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Title
Professional Engineering Services Contract with Halff Associates, Inc. for Floodplain Permitting Assistance Associated with TxDOT I-30 Improvements in Grand Prairie in the amount of $68,000
Presenter
Stephanie Griffin, Floodplain Administrator, and Walter Shumac, Director of Transportation
Recommended Action
Approve
Analysis
The Texas Department of Transportation (TxDOT) is constructing improvements along the access roads of Interstate 30 (I-30) between Beltline Road and Highway 161 in Grand Prairie. TxDOT has asked the City to assist with the floodplain permitting requirements for CSJ 1068-04-149 (Project 149) as the City will benefit from the improvements.
The floodplain requirements for the project include:
• Corridor Development Certificate (CDC) application and permit
• Floodplain Development Permit (FDP) application and permit
• Conditional Letter of Map Revision (CLOMR), if necessary
• Letter of Map Revision (LOMR)
Grand Prairie participates in the Trinity River Corridor Development Certificate (CDC) program that is coordinated by the North Central Texas Council of Governments (NCTCOG). The CDC involves an engineering model, HEC-RAS, to be updated to show the impact of proposed projects along the Trinity River. This information is then shared with and reviewed by upstream and downstream communities, as well as the United States Army Corps of Engineers and State agencies. These entities have the opportunity to voice concerns they may have with the proposed improvement before it is constructed.
The FDP is the City’s floodplain development permit that is required for all projects located in floodplains within the City. The City is required by the Federal Emergency Management Agency (FEMA) to document all work that takes place within the FEMA-regulated floodplains. The FDP is the City’s mechanism used to meet this FEMA requirement. Again, a HEC-RAS model is required to show the impacts of the proposed project considering existing conditions and fully (ultimately) developed conditions.
TxDOT is currently considering the improvement options. TxDOT’s goal is to avoid impacts to the floodway or to the water surface elevation that might result in the need to obtain a CLOMR prior to beginning the project. The project will result in adjustments to the floodplain, which will be documented through the FEMA Letter of Map Revisions (LOMR) process after construction is complete.
Staff has requested and received a proposal from Halff Associates, Inc. to assist with the floodplain requirements for these TxDOT improvements. Halff is recommended because they have been involved with this particular TxDOT project for several years and are very familiar with the floodplain requirements.
The floodplain permitting associated with the TxDOT project is scheduled to begin in June 2016, with the CDC permit to be obtained by April 2017. The LOMR will be pursued after construction is complete.
Financial Consideration
Funding in the amount of $68,000 is available in the Stormwater Utility Surveys and Studies Operating Account (233010/61405).