The La Niña phenomenon and the construction of new Pumarejo bridge, which began in 2015, have been identified as two of the “potential causes” for the formation of an islet in the Magdalena River at kilometers 13 and 18, which can be seen from Avenida del Río.
This was evidenced by the Institute of Hydraulic and Environmental Studies of the Universidad del Norte (Ideha) and its River Observatory in a special report published in January last year in EL HERALDO, in which Several factors that have influenced the formation of the terrain are detailed.
As stated in said report, the Pumarejo works generated a local scour at the bottom of the event due to the effect of the piles.
“This material has also been resuspended from the bed and carried downstream.”Said Humberto Ávila, director of the Institute for Hydraulic and Environmental Studies and the Magdalena River Observatory.
The Ideha also indicated that between 2010 and 2011 morphological changes occurred in the first 115 kilometers of the river due to the La Niña phenomenon, highlighting the situation of Guáimaro, where a high dynamics of the riverbed towards the right bank was identified, as well as referring that Rondón Island went from 1,680 meters to only 960 meters in length.
“But nevertheless, the mass of the material locally undermined by the piles is much less than the material eroded by the river due to the morphological changes that occurred in 2010-2011 ”, Ávila added in the report.
The expert pointed out that the great mass of eroded material entered the current of the river and has been dragged with less speed than the average speed of the river, depositing in sectors with low current: “This drag process can take months or years to move the sediment a few kilometers downstream.”
The Institute of Hydraulic and Environmental Studies of the northern University highlighted that the aforementioned sector, which comprises between the RiverPort pier and the Malecón del Río, corresponds “to a curve where the hydrodynamic process is characterized by having high tangential speeds and secondary currents such as frontal vortices on the outside of the curve, and on the contrary low speeds on the inside “
It is for this reason that “much of the eroded material that has been washed away since 2010 it has been accumulating on the left bank, where speeds are low ”.
In the report, in addition, it is stated that the area of greater depth in the external part of the curve has greater speed, “Therefore, an erosion process has been induced on the right bank between 2010 and 2018”.
Hence, the Ideha emphasized that sedimentation on the left bank along the Malecón del Río, corresponds to “a natural process” and is related to the sum of “various natural and anthropogenic conditions”.
Given the formation of the islet in the sector of Avenida del Río, the district administration of Barranquilla advances in the review of the report carried out in 2019 by the Universidad del Norte to identify the different variables and make a request to Cormagdalena to endorse a possible intervention in the area.
“The study at the Universidad del Norte will be our support for the petition to Cormagdalena. When the island was forming, we sent several letters to Cormagdalena on the subject and we never received an answer or explanation about this situation, “said Alberto Salah, manager of the District Infrastructure Agency (ADI).
The official confirmed that the islet is part of the jurisdiction of Cormagdalena, For this reason, it is necessary to receive authorization to carry out -in said area- a series of environmental and ecological projects, which have already begun to be structured.
Salah also said that the appearance of the islet has led to “make a totally different planning for the initial purposes in which this public work was designed and built “, with activities other than the contemplation of the river.