Posted on May 29, 2018
By Tom Lisi, Herald&Review
Crews dredging sediment from Lake Decatur have been waiting to get to work since April after engineers encountered a problem with the project: The basin where sediment is being stored has reached maximum capacity earlier than expected.
The engineering contractors for the project, Chastain & Associates, felt the sediment “would settle more than it did or what have you, but it just did not and we needed more room in the sediment basin,” said Matt Newell, the city’s public works director.
The storage site, a 523-acre basin off Angle Crossing Road on the city’s northeast side, was expected to hold all of the sediment that crews have been pumping out of the bottom of Lake Decatur since the work began in fall 2014. Crews from Terra Contracting Services worked from February 2014 to August 2016 to raise the berms by 10 feet — but that turned out not to be enough.
Earth-moving crews are now at work fortifying the berms that wall in the sediment, essentially raising the height by about four feet, Newell said.
Newell said the city expects for the dredge to be back up and running sometime in June and it should not affect the project’s schedule to finish all work by next year.
But it could affect the chances for the dredging to finish early and under budget, as it was on pace to do last year.
The total goal of the project is to remove 10.7 million cubic yards of material from the lake. One cubic yard equals about 200 gallons of material.
It’s unclear exactly why the sediment is taking up more space than previously calculated. Kevin Myers, a managing principal engineer at Chastain who is overseeing the project, could not be reached for comment Wednesday.
Soil runoff is a persistent problem for Lake Decatur, the source of water for Decatur residents and large industrial employers like Archer Daniels Midland Co., due to the substantial agricultural land in the lake’s watershed. A lot of topsoil from those nearby farms is washed away by rain events and ultimately settles at the bottom of Lake Decatur.
City officials are in talks with Chastain & Associates concerning the costs associated with the delay. Workers with the Great Lakes Dredge and Dock, which is handling the dredging of the lake bottom, are waiting to get back to work.
“When the contractor’s idle, and he’s got all of his people and they’re ready to work, there’s usually a cost associated with that,” Newell said.
On Monday, Decatur City Council members approved the fourth and final bond issue related to the dredging project for $29 million. City officials will be paying up to $2.7 million a year in debt payments until 2038 to cover the cost.
The bond will also cover the construction of the new Fire Stations No. 1, 3 and 7 at the Decatur Airport. The proceeds will also repay a loan from Busey Bank that was used to pay for the renovations of three existing fire stations.
Councilman David Horn noted at Monday’s meeting that including interest costs to finance the 20-year bonds puts the real cost of dredging at more than $140 million, more than the $91 million cost of the immediate project.
Source: Herald&Review
