Lessons from Iowa's Epic Floods

Cities Stress Resilience Along with Redevelopment After Record Storms

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Sandy Pumphrey is a flood mitigation project engineer for the city of Cedar Rapids, Iowa.

Sven Leff is director of parks and recreation for the city of Cedar Rapids, Iowa.

Brenda Nelson is a landscape architect with Confluence, Cedar Rapids office.

Kasey Hutchinson is stormwater coordinator for the city of Cedar Rapids, Iowa.

Joseph Spradling is senior transportation engineer in the Des Moines office of HDR, Inc.

Andrew McCoy is a senior water resources engineer for HDR, Inc., in its Des Moines office.

Posted: Wednesday, November 4, 2015 4:00 pm

Rivers can be incomparable amenities in cities, attracting visitors, residents, industry and wildlife. However, when rivers rise out of their banks and inundate neighborhoods, businesses and transportation corridors, they require complex and costly action.

In the case of two Iowa cities – Cedar Rapids and Ames – epic floods led to flood control and flood mitigation plans that officials hope will make their communities even better than they were before.

Cedar Rapids is a city of 128,000 that gets its name from the river that flows through the heart of its downtown. In 2008, the Cedar River crested at a record 31.1 feet, flooding 14 percent of the city's previously dry land. Residents still remember 2008 as the “year of the river,” said Sandy Pumphrey, a project engineer who works on flood mitigation for the city.

Although there were no deaths, more than 10 square city miles were under water, affecting 18,000 citizens. In the aftermath of the flood, Pumphrey said, the city developed a flood recovery philosophy that considers a triple bottom line – economic, social and environmental sustainability.

“This set a course for months and year to come, not just to recover to what we were but to come back better than before, more resilient than before,” Pumphrey said.

The action plan included reinvesting in housing, businesses and neighborhoods, rebuilding public facilities and improving flood protection.

Sven Leff is the city's director of Parks and Recreation. He described how devastated residential and commercial neighborhoods will be redeveloped with bike lanes, trails and a walkable urban environment. A centerpiece of the project is an amphitheatre that seats 5,000 people.

“This is something that draws people back in,” Leff said. “It attracts people from beyond Linn County – that’s economic impact.”

Along with the amphitheatre came levee construction and demountable flood walls that allowed the city to work on another goal: affordable housing. In addition, the city partnered with the school district to construct a recreation center and build a new city hall and fire station.

Beyond neighborhood redevelopment, the flood control system master plan focused on alignment, aesthetics and amenities, Leff said. A group came together to evaluate 22 flood management tactics. Those judged to be most effective were to develop a dry reservoir upstream, flood protection at the river’s edge, flood protection offset from the river, and a diversion channel around a portion of the river. Public input was an essential part of determining the correct approach, Leff added.

The development of a greenway, or linear park, also was part of Cedar Rapids’ flood mitigation approach, he said. Its vegetation absorbs encroaching floodwaters and  provides a focal point for a vibrant recreational space.

“Holistic sustainable flood recovery is much more than environmentally sensitive design,” he said. “It creates social and cultural vibrancy, economic viability and sustainability, environmental health and responsibility.”

To design the greenway the city brought in the expertise of Brenda Nelson, a landscape architect with the consulting firm Confluence. The firm has offices in Cedar Rapids and other cities in the Midwest.

The greenway masterplan has a series of visions and goals, Nelson said. These include creating a vibrant, destination riverfront, providing signature neighborhood parks and a quality park system, promoting diverse recreation opportunities and quality indoor facilities, increasing connectivity awareness, and improving the ecological health of the city. It must do these things and also be efficient and cost-effective to maintain.

The first phase of the greenbelt project was to conduct a site analysis, “to learn about the history and demographics of the area,” Nelson said, and phase two, the design phase, required a great deal of input solicited through public meetings, neighborhood meetings and online surveys. When local residents were asked what activities would bring them to the greenway on a regular basis, the No. 1 answer was walking and biking trails, followed by festivals, fairs and farmers markets.

There are several components for the success of a greenway masterplan, Nelson said. Cultural and social components include connectivity to neighborhoods, while plentiful activity centers encourage social engagement with others and the environment. Recreational components include activities for all ages that are easily accessible to neighborhoods. That, in turn, increases the health and wellness of citizens.

Blending together the flood mitigation plan with the greenway plan made sense because of geographical components, but in some cases, compromises needed to be made. According to Leff, the final greenway plan was for 72 acres, but some of the park had to be able to withstand occasional flooding. That meant that acreage farther away from the river could be devoted to playing fields and trails, but planting native prairie and tree species was more appropriate closer to the water’s edge.

The city adopted the greenway masterplan about a year ago, Leff said, and since that time the development of recreational fields has begun, as well as planning for a farmers market/festival space in the Czech Village neighborhood, a bike pump track, and turf improvement for playing fields.

Neighborhood redevelopment and park space are essential, but the city could not forget about the nitty-gritty problems of flooding, such as stormwater management. It is the job of Kasey Hutchinson, stormwater coordinator for Cedar Rapids, to find ways to increase stormwater infiltration, reduce runoff and protect water quality. Policy planning is taking place to consider changes in the stormwater utility rate structure.

“A tiered flat-rate system is in place now but people pay very different rates,” Hutchinson said. “A revision is being reconsidered to make it more fair and tied to sustainable practices”

Hutchinson said the state had required that topsoil be 4 inches in depth, but after an “outcry” from developers, the rule was revised earlier this year. Now developers adhere to what is “technologically possible or economically practicable” and local jurisdictions are allowed to implement their own rules and policies, Hutchinson said.

Cedar Rapids has learned several lessons from this process, said Pumphrey.

“Sustainability is multifaceted,” he said. “Implementation takes time and community vision, public participation is key and master planning is essential.”

A hundred miles west of Cedar Rapids, the people of Ames, Iowa, also experienced an epic flood. This city of 62,000 is at the confluence of Squaw Creek and the South Skunk River. When the waters of this 500 square mile watershed rise, flooding covers major transportation corridors. People might be cut off from the city’s only hospital to the north, or from the airport and fire and rescue services to the south.

After repeated flooding, including a record-breaking storm in 2010 that exceeded the previous peak flood stage by more than a foot, the city council commissioned a study to determine the feasibility of mitigation strategies. They brought in Joseph Spradling, a senior transportation engineer for HDR, Inc.

The goals of the study were to update flood hydrology, hydraulics and mapping, to incorporate additional sensitivity into analysis, to look at impacts of climate variability and to develop flood mitigation alternatives, Spradling said.

“It is important to use transparent processes and receive public input from the greater Ames community,” he said. It also is important to “screen the alternatives, including economic and environmental components with public input and present the best alternatives and strategies for future implementation with public input.”

As a result of the study, the city has explored three alternative alignments that create a new crossing over Squaw Creek, keeping in mind the environmental considerations and property impacts. Long range planning for flood mitigation in Ames needs to relate to its other long range transportation planning, said Andy McCoy, a senior water resources engineer for HDR. It also needs to adhere to national environmental policy because federal funds are involved. Executive order 13960, signed into law by President Obama, stresses the concept of community resilience to flooding. It also changes the elevation standards for structures. The floodplain is now defined as "the elevation and flood hazard area that result from using a climate-informed science approach that uses the best-available, actionable hydrologic and hydraulic data and methods that integrate current and future changes in flooding based on climate science.”

With stricter definitions and impending changes to something as simple as getting around town, citizens can become stressed and concerned even when rivers and streams stay in their banks. Getting public feedback on alternative alignments through a community engagement process is incredibly important, McCoy stressed, adding “there are no silver bullets, but channel and bridge improvements that were feasible were presented as viable alternatives.”

With one year left in the study, Spradling said the public involvement period will continue as alternatives are analyzed. They will conduct an environmental analysis, prepare a draft environmental assessment, prepare a FONSI (finding of no significant impact), secure construction funding, then construct the improvements. The end game is to respond to public and city council desires to reduce flood risk and provide a resilient transportation corridor that can withstand a repeat of the 2010 flood.

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