Environmental dredging of sediments in the O Burgo estuary fsantin October 27, 2022

Environmental dredging of sediments in the O Burgo estuary

The 24th of October was the world day against climate change and the O Burgo estuary is an example of an initiative to alleviate it, as it is achieving the reduction of pollution and the cleaning of its waters. Work is being carried out to sanitise the estuary, which will restore a very characteristic area of A Coruña to its natural state.

This sustainable project takes place in the area where the municipalities of A Coruña, Culleredo, Cambre, Oleiros converge and will have an impact on the almost eleven kilometres of promenade along the estuary, as well as improving the quality of the Santa Cristina beach.

The area around the construction site, which is frequented by many people who travel between the four municipalities on a daily basis, has suffered for years from industrial and urban waste that has polluted its waters, producing a negative visual impact and damaging the species that inhabit this environment.

The works concession has been awarded to the O Burgo joint venture, made up of Acciona and MAB Obras Públicas, with the Ministry for Ecological Transition and the Demographic Challenge (MITECO) as promoter.

To keep track of the project, a monthly report is being produced which includes a summary of the work carried out in the estuary, as well as the investment of more than 32 million for this project which runs until 2024.

Work in the O Burgo estuary 

For the dredging of the Ría do Burgo, specialised tools, expert personnel and specific means are used to carry out this task successfully. The materials used include turbidity measuring buoys, which have been analysing the state of the water in the estuary for months.

Another important element to support the work is the turbidity barrier, whose function is to protect the marine flora and fauna from sediments carried by the dredging operations. In addition, in order to avoid interfering with the life of the species that inhabit the estuary, the habitats of wintering birds and the phanerogam fields, comprising 227,310 square metres, existing in the marshes will be preserved.

Noise pollution caused by the works has also been taken into account, and anti-noise barriers have been installed to prevent it. These concrete structures prevent the work from causing a nuisance to passers-by and inhabitants of the area around the estuary.

The sod transplanting work was carried out by 60 workers, shellfish gatherers and shellfish gatherers from the Cofradía, who replanted 8,000 sods of very high intensity, some 2,000,000 specimens of Zostera noltii.

Sediment dredging 

The water drainage of O Burgo is being carried out with a pipe system, made of high density polyethylene (HDPE) and designed specifically for this project, with a diameter of 355mm and a length of 400m, which is mounted on reels.

In addition to draining contaminated materials from the estuary, the polyethylene pipe system will restore contamination-free sediments to the original water and bottom. This will favour the recovery, productivity and quality of shellfish stocks, as well as boosting the recreational use of the estuary.

Polyethylene: benefits of its use in the dredging of the O Burgo Estuary 

The use of polyethylene in the project works in the O Burgo estuary has the following advantages:

  • Absence of corrosion. . There is no corrosion in PE pipes, so there are no incrustations that allow bacteria to reside and multiply, according to the criteria established in RD 865/2003 on prevention and control of legionellosis.
  • Flexibility and adaptation. Thanks to its elasticity, the installation process is simple and inexpensive and, in addition, it adapts perfectly to the natural environment of the estuary, with the variations in water level caused by the tide.
  • Resistance to abrasion caused by the transfer of suspended solids.
  • Recycling. Polyethylene pipes can be recovered for other uses and thus give the material a new life as a solution to pollution and climate change.

The dredging of the O Burgo estuary is an example of a public-private partnership project made possible by the cooperation of MAB, Acciona, and MITECO. This is a project that seeks the environmental recovery of a protected natural area, a challenge that we at ABN take on with great enthusiasm, contributing to the sustainability objectives that we promote from the company in line with the 2030 Agenda.