A little more than a year ago, Des Moines City Manager Rick Clark received a piece of shockingly bad news that is likely to take years and nearly $40 million to fix.
The gist of the news was that federal officials had recalculated a worst-case flood on the Des Moines River, and the new numbers showed water in downtown Des Moines was likely to rise nearly two feet higher than previously projected.
The new flood estimates from the U.S. Army Corps of Engineers arrived in December 2010, just as the city and Principal Financial Group were ramping up to complete the final phases of the downtown Principal Riverwalk.
The new calculations meant that the flood specifications used in the design of the $70 million riverwalk were no longer valid. It meant that the riverwalk, and several million dollars’ worth of flood protection associated with it, was designed and built based on a worst-case flood that was nearly two feet lower than what the new numbers indicated.
