The aim of this work is to assess the effect of rainfall patterns on the main flows and affluent loads of wastewater treatment plants. This evaluation will be supported by a studying based set of circumstances, on which a quantitative and qualitative monitoring model of the effluents in an urban wastewater inter-system will be developed in order to identify methodologies to improve environmental management. After a conceptual investigation, it will be analyzed, as a point of studying, the drainage front 4 (FD4) of the Integrated System of Depollution River Ave Valley (SIDVA) specifically, the sub basin of Nespereira. At the starting point a register survey of the entire urban wastewater drainage infrastructure will be made. At the place where all the upstream wastewater converges, a continuous measurement point of the drained flows will be done as well as the representative qualitative limits monitoring, which later will be related to the rainfall data, a monitoring site called the Monitoring and Control Zone (MCZ). It is thus suggested to analyze the hydraulic behavior of the drainage network in detail by modeling the system based on a hydrodynamic model and, in addition, to establish a combination with urban wastewater monitoring and control methods, quantifying variations in flow rates and organic load in different rainfall events.