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County Manager's Office

Phone: 913-715-0725

111 S. Cherry St., Suite 3300, Olathe, KS 66061

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Tomahawk Creek Wastewater Treatment Facility Project

Tomahawk Creek Wastewater Treatment Facility construction site

(Updated May 31, 2020)

Project Name: Tomahawk Creek Wastewater Treatment Facility (WWTF) Expansion

Date Authorized: July 31, 2014 (project def.); May 5, 2016 (design); March 2, 2017 (pre-construction); March 29, 2018 (construction)

Project Authorization: $4,100,000 (project definition); $21,387,000 (design); $2,680,000 (preconstruction); $306,678,678 (construction funding including $23,131,462 (engineering construction services), $267,892,045 (Construction GMP, and bonds, PAF, and other project costs)) Total Project Authorization = $334,990,678

Delivery Method: Construction Manager at Risk (CMAR)

Design Firm: Black & Veatch/HDR Engineers

Contractor: McCarthy Building Companies, Inc. (CMAR)

Completion Date (Estimated): March 1, 2022 (Substantial Completion)

Major Milestones:

  • Evergy (formerly KCPL) electrical substation was completed and energized in May.
  • All tower cranes came down in April.
  • Two buildings, the Peak Flow Pump Station and Admin Building are scheduled to be completed in June-July of 2020.  
  • In an effort to accommodate an additional request from Leawood, we have moved the raising of Lee Blvd to June 29th. Leawood canceled their July 4th celebration but may postpone it to Labor Day.
  • Next contractual milestone is completing the liquids treatment process by October 25, 2021. This will allow JCW to begin reducing flow sent to KCMO.

Future Pending Action(s):  

  • None.


  • Conducting work activities according to COVID-19 social distancing and safety recommendations continues to be a high priority for the team.  McCarthy has continued their approach of following CDC guidelines including but not limited to extra signage, handwashing stations, social distancing, face coverings, etc. to maintain a safe and productive work site. 
  • The RPR review of contractor’s work continues onsite and is following McCarthy’s safety protocols. The remainder of the project team is conducting meetings and correspondence through teleconference.
  • McCarthy is currently on schedule and on budget.  
  • Construction is approximately 60% complete.
  • Approximately 97% complete with structural concrete.
  • Underground utilities are over 85% complete.
  • Masonry work is approximately 35% complete.
  • The majority of work in progress includes masonry, interior piping, mechanical work, plumbing, installation of equipment, and finalizing the facility control system programming and hardware.
  • Leakage testing on water retaining structures will continue through the year.
  • Lee Blvd work will require approximately 2-3 months for shut down of Lee Blvd. The team has been working with Leawood to minimize impact to residents and the City’s holiday schedule. The work is scheduled to occur from June 29th to September 4th of 2020.  
  • The team is posting information to Johnson County Facebook page and the project website (www.jcwtomahawk.com) about wastewater treatment at the Tomahawk Creek WWTF as part of a monthly educational outreach series. 11 segments have been posted to date, with 12 more to be posted in the future.

Project Website


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