116 3rd St SE
Cedar Rapids, Iowa 52401
From devastation to resilience: Here’s how Cedar Rapids’ flood control system will work
Nearly one-third of the network of gates, levees and pumps is complete
Jun. 11, 2023 5:30 am, Updated: Jun. 19, 2024 10:42 am
CEDAR RAPIDS — Watching a concert and grabbing a beer at McGrath Amphitheatre. Taking wedding photos along the flood wall in Czech Village. Biking the trail that spans the top of a Cedar Lake levee. Skateboarding at a newly rebuilt Riverside Park.
These are among the activities that construction of Cedar Rapids’ flood control system has made possible 15 years after the historic 2008 flood devastated Cedar Rapids. On June 13, 2008, the Cedar River crested to its highest level in Cedar Rapids history — 31.12 feet — and inundated 10 square miles of the city, causing what the Army Corps of Engineers estimated to be $5 billion worth of property and economic damages.
Since work began in 2014, city and federal crews have ramped up construction of permanent flood protection in preparation for the next time the Cedar River swells, seeking to hide flood control in plain sight by blending it with community amenities.
An influx of local, state and federal funding is accelerating construction of the city’s massive network of flood gates, walls, levees and pump stations. The system’s estimated price tag totals $750 million, though record inflation may push that figure closer to $1 billion by the time work is complete about 2035. Some projects may stretch beyond that date since the system is not fully funded yet.
Fifteen years after the devastating flood, Cedar Rapids’ flood infrastructure construction is about 30 percent complete, said Public Works Director Bob Hammond. Work on the east side of the river is expected to be done by the end of 2026.
When floods threatened again in 2016, 9 miles of temporary HESCO-brand sand barriers were used to protect the city — the barriers stacked three high. With progress on the permanent system so far, that number would drop to 7 miles.
Guided by the creative vision of Flood Control Program Manager Rob Davis, the flood control system is full of engineering marvels and projects that Davis said “give you the biggest bang for your buck” in terms of flood protection. Each segment of permanent protection reduces the amount of costly temporary measures the city must put in place when the river threatens to flood again.
“Trying to put a flood control system in a developed community for 150-plus years is not an easy task,” Davis said. “There are a lot of factors you have to consider.”
The Gazette looked at how various segments of Cedar Rapids’ flood control system come together to fortify communities and businesses against flooding.
Keeping water out
The National Czech & Slovak Museum & Library stands in Cedar Rapids’ Czech Village, where in 2011 the 2.8 million-pound structure was moved away from the Cedar River nearly 500 feet and elevated after being flooded.
It gained a new neighbor last year: a flood wall that shields the museum from the river. But it has been carefully designed to blend into the community it protects.
The concrete wall stretches 13 feet high, extending to the 16th Avenue Bridge. On the Czech Village side, it’s lined with grassy terraces for visitors to lounge or for events to take place. The design on its floodgate — left open for vehicles to pass through — matches the pattern of the bridge railing. A light-up sign stretches atop the roadway, signaling the destination across the river: the New Bohemia District.
“It can be imposing, but we don't want people to feel trapped by it,” Davis said about the flood wall.
It marks part of the 3.71 miles of flood walls and flood gates planned to line the Cedar River throughout Cedar Rapids and keep high water levels out of the city. Just under 1 mile has been completed so far.
Their height is typically 13 feet — based off 2008 floodwater levels and designed to handle 143,300 cubic feet of water per second. The typically 5-feet-thick and 60,000-pound gates, usually open for vehicles and trains to pass through, can be rolled shut within an hour when needed. Some of the flood gates can be swung shut.
Not all of the city’s flood walls will be permanent. About 12 percent — or about 1 mile — of Cedar Rapids’ flood infrastructure will be removable. When needed, approximately 11-foot-long panels can be slotted horizontally between removable posts like Lincoln Logs to create flood walls. The removable sections, like one near the CRST building on Third Avenue SE, require less maintenance and maintain community access to the river but can take up to eight hours to erect.
On the other side of the 16th Avenue Bridge floodgate, the flood wall connects to a levee. Like flood walls, levees are flood infrastructure projects designed to obstruct water from entering the city. They are constructed by layering and compacting earthen materials into big, tall berms.
Upon the system’s completion, there will be 3.64 miles of levees throughout the city. One at Cedar Lake is in progress; another will sprout next year on F Avenue NW.
Just as the 16th Avenue flood infrastructure was made with the Czech Museum in mind, the city accelerated work on a flood wall between First Avenue W and E Avenue NW to align with construction of the Pickle Palace bar and grill and Big Grove Brewery on the nearby mixed-use First and First West development, off First Avenue W and First Street SW near May’s Island.
First Street NW will be rebuilt and elevated over the flood wall, and moved closer to the development near the area that will host Pickle Palace. Davis said city staff also considered how future river recreation with a 5-in-1 Dam bypass channel would factor in.
“We said OK, let's put all those amenities there first, and then how do we fit the flood control system around that, because when you do that, then it truly blends,” Davis said.
River water can’t just infiltrate Cedar Rapids from above ground — it can also creep through the storm sewer system that webs underneath the city. The network originally was built to bring precipitation to the Cedar River at 48 outfalls. But in flood stages, those outfalls get backed up with water that pushes up through the pipes and drowns the city from below.
During the 2016 flood, city staffers took days building 12-foot-tall concrete cones, placing them around storm sewer intakes in the street and lining them with sandbags and pumps. Now, Cedar Rapids is working on consolidating the storm sewer system into fewer outfalls, outfitted with stormwater gates that can be closed during floods.
“It's much more reliable” than using the concrete cones, Davis said. “To try to build hundreds of these versus having 12 gates at the river is much more sustainable.”
Moving and holding water
Flood walls, flood gates and levees can be effective at keeping flooding rivers from swelling into nearby communities. But the barriers work both ways: Any precipitation that falls on the city side of the structures will be trapped.
On the west side of the Cedar River, for instance, 9 square miles typically drain into the storm sewers and then into the waterway. When stormwater gates are shut due to flooding, a large rainfall event could flood neighborhoods without a drop of river water.
That’s where pump stations come into play. The facilities sit next to flood walls and levees and are outfitted with strong machinery that pumps water from the city side to the river side of the barriers. Cedar Rapids currently has five — 16 are planned in total.
Like the city’s flood walls, some pump stations were designed to match the aesthetics of the communities they’re built in. The brick pump station in NewBo, for example, was designed to match the Cedar Rapids Czech School in front of it.
The largest stormwater outfall to the Cedar River — a 9-foot diameter pipe — runs underneath a portion of that pump station. During floods, the outfall can be gated shut. Any stormwater from the city is diverted to a rotating trash rack that collects large debris. Then, three 12,500-gallon-per-minute pumps send the water up and over the adjoining flood wall into the Cedar River.
Pump stations can only do so much, though, before they’re overwhelmed with drainage from storm sewers. Pairing the infrastructure with detention basins can help prevent that. The basins hold and slow stormwater before feeding it to pump stations — thus reducing the amount of work pump stations must do.
The city is constructing a detention basin where Riverside Park’s playground and skate park once stood. A pump station will be built alongside the nearby flood wall — but, thanks to the detention basin at its mouth, its size was reduced — saving $6 million. Two storm sewer pipes with 7-foot diameters will be redirected into the basin instead of the pump station.
“Being able to store the water is a very efficient way to build your pump stations drawing on gravity and not mechanical equipment,” Davis said.
This segment has drawn perhaps the most community engagement of any flood control project. City staff worked with skate park users to design obstacles in the new concrete facility, which will open later this summer. The relocated park and skate park were moved closer to C Street SW to make way for the detention basin.
Giving water space
Flood infrastructure better protects the structures it’s carefully crafted around. But it can also constrict waterways, causing them to rise higher in times of flooding. By the end of the project, Cedar Rapids’ own flood infrastructure would add about 3 feet of rise to upstream water levels if a flood comparable to 2008 happens.
That’s why structures built along the Cedar River must be balanced by giving the waterway more space to expand.
The biggest example in Cedar Rapids is in the Time Check neighborhood, where the levee system was set back four blocks from the river. The city is looking to use eminent domain to acquire 27 remaining properties in the Northwest Neighborhood to make way for flood protection.
Staff are designing a levee segment from Ellis Boulevard NW to O Avenue NW, but some homes are located where the levee is planned. Other projects in the area also are in the design phase, including the Time Check levee tie-off, where the north portion of westside flood control ends at Ellis Lane NW, and the O Avenue NW elevation over the levee.
Altogether, the city is opening up 77 acres of flood plain after purchasing more than 1,300 properties. And raising roads and bridges can give the Cedar River and its tributaries more room to expand, too.
Shaver Road, for instance, is a major truck route that crosses McLoud Run. Instead of installing a floodgate on the road, the city reconfigured it as a raised bridge. That way, the route can remain open as floodwater rushes underneath.
Adjacent flood walls pass under the bridge, where McLoud Run will be widened and transformed from concrete to a meandering, low-flow channel. Bike trails, sidewalks and fishing spots also will line the waterway.
“All those things allow room for the river to breathe,” Davis said. “From a regulatory standpoint, we can't just build right at the river banks and then back that water up and cause problems upstream.”
Other bridges are being raised as well, including Edgewood Road SW and Sixth Street SW over Prairie Creek. But the biggest such project will be the demolition and reconstruction of the Eighth Avenue Bridge over the Cedar River. It will cost up to $90 million, much of which the city is hoping to secure in grants.
The new cable-stayed bridge will have fewer bridge piers, be 15 feet higher and be accessible during high water levels. The modifications allow the Cedar River to flow more efficiently underneath — hindered by less obstructions and, if in a flood stage, allowed to rise higher than before.
The bridge will provide a key access point for residents and emergency services when all other city bridges over the Cedar River close during flooding and only Interstate 380 remains open downtown.
“Each one of those piers causes friction,” Davis said. “If we can do some things to be more efficient with the friction … that can actually take the water back down.”
Brittney J. Miller is the Energy & Environment Reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.
Comments: (319) 398-8370; brittney.miller@thegazette.com
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