LAKE DELHI, Iowa - The Lake Delhi dam failed Saturday as rising floodwater from the Maquoketa River ate a 30-foot-wide hole in the earthen dam, causing water to drop 45 feet to the river below and threatening – at least for a while – a few towns downstream.
"I've never seen anything like it," said DNR Environmental Specialist Tom McCarthy who was on the scene Saturday.
Fred DeShaw, 52, of Worthington, said he was only about 150 feet away when the earth gave way at the dam in Delaware County. He estimated a swath about 125 feet wide and 30 feet deep opened up before his eyes as a "roar" of water went through. "Anything and everything was going through," DeShaw said.
As the river began to flow over the top of the dam, the man who knows the most about the structure discussed its demise not in terms of if it would be breached, but when. "This is a warning, not a watch. I don't like the look of it," Dave Fink, dam operations supervisor for the Lake Delhi Recreation Association, said around 11 a.m. Saturday.
With water coursing across the south approach to the dam and half the roadway on the north side undermined by moving water, Fink said, "I think one of the approaches would be the one to go."
At 12:49 p.m., when the first large chunk of roadway disintegrated before the horrified eyes of more than 100 onlookers on both sides of the river, Fink's formerly pessimistic assessment suddenly seemed realistic.
With the lake level about 15 feet higher than the openings in the dam, water roared into the ever-widening breach, quickly cutting a gorge through which the impounded water cascaded 40 feet to the river below.
As more of the roadway gave way, utility poles toppled into the flood, and adrift boats and docks from the lake crashed into the opening. A liquid propane tank ignited just below the dam shooting flames high into the sky, adding to the disaster movie impression.
"I've seen fully grown trees washed downstream in less than a minute," said McCarthy, the DNR specialist.
Though Fink and public safety officials feared a catastrophic release of water and pent-up energy, especially in the immediately downstream towns of Hopkinton and Monticello, the surge of floodwater spread out in downstream farm fields and lost most of its punch before arriving about three hours later in Hopkinton.
Delaware County Sheriff John LeClere said an Iowa State Patrol pilot watching the swollen Maquoketa River reported that the water spread into river bottoms along Pioneer Road. "To my knowledge, there've been no injuries, which is the main thing," LeClere said.
At 3:30 p.m., Hopkinton Fire Chief Craig Wilson estimated that the river had risen 18 inches in three hours. But many of the homes closest to the river were still not in danger, he said. A few miles north of town, firefighters reported to Wilson around 4 p.m. that the water was starting to recede.
Monticello officials warned residents of low-lying neighborhoods to expect a big rise in the river, but no mandatory evacuation orders were issued. With the surge dissipating over thousands of acres of farmland, worries eased, and Monticello Police Sgt. Britt Smith, the department's acting chief, warned against "rumors you're hearing about a tidal wave, a tsunami, or anything like that."
"The local officials seem to be doing a great job getting people out of harm's way," said Gov. Chet Culver, at an improvised command post in Monticello. Culver issued a disaster proclamation for Delaware and Jones counties that allows use of state resources to deal with damage caused by the recent flash flooding. Culver, who also activated the Iowa National Guard, said assessment teams were in Monticello, Delhi, and points between Saturday afternoon.
The Maquoketa River had been expected to crest in Manchester on Friday evening at 22.5 feet before another round of heavy rains fell on its watershed. It finally crested there at a record 24.53 feet about 12:30 p.m. Saturday, according to Jack Klaus, a spokesman for Delaware County Emergency Management.
More than a dozen downtown businesses sustained heavy damage as floodwaters filled them to depths of several feet.
The dam breach lowered Lake Delhi by as much as 10 feet in a few hours, bringing some relief to the scores of lake residents whose homes sustained first-floor flooding.
The Freddy's Beach area, where homes sit not far above the lake level, was among the hardest hit.
"I never, ever expected anything like this," said Dorothy Thomas, 85, who with her husband Fred founded the Freddy's Beach resort area in the 1950s. For the first time in her 60 years on the lake, floodwaters forced her from her home about 1:30 a.m. Saturday, she said.
Cedar Rapids resident Mike Reutzel, whose weekend cottage flooded for the first time in his 30 years on the lake, said the experience reminds him of the 2008 Cedar Rapids flood, which damaged his home and business. "We had a lot of rain on top of a record crest," he said.
The Lake Delhi dam was last fully inspected by the Department of Natural Resources in May of 2009 Although a few minor repairs were still needed following the flooding of 2008, no major structural problems were found on the dam, said Lori McDaniel, supervisor of the DNR's flood plain and dam safety section.
Jim Willey, president of the Lake Delhi Recreation Association, said it will take a lot of time and effort, but the dam will be rebuilt.
Downstream, a record crest of nearly 35 feet 11 above flood stage is expected late this afternoon at Maquoketa. That's enough to top the levee protecting the industrial section at the north end of town, according to the National Weather Service.
Background on the Lake Delhi Dam
The Lake Delhi dam is 81 years old. The dam was completed in 1929 by the Interstate Power Co., according to Gazette archives. The dam generated power until 1973. In 1974, Interstate Power sold the dam to the Lake Delhi Recreation Association, a group of residents seeking to preserve recreational opportunities at the lake. The association still owns the dam
Multiple efforts had been under way to again generate power from the dam, with the latest effort starting in 2008. Lake Delhi is roughly a 450 acre lake, according to the United States Geologic Survey.