City Council Meeting Date: June 9, 2026
Date: June 1, 2026
To: Erin Rinehart, City Manager
From: Jonathan Wheat, P.E., Director of Engineering
Shannon Hicks, P.E., Assistant City Manager
Title
Consider A Resolution Authorizing The City Manager To Execute Contract Amendment No. 6 With Walter P. Moore And Associates, Inc., For The Citywide Flood Mapping Study By An Amount Of $36,700.00, For An Adjusted Total Contract Amount Not To Exceed $1,070,372.05.
Body
Summary:
The purpose of this item is to execute a contract amendment with the City’s engineering consultant to complete the Citywide Flood Mapping Study.
Background:
The City has historically updated floodplain maps every 15 years. These maps are a crucial part of the City’s floodplain management, providing information on expected flood chances and risks. These maps are also utilized as flood insurance rate maps that help guide the requirements of flood insurance requirements. Any mortgaged property within the 100-year flood plain is required to have flood insurance. As you may recall, an introduction to floodplain management and flood maps presentation was provided on February 20, 2024, and explains this process with a little more detail.
The professional services agreement with Walter P. Moore and Associates, Inc., was initially approved by Council on January 18, 2018, in the amount of $735,380.00, and provided for a city-wide floodplain study to update all FEMA Flood Insurance Rate Maps and design and install a flood warning system. Since the floodplain study was initiated, all streams and tributaries in Carrollton are in the process of being assessed via hydrologic and hydraulic analysis. Additionally, the consultant, Walter P. Moore, is tasked with coordinating with various entities to ensure that the analysis is performed according to standards as set forth by NCTCOG, the US Army Corps of Engineers, FEMA, and the City of Carrollton’s own Flood and Stormwater Ordinance. Previously, this contract has been amended five times before:
• Amendment No. 1 - put in place February 2019 to remove scope pertaining to duplicate mapping efforts from a concurrent project (contract change of -$1,240 to a total of $734,140);
• Amendment No. 2 - put in place in October 2020 to add additional scope for various coordination with federal and local entities and more detailed flood mapping in residential areas (contract change of $89,420 to a total of $823,560).
• Amendment No. 3 - put in place in August of 2021 to add additional scope for more detailed flood modeling in areas that are prone to flooding and are in the immediate vicinity of businesses and residential homes near the Country Place subdivision (contract change of $27,800 to a total of $851,360).
• Amendment No. 4 - put in place in July 2022 to add additional scope to address flood modeling in areas that have recently had CIP drainage projects completed within the last 2 years. (contract change of $169,400 to a total of $1,020,760.00).
• Amendment No. 5 - put in place in July 2025 to add additional scope to create a presentation overviewing progress made on the project as a whole and explain floodplain revision impacts to residents and businesses (contract change of $12,912.05 to a total of $1,033,672.05).
Contract Amendment No. 6 will address ongoing coordination with FEMA for reviewing extensive modelling along Hutton Branch. The comments received from FEMA on Hutton Branch were extensive and require a large amount of additional work, including updates to flood modeling and additional applications for multiple letters of map revisions. The City of Carrollton requires FEMA’s approval on the changes to the models, and FEMA is requiring additional reviews to ensure the Hutton Branch levy system is modelled to meet the FEMA requirements. As such, the consultant has asked for the contract to be amended to allow for an additional $36,700 to be added to the overall cost of the project to account for the excessive review time and effort. This sixth amendment will bring the contract total to $1,070,372.05. The project itself is in its final stages (approximately 95% complete) and this amendment will allow the consultant to complete the remaining work on the project and give the city the most accurate and up-to-date models of the floodplains in the city. Staff has reviewed the consultant’s proposal and has deemed it fair and reasonable.
Financial Implications:
Walter P. Moore has submitted a proposal to perform the additional engineering design services for Contract Amendment No. 6 for an amount of $36,700.00, for an updated total amount not to exceed $1,070,372.05. Funding for this amendment is available in the Drainage Consolidated Fund, Account 854560.
Impact on Community Sustainability:
This project will support the City Council’s strategic objectives and vision of building a community that families and businesses want to call home by:
• Supporting public safety and community confidence by ensuring updated, accurate FEMA floodplain information that protects residents, homes, businesses, and infrastructure. (Hospitality, Healthy)
• Optimizing City processes and service delivery through high-quality hydrologic and hydraulic analysis that improves the accuracy and reliability of floodplain modeling. (Optimize)
• Strengthening infrastructure resilience and long-term planning by providing current flood models that support redevelopment decisions, capital planning, and flood mitigation strategies. (Revitalized)
Staff Recommendation/Action Desired:
Staff recommends adopting a resolution authorizing the City Manager to execute contract amendment no. 6 with Walter P. Moore and Associates, Inc., for the Citywide Flood Mapping Study by an amount of $36,700.00, for an adjusted total contract amount not to exceed $1,070,372.05.