Drainage basin may have sunk depot project
That big drainage basin dug in front of the century-old Union Station two years ago may have doomed the aging railroad depot, according to a recent report by soils experts.
The soil under the depot, which was built in 1901 and scheduled for demolition in 1978 before a community outcry saved it, has been settling the past two years, causing increasing structural damage, according to a report done by Alt & Witzig Engineering Inc. of Evansville. The city of Henderson's architect discovered the foundation shifting, and asked the city to approve further investigations, which Alt & Witzig did last month.
“It appears that the most likely cause of settlement is due to the decrease in (the) groundwater table at this site,” the Alt & Witzig report says. “The decrease in the groundwater table can be attributed to the construction of the large detention pond located on the opposite side of Clark Street.”
The basin, which is about an acre in size and about 25 feet deep, was constructed by the Henderson Water and Sewer Utility to temporarily hold groundwater flowing from Julia-Center street area, alleviating long-standing flooding problems there.
The Alt & Witzig report said lowering the water level caused the building's foundation to place more stress on the soil layers below the new water level, which are made up of highly compressible soils. When the water level was higher, the report says, the load was borne by soils higher up that could better distribute the weight.
The report goes on to say that “restoration of the foundation system for this structure is anticipated to be difficult due to the age of the structure and the unknown condition of the existing foundation system.” In fact, the report says, it is unclear “as to whether or not an economically feasible recommendation can be made beyond what is outlined in this report.”
The recommendations involve stabilization of the foundation and repairs to the exterior brick, which the city's architectural firm of Skinner-Groves estimates will cost $750,000.
“This obviously would only stabilize the building, “according to a memo written by John Talbert, the city's community development director. “The architects advise that full restoration of the depot, exclusive of the cost of redressing structural deficiencies, will cost an additional $971,000.”
The city already has in hand a $300,00 federal grant that is to be used for exterior renovation of the building. Talbert also has written an application for an additional grant of $312,000, for which there would need to be a local match of $138,000. The Henderson City Commission will consider a resolution authorizing that grant application when it meets Tuesday evening.
City Manager Jeff Broughton, in his memo to the commission, noted that it appears it will cost about $1.9 million to fully renovate the depot, which means there would probably have to be a local match of about $380,000.
“The board (of commissioners) is asked to carefully consider the overall cost of the project and its relative priority when measured against other capital projects and needs of the city,” Broughton wrote.
Contributed by Netta Mullin, HCH&GS
Copyright 2007 HCH&GS