ABSTRACT
This work is part of the researches that have been developed in the recent decades. The drinking water quality is one of the existing issues for water supply systems managers and for the engineering research centers of urban water. This aspect is tackled from different points of view, mainly motivated by the consequences that imply the consumption of contaminated water.  In this sense, and because the protection of public health depends on this, it is essential to have greater knowledge in all the ways that the drinking water has been seen vulnerable.  
The water distribution networks, like all engineering facilities, have a useful life. Majority of the cities have infrastructure where the live cycle have finished, and as a result of adverse circumstances physical problems may be increasing in the pipes over the time. In recent decades, the problem of water quality is decreasingly on the production and treatment of the drinking water. However, on the distribution networks the water quality has been increasing because of pollution situations that have been documented mainly by epidemiological events. Among others factors identified in this problematic the pathogen intrusion phenomenon can be found.
In this research, pathogen intrusion is analyzed as an event directly related with leaks on pipes of water supply networks. This kind of intrusion is produce with entrance of surrounding flow to the pipes through the defects on them when the conditions of pressure are adverse in the infrastructure.
Thus, the situation of physical leaks is considered a determinant factor in the hydraulic performance of the network, and besides it can represent a risk for water quality in the supply and therefore for the public health when the reliability in the operation is not entirely safe.
The proposed methodology is based on model the adverse events in the pipes for the generation of the intrusion.  The interest to carry out these works is because most of the studies consulted in this aspect consider that the quantification of the intrusions in the network is a fundamental factor to have greater management control of this type of adversities. Therefore, experimentation controlled was carried out, and then reproduce numerically the hydrodynamic event. Many scenarios were made like are present on the networks, with tools that were validated with physical models and thus have the reliability of the results on specific intrusion events that may arise in particular cases in the distribution networks.
A way to consider some elements in the intrusion is the classification of the type of failures existing in the pipes. So, different scenarios were proposed to study the physical and numerical models to achieve a better adjust of the intrusion event that occurs in the network. In this way, it seeks to improve the reproduction of conditions that are present on the distribution networks with regard to parameters that depend on the physical characteristics and with it the alteration in the hydraulic events. The porous media is another decisive factor in the interaction of fluids between the interior of the pipes with the outside of them. It plays an important role when the internal pressure forces are comparable with the forces of retention and loss pressure that could generate this media. In this way the porous media has been included in the models to improve the hydrodynamic representation of the intrusion phenomena. 
The quantification of the intrusion on transient events is one of the most requested themes on previous studies of this line of research; the focus of this issue has been one of the topics that have placed more emphasis. Therefore, it has made physical and numerical representation of the most adverse conditions for the generation of the intrusion related to this aspect. In this way the cases were undertaken where the events can be more aggressive with the water quality.
Finally, with validated numerical tools, specific scenarios have been reproduced where the vulnerability of the network is compromised. With the results, a greater knowledge is achieved in order to model the possible situations that could arise during unexpected events or by management issues in the distribution due to the intermittent supply.