Deltares has developed the Aquality App (formerly: Nitrate App) for smartphones to enable citizens to measure and share water quality measurements. The project’s aim is to enable farmers to participate in the collection of nitrate measurements in order to establish the relationship between different agricultural practices and water quality. This requires a method that allows participating farmers to both collect measurements and share this information easily. We hope to achieve this by collecting water quality data by using test strips and sending the results via smartphone. It's also possible to do salinity and soil Nmin measurements using the Aquality App.
Also check out the getting started, results, tips & tricks, accuracy and FAQs sections.
Joint-fact-finding
Innovative governance strategies include involving stakeholders in a joint-fact-finding process. The Deltares Aquality App is used to involve farmers in water quality monitoring. This can bridge the knowledge gap between regional water quality monitoring networks showing non-compliance and the impact that activities of individual farmers have on this. This awareness promotes the willingness to adapt best management practices in cooperation with water authorities. After their implementation, the effects of the solutions can be measured with Aquality as well. The Aquality App has been used like this in circa 70 farmer groups, including around 500 farms. Around 12 water boards, agricultural cooperations, and consultants are involved in joint-fact-finding projects with farmers using the Aquality App.
Fresh water availability
The option to measure salinity (Electrical Conductivity or EC) was added to the Aquality App in 2022. This enabled farmer and citizen participation in collecting data on fresh water availability in saline coastal areas. Salinization is an increasing challenge for farmers using groundwater or surface water for irrigation. Within the province of Zeeland (Southwest Netherlands) 300 farmers and agricultural students have been collecting around 7000 measurements. This detailed data helps authorities and farmers to define where fresh water conservation measures are most needed.
Salinity (EC) measurements with the Aquality App and screenshots of measurements in March 2023
Nature reserve protection
In Nature reserves, the Aquality App helps to identify inputs of nutrients and to distinguish water types (groundwater, precipitation water). Deltares used Aquality studying Natura 2000 reserves Springendalse beek and Lemselermaten, which are both affected by nitrate rich groundwater input. The NGO Mens, Dier en Peel uses Aquality App in cooperation with Fontys Applied University to map nitrate levels around the nature area ‘De Peel’ in Southeast Netherlands.
Salinity (EC) measurement in a groundwater dependent natural grassland in Eastern Netherlands
Education
The Aquality app is used for educational purposes by several schools ranging from primary schools to universities. Among the universities actively using Aquality are Free University of Amsterdam, University of Groningen, University of Rennes, University of Groningen, Utrecht University, Aeres Applied University, Fontys Applied University, HAS Den Bosch Applied University. Around 100 students per year apply the Aquality App, mainly in field courses.
Measuring nutrients
The Deltares Aquality app is useful for finding hotspots of nitrate losses in agricultural catchments. This helps Water Authorities to take effective measures at the right locations instead of imposing sometimes ineffective generic regulations on all farmers. Routings with the Aquality App have been done in ca. 30 catchments covering ca 30.000 hectares and 1200 farms.
The Aquality App is used by law enforcers of water authorities as a communication tool but also for finding unknown or illegal wastewater discharges to surface water. Both nitrate and EC can also be an indicator for other possible pollutants (such as Pesticides). After their discovery, the spills can sometimes be easily mitigated. An example is a wastewater spill from a glasshouse in Southeast Netherlands. The discharge was redirected to the sewage system which instantly reduced nitrate concentrations in the receiving surface waters. Another case was a strawberry grower, who flushed his water filters with fertilized water. This nitrate load was mitigated by using rainwater for this. Around 6 Water Boards in The Netherlands apply the Deltares Aquality app for this.
Rural communities worldwide depend on local drinking water sources which can be rich in nitrate or other pollutants. For example, in the Salinas and San Joaquin valleys in California, around 250,000 people use 10,000 domestic drinking water wells and are at risk of excessive exposure to nitrates. The Aquality App has been piloted as a pre-screening tool for these domestic wells by the California State Water Resources Control Board and the Central Coast Water Board. Wells with high nitrate levels were sampled for laboratory analyses for a wide range of pollutants.
