Construction crews tested the last of East Grand Forks' dike closures Thursday to ensure that it's ready for the next flood fight.
The River Road closure, located north of Sherlock Park, is a critical part of the city's flood protection because the low-lying area where it lays is among the first touched by floodwater.
Last spring. . .
During last spring's flood, the city had to pile clay in front of the uncompleted closure, an operation that's both costly, messy and takes a relatively long time to remove.
Virginia Regorrah, the U.S. Army Corps of Engineers resident engineer charged with the project, said the aluminum stop logs used in the completed closure will be much easier and cheaper to set up and remove.
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What crews were testing Thursday is whether those stop logs, and the upright posts that they're attached to, fit properly or not. The tests are all recorded on video for the city's future reference, according to Regorrah.
The city's "invisible floodwall," essentially a series of closures along the Boardwalk area and Cabela's parking lot, will get its own test starting March 5. Because the floodwall is so long, crews will take a minimum of two days to install the stop logs, during which the Boardwalk parking lot and a part of Cabela's lot would be closed.
The performance of the stop logs had received an earlier real world test during the 2006 flood, with the fifth highest level in the recorded history of the Red River.
Some leakageRegorrah said they worked fine, but there was some leakage where there was metal-on-metal contact at the DeMers Avenue closure downtown. Usually, there are gaskets between different parts of the closure ensuring the whole structure is water tight, she said.
East Grand Forks' dike system is made up of two separate ring dikes. The north-end dikes are, according to the corps, functionally complete. The south-end dikes, protecting the Point, are not yet done because of the discovery of soil instability in a few areas. Construction crews are working to fix those problems.
