Price of flood protection in Libertyville could reach $72.6 million
In Libertyville, the price of relative dryness during the heaviest rains could top $72.6 million, according to information compiled and analyzed during the past year.
That's the estimated cost to proceed with projects to improve how stormwater is managed and protect against a so-called 100-year storm.
While it's unlikely the total tab will be that high, all but two of the projects are recommended for the highest level of protection that could present village officials with potential costs in excess of $46 million.
"We know what the issues are and what it's going to take and now we have to figure out how to resolve it," Mayor Terry Weppler said.
Determining what that will entail and how it will be paid are among the next steps in a what has been a yearlong assessment of Libertyville's stormwater master plan by Christopher B. Burke Engineering Ltd.
"There are several items in here we want them to look at again, and are there other ways of doing it to save money?" Weppler added.
Engineers recently updated the village board on the study commissioned just before a historic 7 inches of rain fell in 12 hours. That storm in July 2017 overloaded drainage systems throughout Lake County and in Libertyville, where more than 400 flooding reports were tallied. It was considered a 130-year storm, meaning there is a 0.8 percent chance of it occurring in a given year.
A 100-year storm means there is a 1 percent chance a storm of that magnitude will occur in a given year compared with a 2 percent chance of a 50-year year storm happening, for example.
Some areas in Libertyville, like other older communities, were developed before modern stormwater management practices. In some cases, trunk storm sewers were undersized, and in others, development blocked historical drainage ways and left insufficient overland paths for water to flow.
"This same story is seen everywhere," said Darren T. Olson, senior project manager for Burke.
The July 2017 storm allowed consultants to gather valuable real-time data to develop models for 12 study areas in the village.
Engineers weighted their findings toward problems that affected structures and identified flood reduction projects. The detailed study presents potential projects and costs to deal with varying levels of storms.
The extent of work in a given area and how to pay for it will be determined by the village board.
The area near Nicolas Dowden Park in the south central part of town, for example, has a 2-year level of storm protection. The 50-year recommended level would cost $7.5 million and the 100-year $21.3 million, according to Public Works Director Paul Kendzior.
The board is expected to again review the findings before scheduling a public open house/information session.
The stormwater projects are considered akin to a multiyear local road program for which residents in 2012 approved a tax hike. The challenge will be explaining how the work will benefit all residents even if they live in an area that doesn't flood, Weppler said.