beyond data availability, in the broader societal benefits that these projects aspire or claim to achieve. In turn, these benefits could improve the way we approach water quality issues. The list of claimed and potential benefits is long: raising awareness, democratisation of science, development of mutual trust, confidence, and respect between scientists, authorities and the public, increased knowledge and scientific literacy, social learning, incorporation of local, traditional and indigenous knowledge, increased social capital, citizen empowerment, behavioural change, improved environment, health and livelihoods, and finally motivational benefits [3].

Many of these broader societal benefits of public engagement with water research are especially important to battle water related issues worldwide. Increased ‘water awareness’ among the public is needed to encourage a general sense of urgency and hence support for research investments and policy measures. In the Netherlands, like in many other countries, many citizens take safe and clean (drinking) water for granted [4]. Therefore, people are not sufficiently aware what investments are needed to provide safe tap water and what they themselves should do to reduce domestic water pollution. To truly counter the dangers of deteriorating water quality, water science and policy must be organised more inclusively and democratically.

The potential societal effect of CS in the water quality sector is substantial. In the Netherlands alone, more than 100,000 citizens volunteer as ‘sensors’ or observers in the numerous nature oriented research projects, in which they, for example, count aquatic animals or measure the chemical composition of river water. These projects are generally low-threshold, because the research tasks are relatively simple and adapted to the limited expertise and research skills of the participants. The large-scale and long-term monitoring done by volunteers would be unaffordable if carried out by professionals [5]. In other CS projects, though smaller in quantity, citizens have a larger degree of control. This is a gradual difference, typically divided in four categories, ranging from contributory (lowest level of control) to collaborative, co-creative and finally collegial [6]. Alternatively, these levels have been designated crowdsourcing, distributed intelligence, participatory science and extreme citizen science [7]. We consider all these levels of control as participating in research, even when the volunteers merely function as observers.

Although the potential benefits of citizen involvement with research projects are numerous and the potential societal impact is high, there are two main obstacles that must be overcome. First, the actual effects of these types of projects, other than the well-reported scientific benefits, remain largely unknown [3, 8, 9]. Do participants have an increased understanding of the concerns of water quality researchers? Do they flush fewer medicines down the toilet? Do they avoid using pesticides in their gardens? Moreover, in order to truly raise public awareness and support for policies addressing water quality, it is important to not only get people involved who are already interested in nature, water quality and/or scientific research. The challenge is to have a diverse group of participants and to involve hard-to-reach groups [10].

Second, the dominant picture of CS projects, in our own Dutch based study as well as all across the world [3], is that most citizens participate in the collection of research data. Recalling Shirk et al.’s typology of involvement [6], this can be considered the lowest level of control and participation. Researchers, policy makers and interest groups hope that this type of involvement will generate public support for more scientific research and more effective policy measures to improve water quality, but citizens performing more significant roles in the research process is still uncommon.

From our analysis, we draw three recommendations to overcome these obstacles and to move beyond CS in water research for the sake of research only, in order to make it more meaningful in a broader, societal sense. For a start, we recommend to thoroughly evaluate the effect of citizen science on the attitudes, behaviour and knowledge of participants and on the system as a whole. As mentioned above, and also pointed out by Somerwill & Wehn [9], ‘the exact impacts of citizen science are still to be fully and comprehensively understood, while up to date impact assessment methods and frameworks are not yet fully integrated in practice’. Since the potential and claimed benefits are substantial, there is a considerable responsibility to prove these effects and to improve CS project designs to stimulate the occurrence of these benefits. Recent work provides the necessary tools to guide professional researchers and citizens to build the right project designs [11, 12], integrate working evaluations [9], and consider several factors for successful CS projects [2]. It also needs to be established how to include diverse groups of participants, including the ones with a low interest in nature and environmental issues.

Secondly, we recommend to involve participants more intensively in agenda setting and research design. Currently, the threshold to participate in CS projects tends to be fairly low, but so is the level of control and participation. Tasks of citizen scientists are typically limited and so is their sense of project ownership, although the likelihood of actual effects taking place increases with an increased degree of control for participants [3]. For instance, a number of projects report a rise or restoration of trust in local authorities and research institutions ‘due to the co-production process and the appreciation of local knowledge’ [3, 13].

There is ample potential to increase participation to more shared decision-making on the purpose and design of the research. An important step would be to open up the drafting of research agendas to diverse groups of citizens and societal actors. This type of citizen involvement is already common practice in other fields of research. One might look at some research fields within health and healthcare studies as good practices. ‘Nothing about us without us’ has become a guiding principle, also within health research (see one of our other studies, on public engagement in psychiatry research [14]).

In the Netherlands, it is becoming common practice for experts by experience (current patients, recovered patients, patient associations) to have a seat at the table when funding decisions are made. Funding agencies increasingly demand applicants to demonstrate how they included patients or other experts by experience in the development of their research proposal. Funding agencies also include patient associations in the development of their research and funding agendas. These practices show that more shared-decision making processes are possible. We consider three conditions that are crucial for meaningful involvement: A) leadership and management of funding agencies to actively value and endorse public engagement leading to changes in their modus operandi; B) training and support for participating citizens, experts by experience and other societal stakeholders; C) researchers who do not regard public engagement as just another box to tick, but who truly integrate public engagement in their research design. This also means these researchers should be incentivised to integrate public engagement in their research, which points to necessary changes in the way they are recognised and rewarded [15].

Lastly, we recommend to employ public involvement as an extra stimulus for the practical application of knowledge. For professional scientists, the participation of volunteers in research has concrete value. They use the inputs to improve data availability, improve data quality and for their publications. For participants, the benefit is less tangible. Often, their only reward is the joy of the experience itself. However, as participants contribute more, there is a risk of exploitation. We emphasise that intrinsic motivations are most important for participants, but these motivations go beyond the joy of the experience, such as learning, environmental concern, making a difference, and social aspects of participation [2, 16]. Rewards should fit these main drivers of participants for instance by showing how their engagement makes a difference, and by public acknowledgement for their work. A stronger incentive for participation could be provided by showing how the research contributes to the improvement of the (local) natural environment, water quality and biodiversity. Therefore, researchers should provide the volunteers with feedback about the results of the study to which they contributed. Beyond this act of courtesy, they should derive inspiration from the interaction with societal actors to focus more on the societal impact of their work. Some scholars emphasise how several motivations and effects of CS projects reinforce one another to create a desired upwards spiral (e.g. more knowledge and scientific literacy → more environmental concern → intrinsic motivation to make a difference → greater participation in CS projects → more knowledge and scientific literacy) [2], [3]. Professional scientists could and should play an active role in realising these societal effects.

In all, citizen science has great potential in water quality research. In fact, numerous projects already illustrate the value of CS to improve water quality around the world. It may help fight the dire threats of water pollution, by raising water awareness, strengthening public support for research, and ultimately for better policies and changes in behaviour. Yet, to reap success with citizen science fully, it should be purposefully designed for such broader societal goals. Therefore, efforts must be made to get a better understanding of the effects of research participation on volunteers, to involve citizen scientist in research agenda setting and the design of research projects, and to listen to them for the practical application of research results.

This article is based on the Dutch report Scholten W, Schölvinck AFM, Van Ewijk S, Diederen PJM. Open science op de oever–Publieke betrokkenheid bij onderzoek naar waterkwaliteit. The Hague: Rathenau Instituut; 2020. Available from: https://www.rathenau.nl/nl/vitale-kennisecosystemen/open-science-op-de-oever [17].