## 4 Results and Discussion
### Long-Term Dataset of In Situ Turbidity, Hydrodynamics and Meteo-Marine Forcing  
A 3-month extract (July-September 2020) of the time series of continuous acquisitions from the instrumental network is showed in Figure 7. The plots report water discharge calculated for the two TRP and SN sections, surface turbidity measured at the two fixed monitoring stations and vertically averaged turbidity derived from the conversion of acoustic backscatter from the bottom-mounted ADCPs. Turbidity values extracted from satellite maps at the two fixed stations were superimposed on the surface turbidity plot. The figure also shows tide level and wind speed and direction recorded at Lido Sud station. This 3-month interval was selected because it includes representative tidal conditions and interesting meteo-marine events, and cloud-free satellite images were available. Unfortunately, in this period the ADCP at TRP had to be removed for maintenance (8 July till 7 August), interrupting the data continuity, whereas for the ADCP at SN backscatter data was not available from 14 th to 30 th July. During the time interval in Figure 7, the trends of surficial and vertically averaged turbidity in the two sections are very similar and are mainly modulated by the semidiurnal tide excursion and by the spring-neap tidal cycle. The amplitude of the observed variations is, generally, higher during spring tides and lower during neap tides. As visible in the Figure 8 left panel, referred to the period 18-20 August 2020, the most pronounced turbidity peaks generally correspond to the ebb-tide phase. The lowest variations are instead found during neap tides, such as, for instance, the period 8-10 September 2020, Figure 8 right panel. This evidence combined with the trend of discharge suggests a tendency to a loss of  
Figure 7: July–September 2020: hourly time series of tidal level (**a**) and wind speed and direction (red = 0\({}^{\circ}\)–90\({}^{\circ}\), yellow = 90\({}^{\circ}\)–180\({}^{\circ}\), green = 180\({}^{\circ}\)–270\({}^{\circ}\), cyan = 270\({}^{\circ}\)–360\({}^{\circ}\)) (**b**), measured at the Lido Sud station; time series of discharge estimated with the index-velocity method from data of the bottom-mounted ADCPs (positive values of discharge indicate a seaward flow) (**c**); time series of surficial turbidity measured at fixed TRP and SN stations (circles represent turbidity values extracted from satellite maps at the two stations) (**d**); the vertically averaged turbidity derived from the conversion of acoustic backscatter from the bottom-mounted ADCPs (**e**). Red areas mark the periods described and discussed in text. suspended sediments from the lagoon in normal conditions, which is also confirmed by the vertically averaged turbidity derived from the ADCPs backscatter. The effect of meteo-marine forcing was also noticeable in the time series in Figure 7, even if the time window did not include particularly strong meteorological events. Only during the 5-7 July 2020 event, the wind speed was higher than 15 m s\({}^{-1}\) for a few hours (Figure 9). During this event, bora wind at Lido Sud station reached 17.7 m s\({}^{-1}\) on 7 July at 3:00 AM. The flow associated to flood tide-induced surface turbidity peaks at SN and TRP fixed turbidimeters (36.4 and 25.9 FNU, respectively) around 8:00 AM, whereas vertically averaged turbidity from ADCPs backscatter slightly differed in the two stations. At SN, two consecutive peaks were recorded: the first reached 27 FNU at 3:00 AM during the maximum wind intensity and at the late ebb-tide phase, the second reached a value of 40 FNU at 9:00 AM and corresponded to the early flood tide phase during the period of maximum current velocity. While the second peak represented the transport related to flood tide currents, the effect of which is measured also at the surface, the first peak was mainly related to the bottom shear stress associated with tidal currents and it was not detected by surficial fixed turbidimeter.