With little flood storage at Gavins Point, U.S. Army Corps took rare steps during flooding

With little flood storage at Gavins Point, U.S. Army Corps took rare steps during flooding
World-Herald News Service

From the air, Lewis and Clark Lake along the Nebraska-South Dakota border appears immense as it stretches some 25 miles behind Gavins Point Dam.

It would be logical to think of the sprawling lake — formed by damming the Missouri River — as a big deal in flood protection.

There’s 90 miles of shoreline along this watery playground that draws 2 million visitors a year.

It is formed by one of six massive dams on the Missouri River, all operated by the U.S. Army Corps of Engineers.

Together they constitute the largest reservoir system in the United States.

And together, they deny the Missouri River its nearly annual habit of flooding twice a year because of snowmelt — first from the plains and then from the mountains.

When an epic storm hit in mid-March, the gargantuan system had 22 percent of its space set aside for flood storage, and a full 96 percent of that stood empty and ready to take in water.

Yet on the night of March 14, when historic and previously unimaginable flooding washed down the Niobrara River into Lewis and Clark Lake, the limitations of Gavins Point Dam became apparent.

It’s small, holding back less than 1 percent of the water in the six reservoirs. It’s not even Nebraska’s largest lake  it’s about one-fourth the size of Lake McConaughy.

Gavins Point is small compared to other dams
This chart shows the capacity of the six large dams on the upper Missouri River. The lowest dam, Gavins Point, is the final one before the water flows downstream toward Omaha and points southward.

And there’s another thing: The dam, as it turns out, is not designed for significant flood control.

“It’s not?” said Ken Doyle, who lives downstream of the dam in Dakota Dunes, South Dakota, a community that flooded in 2011 and was evacuated in March. “That’s crazy. I was always told all those dams were for flood control.”

Instead, Gavins Point’s main purpose is to smooth out widely fluctuating discharges from the much larger hydroelectric dam immediately upstream. If Gavins Point weren’t in place to do so, river levels downstream would rise and fall, perhaps multiple times and sometimes as much as 5 to 6 feet, on any given day. About 30 percent of the space behind Gavins Point Dam is set aside for flood control.

Only four of the six reservoirs are designed to impound significant runoff. As luck would have it, the record-shattering runoff from this historic storm occurred downstream of those four.

So when the Niobrara dumped its floodwater into Lewis and Clark Lake  on the peak day of flooding, 31 times the river’s average March flow was pouring into the lake  the Corps of Engineers had few options but to open the floodgates.

The timing couldn’t have been worse: Downstream, the Platte River was pouring even more water into the Missouri River, which was swelling to record levels. South of the Platte, levees were overtopped, broken or weakened. Low-lying neighborhoods, businesses and cropland flooded.

In information provided to The World-Herald, the corps said the largest single source of floodwaters entering the Missouri was the Platte River. Significantly, the corps says, the levee that protects Hamburg, Iowa, was overtopped well before the increased discharges from Gavins Point reached that stretch of river.

Corps officials say they did what they could, undertaking rarely or never used actions:

» Shutting off Missouri River flows coming out of Fort Randall Dam immediately upstream of Gavins Point.

“We stopped the upper 1,440 miles of the Missouri River, the longest river in the nation … for four days,” said Col. John Hudson, commander of the Omaha District of the Army Corps of Engineers. Eventually those flows would be halted for a total of eight days, interrupted by modest releases over two days.

» Raising the Gavins Point floodgates in a manner that allowed the height of the lake to rise 1.6 feet higher than ever before in its 62-year history. Doing so required a determined effort because two of the 14 gates had become frozen in place during late winter’s bitter cold.

» Boosting, temporarily, Gavins Point releases to 100,000 cubic feet a second, second only to the amount released during summer 2011.

At the height of the flooding, the corps sent 44 percent less water downstream than was coming into the lake.

“There was far more water flowing into Gavins Point than we could hold in that reservoir,” said John Remus, chief of the corps’ Missouri River Management Division. “We kept flows as low as we possibly could, and we delayed increases as much as we could.”

The corps’ explanations of what it did and why will do little to soothe people who experienced flooding along the Missouri River. Political leaders are leveling varying degrees of criticism.

“Perhaps a good scrubbing of the (corps guidebook) may help clear wax out of bureaucratic ears that haven’t gotten the message: The number one priority of the corps should be flood control. Period,” said Sen. Chuck Grassley, R-Iowa.

Due to high precipitation, flood control has been the guiding priority for the corps since March 2018, Remus said.

Any semblance of its natural flows have been engineered out of the otherwise flood-prone Missouri River. Congress has directed the corps to manage the river according to eight priorities: flood control, navigation, hydroelectric power, irrigation, water supply, water quality, recreation, and fish and wildlife, including endangered and threatened species.

Years ago, flood control was the corps’ top priority, but changing conditions, including extreme drought and continued ecological degradation, led to numerous lawsuits by interest groups and political wrangling among states.

In 2004, a federal judge ordered the corps to do more for threatened and endangered species. Subsequent flooding set the stage for another lawsuit, this time a victorious one by landowners who blamed the corps for damage to their property. (The controversial spring pulses undertaken to help endangered and threatened species haven’t been done since 2009 and were removed from the corps’ guidebook in 2018.)

One thing that hasn’t changed over the years, Remus said, is the amount of space set aside for floodwater.

“There has been a lot of mentioning in press lately by people and some politicians about changing our storage for fish and wildlife,” he said. “We have not changed” the floodwater allocation.

Any effort to boost storage space for floodwater, even at “small” Lewis and Clark Lake, would require a re-examination of the entire complex system, Remus said. And there’s no guarantee that doing so would prevent the next flood.

Still, corps officials say they will study what has occurred this year.

“There’s always something to learn,” Col. Hudson said. “We’re not suggesting we couldn’t have done better. We’ll look at how we communicated, we’ll go back and look in detail at what could have been done better.”

Q&A: We ask the corps about Missouri River management during recent floods

In March, Gavins Point Dam on the Missouri River was put to one of its greatest tests in its 64-year-history: Record-breaking runoff in the dam’s watershed, primarily from the Niobrara River, exceeded its capacity.

That prompted the second-highest discharge from the dam since it started operating in 1955.

Simultaneously, about 180 miles downstream, flooding on the Platte River sent record amounts of water into the Missouri River. From Plattsmouth south, the Missouri River reached record levels. Levees broke, towns flooded, farmland was inundated, and livestock, crops and equipment were lost.

Here, U.S. Army Corps of Engineers officials address questions The World-Herald has been hearing about management of Gavins Point Dam during the flooding.

Talk, for a minute, about some of the actions taken by the corps that succeeded in lessening flooding along the Missouri River.

First, the corps shut down releases from Fort Randall Dam, which is immediately upstream of Gavins Point, on March 13, during the time that the Niobrara River Basin was peaking. The surge in releases from Gavins Point Dam came from the unregulated Niobrara River and the smaller watersheds immediately around the dam. None of it came from that portion of the Missouri River impounded by the five upstream dams.

Second, the corps operated the Gavins Point spillway gates to raise the pool behind the dam — peaking 1.6 feet higher than its previous peak of 1210.7 feet in 1960.

How did inflows into Gavins Point compare to its flood storage capacity?

On March 13, the Gavins Point pool had 107,000 acre-feet of flood control space available. If no releases had been made from Gavins Point, the March 14 inflow of 250,000 acre-feet would have filled the available space in about 10 hours. If all of the flood control storage space were available, it would have been about 13 hours.

Could Gavins Point’s base elevation be lowered so that it holds back more floodwater in addition to re-regulating Fort Randall’s discharges?

Gavins Point Dam is one of six Missouri River dams. To set aside more space behind Gavins Point Dam would affect all six dams and require an examination of the potential effects to each of the authorized purposes throughout the system and along the full length of the Missouri River.

Even with Fort Randall releases of zero cubic feet per second and the Gavins Point reservoir empty, significant releases from Gavins Point would have been necessary.

How did flows coming out of Gavins Point compare to the flows entering the Missouri from the Platte River?

The Platte River contributed significantly more flow to the Missouri River than Gavins Point or any of the other tributaries between Gavins Point and Plattsmouth. At its peak on March 16, the U.S. Geological Survey estimated that the Platte River contributed more than 190,000 cubic feet per second into the Missouri River.

When did the surge in releases from Gavins Point start reaching Plattsmouth and when did it subside (in other words, how long did it last)?

The travel time for water between Gavins Point and Plattsmouth is three to four days. The large increases at Gavins Point began early March 14, starting at 33,000 cubic feet per second, peaked temporarily in the early hours of March 15, at 100,000 cubic feet per second and were stepped down from there. By March 20 releases were back to 24,000 cubic feet per second.

During February and early March, as snowpack built up in the Gavins Point Dam watershed, how come the corps didn’t start boosting releases from the dam to make room for additional runoff?

The corps was making above-average winter releases of about 20,000 cubic feet per second (normal range is 12,000 to 17,000 cubic feet per second) throughout winter to finish evacuating all of the 2018 stored floodwaters. This was accomplished in late January.

We monitor basin conditions on an ongoing basis, including mountain and plains snowpack. Our March 1 upper basin runoff forecast indicated that runoff would likely be slightly above normal and that we might need to start initiating flood storage evacuation measures once the river ice conditions between the reservoirs no longer presented a risk for ice jams from increased releases (typically in mid- to late March).

In mid-March, when the “bomb cyclone” was forecast — rain on top of the snowpack — how come the corps didn’t, at that point, ratchet up releases from Gavins Point to adjust for the impending glut of runoff?

The National Weather Service is the agency that forecasts precipitation and river levels. In the final days before the storm hit, forecasts changed, with the heaviest rains falling farther north than originally expected.

The record runoff came from a combination of three things: 1) moderate to heavy rainfall, 2) on top of a heavy plains snowpack, 3) on top of frozen soils. The soil normally absorbs some of the rainfall and snowmelt. During this event, it’s estimated that the top 1 to 2 feet of soil was frozen, and nearly all of the rain and snowmelt became direct runoff.

Assessing the volume of runoff that was going into Gavins Point reservoir was extremely challenging, both for the National Weather Service and the corps.

“At the end of the day, it was an event that, every time we got the new forecast and expectation of what was going to happen on the river, it kept going up,” said Col. John Hudson, Omaha District commander. “There was very little time to react.”

As early as March 7, the National Weather Service in Valley was warning of major flooding, and by March 15, it was warning that people shouldn’t assume levees on the Platte, Loup and Elkhorn would hold. Why didn’t the corps have similar concerns about the Missouri River levees in the flood-prone stretch of river between Plattsmouth, Nebraska, and St. Joseph, Missouri?

A chain of command exists for emergency communication — from the corps to the state to the county and below. If the corps usurps that chain of command, it sets up a potential for conflicting messages among various governmental agencies. Advising residents on local conditions is a fundamental responsibility of mayors and the local community.

“If there are questions about whether farmers should move their equipment or anything out of a field, if the water is going to be up on a levee, we’re talking to state emergency officials and they’re talking to their county emergency managers, who are pushing that down to the local level where decisions are made,” said Matt Matthew Krajewski, readiness branch chief.

The L-575 levee near Hamburg, Iowa, was overtopped about midnight March 14, less than a day after the storm hit the area. At that time, the Missouri River in this stretch was carrying 214,000 cubic feet per second. The Gavins Point contribution, based on releases March 10 and a four-day travel time, would have been about 20,000 cubic feet per second.

Regarding the overall management of the river: When was the last time the corps adjusted flows out of its dams to provide for endangered and threatened species?

In spring 2017, we performed two three-day cycles from Gavins Point Dam. A “cycle” lowers and then increases releases so that downstream river fluctuations discourage threatened and endangered birds from nesting in the lower portions of sandbars.

The Gavins Point spring pulse, which was only conducted in 2006, 2008 and 2009, was removed from the corps’ 2018 Master Manual.

Salvation Army opening a Council Bluffs distribution site for flood victims

The Salvation Army is opening a distribution center in Council Bluffs to help flood victims.

The organization’s Disaster Resource Center will be like the distribution site that’s been operating in Omaha, near 84th and Center Streets, where people in need can pick up flood-relief items and people can drop off donations, the Salvation Army said Sunday in a press release.

The resource center, at 715 N. 16th St. in Council Bluffs, will open Monday.

A caseworker will be on hand to help flood victims through a process to pick up supplies, the Salvation Army said. That process involves filling out a brief form. Anyone seeking flood-relief items will need to bring a photo ID.

The resource center will be open 9 a.m. to 7 p.m. on Mondays and Thursdays; 9 a.m. to 4 p.m. on Tuesdays, Wednesdays and Fridays, and 9 a.m. to noon on Saturdays. The center will be closed on Sundays.

Nebraska flooding part of Capitol Hill climate change debate

Flooding makes for hot topic on the hill

Midwestern flooding was featured in debates across the Capitol last week, popping up in discussions about everything from the importance of crop insurance to the effects of climate change.

Democrats cited the flooding repeatedly in the debate over the Green New Deal. That nonbinding resolution calls for an aggressive approach to climate change. Rep. Alexandria Ocasio-Cortez, D-N.Y., introduced the measure, which includes ambitious goals for the next decade on protecting the environment but also delves into areas such as housing and jobs.

Supporters say the resolution is just the kind of sweeping call-to-arms needed to confront the looming environmental crisis. Critics, meanwhile, have derided it as a liberal wish list and government intervention into many aspects of American life.

Senate Republicans sought to put Democrats on the spot by bringing the measure up for a vote last week. All Republicans voted against it, as did a few Democrats. Most Senate Democrats simply voted “present,” saying Republicans weren’t engaging in good faith and stressing that robust action is required on climate change.

About the same time, one Republican House member was arguing in a committee hearing that the resolution represents an economic hit to the poor. He said it sounds great to rich elites who can easily sustain the extra costs in housing and other areas.

Ocasio-Cortez responded by saying that concern for clean air and water isn’t elitist. She cited children in the south Bronx suffering from asthma, residents of Flint, Michigan, poisoned by lead-contaminated water and those suffering in the Midwest.

“This is about our constituents and all of our lives,” Ocasio-Cortez said. “Iowa, Nebraska, broad swaths of the Midwest are drowning right now, underwater. Farms, towns that will never be recovered and never come back.”

War between the districts

Nebraska’s all-GOP congressional delegation gathers each week they’re in session for a breakfast with visiting constituents. At the most recent session, talk turned to which House district has the most military firepower.

Rep. Adrian Smith represents the sprawling 3rd District that covers most of the state.

Smith pointed out that his Omaha area colleague Rep. Don Bacon is a retired Air Force brigadier general and that Offutt Air Force Base is located in the 1st District, represented by Rep. Jeff Fortenberry.

“Western Nebraska is not known for our military installations but we do have missile silos in western Nebraska,” Smith said. “My district can probably blow up Fortenberry’s district, even though he has the base.”

The comment brought some chortling from both the audience and other delegation members.

When breakfast emcee Sen. Deb Fischer took back the microphone, she noted that Congress had recently returned from a recess.

“We weren’t here last week so we’re all feeling a little feisty,” she said.

Legislative versus executive branch

Sens. Ben Sasse and Chuck Grassley joined several Republican colleagues recently to introduce legislation aimed at reining in federal agencies.

At issue are court rulings that have granted a general deference to administrative agencies’ interpretation of the statutes adopted by Congress.

Critics say that approach has allowed agencies to stretch their authority beyond congressional intent.

The senators’ legislation would require that courts decide for themselves “all relevant questions of law, including the interpretation of constitutional and statutory provisions and rules made by agencies.”

“This bill tries to restore some accountability by making sure that judges don’t automatically defer to Washington’s alphabet soup of bureaucracies,” Sasse said in a press release.

Democrats made their own “separation of powers” argument when lawmakers took up a resolution to shut down President Donald Trump’s border wall emergency declaration. They described that move as reasserting congressional authority after the president sought to circumvent Capitol Hill and unilaterally divert billions to building the wall.

Trump vetoed the measure and House Democrats fell short of the number of votes required to override.

All Republican lawmakers from Nebraska and Iowa sided with the president in that fight, citing the importance of border security.