Spring brings more fears for #MissouriRiver flooding — The Kirksville Daily Express

2019 Nebraska flooding. Photo Credit: University of Nebraska Lincoln Crop Watch

From The Kirksville Daily Express (Mike Genet):

A year after flooding battered the Missouri River’s levee system, inundating towns and farmland and causing multiple closures to the nation’s interstate highway system, early forecasts warn that more of the same could be on the way: above-normal rainfall, greater than normal spring runoff. A USA TODAY Network analysis delves into records of an aging system of nearly a thousand levees where nobody knows how many were damaged last year or how many were repaired…

The forecast is a veritable index of meteorological plagues: above-normal rainfall; greater than normal spring runoff; thoroughly saturated soils; and an aging system of nearly a thousand levees where nobody knows how many were damaged last year and in previous floods or how many were repaired.

The 855 levee systems throughout the Missouri River basin protect at least half a million people and more than $92 billion in property. Yet a USA TODAY Network analysis of Army Corps of Engineers’ records found at least 144 levee systems haven’t been fully repaired and that only 231 show an inspection date.

Of those, nearly half were rated “unacceptable,” which means something could prevent the levee from performing as intended or a serious deficiency was not corrected. Only 3.5% were deemed acceptable; the rest were found to be “minimally acceptable.”

U.S. levee systems map via the U.S. Army Corps of Engineers. Click on the map to go to the interactive website.

Only 231 of the levee systems show any inspection date. For 38, the most recent inspection date was more than five years ago.

In the Army Corps’ Kansas City district, for example, about 70 projects, spanning 119 levees that requested repair assistance, are eligible for funding, but that doesn’t mean they’ll be ready if the waters rise like they did last year.

“Some of them have been repaired, but from a total system perspective, I don’t think any of them are whole,” said Jud Kneuvean, the district’s chief of emergency management, who expects full levee rehabilitation and repair to take at least another year.

In the meantime, the extent and impacts of flooding will depend on when and where the rain falls…

The 2,300-mile Missouri River begins in southwestern Montana, where the Gallatin, Madison and Jefferson rivers converge near the community of Three Forks, before gathering water from 10 states and parts of two Canadian provinces to become the “Big Muddy,” North America’s longest river.

In recent years, more rainfall has been pouring into the Missouri River basin, raising questions about whether climate change is bringing worsening floods more often. Data from the National Oceanic and Atmospheric Administration dating back to 1895 shows record-setting rainfalls in the area occurring more often. Last year, for example, was the wettest on record in North Dakota, South Dakota and Minnesota.

All that water adds to the challenge faced by Corps policymakers, who juggle sometimes conflicting priorities that include maintaining navigation; managing the reservoir system to prevent flooding; providing farmers with irrigation and hydropower; protecting endangered species; and preserving recreational opportunities.

While the priority is protecting human life and safety, the Corps’ decision-making sometimes puts special interest groups at odds, and the agency remains embroiled in controversy over whether the engineering of the river exacerbates flooding.

Things came to a head last year when a bomb cyclone in March melted all the snow in Nebraska and Iowa at once and dumped tremendous rain, swelling not just the Missouri, but the Elkhorn, Platte, James and Big Sioux rivers.

The Niobrara River in Nebraska breached the Spencer Dam on March 14, sending a wall of water downstream and into the Gavins Point reservoir near Yankton, South Dakota. At the peak, water flowed into the reservoir at 180,000 cubic feet per second — nine times more than the normal average for March. Meanwhile water was coursing into the rivers downstream of the dam and the effects of all that water were felt in nearly every community downstream.

Two other big rain events occurred in May and September. When the Corps’ Kansas City district deactivated its emergency operations center in December, it had been open for 279 days, the longest period on record…

Construction of the higher levee is in the administrative and planning stages, with actual construction activity set for fall.

Most of the Missouri’s levees fall into one of two categories: either federally built and locally operated or locally built and operated. The Corps inspects — and helps pay to repair — only the levees maintained to federal standards that participate in the federal flood program.

That exception means no one has a full list of damaged levees still in need of repair.

The number of levees that aren’t regularly inspected doesn’t surprise Neal Grigg, an engineering professor at Colorado State University who chaired a Corps-appointed review panel after 2011 flooding.

In an ideal management system, every levee “would be under the responsibility of some authority that was responsible and had enough money and good management capability to do that,” Grigg said.

But that’s not realistic, he added, noting that the Corps has tried through a task force to get some organization to the levee systems along the river, but it’s problematic, in part, because there are so many conflicting interests.

A host of agencies are cooperating to repair levees, but the progress is slow, said Missouri farmer Morris Heitman, who serves on the Missouri River Flood Task Force Levee Repair Working Group.

In addition to the Corps, the Federal Emergency Management Agency, the state of Missouri, the USDA Natural Resources Conservation Service and a large number of local levee districts all work to repair levees.

“We’re trying to dance with different agencies,” Heitman told the University of Missouri Extension. “All these agencies have their own requirements and parameters, and we’re trying to coordinate those to build a secure system against the river.”

Fixes to the 144 levee systems listed in disrepair in the Corps’ Omaha and Kansas City districts are in various stages of completion, and some aren’t expected to be done for more than a year.

In the Omaha district that includes Nebraska and Iowa, “pretty much all of the levees were damaged in one way or another,” said the corps’ Matt Krajewski.

While almost all of the district’s levees that qualify for federal aid have been restored to pre-2019 flood heights, Krajewski said they don’t offer the same level of “risk reduction” because they need final touches such as sod cover and drainage structures to protect against erosion. The Corps hopes to complete those repairs this summer.

In the meantime, the Corps is working to prepare its flood storage capacity by releasing more water than normal from its dams.

“We’re being really aggressive with our releases and trying to maintain our full flood storage,” said Eileen Williamson, a Corps spokeswoman for the Northwestern region.

But the projections for spring runoff don’t look good and may limit how much the Corps can do.

In February, the runoff was twice the normal average, said Kevin Grode, with the Corps’ Missouri River Basin Water Management district.

The James River, a tributary that flows out of South Dakota, has experienced flooding since March 13 last year and that flooding is forecast to continue. Moderate flooding is expected along the Big and Little Sioux Rivers in South Dakota and Iowa, and possibly in Montana’s Milk River basin. A risk of minor to moderate flooding is forecast from Nebraska City to the river’s confluence with the Mississippi in St. Louis.

But it’s not just the spring runoff that’s a problem, Grode said. The forecast also calls for “above average runoff for every month in 2020.”

John Remus, chief of the Corps’ Missouri River Water Management Division, said during a March briefing that if those projections are realized, “the 2020 runoff will be the ninth highest runoff in 122 years of record keeping.”

In March, a three-man team with Montana’s Helena-Lewis and Clark National Forest set off on horseback for a 35-mile, five-day journey into the wild North Fork of the Sun River, a tributary of the Missouri River.

They rode horses for the first 12 miles. When they reached a foot of snow, they switched to skis and took turns breaking trail.

Greeted by a half inch of new snow each morning, higher and higher they skied, encountering snow depths of 19 inches, then 2 feet, 9 inches and finally, 3 feet, 3 inches.

Karl Wetlaufer (NRCS), explaining the use of a Federal Snow Sampler, SnowEx, February 17, 2017.

At each elevation, aluminum tubes with non-stick coating were stuck into the snow to collect core samples used to measure the depth and water content of the snowpack.

“The numbers are used for everything from dam control along the Missouri River to regulating the locks on the barges of the Mississippi,” said Ian Bardwell, the forest’s wilderness and trails manager, who led the snow survey expedition. “It just depends on what level you are looking at it from.”

As of Wednesday, mountain snowpack in the Missouri River basin in Montana was 112% of normal, said Lucas Zukiewicz, a water supply specialist with the Department of Agriculture’s Natural Resources Conservation Service in Montana.

In 2018, Montana’s April snowpack was 150% of normal, then 7 to 9 inches of rain over six days drenched the Rocky Mountain Front, inundating communities in its shadow. The Corps was forced to release water from the Fort Peck Dam spillway, a rarity, as a result of surging flows. Had that same thing happened last year, flooding in states downstream would have been even worse.

“With the way things are changing with our climate,” said Arin Peters, a senior hydrologist for the National Weather Service in Great Falls, Montana, “it’s probably a matter of time before something combines to create a big catastrophe downstream.”

Yet for this year, there may be some good news downstream from the Montana snowpack, at the Gavins Point Dam in Yankton.

Gavins Point is what’s known as a reregulation dam, its purpose to even the Missouri’s flow from the reservoirs upstream. Because Gavins Point wasn’t designed to hold floodwater, its gates had to be opened last year, sending a surge downstream after Nebraska and parts of South Dakota were hit with rain and the bomb cyclone.

In November and December, Gavins Point was still releasing water at a rate of 80,000 cubic feet per second — more than five times the average flow, and something that had never happened before, said Tom Curran, the dam’s project manager.

The good news? Releasing all that water through the winter left the mainstem dam system drained to its multipurpose zone, where it has capacity to absorb runoff while also fulfilling its other functions, including recreation and downstream barge traffic.

Created by Imgur user Fejetlenfej , a geographer and GIS analyst with a ‘lifelong passion for beautiful maps,’ it highlights the massive expanse of river basins across the country – in particular, those which feed the Mississippi River, in pink.

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