Sado Estuary - EU Directives

Overview

Estuary Loads

Location

Rivers discharges

Model Implementation

Domain

Hydrodynamics

Transient Circulation

Residence Time

Conclusions

Reference Scenario

Time Series Results

Boxes Concentration Validation

Properties Spatial Distribution

Annual Budgets

Scenario1- 50% Reduction in nitrate river load

Properties Spatial Distribution

Boxes Concentration

Conclusions

• A reduction of 50% of the discharge of nitrate from the rivers Sado reduces the concentration of nitrate in the estuary of the same order of magnitude but the concentrations of phytoplankton, ammonia and organic matter are reduced only of the order of 5 to 10%. A reduction of the primary production was expected because nitrogen was identified as a limiting factor of the primary production.

• The reduction of the nitrate discharged by Marateca stream reduces the production of phytoplankton in the upper part of the bay, which becomes an importer of phytoplankton, ammonia and dissolved matter from downstream.

   

• A reduction of the nitrate discharged in the estuary does not reduce substantially the values of the primary producers, but it reduces levels of the second producers and the turnover of the phytoplankton.