DPW and Brown & Caldwell continue Northland/Bel Air flood study; Memorial Park pond expansion surfaces as cost-effective component

Department of Public Works staff and consultant Brown & Caldwell reported progress on the Northland/Bel Air watershed stormwater evaluation during an information item update to the Appleton City Utilities Committee.

The study, authorized by Common Council on Nov. 20, 2024, covers a roughly five-square-mile area bounded by I-41 to the north, 441 to the east, Mason Street to the west and Packard Street to the south. Staff reported completed tasks including updating system models, merging previously separate watershed models, field verification, and sensitivity analyses for 10- and 100-year storm events. The consultant has been conducting site visits and checking utility conflicts for proposed conveyance improvements.

Staff said work since the previous update has included obtaining upstream modeling for planned improvements in the town of Grand Chute and early modeling of a potential expansion to Memorial Park South Pond (MPS Pond). "An expansion of the Memorial Park South Pond seems to be shaping up to be a very cost effective component of what could become a favored alternative or part of a series of favored alternatives," staff said.

Ongoing and future tasks include refining storage and conveyance improvement alternatives, analyzing utility conflicts, updating cost estimates for previously studied conveyance alternatives (including piping to the Fox River), and developing 2D surface-water quantity models in priority areas to enhance flood extent accuracy. Staff anticipates update number 4 in January 2026 and continued analysis of potential combinations of conveyance and storage components with design refinements to resolve utility conflicts.

Multiple residents from Northland and Viola Street described persistent flooding at their properties, significant personal repair costs and frustration with response times. Residents asked whether the combined Northland and Bel Air modeling would capture interflow between watersheds; staff said that was a primary reason the two watersheds were modeled together. One resident estimated millions in damages on a single block; staff acknowledged the area is a priority for more detailed modeling work.

Staff said timing underground conveyance work to coincide with planned street reconstruction projects could reduce pavement restoration costs. The committee and residents were told that more detailed alternatives, cost estimates and design-level recommendations are expected as the study continues; staff stressed care in not prejudging alternatives until further analysis is complete.