Tower trouble –

Call from the FAA halts water tower project

Wednesday, August 21, 2013

The planned 140-foot water tower to add to Le Mars’ water system can’t be built as proposed because it could be an “airway obstruction” for the local airport.
This ruling came from the Federal Aviation Administration (FAA) in the midst of the city bidding the project for construction.
“Current determination by the FAA is that any tower above 86 feet at the 24th Street South and Sixth Avenue West location would be hazardous to flights,” information for Tuesday’s Le Mars City Council meeting stated.
A project redesign for the planned 1-million-gallon tower is necessary, said Scott Langel, Le Mars city administrator.
He said he’s hoping the project can be “put back together” by October.
McClure Engineering, of Fort Dodge, is already re-reviewing the location and design of the tower, he said.
The firm is also seeking more information from the FAA regarding its ruling.
McClure will likely come back with multiple options for the city, Langel added.
If the FAA’s ruling stands, the city would have to either build a water structure 86 feet high or shorter at the planned location or consider another location.
The city already opted to purchase 2.34 acres of land for the water tower and booster station in southwest Le Mars — about 280 feet east of the intersection of Sixth Avenue and 24th Street Southwest.
“We think that the location is in fact the best location, and as a result of that we really are reluctant to change the location,” Langel said.
He explained the tower needs to be close to the water source for the water system to function efficiently.
“That’s the most critical factor,” he said.
To stay at this location and meet FAA requirements, the tower would likely have to take on a different shape than planned, Langel said.
Prior to this, the design for the proposed 140-foot water tower called for the supporting column to be about 90 feet tall and the bowl’s height to be about 50 above that.
Now, one possibility that would keep the height below 86 feet is to construct a ground-level water tank with no support column, Langel said.
However, having a water structure at or below 86 feet is not ideal for Le Mars’ water system, Langel noted.
“If you have multiple towers that are connected to the same distribution system, it’s always most advantageous to have towers that are at the same total height,” he said.
However, towers don’t have to be at the same height — there is an engineering method to allow for water towers at different heights, he said.
“There is a valving system that can be installed to not cause the taller tank to overflow the lower tank,” Langel said.
He noted that, as McClure works on the redesign for this project, the firm will likely be working with Bolton & Menk, of Ames, which is working on the airport’s master plan.
“We value the airport and we value the water system,” Langel said. “We don’t want one to trump the other and vice versa.”
On Tuesday, the Le Mars City Council chose to reject all bids on the water tower and booster station to allow for redesign.
The council had been planning to award bids for these projects in mid-July, but delayed that action to await word from the FAA about whether the new tower would interfere with air traffic at the Le Mars Airport.
“They (the FAA) have got rules to live by, and we want it safe because we want a very viable, functional airport,” Langel said.
Prior to this, the city had checked with the FAA on the project, Langel said.
The water tower project has been in planning stages for more than one year.
Money to pay for the tower and other water projects will come from increases in rates paid by all water customers.
A rate increase of 5 percent each year for three years was previously approved by the council to pay for the water system improvements.

© Copyright 2013, Le Mars Daily Sentinel

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