Castle Creek Improvements

Project Overview

The Castle Creek Improvements Project is the result of recommendations from the Warner Lagoon Water Quality Plan and the Warner Park and Cherokee Marsh Watershed Study. The project will consist of tree clearing, removal of the concrete section of the existing channel, and regrading to widen and lower the existing channel.  The intent is to provide increased stormwater conveyance through the channel to mitigate flooding on Trailsway and nearby streets and allow for future upstream storm sewer improvements identified as part of the Watershed Study. Additionally, the project design is intended to improve stormwater quality by capturing sediment and improving the maintainability of the channel. 

Project Design Information

Preliminary Design concepts were presented with the Warner Park and Cherokee Marsh Watershed Study. Engineering is working to refine the design based on wetland delineation, topographic survey, and tree condition surveys completed initially in 2023 and expanded in May 2026. The proposed improvements include widening the channel to create a low flow channel which will have ponded water most of the time and a floodplain “bench" which will contain larger flows or ponded water during high water periods. Additional conceptual information is provided below. Additional information will be provided during public outreach for feedback prior to construction. 

The overall design approach was to maximize the amount of water the channel can safely pass for large storms, improve water quality entering the lagoon and maintaining or improving habitat.  The widened channel design will slow water flow for smaller storms to allow more sediment and debris to settle in the channel before it enters Warner Lagoon. While many trees will need to be removed to complete the project, the channel modifications have been designed to preserve many, mature, healthy, non-invasive trees. Finally, the full channel improvement area will be restored after construction with native vegetation to provide habitat for native species. 

Additional design considerations are minimizing impacts to the active park spaces and maintaining access to the park from Trailsway.

Project Limits

The project will be occurring within Warner Park and the existing Castle Creek Corridor north of Trailsway. Generally, within the existing areas of unmaintained vegetation. 

Project Schedule

Design and permitting will be occurring through the summer of 2026 with anticipated construction starting early 2027. 

Public Involvement

There are a number of points of contact during this project where the public is encouraged to give feedback as part of public information meetings and public hearings. Dates, times and locations are indicated below when available:

Public Information Meetings

Aug. 5, 2026 Public Information Meeting Recording

Aug. 5, 2026 Public Information Meeting Presentation

City Process, Meetings

Common Council: Information will be posted when available.

Board of Public Works

A public hearing will be held on September 23, 2026 at 5:30 PM at the Board of Public Works Meeting to present information and receive feedback on the planned tree removals associated with the Castle Creek Improvements project. Information on how to register for and attend this meeting is provided below.

Public Hearing Notice Letter and Figure

Click to view larger map

The project team has focused on minimizing tree impacts with the proposed improvements. The design worked to protect and keep as many mature, healthy, and native trees as possible while balancing the need to remove some trees to achieve flood mitigation targets for Trailsway and the Brentwood Neighborhood. In total approximately 200 trees will be removed with the project. Many of which are already dead, in poor condition, or invasive; and approximately ½ of the trees are less than 6" in diameter. Additionally, the project team is working with a certified arborist on the project to reduce tree impacts in planning, design, and construction. 

Following the meeting a pdf of the presentation will be provided. If you wish to speak at the virtual meeting, you must register in advance. 

You can register at http://www.cityofmadison.com/city-hall/ committees/meeting-schedule. Registration will open once the meeting is published on the Calendar, typically around noon on the Monday preceding the meeting, which in this instance is Monday, September 21, 2026. Interested participants need to search for the date, click on the Board of Public Works meeting, then click “Register for Public Comment."