Madison unveils phased Crooked Creek flood‑mitigation plan after 2021 flash floods

Madison officials on Monday presented a multi‑phase plan aimed at reducing flood risk in the Crooked Creek watershed, an area hit by catastrophic flash flooding in 2021 that the city says sent more than 70 million gallons of stormwater through neighborhoods in hours.

The Board of Public Works and Safety heard a detailed briefing from Commonwealth Engineers, which, working with the U.S. Army Corps of Engineers, evaluated 25 potential measures and narrowed them to six alternatives before recommending a phased approach. Rob Baluchi of Commonwealth Engineers summarized the team’s findings and recommended package, stressing that the plan is intended to mitigate—not eliminate—flood risk in the floodplain.

Why it matters: Officials said the 2021 event and a similar 2015 storm showed Crooked Creek and Dugan Hollow can produce highly damaging, rapid floods. The plan aims to reduce peak water‑surface elevations and protect residents in the Walnut and Jefferson Street corridors by combining storage, channel capacity improvements and targeted structural work.

Commonwealth recommended a mix of measures organized in four implementation phases, balancing benefit, cost and community impact. Near‑term (phase 1) items include installing backflow prevention at cross‑connects, an early‑warning gauge network and public education on residential flood proofing. Phase 2 would add selective dredging and detention at targeted low‑lying sites such as Walnut Street. Phase 3 expands storage into park green space (Lorenz Park), and phase 4 considers more extensive channel widening north of Jefferson Street and targeted bridge replacements to remove bottlenecks.

“We identified roughly nine distributed storage sites and modeled about 200-plus acre‑feet of practical storage in the corridor,” Baluchi said. “That’s a lot of water, but phased storage and targeted channel work can measurably lower water‑surface elevations and protect homes.”

City leaders said the report incorporates Corps modeling and local fieldwork; the team compared alternatives on technical performance, cost, environmental effects and community disruption. Baluchi said the Corps’ earlier analysis identified approximately 181 acre‑feet of storage to produce a measurable benefit; Commonwealth’s localized plan distributes storage and combines it with channel improvements to achieve comparable reductions while reducing impacts to private property.

Board discussion flagged next steps and funding: the mayor said the city plans to post the report on its website, continue liaison with the congressional office for grant support, and return to the Board for more detailed discussion and adoption at a future meeting. Commonwealth warned the recommended measures will require significant planning, phased construction and partnerships with state and federal agencies; the city will also need to evaluate environmental and right‑of‑way impacts for channel work and bridge modifications.

What remains uncertain: The presentation outlined conceptual costs and phasing but did not give a single total project price. Commonwealth emphasized further site‑level design and permitting work is required. Board members asked for follow‑up on specific locations, potential property impacts and clearer cost estimates to inform funding decisions.

The board scheduled additional discussion of the plan at an upcoming meeting; staff said the city will create a web page with the full report for public review.