PILLAR: Sustainable
AGENDA DATE: March 25, 2026
COUNCIL DISTRICT(S): 2, 14
DEPARTMENT: Dallas Water Utilities Department
PRIORITY: Infrastructure
______________________________________________________________________
SUBJECT
Title
Authorize Supplemental Agreement No. 3 to the professional services contract with Garver, LLC to provide additional engineering services required for flood management and stormwater drainage improvements at two locations (list attached to Agenda Information Sheet) - Not to exceed $585,628.50, from $799,730.00 to $1,385,358.50 - Financing: Flood Control (D) Fund (2017 General Obligation Bond Fund)
*In alignment with Bond Implementation Program.
Body
BACKGROUND
On October 23, 2019, the City Council authorized a contract with Garver, LLC to provide engineering services required for flood management and storm drainage improvements at six locations, including Gilford-Roanoke, 1300/1301 Munger Boulevard, 3700 Alderson, 3215 Homer Street, State Thomas - Flora/Boll to Fairmont and State Thomas - Hallsville/Worthington. The City of Dallas determined that these locations require improvements to provide adequate capacity for the conveyance of storm water flows and to address localized flooding during storm events.
During the design of these projects, additional engineering services beyond the scope of the original contract were determined to be needed. The additional services include construction administration for all six locations, hydrologic and hydraulic modeling, environmental analysis and permitting, and survey/easement preparation for the Gifford-Roanoke Relief System project, and water/wastewater utility improvements for the 3700 Alderson Street, 3215 Homer Street, and State Thomas - Flora/Boll to Fairmont projects. The additional modeling, environmental analysis, survey and easements, water and wastewater utility relocations, and construction administration services were not included in the initial project scoping but were necessary to utilize the recently adopted regulatory floodplain model and complete the required drainage improvements. These additional services were authorized under Supplemental Agreement No. 1 on June 8, 2022, by Resolution No. 22-0880.
On September 12, 2024, Supplemental Agreement No. 2 to the professional services contract with Garver, LLC, was authorized for a 36-month time extension by Administrative Action No. 24-6332. The extension allowed the consultant to continue to perform the engineering work as described in the scope including design and drainage reports.
During analysis and design of the 3700 Alderson project, Dallas Water Utilities Department staff coordinated with the St. Thomas Aquinas Catholic Parish for necessary easements on their property. It was determined that additional improvements would be needed to extend the drainage outfall for the project to connect to an existing box culvert system. This extension allows the St. Thomas property to be improved in the future for private, passive uses that will not impact the future operation and maintenance of the storm sewer system. The work in this supplemental agreement includes the necessary evaluation, modeling, and plan preparation to extend the outfall utilizing 8 feet by 5 feet reinforced concrete box culvert and to upsize previously designed sections of upstream pipe due to the smaller outfall capacity. After bidding and prior to award of a construction contract, the St. Thomas Aquinas Catholic Parish will be required to advance funds for the additional improvements to the City of Dallas. An item authorizing the necessary easements and the Participation and Funding Agreement with St. Thomas Aquinas Catholic Parish will be included on the March 25, 2026 agenda and should be considered together with this item.
In addition to the work for 3700 Alderson, this supplemental agreement includes engineering services required to provide hydraulic and hydrologic analysis for future drainage improvements to resolve flooding issues in the Gilford-Roanoke vicinity as a continuation of the Phase I improvements. Services include research and development of downstream boundary conditions, a modified, proposed conditions model to evaluate seven alternative improvements, and a preliminary engineering report with conceptual alternatives and cost estimates for future Phase II improvements.
Garver, LLC has submitted an acceptable proposal to complete these additional engineering services, and the Dallas Water Utilities Department recommends that the contract be modified to include the additional hydraulic and hydrologic analysis, modeling, survey, geotechnical investigation, topographical survey and development of construction plans and specifications.
This action will authorize Supplemental Agreement No. 3 to the professional services contract with Garver, LLC to provide additional engineering services required for flood management and stormwater drainage improvements at 3700 Alderson and the Gilford-Roanoke area.
ESTIMATED SCHEDULE OF PROJECT
Began Design November 2019
Complete Design December 2026
PRIOR ACTION/REVIEW (COUNCIL, BOARDS, COMMISSIONS)
On October 23, 2019, the City Council authorized a professional services contract with Garver, LLC for the engineering design of Storm Drainage Contract D by Resolution No. 19-1684.
On June 8, 2022, the City Council authorized Supplemental Agreement No. 1 to the professional services contract with Garver, LLC to provide additional engineering services required for developing construction plans and specifications related to storm drainage and water and wastewater main improvements at six locations by Resolution No. 22-0880.
FISCAL INFORMATION
|
Fund |
FY 2026 |
FY 2027 |
Future Years |
|
Flood Control (D) Fund |
$585,628.50 |
$0.00 |
$0.00 |
Original Contract $ 599,921.00
Supplemental Agreement No. 1 $ 199,809.00
Supplemental Agreement No. 2 $ 0.00
Supplemental Agreement No. 3 (this action) $ 585,628.50
Total amount not to exceed $1,385,358.50
Council District Amount
2 $275,000.00
14 $310,628.50
Total $585,628.50
LOCAL PARTICIPATION
|
Prime |
Status |
Workforce % |
|
Garver, LLC |
Local |
58.82% |
OWNER/EXECUTIVE
Garver, LLC
14160 North Dallas Parkway
Suite 850, Dallas, Texas 75254
Brock Hoskins, Chief Executive Officer
MAPS
Attached