Experts and staff: Hurricane Debbie flooding largely driven by rainfall runoff; county plans watershed updates, maintenance and grant applications

Manatee County’s Feb. 29 work session turned to stormwater after lunch, where an independent hydrology review and county engineers told commissioners that heavy local rainfall and constrained local drainage — not a dam breach — explained most of the flood peaks after Hurricane Debbie. County staff laid out completed and in‑progress watershed management plans, routine maintenance backlogs, and a long list of mitigation projects for future funding.

Why it matters: Commissioners were shown technical analysis and a long list of capital and maintenance needs. The session highlighted two immediate policy needs for the board: (1) identify priority projects the staff should pursue for available disaster‑recovery grant funds and (2) adopt a longer‑term funding and maintenance plan for county conveyances — including a possible dedicated stormwater fee or MSTU — to pay for ongoing maintenance and new infrastructure.

What the consultants found: Patrick Terra of Interra, hired to review flooding around the Manatee River and Lake Manatee, told the board he examined observed rain gauges, tide and surge records, and watershed models. Terra said: (a) rainfall totals during…