**4. Results and discussion**

We have developed a numerical model that solves the two-dimensional Saint-Venant equations and the Advection-Diffusion-Reaction equation to study the pollutants transport.

A Study Case of Hydrodynamics and Water Quality Modelling: Coatzacoalcos River, Mexico 59

and they are in the same order of magnitude. Fig. 9 shows some of the obtained results (each

**(cm/s)** 

Fig. 7. Comparison between measured and calculated velocities for the river mouth

17.96468 -94.5529350 -24.06 -42.34 0.49 60.39 17.97063 -94.4749317 4.75 23.65 0.24 78.65 18.01482 -94.4479867 -43.56 -8.69 0.44 11.28 18.06698 -94.4156000 -11.32 58.24 0.59 -79.00 18.08841 -94.4215717 -10.74 39.62 0.41 -74.83 18.1023 -94.4374683 9.38 -5.57 0.11 -30.69 18.1117 -94.4217833 36.78 -58.26 0.69 -57.74 18.12396 -94.4148883 34.06 -1.98 0.34 -3.33 18.13607 -94.4112700 6.62 -16.16 0.17 -67.72 18.16384 -94.4154150 -7.14 1.02 0.07 -8.15

**North Vel. (cm/s)** 

**Resultant (m/s)** 

**Direction (º)** 

point represents a measurement station and the solid line the model result).

**Station Latitude Longitude East Vel.** 

Table 1. Measurements of water velocity

The model results show agreement with measurements of velocity direction and magnitude, as well with water quality parameters. Therefore, it is considered that the developed model can be implemented and applied to different situations for this study area and others rivers with similar characteristics.
