## 4 Results and Discussion
### Demonstration Case of 15-17 September 2020. Test of the Integration of the Analyzed Variables
The maps of Figure 11 show how the hydrodynamics influenced turbidity distribution in the investigated area: a positive gradient is observable along the tidal channels moving from the sea to the internal sectors of the lagoon. Higher values of turbidity, up to 15 FNU, were estimated around the city of Venice and the island of Murano, possibly related to sediment resuspension by water traffic around and alongside the main channels as already observed by [43]. In the inlet channel, turbidity values on the 15 th and 16 th were quite similar to those of the open sea (3-6 FNU) where relatively calm conditions prevailed. This is particularly evident also in the true-colour images where natural bottom features such as nearshore parallel bars and artificial structures such as submerged breakwaters on the coast and the MoSE mobile barriers at the bottom of TRP are visible (see Supplementary Materials Figure S1). The more intense flow on the 17 th determined the formation of turbulent wakes in the inlet channel, in correspondence to the head of the southern jetty and in the lee of MoSE structures, marked by trails of higher turbidity. The central part of the inlet channel was instead characterized by less turbid water from the open sea flowing through the deeper pass between the tip of the northern jetty and the breakwater. South of the inlet, a complex turbid pattern was also observable, which was originated by interaction of the outflowing jet with the longshore current and the artificial structure of the breakwater in the previous tidal cycle. Figure 10: Subset of the time series presented in Figure 7 for the period from 15 to 17 September 2020: tide level measured at Lido Sud meteo-marine station (**a**); 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**); time series of discharge estimated with the index-velocity method from data of the bottom-mounted ADCPs; positive values of velocity and discharge indicate a seaward flow (**c**); time series of surficial turbidity measured at fixed TRP and SN stations (**d**); and the vertically averaged turbidity derived from the conversion of acoustic backscatter from the bottom-mounted ADCPs (**e**) Vertical blue lines mark the satellites overpass time. S2: Sentinel-2; L8: Landsat 8. The spatial resolution of the maps also permits the identification of small-scale details such as the plumes of sediment resuspension (turbidity up to 14 FNU) generated by dredging activities and visible in the proximity of the MoSE structures, close to the artificial island, on 15 September. Interestingly, the dispersion of two plumes followed the same opposite direction of the flow in the two channels. Satellite images provide information on the surface water layer with a synoptic view of the whole study area. However, the integration of in situ data from all sources with the satellite-derived turbidity maps adds in-depth information on the water column, allowing the description of the three-dimensional pattern of suspended sediment transport. Figure 12 shows the interpolation of CTD profiles acquired on 15 September along the lagoon-sea transect (white dotted line in Figure 1). The sections of salinity, temperature and turbidity show a well-mixed water column, a condition that extended up to St3, located 5 km along the transect in the lagoon-sea direction. In the proximity of the St4 located just outside  
Figure 11: Satellite-derived turbidity maps of the study area for the investigated period: panel (**a**) Sentinel-2A 15 September 2020; panel (**b**) Landsat 8 16 September 2020; and panel (**c**) Sentinel-2B 17 September 2020.  
the inlet, a buoyant plume of colder and relatively fresher water (24.3 \({}^{\circ}\)C and 32 psu, averaged values between 1 to 3 m of depth) was observable.