Measuring biological water quality by volunteers has an added value to monitoring by professionals. It helps to obtain a fuller picture of water quality in Dutch ditches, streams, ponds and canals. Thus concludes a study by Wageningen University & Research, one of the consortium members of the Waterdiertjes.nl platform. The study was recently published in the PLOS-ONE scientific journal.
Anyone who carries a scoop net and a smartphone can catch aquatic animal species and report their observations to the Dutch Waterdiertjes.nl platform. Immediately after registering their catch, users will receive a score indicative of the quality of the water examined. These scores are based on the indicator values of the species observed. In this way, volunteers help researchers of Wageningen University & Research, the Netherlands Institute of Ecology (NIOO-KNAW) and the regional water authorities to get a better picture of the water quality and aquatic life throughout the Netherlands.
The recent study, to which also De Waterspin Advies, GLOBE-Nederland, NIOO-KNAW and Waterschap Brabantse Delta contributed, has analysed the inventories performed by volunteers. Edwin Peeters of Wageningen University & Research and first author of the study: “Since the launch of this citizen science project in 2018, we have stored the data about the water animals as registered by the volunteers. We have compared this information to the water monitoring data by professionals of the regional water authorities.”
The analysis shows that volunteers search for aquatic animal species in different places than professionals. Professionals collect data mostly in streams and canals. On the other hand, volunteers more often examine ponds and ditches, as well as water bodies in the urban environment. In this way, samples taken by citizens prove to be a valuable addition in obtaining the broadest possible picture of water quality in the Netherlands.
Both professionals and volunteers mainly took their samples in spring. In 2020 volunteers also collected a lot of information in autumn, which was remarkable. This probably was a result of the lockdown related to the corona pandemic.
The study shows that some adjustments will increase the usability of the Waterdiertjes.nl platform for water managers. Peeters: “We have seen that volunteers most often observe the larger and faster moving species. These are generally species that live on the water surface, such as water striders, or in the open water and between the aquatic plants, such as boatmen. The species that live at the bottom, or in the sediment, are hardly registered by volunteers.” The absence of data about such benthic species may cause water quality scores to be overestimated. For this reason, the indicator value of some species will be adjusted in the next version of the platform.