System for predicting the impact of discharges into river channels.

Implementation period

September 2020 – March 2021

Scope of work

Digital technology

Adaptive management and governance


This project has been funded by the national programme for clusters support “Ayudas a Agrupaciones Empresariales Innovadoras” (AEIs).


The mixing zone is the volume of water in which the homogeneous dissolution of the discharge is achieved by hydrodynamic processes. In these areas, pollutant concentrations exceed environmental water quality (ECA) standards.

The water in this area is not suitable for consumption and can cause problems for the ecosystem, so it is necessary to know its extent in order to establish adequate control of the discharge and its impact.


Computational fluid dynamics (CFD) makes it possible to simulate a discharge’s behaviour considering the river’s hydraulic characteristics. To feed and validate this model, it has been necessary to perform the following:

  1. Bathymetries of the river basin.
  2. Sampling and analysis in the laboratory along the river.
  3. Thermographic imaging with drones to complement the previous data.

Once the model is operational, it will allow:

  • Perform predictive simulations of the impact of the discharge on the river channel.
  • Establish corrective measures.


The experimental data are in good agreement with those obtained from simulations carried out independently of the river boundary conditions.

All the parameters of the pollutants studied (conductivity, temperature, colour, chlorides, and sulphates) behave as if they were transported substances (unreacted).

There is a very pronounced gradient along the transverse line of the river where the pollutants are totally diluted. The river’s flow varies seasonally so that in times of low flow, the mixing zone can increase significantly, reaching up to 200 meters. The solutions proposed by the simulation models predict a large capacity for improvement by increasing the number of points where the discharge occurs and by inserting it in the most central areas (avoiding the riverbanks).