Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Flooding Drainage topic
No spam. Unsubscribe anytime.
Iberia Parish consultants recommend detention ponds and canal cleanup to ease frequent T Bayou flooding
Summary
A planning-level study presented to Iberia Parish officials recommends upstream detention ponds plus canal cleaning as the most cost-effective way to reduce frequent flooding along T Bayou, with modeled reductions up to about 14 inches in key reaches and a planning estimate of roughly $12.5 million for the pond components.
Consultants briefing Iberia Parish on a planning-level drainage assessment on T Bayou recommended a combination of upstream detention ponds and cleaning of the Park/Far Canal as the scenario that produced the most flood-reduction benefit in the study area.
The parish president framed the project as a response to recent flooding and said the parish is seeking partner funding; he told attendees the study’s planning-level cost estimate for the proposed ponds is in the neighborhood of $12–12.5 million. Olivia, a presenter from the consulting team, explained the work was a planning-level update to a hydraulic/hydrologic (H&H) model that used recent topographic surveys, higher-resolution LIDAR and modern rainfall inputs (Atlas 14) to reflect current conditions.
The consultants tested more than 10 scenario combinations, including channel widening and regrading, a diversion alignment, and upstream storage ponds paired with canal cleaning. The team reported the most benefit from a design that combines approximately 25 acres of detention ponds providing about 200 acre-feet of storage together with cleaning/widening of the Park/Far Canal. In the model for a 10-year storm, that scenario removed around 500 acres of inundation and lowered water-surface elevations by as much as about 14 inches at the most impacted reach and about 9 inches at some road crossings.
Dax, who identified himself as working with a consulting firm, told the meeting he has seen similar ponds reduce local flooding elsewhere in Acadiana, and explained the basic operating concept: the ponds store runoff during storms and release it in a controlled manner so downstream channels have capacity to drain between events. Presenters emphasized the results are planning-level estimates; they said feasibility-level work would be required to optimize pond footprints and control structures, confirm downstream capacity, and evaluate impacts on individual properties.
Speakers at the meeting repeatedly raised local constraints. Multiple attendees and council members pointed to bridges and an elevated roadway (referred to in discussion as Emil Verrett and adjacent crossings) that act as chokepoints; presenters said right-of-way limits and private development close to the channel make channel widening or regrading costly and sometimes infeasible without property acquisition. Consultants said ponds are often more attainable where open land exists, while widening can require complex acquisitions or servitude negotiations.
The team also reported sensitivity testing of downstream (tailwater) conditions: increasing the downstream boundary level in the model moderately did not materially change upstream water-surface results in the planning scenarios shown, but consultants noted coastal ‘perfect storm’ conditions (extreme extended rainfall plus high coastal water levels and sustained wind) are outside the scope of this planning-level analysis and would require a separate coastal/storm surge modeling effort.
Presenters and council members discussed related policy choices: updating parish drainage ordinances and subdivision standards (to require more on-site retention), trade-offs between retention design (10-, 25- or higher-year design standards), and the high cost of structural solutions such as levees or large pumps. The consultants recommended proceeding to a feasibility-level analysis before design and construction; that next phase would examine property impacts, downstream capacity, detailed siting and cost-benefit assessments and is the step parish officials were asked to consider approving.
No formal vote or ordinance was taken at the presentation. Organizers closed the formal remarks by inviting attendees to an open-house session with boards and technical staff to discuss specific site questions and next steps.
Ending: The parish will need to secure funding and authorize feasibility-level work before design or construction; presenters said the study provides a toolset for those next decisions and that parish staff would continue stakeholder engagement as the project advances.
