Two years ago HidroXacbal the division in charge of the Xacbal Dam in Guatemala approached IMS Dredges to remove sedimentation from the dam and in 2013 the client’s IMS Depth Master dredge began dredging at the dam which produces energy in Guatemala City.
To inspect the Xacbal Dam Ryan Horton IMS global sales director and Felix Montes IMS territory manager flew to Guatemala and then took a one-hour helicopter ride to the remote mountain location.
IMS brought Oscar Caniz president of Caniz International Corporation and a leading freight expert to the site to assess the travel route from the seaport to the dam. The steep cliffs and its roads were a logistics challenge for the project Horton said.
The IMS Depth Master dredge Model DM-55 is operating in the Xacbal Dam in Guatemala removing sediment in order to keep the turbines operating and generating power for Guatemala City.
“There were 90 degree turns in villages with dirt roads and buildings on all sides of the road. The scariest part of the route to the site was the roads with deep drops into canyons with no guardrails and no anti-erosion measures. It was basically a worst case scenario logistics situation” Horton said.
Fredy Valle from HydroXacbal which operates the dam meets with Ryan Horton IMS global sales director to assess the job site in 2011.
To maneuver the waterway the project needed a 55-foot (16.7-meter) dredge which could be transported on two trucks. To work in the dam the dredge also has a low turbidity horizontal cutterhead. It also includes several protections for the poly-lined dam which Horton said is very important to the structure and protects the cement in the dam from moisture to improve its lifespan.
A cutterhead cage prevents the cutter from contacting the poly liner. Wheels on the sides of the horizontal cutterhead keep the shroud and the cage from touching the bottom. Bottom sensors detect the position of the cutter in relation to the bottom of the reservoir and automatically lift the cutter before it touches the bottom.
HidroXacbal considered using a siphon-type dredge but had concerns over the crater effect caused by the system. Other hanging pump options were considered but IMS said underwater cave-ins have been known to bury these pumps which then need to be replaced if the hoisting line snaps during a collapse.
The narrow roads in the steep mountain passes and sharp turns along the dirt roads in villages presented a logistics challenge in getting equipment to the job site.
The dredge needed to remove the sediment in layers and prevent major material collapses underwater which was suited to the even bottom profile of the Depth Master dredge IMS said.
To navigate the narrow roads in some of the mountain passes IMS had to remove the power units ladder system pump and cutterhead and ship them separately. These modifications lowered the center of gravity and eased transport on the mountain roads and through villages. Upon arrival IMS Field Service Technician Victor Tirado flew to the site and guided the HidroXacbal personnel on how to assemble the dredge.
The dredge started at the dam in late 2013 and IMS did another follow-up training and maintenance visit in 2014. Dredging will be done on an annual basis for several months a year. Horton said the rainy season kicks a lot of sediment downstream and the silt trap in the dam can’t catch it all so the dredge will need to work there for years to come.
IMS said the Depth Master product line includes systems that can reach 12 to 18 meters and are all two-truck transportable. All models are available with cable drive and/or propeller drive. The dredge is ideal for dam and port maintenance and river sand mining operations.