Too-high Cedar River crest forecast blamed on faulty gauge

UPDATE: A faulty river gauge in the Cedar River at Waterloo provided a river level 0.9 feet higher Friday than the actual river height and, as a result, led to an overly high flood forecast downstream in Cedar Rapids, the National Weather Service office in the Quad Cities said Saturday.

The U.S. Geological Survey discovered the misreading late Friday morning, and the National Weather Service subsequently reanalyzed its river data and lowered its river level forecast for Cedar Rapids, Andy Ervin, meteorologist for the National Weather Service in the Quad Cities, explained on Saturday afternoon.

Friday evening, the Cedar River was forecast to crest in Cedar Rapids on Sunday afternoon at 19.8 feet, the fourth highest level in the city's history and second highest level since 1929. The city's flood disaster of 2008 saw the river climb to 31.12 feet.

By Saturday morning, the National Weather Service had lowered the Cedar Rapids crest forecast to 18.5 feet with the projection that it will arrive late Saturday or early Sunday.

Ervin said a lack of rain on Friday above Cedar Rapids in the Cedar River watershed had been forecast, and so has not changed the river crest prediction.

At 2 p.m. Saturday, the river at Cedar Rapids hit the 17.66 foot level, high enough to send a little water on to a low point of Edgewood Road NW at Ellis Boulevard NW. Southbound lanes of Edgewood Road NW were closed, while city officials were monitoring the spot as river water was projected to rise another foot.

The road closed just before 4:30 p.m. Saturday, along with the Edgewood Road bridge. The road historically has closed when the river reaches 17.9 feet, Hansen said.

(Update: As of 1:30 p.m., on Sunday June 2, the northbound traffic lanes of the Edgewood Road bridge over the Cedar River are open.  The southbound lane is also expected to open later on Sunday as the water recedes.)

Hanson said city crews also were watching a storm sewer in New Bohemia, which historically has backed up when the river hits 18.1 feet. This time, a new plug in the sewer line should prevent any problems, but four to five inches of water could come on to streets if the plug fails, Hanson said.

One surprise Saturday came at the city's new City Hall — the renovated former federal courthouse alongside the river at 101 First Street SE. Water began entering the building's finished basement, prompting city employees to scurry to move furniture from basement conference rooms and equipment from the building's exercise room to safety.

City Manager Jeff Pomeranz on Saturday said he discovered the basement water in City Hall at 7:30 a.m. Saturday when he arrived to exercise.