WW-2 and WW-3 Warson Woods Sanitary Relief (12302)

WW-2 and WW-3 Warson Woods Sanitary Relief (12302)

As part of a long-term effort to reduce basement backups and sewer overflows, MSD Project Clear is designing a project to replace undersized sanitary sewers in Warson Woods, Ladue, Kirkwood, Rock Hill and Glendale.

This project is estimated to begin construction in Fall 2023.

Project Map

Public Meeting Recording

Since this meeting was recorded, the project schedule has been revised. Please see “What is the timeline” below for the most up-to-date schedule.

Why is this project being designed?

A number of residents have experienced building back-ups, mainly due to overcharged sewers that cannot handle the increased amount of flow experienced during rainfall.

In addition, the sewer system in this area uses old technology called overflow points where untreated wastewater is discharged into waterways during heavy rainfall to prevent the water from backing up into buildings. There are three of these overflow points that need to be removed in this area.

What is the goal of this project?

MSD Project Clear is investing approximately $15 million to design and construct this project to increase the size and depth of the existing sewer.  This will alleviate existing problems resulting from undersized sewers.

Project Facts

  • Construction is estimated to begin Fall 2023.
  • MSD Project Clear will replace approximately 10,700 feet of sanitary pipe.
  • The pipe size will increase to between 8 to 30-inches in diameter allowing a larger amount of wastewater to flow through the system.
  • This project will remove 3 constructed overflows to prevent untreated wastewater from spilling into local waterways.

What can residents expect?

Though construction for this project is not estimated to begin until Fall 2023, it is important to be prepared for what to expect. By the Fall of 2021, residents whose property will need to be accessed to construct the project will be contacted in order to obtain necessary easements.

Type of Construction:

With any type of construction, residents can expect to see and hear heavy equipment during the sewer excavation process. The majority of this project will be constructed by digging through the surface of the ground, in a process known as “open-cut” construction. The pictures above depict what a neighborhood will look like before, during, and after a typical open-cut project.

To minimize traffic impacts, “tunneling” will be used to cross Manchester Road. This means that a hole called a boring pit will be dug at multiple locations to lower a Tunnel Boring Machine underground to dig through the soil and rock. Tunneling is being used in this area to ensure that the surface of Manchester Road is disturbed as little as possible.

Traffic Impact: 

As a part of this project, MSD Project Clear does expect traffic impacts to residential streets in this area. Impacted roadways in which construction will take place include Des Peres Avenue, Warson Woods Drive, Glen Elm Drive, Glenway Drive, Alexandra Avenue, Alexandra Drive, Belson Court, and Brownell Avenue. Construction will also impact Royal Oaks Park/Memorial Park in Warson Woods, an office building and shopping center, and a car dealership. More specific information including timing and locations of these closures will become available once the project has a Contractor and they can determine a set schedule.

MSD Project Clear also expects that there will be instances where property owners could have reduced or limited access to their properties due to this project. However, the Contractor will be required to maintain access to both residential and commercial properties. The Contractor will provide notice to affected residents before construction takes place.


After all new sewer pipes are installed, the Contractor will restore the construction site according to all District and local requirements. This could include sodding any disturbed areas, replacing disturbed pavement, reinstalling fences, etc. More detail on this will become available after a Contractor is selected for the project ahead of construction in the Fall of 2023..

What is the timeline?

This is the current tentative project schedule. This is subject to change based on a variety of factors including weather.

  • Project design completion: Winter 2021/2022
  • Easement acquisition completion: Winter 2022/2023
  • Estimated construction start: Fall 2023
  • Estimated project duration: Two years, Winter 2025


No, the Contractor will maintain utility service at all times.

In accordance with MSD policy, the Contractor will restore all disturbed surfaces to previous or better conditions.

The Contractor will be committed to minimizing any instances of access issues to residential or commercial property. It is expected that there will be instances of temporary access issues to both commercial and residential properties. Once the Contractor is selected, they will provide notice to residents before their properties are affected by construction.

The District will be removing and replacing portions of the sewer and abandoning other portions in place depending on the accessibility to the current system. There will be other portions of the existing sewer system that will remain and be used in place.

Depending on where the crew is working the equipment will stay next to the open trench within the easement limits or in the street right of way. When the crew moves from one reach to the next, they might stage the equipment at a specific location before work starts on that next reach. During normal operation, the equipment will not be moved on a nightly basis.

Typically, construction of a gravity sewer starts at the downstream end. The downstream end in this project is the North end of the project near the manhole by Old Warson Rd. The Contractor will then proceed upstream, in this case moving South.

Yes. As a part of easement negotiations, MSD will provide the property owner an opportunity to specify what type of sod they would like replaced. In locations where easements already exist, MSD will attempt to identify the already existing sod in order to match it after construction. Wooded areas that are not maintained are typically not sodded.

Since this is an extensive project that will take time, there are no plans on closing the entirety of this stretch of Warson Woods Dr for the duration of the project. However, there are times that there will be temporary full closures on parts of Warson Woods Dr in order to construct the sewer. More specific information on locations and timings will be provided once the Contractor is selected and they develop a Traffic Control Plan. However, the Contractor is required to maintain full access for emergency vehicles at all times.

During the construction process, as the Contractor gets closer to properties, they will leave door hangers and/or send letters of notification to each property that will be affected at that time by construction. Typically, these notifications are provided 2 weeks prior to work being done.

This project deals only with improving the wastewater system. MSD does not currently have a funding source to legally address overland flooding.

MSD’s Operations Department will review each SSP as a part of the construction process. On a case by case basis, they will determine whether or not it would be effective to leave the SSP in on each specific property.

The Contractor is required to control erosion throughout the duration of the project. The specific means and methods will have to be approved by MSD and those details will be available once construction begins. Additionally, this project is large enough that it will require a Stormwater Pollution Prevention plan to be developed prior to construction.


Stay Informed

Sam Bush
MSD Project Manager

Curt Kimmel
Burns & McDonnell Project Manager