Nick Fetty | June 23, 2016
Sections of the Cedar River reached “flood level” after heavy rains earlier this week.
Data from the Iowa Flood Information System show that National Weather Service (NWS) sensors near Conesville and Palo detected levels in the Cedar River that exceeded “flood level” stage. NWS sensors use a four-point scale to rank flood severity: “Action Level, “Flood Level, “Moderate Level,” and “Major Level.” While “flood level” typically does not present a serious immediate threat, the system is meant to warn communities, landowners, and others about potential upcoming threats.
Sensors at Palo – which is about about 10 miles northwest of Cedar Rapids – recorded levels that exceeded “flood stage” over the weekend and on Monday but those level began to recede by Tuesday. Sensors at Conesville – roughly 60 miles southeast of Cedar Rapids – recorded “flood stage” levels around the middle of the day Wednesday. Unlike the Iowa River, the Cedar River does not have a dam or reservoir which helps to control flow rates downstream after heavy rains.
Spikes in nitrate levels were also detected in the Cedar River following this week’s rainstorms, according to data from the Iowa Water Quality Information System. The sensors at Palo and Conesville detected nitrate levels 2 mg/l or more above 10 mg/l, which is the Maximum Contaminant Level allowed for drinking water as established by the U.S. Environmental Protection Agency.
The National Weather Service issued a Flash Flood Warning early Wednesday morning for parts of Benton, Iowa, Johnson, and Linn Counties. The precipitation elevated humidity levels across much of the state and a heat advisory was issued Wednesday for Southern Iowa, with parts of the region experiencing heat index values that exceeded 100 degrees. These heavy rains and elevated river levels follow weeks of “abnormally dry” conditions in Southeast Iowa.