Davenport residents want a permanent solution to more frequent flooding along the city's riverfront and better infrastructure to reduce flood response, but not a flood wall.
"They want a flood strategy that is permanent and doesn't require much operation during a flood event, requiring less maintenance and providing protection at the highest flood possible," said Teresa Stadelmann project manager with environmental consulting and engineering firm HR Green, Inc.
The Cedar Rapids consulting firm has been working since late August to determine how best to handle Davenport's riverfront and implement mitigation strategies to protect properties and prevent another downtown flood as part of an ongoing flood study by the city.
Stadelmann on Tuesday presented aldermen with the results of an online survey and other public feedback gathered on conceptual strategies to ease or prevent disruptions caused by Mississippi River flooding.
The strategies include a mix of incremental improvements — from upgrading storm sewers to elevating sections of River Drive and adjacent streets prone to flooding — to transforming large spans of the riverfront with the construction of landscaped berms, levees and flood walls.
Overall, residents said the city needs to invest in long-term solutions with the anticipation of more frequent and more intense flooding, whether that be reconfiguring the city's storm sewer system, adding gates on storm sewer outfalls and installing pumping stations to prevent river water from backing up through the storm sewer system and inundating low-lying areas; raising sections of River Drive; or both.
Other suggestions include constructing four to five miles worth of levees, berms, flood walls and storm water pumping stations to match a 100-year flood event or greater.
"There does seem to be strong support for trading some permanent solutions instead of operational responses to flooding," Stadelmann said. "People feel that they do want to build some things that will make that flood response simpler or reduce that operational effort each time that if floods."
Residents also said they wanted to see more things to do along the riverfront and more natural areas to enjoy along the Mississippi — paired with some sort of permanent flood protection.
"Access was a big issue that people had about flooding, whether it was impact to their business because roads were closed and they couldn't get there, or just getting across town and access to city facilities," Stadelmann said. "And then, of course, the impact of flooding that is has on businesses, on people and their residences, and on community infrastructure."
More than 500 individuals responded to the online survey. Of those who responded, 74% were Davenport residents. The rest predominantly either worked or owned a business in Davenport or lived elsewhere in the Quad-Cities, according to HR Green.
Key takeaways from the survey include:
- 73% of respondents said the city's flood strategy needs to prioritize protection for businesses and commercial buildings; 63% said a flood plan should prioritize homes and residents
- 64% said any flood plan should provide protection to the highest elevation possible
- 60% supported underground sewer improvements, seen as more cost effective and a first step that sets the groundwork for future improvements but are quicker to implement and would help prevent streets from flooding at certain flood stages. Other respondents saw it as too low of a bar for flood protection that requires too much maintenance
- 50% supported the construction of berms and elevating roads, feeling the former was more visually attractive than a wall. Residents also saw the strategy as an opportunity to still allow pedestrian and recreational uses along the riverfront while providing permanent and reliable flood protection at a lower maintenance cost. Others expressed concerns of obstructing views of the riverfront. Some expressed concerns about pushing flooding downstream
- 40% said they support construction of a flood wall as a viable long-term investment that will help protect businesses homes, residents and city infrastructure from flooding that's forecast to only get worse
Davenport Public Works Director Nicole Gleason said Davenport aldermen will be asked to provide feedback and direction to HR Green in the coming few weeks on the conceptual strategies to help the consultant refine the preferred strategies and draft recommendations.
Gleason said HR Green will launch another round of public engagement this summer to gather feedback on proposed recommendations before presenting a full report and finalized proposal to aldermen this fall, including proposed funding and implementation strategies.