The drainage basin covers an area of almost two hundred thousand hectares. A dense network of rivers and canals runs through it, bringing fresh water to the lagoon.

The basin is the area of land from which rain and river water drains into the lagoon. The transport of this water can be natural or mechanical.

Its surface area covers about 2000 square km, with the 503 square km of lagoon water.

These areas make up the drainage basin:

  • islands of the open lagoon;
  • confining banks of the fish farms;
  • banks and internal islands of the fish farms;
  • hinterland draining into the lagoon;
  • coastal strip areas draining into the lagoon.
  
     
The waters of the drainage basin flow into the lagoon through a complex hydrographic network. There are 29 input points made up of natural or artificial water courses. In addition, there are a considerable number of waste water discharges where sewage networks and water from civil and industrial purification plants empty out into the lagoon. The river mouths of the drainage basin are connected to different extension basins or different hydrographic systems which can be extremely articulated. The flow of fresh water to the lagoon carries with it excessive loads of nutrients and pollutant substances.
Areas where mechanical drainage is necessary make up 28% of the drainage basin mainland.
Water from these areas are channelled through water pumps.		  
    The hydrographic network of the drainage basin
Urban areas. The population density of the drainage basin varies, including densely populated urban areas like Mestre or Riviera del Brenta, and typical sparsely populated rural areas.
Industrial activities. Other than a few areas of dense industrial concentration, the Veneto development model is mainly based on medium and small-sized activities. Often the latter activities operate without respecting territory regulations. In fact, there has frequently been an uncontrolled spread of productive plants and an uncontrolled dumping of materials.
Agricultural activity. Nutrient and pollutant loads derive from fertilisers, insecticides, and defoliants used in agriculture; they vary according to what is being farmed and cultivation techniques. Rain and irrigation washout the soil and thereby transport part of these substances along the surface or through the underground water supply to the hydrographic network. Agricultural areas cover more than 60% of the overall surface of the drainage basin.
 
     

 

   
   
   
   

 
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