PILLAR Sustainable
AGENDA DATE: October 8, 2025
COUNCIL DISTRICT(S): Citywide
DEPARTMENT: Dallas Water Utilities Department
PRIORITY: N/A
______________________________________________________________________
SUBJECT
Title
Authorize a professional services contract with Halff Associates, Inc. to provide engineering services for storm drainage system improvements in the Mill Creek, Peaks Branch, East Peaks Branch watersheds - Not to exceed $5,994,800.00 - Financing: Flood Protection and Storm Drainage (C) Fund (2024 General Obligation Bond Fund)
Body
BACKGROUND
The 2006 and 2012 Bond Programs provided funding for the design and construction of storm drainage relief improvements in the Mill Creek, Peaks Branch, East Peaks Branch, and State-Thomas watersheds. The Mill Creek / Peaks Branch / East Peaks Branch / State-Thomas Drainage Relief Tunnel (Mill Creek Tunnel) Project is a five-mile, 30 to 35-foot diameter tunnel, located between 70 and 150 feet underground. It will provide flood relief in the lower areas of the Mill Creek watershed (Baylor Hospital area), Peaks Branch watershed (south of Buckner Park), East Peaks Branch watershed (Fair Park area), and State-Thomas area near Woodall Rodgers when completed. The Mill Creek Tunnel project is under construction and includes an outfall structure on White Rock Creek and five intake shafts that will connect to existing storm drainage systems and collect overland floodwater during heavy rain events. Street and surface drainage improvements are also included at the intake and outfall sites. The tunnel construction is anticipated to be completed by 2028.
The Mill Creek / Peaks Branch / East Peaks Branch Drainage Relief Project is a multi-phase, long-term investment by the City of Dallas to reduce recurring flooding and improve stormwater infrastructure in some of the city's most flood-prone urban neighborhoods. Undersized drainage systems in the Mill Creek, Peaks Branch, and East Peaks Branch watersheds lead to frequent flooding. The Mill Creek Tunnel is the first step to provide flood relief for these areas. Additional improvements are necessary to complete the system and provide flood relief to the existing undersized drainage systems that connect to the Mill Creek Tunnel. These drainage systems were constructed in the first half of the 1900s according to the drainage standards at that time. Currently, the existing system reaches capacity quickly when a storm event occurs.
$20 million was allocated in the 2024 Bond Program, Proposition C for the engineering design of drainage system improvements upstream of the Mill Creek Tunnel. The project limits include the portions of the Mill Creek, Peaks Branch, and East Peaks Branch watersheds that drain to the Mill Creek Tunnel. This next phase will provide engineering designs to reduce flooding and improve upstream collection and conveyance systems for each watershed. Proposition C also provided funding to support the identification of right-of-way acquisition needs, design upper basin relief systems, and reroute existing system trunk lines located on private property or crossing mid-block. These improvements will maximize the tunnel’s effectiveness and extend the flood relief further upstream.
This action will authorize a professional services contract with Halff Associates, Inc. for the preliminary engineering phase of improvements upstream of the Mill Creek Tunnel. Services will include the evaluation of current master planned drainage improvements, updating and preparing hydrologic and hydraulic models, analysis of construction methods and alignments, survey and field studies, subsurface utility exploration, environmental services, agency coordination and outreach, preliminary geotechnical investigations, preliminary engineering design to a 15 percent design level, and preliminary construction cost estimates for each watershed. Preliminary engineering services are anticipated to take two years to complete. After completion of preliminary engineering services, the final engineering design phase will begin and is expected to take an additional three to four years to complete. Any easement acquisition needs will be initiated during the final engineering phase once design plans have progressed to a level that easement needs are well defined and survey documents can be prepared. A future supplemental agreement is anticipated to authorize final design services utilizing the remaining funds in the 2024 Bond Program. Future funding for construction will be included in stormwater capital improvement plans and improvements are currently estimated to cost approximately $400 million.
Halff Associates, Inc. is uniquely qualified due to their long-time engagement on the Mill Creek Tunnel Project and their extensive work on Drainage Master Plans for each watershed. This experience provides them with an unmatched, comprehensive knowledge of the necessary and proposed drainage improvements.
ESTIMATED SCHEDULE OF PROJECT
Begin Services December 2025
Complete Services December 2027
PRIOR ACTION/REVIEW (COUNCIL, BOARDS, COMMISSIONS)
This item has no prior action.
FISCAL INFORMATION
|
Fund |
FY 2026 |
FY 2027 |
Future Years |
|
Flood Protection and Storm Drainage C Fund (2024 General Obligation Bond Fund) |
$5,994,800.00 |
$0.00 |
$0.00 |
LOCAL PARTICIPATION
|
Prime |
Status |
Workforce % |
|
Halff Associates, Inc. |
Local |
23.37% |
OWNER/EXECUTIVE
Halff Associates, Inc.
Jessica Baker Daily, PE, President
MAP
Attached