The rapid implementation of large scale floating solar panels has consequences to water quality and local ecosystems. Environmental impacts depend on the dimensions, design and proportions of the system in relation to the size of the surface water, as well as the characteristics of the water system (currents, tidal effects) and climatic conditions. There is often no time (and budget) for thorough research into these effects on ecology and water quality. A few studies have addressed the potential impacts of floating solar panels, but often rely on models without validation with in situ data. In this work, water quality sensors continuously monitored key water quality parameters at two different locations: (i) underneath a floating solar park; (ii) at a reference location positioned in open water. An underwater drone was used to obtain vertical profiles of water quality and to collect underwater images. The results showed little differences in the measured key water quality parameters below the solar panels. The temperature at the upper layers of water was lower under the solar panels, and there were less detected temperature fluctuations. A biofouling layer on the floating structure was visible in the underwater images a few months after the construction of the park
Floating urbanization is a promising solution to reduce the vulnerability of cities against climate change, population growth or land scarcity. Although this type of construction introduces changes to aquatic systems, there is a lack of research studies addressing potential impacts. Water quality data collected under/near floating structures were compared with the corresponding parameters measured at the same depth at open water locations by (i) performing scans with underwater drones equipped with in situ sensors and video cameras and (ii) fixing two sets of continuous measuring in situ sensors for a period of several days/months at both positions. A total of 18 locations with different types of floating structures were considered in this study. Results show small differences in the measured parameters, such as lower dissolved oxygen concentrations or higher temperature measured underneath the floating structures. The magnitudes of these differences seem to be linked with the characteristics and type of water system. Given the wide variety and types of water bodies considered in this study, results suggest that water quality is not critically affected by the presence of the floating houses. Underwater images of biofouling and filter feeders illustrate the lively ecosystems that can emerge shortly after the construction of floating buildings.
Stormwater runoff can contain high amounts of Potential Toxic Elements (PTE) as heavy metals. PTE can have negative and direct impact on the quality of surface waters and groundwater. The European Water Framework Directive (WFD) demands enhanced protection of the aquatic environment. As a consequence, the WFD requires municipalities and water authorities to address the emissions from drainage systems adequately and to take action when these emissions affect the quality of receiving waters together with mitigating the quantity challenges in a changing climate (floodings and drought). NBS is the most widely used method for storing stormwater and infiltrating in the Netherlands. However, there is still too little knowledge about the long-term functioning of the soil of these facilities. The research results are of great importance for all stakeholders in (inter)national cities that are involved in climate adaptation. Applying Nature-Based Solutions (NBS), Sustainable Urban Drainage Systems (SuDS) or Water Sensitive Urban Design (WSUD) are known to improve the water quality in the urban water cycle. The efficiency of NBS, such as the capability of bio swales to trap PTE, highly depends on the dimensions of the facility and on its implementation in the field [Woods Ballard, B et al, 2015]. For the determination of the removal efficiency of NBS information about stormwater quality and characteristics is essential. Acquiring the following information is strongly advised [Boogaard et al. 2014]:1. stormwater quality levels (method: stormwater quality database);2. location of NBS (method: mapping NBS in international database);3. behaviour of pollutants (method: cost effective mapping pollutants in the field). Stormwater quality contains pollutants as heavy metal in higher concentrations than water quality standards dictate. Over 500 locations with bio swales are mapped in the Netherlands which is a fraction of stormwater infiltration locations implemented in 20 years’ time. Monitoring of all these NBS would acquire high capacity and budget from the Dutch resources. This quick scan XRF mapping methodology of topsoil will indicate if the topsoil is polluted and whether the concentrations exceed national or international standards. This was only the case in one of the youngest pilots in Utrecht indicating that there are multiple factors other than age (traffic intensity, use of materials, storage volume, maintenance, run off quality, etc.). Several locations show unacceptable levels, above the national thresholds for pollutants where further research on the prediction of these levels in relation to multiple factors will be the subject of future research.The results of study are shared in 2 national workshops and valued as of great importance for all stakeholders in (inter)national cities that are involved in implementation of NBS for climate adaptation. The Dutch research results will be used to update (inter-)national guidelines for design, construction and maintenance of infiltration facilities this year. Stormwater managers are strongly advised to use this quick scan method within the first 10 years after implementation of swales to map possible pollution of the top soil and prevent pollution to spread to the groundwater in urban areas.
Vezelversterkte kunststoffen (composieten) worden in veeleisende toepassingen gebruikt, zoals in tanks voor chemicaliën of als lichtgewicht constructie-delen in vliegtuigen. Voor deze toepassingen zijn de composieten optimaal ontworpen en getest, maar ze worden met het oog op veiligheid gedurende het gebruik ook regelmatig geïnspecteerd, vaak met ultrasone analyse. Het permanent kunnen monitoren van het vervormingsgedrag van het materiaal levert een voordeel op voor zowel de veiligheid als de kosten. Zo kunnen onregelmatigheden die optreden direct worden gesignaleerd. Een intensief inspectieprogramma wordt zo verlaagd in frequentie. Met high-performance rek-sensoren op een composietproduct wordt het vervormingsgedrag gemeten en met datacommunicatie kunnen dan gegevens continue worden doorgestuurd voor beoordeling elders. Zo ontstaat een ‘smart composite structure’ waarbij permanente monitoring van composiet mogelijk is. Echter kennis ontbreekt nog over de correlatie tussen vervormingsgedrag en resultaten van een ultrasone analyse. Verder is nog niet bekend hoe de high-performance rek-sensoren functioneren over een langere tijd bij heersende bedrijfsinvloeden zoals vochtinwerking, temperatuurfluctuaties en lokale belastingen. Het project richt zich op het onderzoeken van de haalbaarheid van rek-sensortechniek die geschikt is voor het langdurig continu monitoren van het vervormingsgedrag van composieten in bedrijfssituaties. Daarbij moet binnen dit project een antwoord komen wat de voorspellende waarde is van deze monitoring t.b.v. optimaliseren van in-situ preventieve inspecties met ultrasone analyses. Daarnaast moet het onderzoek tijdens dit 1-jarige onderzoek een eerste inzicht geven op het functioneren van de high-performance rek-sensoren en de elektronica in de heersende omstandigheden over langere tijd. Het Lectoraat Kunststoftechnologie verzorgt de projectleiding en het onderzoek. Het lectoraat heeft expertise op het gebied van high-performance rek-sensoren voor vervormingsmeting op composieten. De deelnemende partners hebben belang bij de resultaten van het project. Daarnaast brengen zij specifieke expertise in die met de kennis bij het lectoraat kan leiden tot succesvolle resultaten in het onderzoek.
