DIVERSION OF URBAN SEWAGE COLLECTOR IN ERRENTERIA-LEZO

Area of activity
WATER AND ENVIRONMENT

Service
Sewerage and drainage systems

Client
Aguas de Añarbe (AGASA)

Scope

• Information and data collection
• Analysis of the pre-selected solution
• Hydraulic modeling
• Detailed design project development

Duration
2021-2022

The recent start of the urban planning process for the Altzate Area on the right bank of the estuary, between the Iztieta footbridge and the Madrid-Irun railroad bridge, has highlighted the effect that this development will have on the new collector.

This effect, together with the fact that the different routes proposed in the study of alternatives run, to a greater or lesser extent, through the area to be developed, makes it necessary to draw up a construction project to define the works to be carried out to modify the route of the collector and thus be able to coordinate both works.

Therefore, the object of the project is the definition of the necessary construction works for the modification of the layout of the collector outside the DPMT area from Ugarritza Avenue in the Olibet neighborhood and the boundary with the Port of Pasaia in front of the Errenteria WWTP, developing the alternative 4 layout (Inca with blind shield).

The modification of the layout of the collector will have objectives or aspects to be considered, such as the consideration of the PAU (Programa de actuación urbanística) of Altzate and the progress of the urbanization project of the same. Likewise, the works of the municipal sewage network necessary to connect to the future collector the connections that the current collector has, and also the connections of the current and future buildings, will be defined.

On the other hand, the upstream network from the Lekuona cultural center to the Gabierrota area will be analyzed to see the existence of rainwater contribution to the network and the possibility of disconnecting it. In addition, it will include the definition of the works to remove the current collector, which is located in the maritime-terrestrial public domain area, and the soils will be characterized to determine their correct management. The corresponding Excavation Plan will also be drafted for approval by the environmental authority.

The main characteristics of the alternative route of the selected sewer begin in the surroundings of the Gabierrota neighborhood and runs parallel to the Oiartzun river up to the Olibet neighborhood, through an entirely urban area. It is worth mentioning that at the beginning of the section the collector only collects the waste from the Olibet area, whose network is supposed to be separate and serves about 2,000 inhabitants. However, the incorporation of these networks into the collector should be considered.

Prior to the Lezo bridge, road access between the municipalities of Errenteria and Lezo, the sewer route crosses the existing channeling wall next to the railroad station. The route of the planned collector then runs alongside the breakwater at the foot of the channeling wall up to the Errenteria WWTP. At this point, it is planned to connect the new collector with the Donibane-Lezo general collector and with the Papresa paper outfall, to continue in a pipe drive across the Oiartzun river to the Errenteria WWTP.