Wastewater discharge by estuarine transition flow and thermoaline conditioning in shore habitat near Cesenatico breakwaters

Field of the present survey is the pulmonary system of Cesenatico canal harbour and the near coastal zone characterized by submerged breakwaters in North direction and by emerged breakwaters in South direction.Cesenatico canal harbour basin reveals a typical intermediate condition where pulmonary area and input freshwater from Cesenatico WWTP (100.000 AE) and Cesena WWTP (200.000 AE)produce in mouth of canal vertical profiles of velocity, turbulent thermoaline mixing and depth of upflowing layer daily and hourly varying in function of tidal type and phase. Aim of the work is to describe and compare, in dry weather and different tidal conditions thermoaline profile and freshwater distribution. Morphologic, hydraulic and water quality measurements have been executed into transition estuary and sea outlet of the harbour canal and near mouth of adjacent breakwaters. RESULTS: The behaviour of vertical salinity profiles into the canal gives account of the presence of an upflowing surface layer varying in thickness and salinity in function of mouth distance and tidal phases. Dispersion plume and thermoaline balance throw breakwater mouths are strongly conditioned by coastal sea current varying in intensity and direction because of wind and tide conditions. A 3D model application have been applied to interpret collecting data in order to describe, in summer steady weather conditions, canal discharging plume and fresh-water balance at mouth breakwaters.