By John Balch
Things at Narrows Dam have slowed this week – both the flow of water and the constant stream of visitors out to get a look at another historic overtopping of the 563-foot tall structure.
When flood waters pushed Lake Greeson over the dam’s spillway on Friday, March 2, it was only the third time in the dam’s 68 years. The other two times were May 18, 1968 and May 14, 2009.
Just like with the other events, hundreds, perhaps thousands, made the trek up Highway 19 North to see the spectacle. License plates from all over the country, many likely from those already in town to visit the Crater of Diamonds State Park, were noted parked nearby or slowly cruising across the bridge.
Some likened the snow-white sheet of falling water and the heavy mist and deafening roar of two nearby release valves to Niagara Falls. Some embraced and kissed as they stood on the bridge while others took photos and selfies. Many made return trips as the spill progress and several had seen all three historic spills.
By Monday morning, the water had begun to slowly recede and on Tuesday the spill had subsided. Only the roar of the dam’s two “bungar” release valves remained as the U.S. Corps of Engineers continued its efforts to get Lake Greeson out of the flood plain.
The lake’s level was at 562.16 feet Tuesday morning, according to Andrea McRae, civil engineer technologist at lake. McRae said the water peaked at about six inches deep during the spill. In 2009, the water was seven inches deep on top and in 1968 reportedly was 18 inches deep at its peak.
The two release valves, currently running at between 50 and 75 percent each, will continue to be used until the lake’s level drops out the flood plain at 548 feet.
The Corps initially reported last week it was not expecting an overtopping. But, the lake level was pushed up by persistent heavy rain and runoff and compounded by work on the dam’s power plant switchyard that is preventing all but one of the dam’s generators to be utilized. McRae said that one generator is being used to create electricity for the dam itself and the powerhouse.
Though it did create a pretty scene on the downside, on the upside is another story.
“It’s a mess and it’s going to be a bigger mess right here at the time we really start our spring season,” said one Corps official.
The flood conditions on the lake had already resulted in the scheduled March 1 opening of some of the campgrounds that had been closed for winter to be delayed. Roads and virtually every campground are now underwater and will remain closed until further notice. The lake’s marinas are also battling the high water after months of battling low water. There is also lots of debris and trash along the shoreline and floating in the lake, so boaters are advised to use extreme caution.
As the lake level drops, more damage will reveal itself and plans for clean-up will be determined.
“We’ll have to wait and see what we have,” said McRae.
Even though the spill has subsided, the high-water level requires the dam to be monitored by Corps personnel with inspections every two hours – by foot and elevator – around the clock.
Narrows Dam is an all-concrete dam. Construction began in April 1947 with the first bucket of concrete placed into the dam in June 1948. Completion of the dam was in 1950 and dedicated in July 1951, upon completion of the entire project.