# Floating Photovoltaic Plant Monitoring: A Review of Requirements and Feasible Technologies
## 7 Discussion  
The trade-offs associated with any potential FPV installation can be accurately studied through fixed and/or mobile (robotic) technologies that can measure and sample, and thus provide a comprehensive assessment of environmental and ecological impacts on water bodies. This knowledge can be used to develop reliable models and strategies to mitigate potential negative impacts of the plant, maximizing the co-benefits of FPV technology and providing synergistic benefits to the water-food-energy nexus. Static sensors, mobile sensors, or a combination of the two different configurations can be used to design the monitoring activities of water quality under FPV plants. The selection of the best monitoring strategy depends on several factors, including the size of the FPV  
Figure 5: Ten AUVs cooperating (data-driven) to efficiently map illicit discharge outflow plume in a water body (0.5 km\({}^{2}\) in 2 h) [courtesy of Hydromea SA] [152]. system and the maximum depth of the water body to be monitored. Table 3 summarizes the experiences of WQM in FPV applications analyzed in the previous paragraphs, with the aim of providing guidelines for the selection of WQM strategies in FPV applications. For each WQM experience in FPV, Table 3 includes information on the dimensions of the FPV, the maximum depth of the water body, the number and position of water columns (WCs) analyzed, the number and depths of measurement points for each water column, and the configuration of sensors adopted, whether fixed or mobile. In terms of the dimensions of FPV, WQM of the largest FPV installation was performed by [PERSON] and colleagues [63], who monitored several parameters (temperature, conductivity, dissolved oxygen, pH, Chl-a) in relation to an FPV implant with a total area of 400 ha, distributed across four coal mining subsidence areas. [PERSON] and colleagues monitored two coal mining subsidence areas with multiple water columns (eight and six) under the FPV, and in open waters (three and six). All the other works performed WQM in relation to small FPV implants (<20 ha), analyzing a single water column under the FPV and a single column in open water (usually at a distance greater than 100 m from the FPV). Among the seven studies reviewed, three of them [60; 61; 78] included an additional water column in fringe areas, a few meters from the FPV. Hence, the literature review suggests that small installations (<20 ha) can be monitored with only two water columns: one at the center of the structure and one in open water. Regarding the depths of water body analyzed, three studies worked with shallow waters (depth < 10 m). [PERSON] et al. 2022 and [PERSON] et al. 2021 monitored each WC at a single depth for each water column, at 0.8 m and 0.2 m, respectively. [PERSON] et al. 2023 measured three depths for each water column at 0.5 m, 2 m, and 3 m. In the rest of the studies, water bodies exceeded 20 m in depth [61; 68; 71], and multiple depths of measurements were used with different strategies. [PERSON] et al. in 2023 monitored vertical profiles by slowly lowering a multiparametric probe with a manual winch (hybrid configuration), binning data at 0.5 m intervals. The manual control of the winch obviously requires the presence of a human operator. A more autonomous solution could be achieved with a variation of this method, by managing the winch remotely and lowering the operation costs. Despite none of the