PILLAR: Sustainable
AGENDA DATE: September 23, 2026
COUNCIL DISTRICT(S): Citywide, Outside
DEPARTMENT: Dallas Water Utilities Department
PRIORITY: Infrastructure
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SUBJECT
Title
Authorize (1) an Interlocal Agreement between the City of Dallas and the City of Denton for an operational yield study of Lake Lewisville and Lake Ray Roberts in an amount not to exceed $250,000.00; (2) the receipt and deposit of funds from the City of Denton in an amount not to exceed $36,250.00 in the Water Construction Fund; (3) an increase in appropriations in an amount not to exceed $36,250.00, in the Water Construction Fund; and (4) execution of the Interlocal Agreement and all terms, conditions and documents required by the agreement - Estimated Revenue: Water Construction Fund $36,250.00 (see Fiscal Information)
*In alignment with Long Range Water Supply Plan.
Body
BACKGROUND
The City of Dallas (Dallas) and City of Denton (Denton) entered into an Untreated Water Purchase Contract agreement dated August 7, 1985, as amended (the “1985 Contract”). Among other things, Dallas and Denton specifically agreed that Dallas’ share of the dependable yield of Lewisville Lake was 95.1835% and Denton’s share was 4.8165%, exclusive of authorized reuse considerations. Dallas and Denton also agreed to share the incremental yield of Ray Roberts Lake (estimated to be 76 million gallons/day (MGD) at the time the agreement was established) with Dallas’ share being 74% (56.24 MGD), and Denton’s share being 26% (19.76 MGD).
The 1985 Contract expired on August 7, 2015, and Dallas and Denton recognize the importance of renewing their understanding regarding the water supply available from the lakes and operational protocols for mutual benefit regarding use of that water supply. As such, Dallas and Denton desire to enter an interlocal agreement (“ILA”) to jointly direct and fund an operational yield study (the “Project”) for the purpose of developing a current and technically sound understanding of water supply yield available in Lewisville Lake and Ray Roberts Lake. The study will inform the joint development of operational protocols that reflect the cities’ mutual understandings and current goals regarding water supply in the lakes. The Project will be performed consistent with the ILA, but the Project will not address the previously agreed proportional sharing of yield unless directed otherwise by agreement of Dallas and Denton.
The ILA for the operational yield study identifies that Dallas and Denton will jointly select and negotiate scope and fee with a consulting firm to complete the study with an estimated budget of $250,000.00. Per the terms of the ILA, Dallas will award and manage the Project in close coordination with Denton. Denton will fund 14.5% of the study cost and Dallas will fund the remaining 85.5%. If the total cost of the Project exceeds the estimate of $250,000.00, upon approval of Dallas and Denton, the additional cost will be shared according to the same proportional amounts of 85.5% and 14.5%.
Once the ILA has been executed, Dallas and Denton will procure a firm to complete the Project. Dallas will then bring forward an item to City Council for approval of a consultant contract to complete the Project. Prior to Dallas City Council awarding the Project to the consultant, Denton shall remit its share of the Project within thirty calendar days of receipt of written request from Dallas. Dallas will refund excess funds, if any, after the completion of the Project to Denton in proportion to Denton’s cost share. The term of this ILA shall be for two years, or until the Project is completed and accepted by both Parties, whichever date occurs last. It is estimated that a consultant contract for the Project would be awarded by the summer of 2027, if not earlier.
PRIOR ACTION/REVIEW (COUNCIL, BOARDS, COMMISSIONS)
Information about this item was provided to the Transportation and Infrastructure Committee on September 14, 2026.
FISCAL INFORMATION
Estimated Revenue: Water Construction Fund $36,250.00
Future cost includes $213,750.00 for Dallas’ portion of the Project in accordance with the Interlocal Agreement between the City of Dallas and the City of Denton.
Council District Amount
Citywide $213,750.00
Outside $ 36,250.00
Total $250,000.00
OWNER/EXECUTIVES
City of Dallas
Kimberly Bizor Tolbert, City Manager
City of Denton
Casey Ogden, Interim City Manager
MAP
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