ASUA RIVER CHANNELING

Area of activity
WATER AND ENVIRONMENT

Service
River hydraulics and flooding

Client
Basque Government

Scope

• Updated detailed design project development

Duration
2012-2013

The purpose of this project is to improve the hydraulic function and drainage capacity of the Asua River between “Industrias Alba” and the Sangroniz bridge to prevent damage caused by flooding. In addition, the project defines the repair and adaptation of the containment system on the left bank of the river Asua, in the area of the Alba S.A. workshops, following the recent events of structural failure of the existing bank wall.

The damages suffered in this bank wall, in the Municipal Term of Sondika, makes unfeasible the use of the maneuvering platform as it is being done at present, disappearing any safety coefficient of this structure.

With the defined works, important extensions of land, currently floodable, vital for the urban development of the area, will be recovered and the environmental conditions of the riverbeds and banks, which are currently very degraded, will be improved.

The projected solution involves the following actions in the riverbeds:

• The layout in plan has been designed to coincide approximately with that which currently exists, adapting to the urban development conditions of the municipalities in order to produce the minimum impact on the land adjacent to the channel.
• Replacement of the existing bridges due to their significant hindering effect on the water surface; they will be replaced by new bridges adapted to the hydraulic conditions of the channelization.

From the environmental point of view, in the design process of the Project, environmental criteria have been taken into account, always limited by the industrial use of the territory and the state of alteration of the river bed and water.

It is proposed to build a new containment system by widening the current channel to 15.00 m. The possibility of increasing the section to a total of 18.00 m as foreseen in the original channeling project is discarded, due to the physical needs of the heavy vehicles that use the platform for loading and unloading.

In addition, at the head of this new structure, a 2.00 m wide reinforced concrete cantilever will be generated. In solidarity with it, this extension would be sufficient to maintain the activity in the current conditions in the area of Alba and Nacon workshops.

The works defined in this project do not contemplate intervention in the riverbed, although the new structure must be compatible with the section planned in the project for channeling the Asua River in this section. What is carried out is the excavation of the right bank, maintaining the level of the current riverbed up to the new section of the retaining wall projected based on micropiles. It is also estimated the modification of the offices located on the left bank of the Asua River next to the Nacon Bridge, in order to be able to build the abutment of this structure.