Missouri River levee fails near Iowa-Mo. border

By the Associated Press | June 13, 2011 | 1:44 PM EDT

HAMBURG, Iowa (AP) — A Missouri River levee failed near the Iowa-Missouri border Monday, prompting a flash flood warning for the area around the town of Hamburg, Iowa.

The failure shortly before 11 a.m. created a 30-foot-wide hole in the levee that had three partial breaches last week, according to National Weather Service hydrologist Dave Pearson.

Pearson described the breach as "pretty substantial" and said "water is flowing through quickly," but it still must cross several miles of rural land to reach the Hamburg area. Pearson said the floodwaters are expected to reach Interstate 29 and the town of about 1,100 people sometime Tuesday.

Hamburg is protected by a secondary levee built last week, but it's not clear yet whether that will hold back the water. It also wasn't immediately clear how deep the floodwaters were Monday.

The southern half of Hamburg was evacuated last week after the first of the partial breaches in the levee located about 5 miles south of the town in rural Atchison County, Mo.

Army Corps of Engineers projections show that in a worst-case scenario, the volume of water released upstream during a levee break could leave 8 feet to 10 feet of standing water in the southern part of Hamburg. The area includes manufacturing and agricultural businesses. Water could reach the fire station and city hall, but it likely wouldn't reach the northern part of town where most residents live.

The Corps has been building up the secondary levee over the past week to protect low-lying areas of Hamburg.

An Army Corps of Engineers spokeswoman would not immediately comment on Monday's breach but said a statement was being prepared.