International Dredging Review

International Dredging Review

The entrance channel of Colombia’s rapidly growing port of Buenaventura is undergoing emergency dredging after sedimentation filled part of the channel much more quickly than expected.

Buenaventura Port located near Cali on the southwest corner of the country is Colombia’s largest port on its Pacific coastline handling more than 50 percent of Colombia’s international imports and exports. In the first half of 2014 it shipped some 5.2 million tons of cargo and 290000 TEUs 13.5 and 20.3 percent increases over last year respectively. Authorities at the port have tried keep up with the growth in recent years with a spate of dredging and expansion projects but just two years after deepening its entrance channel they have been forced to authorize emergency dredging to reestablish the depth.

At the end of 2012 the Regional Port Society of Buenaventura (SPRBUN) dredged the entrance channel through both its inner and outer bay. The outer bay had previously been 8.9 meters (29 feet) deep and was dredged to 12.5 meters (41 feet) deep while the inner bay was 11.5 meters (38 feet) deep and was dredged to 13.5 meters (44 feet) deep. The work which began on June 29 2012 and was completed on Dec. 8 of that year was conducted by Van Oord Dredging & Marine Contractors BV Sucursal Colombia. It conducted the majority of the work with its 13392-cubic-meter (about 17500-cubic-yard) trailing suction hopper dredge HAM 310 and completed the final stages with the 10329-cubic-meter (about 13500-cubic-yard) trailing suction hopper dredge Lelystad. Over the course of the project the dredges removed 11 million cubic meters (about 14 million cubic yards) from the entrance channel according to engineers at SPRBUN.

But just six months after that work was done ship pilots complained that some parts of the entrance channel had lost depth according to Colombian newspaper El Pais at the time. The pilots said the entrance channel had lost nearly two meters (6.56 feet) in some spots. Initially Colombia’s Superintendent of Ports responded to this complaint saying that the seabed was in a process of “normal readjustment” and the changes were not jeopardizing safe navigation. The superintendent’s report said the pilots’ echo sounders were not distinguishing between soft sediments and hard material and the apparent loss of depth was simply a “rearrangement of the ‘carpet’ of soft sediments” that naturally occurs as part of slope-stabilization after dredging the publication reported.

But further investigations revealed that parts of the channel were indeed losing depth due to silt. SPRBUN spokesman Walter Alberto Tenorio Castillo said that emergency dredging was required because the access channel particularly between kilometers 18 and 23 of the outer bay has been oscillating between 9.8 and 11.5 meters (about 32 and 38 feet) of depth due to “naturally occurring sedimentation putting at risk the nautical safety of ships and restricting the port’s capacity.” That restriction is affecting the port’s competitiveness he said.

In order to fix the problem on June 26 SPRBUN approved a contract with Jan de Nul Sucursal Colombia which will reestablish the 12.5-meter (41-foot) depth between kilometers 18 and 23 of the outer bay. The emergency dredging is anticipated to take eight weeks. Jan de Nul will conduct the work with the 11300-cubic-meter (about 14780-cubic-yard) trailing suction hopper Filippo Brunelleschi. The job will require removing an estimated volume of 1.7 million cubic meters (about 2.22 million cubic yards) of material.

Jan de Nul had just finished a separate contract for SPRBUN at the port. Between December 2013 and March 2014 Jan de Nul dredged the port’s docking strip between wharves 1 and 6 to 15 meters (49 feet). The adjacent turning basin was dredged to 12.5 meters (41 feet). They used both the Filippo Brunelleschi and the cutter suction dredge Hondius for the work and removed approximately 900000 cubic meters (about 1.18 million cubic yards) of material.

Jan de Nul was also hired by several terminals within the port to deepen wharves according to spokeswoman Liesbeth Van der Biest. From May to July 2013 and again in April 2014 the dredging company conducted capital dredging for terminal TCBuen. It dredged for newcomer Sociedad Puerto Industrial de Aguadulce from August to December 2013 before starting the wharf and turning basin work for SPRBUN.

For the current emergency dredging the Filippo Brunelleschi has been “dredging thick layers of sediment between kilometres 18 and 23 to guarantee 12.5-meter (41-feet) chart depth in this section of the channel for the ever-growing vessels calling at Buenaventura port” Van der Biest said in an email. “Within only a few weeks this campaign of maintenance dredging will finish meaning another successful contribution of Jan de Nul Group to the development of Buenaventura port.”