Carrollton study recommends berm, floodwall and bridge to reduce Dudley Branch flooding

City engineering and consultant HDR presented results of the Lower Dudley Branch drainage study to the Carrollton City Council on Sept. 9, outlining targeted, lower‑cost options to reduce routine inundation along Frankford Road and a larger crossing improvement at Eisenhower Street.

Leo Matsumura of HDR described two prioritized projects for the Frankford Road area: a roughly 4‑foot L‑shaped earthen berm that would eliminate much of the 25‑year inundation shown in the hydraulic model and a 3‑foot concrete floodwall aligned to prevent 100‑year overflows onto the roadway. HDR's modeling shows the berm would restore access at the Dart station and adjacent apartments during 25‑year events while the floodwall would largely eliminate a 1‑foot inundation estimated in the 100‑year simulation. Matsumura said estimated construction cost for the floodwall is around $359,000.

For Eisenhower Street, HDR evaluated replacing multiple 10x11 box culverts with a single‑span bridge. The firm reported an upstream reduction in 100‑year inundation depth from about 3.25 feet to roughly 2.19 feet, with the bridge estimated at about $3.8 million in construction costs. Councilmembers asked about the planned Fire Station 6 location; staff said modeling indicates the station site remains outside modeled inundation and noted a FEMA map discrepancy. The presentation noted some funding could come from prior Denton County bond allocations or existing local bond dollars, but the Eisenhower bridge is not yet funded and would likely be a future drainage program project.

Council directed staff to return with follow‑up materials on funding options and design coordination with the ongoing Frankford Road work.