Chicago District "weathers" recent storm events
December 26, 2012
"As authorized by Congress, the Army Corps has been involved on the Great Lakes since the early 1800s with the development of harbors and channels for navigation; we also have been monitoring hydrological conditions and lake levels in detail since 1918," said Chicago District Deputy Commander Lt. Col. Jim Schreiner.
The Chicago District maintains seven major harbors on the Illinois and Indiana shores of Lake Michigan, collects hydrographic survey data and performs maintenance of breakwaters, as part of its robust navigation mission.
Though the majority of the Chicagoland area saw negligible effects from Hurricane Sandy, Chicago District navigation infrastructure did receive significant impacts.
A hydrographic survey of the Portage, Ind., Burns Waterway Harbor approach channel was completed on Nov. 3. The survey showed severe shoaling at two locations, and the full project depth (-30 feet LWD) is only available over the northern 150 feet of the 400-foot-wide approach channel in both. The approach channel is now impacted for a length of over 2,000 feet (both shoal areas). As the shoaling extends closer to the harbor mouth, vessels' ability to make the slight turn into the harbor is affected. It will be more difficult to enter the harbor during adverse wind conditions.
"Under calm conditions that channel width is adequate, but passing through this area under any sort of cross-wind creates a high risk of vessel grounding," said Chicago District Operations Project Manager Tim Kroll.
The Waukegan Harbor approach channel sustained massive shoaling, as well - approximately nine to 10 feet deep in line with the end of the north breakwater, adding to the previous seven to 10 feet of shoaling within the outer harbor. The harbor closed to all deep draft navigation on Nov. 5.
"We suspect that the outer harbor of Michigan City Harbor was also impacted, and USACE is currently completing a hydrographic survey," said Kroll.
USACE will continue to perform hydrographic surveys to determine and monitor the impacts of Sandy. Indiana Harbor was not substantially impacted by the storm.
As part of the flood risk management and storm damage reduction mission, the Chicago District works on safe and reliable projects that reduce economic damages and prevent the loss of life from both inland flooding and coastal storms.
"This storm event, like the other large events in the past year, would have continued to damage and compromise the integrity of the reconstruction by the City of Chicago and the Corps of Engineers, had it not been for the Chicago Shoreline Project," said Chicago District Hydraulic Engineer Joel Schmidt.
This project, which is 80 percent complete, was designed to prevent erosion and reduce overtopping through the reconstruction of nearly 10 miles of deteriorated shoreline protection during large wave events like those on Oct. 29 and 30.
In the aftermath of superstorm Sandy, nearly 4,000 USACE employees across the nation engaged to support the emergency management response priorities of supporting power, debris and temporary housing missions. USACE deployees removed 400,000 cubic yards, installed 198 generators in critical locations and provided 512 truckloads, or 18,000 liters per load, of water to N.Y., N.J., Pa. and W. Va.
"Our hearts go out to all those affected by this natural disaster. In all we do, our priorities are safety and to sustain life," said Chicago District Commander Col. Frederic A. Drummond Jr., who deployed to Washington D.C. as part of the Hurricane Sandy USACE Headquarters Strategic Integration Cell.
Two other Chicago District employees provided support to the effort. Geotechnical Engineer Georgette Hlepas deployed to Middlesex County, New Jersey as a local government liaison for the Federal Emergency Management Agency and Geographic Information Systems Specialist J.D. Ennis provided remote GIS support to the emergency power mission for capacity beyond states' capabilities from the Chicago District.
"The Chicago District will continue to provide superior support to response missions, both domestic and overseas, and build up the protection for natural disasters at home," said Drummond.
As previously stated, USACE has been closely monitoring lake levels for nearly a century. In addition to Hurricane Sandy, drought-induced low Great Lakes levels are also a focus of those tracking recent extreme weather.
Currently, Lake Michigan-Huron is 28 inches below its long-term average and approaching historic lows experienced in the early 1960s. In an average year, Lake Michigan-Huron's seasonal rise is close to 12 inches. In 2012, the rise was approximately 4 inches.
Many factors affect water levels. The resultant of lake levels this year is a lack of a solid snowpack during this last winter, coupled with a very hot and dry summer.
"If the water level in Lake Michigan falls below the level of the Chicago River, Chicago Lock operations may need to be modified in close coordination with our partners at the Metropolitan Water Reclamation District of Greater Chicago to minimize the negative impact of Chicago River water on Lake Michigan water quality while balancing our obligation to secure safe and responsive navigation," said Schreiner.
Under normal conditions, the water level in the Chicago River is about two feet lower than the lake.
The Chicago River is a man-made hydrologic connection between the Great Lakes and Mississippi River that was completed by the Sanitary District of Chicago in the early 20th century to address sanitation and flooding. Construction reversed the flow direction in the Chicago River and accommodated increased shipping.
"The Chicago District continues to communicate with all of our navigation stakeholders, both commercial and recreational, to ensure passage through locks and in harbors can continue safely and effectively," said Schreiner.
"We strive to balance our congressionally mandated navigation mission with our commitment to water quality."