PILLAR: Sustainable
AGENDA DATE: October 14, 2026
COUNCIL DISTRICT(S): 2, 7, 14
DEPARTMENT: Dallas Water Utilities Department
PRIORITY: Infrastructure
______________________________________________________________________
SUBJECT
Title
Authorize Supplemental Agreement No. 3 to the professional services contract with Black & Veatch Corporation for additional construction management services associated with the Mill Creek/Peaks Branch/State-Thomas Drainage Relief Tunnel Project - Not to exceed $5,555,000.00, from $32,301,000.00 to $37,856,000.00 - Financing: Flood Protection and Storm Drainage Facilities Fund (2006 General Obligation Bond Fund)
*In alignment with Capital Improvement Program.
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BACKGROUND
On June 15, 2016, the City Council authorized a professional services contract with Black & Veatch Corporation for support services associated with construction document updates and construction management services for the Mill Creek/Peaks Branch/State-Thomas Drainage Relief Tunnel Project. The project was awarded for construction on February 14, 2018, and is currently under construction with an anticipated completion in early 2029. This project includes a deep underground storm drainage tunnel that will provide drainage and flooding relief to the lower areas of the Mill Creek watershed (around Baylor Hospital), Peaks Branch watershed (south of Buckner Park), East Peaks Branch watershed (around Fair Park area), and the Woodall Rodgers and State-Thomas area.
The drainage relief project consists of approximately five miles of 30 and 35-foot diameter storm drainage tunnel that is between 75 and 150 feet deep. It also includes an outfall structure near White Rock Creek and five intake shafts that will connect to existing storm drainage systems and collect overland floodwaters during heavy rain events as well as street and surface drainage improvements at the intake and outfall sites. Construction of the tunnel utilized a boring machine and includes concrete for the finished tunnel that requires specialized inspection and construction management services due to the complexity and sophistication of construction. The construction manager and support staff minimize project risks and serve as an extension of City staff to provide professional supervision and experienced inspection of the construction.
The construction management contract was set up based on assumptions for level-of-effort and completion timeframes prior to the award of the construction contract and includes available details from the contractor on planned shifts and working hours. Supplemental Agreement No. 1 was awarded on January 12, 2022, and authorized additional construction management, contract administration, and construction inspection required for the excavation of the five-mile-long tunnel and five tunnel laterals. The construction contractor typically worked two 12-hour shifts per day, for six days per week, during the tunnel excavation and is working a similar schedule during the concrete lining of the tunnel which is currently underway. This approach involves more hours and requires more supervision than what was included in the original construction management contract.
On February 28, 2024, the City Council authorized Supplemental Agreement No. 2 to the professional services contract with Black & Veatch Corporation for additional construction management, contract administration, and construction inspection. The services were necessary to provide inspection and construction management for added surface drainage improvements related to the project and an additional site for batching and placement of concrete into the tunnel. This additional work and site along with the time to complete the project required additional inspection hours and construction administration services. Services under this supplement were scoped and planned through 2026.
Although originally scheduled to be completed in 2024, construction is now estimated to be substantially complete in 2028 and fully complete by early 2029. Major issues impacting the project timeline include a delay in the delivery of the Tunnel Boring Machine (TBM) due to service interruptions at the manufacturer, COVID-19 and supply chain disruptions, permitting changes affecting concrete production, as well as TBM and supportive equipment breakdowns, long repair times, and production rates for excavation and concrete lining less than originally estimated. The project is currently about 88 percent complete overall with the tunnel lining approximately 64 percent complete. Production rates for the concrete lining have increased from approximately 70 feet per week at the beginning of tunnel lining to more than 250 feet per week over the last 6 months. The construction management team has actively worked with the contractor to address material limitations and improve cash flow, resulting in schedule improvements and an anticipated concrete lining completion of late 2027.
This action will authorize Supplemental Agreement No. 3 to the professional services contract with Black & Veatch Corporation to provide additional construction management, contract administration, and inspection services necessitated by the extended construction schedule. These supplemental services exceed the hours authorized under the existing construction management contract and are required to support the project's extended construction duration. This supplemental agreement will ensure that these important services are provided throughout the scheduled completion of the project. The Dallas Water Utilities Department (DWU) is committed to completing the project as expeditiously and economically as possible to deliver the flood relief benefits of the Mill Creek Tunnel project. The construction management team, including DWU, is diligently working with the contractor to continue maximizing the tunnel lining productivity, while maintaining safety and quality.
ESTIMATED SCHEDULE OF PROJECT
Began Construction March 2018
Complete Construction February 2029
PRIOR ACTION/REVIEW (COUNCIL, BOARDS, COMMISSIONS)
On June 15, 2016, the City Council authorized a professional services contract with Black & Veatch Corporation for support services associated with construction document updates and construction management services for the Mill Creek/Peaks Branch/State-Thomas Drainage Relief Tunnel Project by Resolution No. 16-1033.
On January 12, 2022, the City Council authorized Supplemental Agreement No. 1 to the professional services contract with Black & Veatch Corporation for additional construction management services associated with the construction of the Mill Creek/Peaks Branch/State-Thomas Drainage Relief Tunnel Project by Resolution No. 22-0163.
On February 28, 2024, the City Council authorized Supplemental Agreement No. 2 to the professional services contract with Black & Veatch Corporation for additional construction management services associated with the construction of the Mill Creek/Peaks Branch/State-Thomas Drainage Relief Tunnel Project by Resolution No. 24-0380.
FISCAL INFORMATION
|
Fund |
FY 2027 |
FY 2028 |
Future Years |
|
Flood Protection and Storm Drainage Facilities Fund (2006 General Obligation Bond Fund) |
$5,555,000.00 |
$0.00 |
$0.00 |
Original Contract $19,800,000.00
Supplemental Agreement No. 1 $ 6,994,000.00
Supplemental Agreement No. 2 $ 5,507,000.00
Supplemental Agreement No. 3 (this action) $ 5,555,000.00
Total amount not to exceed $37,856,000.00
Council District Amount
2 $1,499,850.00
7 $2,499,750.00
14 $1,555,400.00
Total $5,555,000.00
LOCAL PARTICIPATION
|
Prime |
Status |
Workforce % |
|
Black & Veatch Corporation |
Non-local |
1.03% |
OWNER/EXECUTIVE
Black & Veatch Corporation
14241 Dallas Parkway, Suite 1100
Dallas, Texas 75254
Mario Azar, Chairman, Chief Executive Officer
MAP
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