Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Levee Safety topic
No spam. Unsubscribe anytime.
Engineers say riverfront plans must address top-of-levee flood conditions as Army Corps review continues
Summary
Engineers reviewing the proposed Lawrenceburg riverfront project told city officials Jan. 21 they still need developer responses showing how structures on and adjacent to the levee will perform at the levee'top flood condition, and that the U.S. Army Corps of Engineers remains closely involved in the permit review.
Engineers reviewing a proposed riverfront development told the Lawrenceburg City Council during a Jan. 21 work session that key technical questions remain about how the project will behave when the Ohio River reaches the top of the levee, the condition used in the Army Corps of Engineers' review.
The engineers said their role as the levee'certifying authority is to ensure any new development on or adjacent to the levee does not jeopardize levee safety or the levee'certification process. "One of my roles is to make sure anything that gets developed or put adjacent to or on the levy doesn't jeopardize the safety of the levy," said John Mundell, who identified himself as the certifying engineer for the levee.
Why it matters: the U.S. Army Corps of Engineers and FEMA evaluate different flood conditions. The Corps looks at the top-of-levee elevation (the condition the levee was originally designed to resist), while FEMA reviews the 100-year (flood-insurance) condition. The engineers told the council there is roughly a 12-foot difference between the 100-year Ohio River elevation (about 490) and the top-of-levee elevation (about 502), so reviewers must evaluate both scenarios and the project's performance at the higher condition.
What happened and what engineers found: Luke Johnstone, an engineer on the review team, said staff received a preliminary (30%) set of plans about a year ago and later received complete (100%) construction plans in September. He told the council the Corps finished an initial review in April, the local review team delivered comments in May, and back-and-forth continued through the fall. "About a year ago we received the first submittal. It was, kind of a preliminary 30% plans," Johnstone said. The design firms cited in the transcript are Moffett & Nichols and StructurePoint.
Much of the review has focused on ensuring the design and specifications for river-side structures and levee-embankment work align and that the plans address Army Corps requirements. The engineers said many comments are straightforward omissions or alignment issues; several major comments require more substantive responses because the Corps will want the same information. Mundell described two technical examples discussed with the design team: deep piles for a riverside platform and gangway attachment details. The design team revised pile details to specify filled (concrete) piles instead of hollow steel and proposed riprap protection around piles; engineers said they are reviewing those responses.
Engineers emphasized the need to analyze the project for the top-of-levee condition, not only for the 100-year event. "The question we have to answer is what's gonna happen to this development when the water is that high?" Mundell said, adding that the Corps and local reviewers will want narratives and analyses that show whether elements will fail and, if so, how failure would affect levee stability.
On Corps permits: participants discussed two separate Corps permit paths referenced by engineers: a Corps 408 authorization (work on or adjacent to federal levees) and a Corps 404 permit for waterside improvements. Engineers told the council the Corps indicated readiness to issue the 404 permit for waterside work but that the 408 authorization remains contingent on satisfactory responses to the levee-related questions and on the LCD (Lawrenceburg Conservancy District) addressing final comments. "They want the LCD's comments to be addressed first," one engineer said, repeating the Corps' request relayed by a Corps contact.
Timeline and next steps: engineers said they received the latest developer submittal on the Thursday before the Jan. 21 meeting and were reviewing the responses that week. John Mundell said that once he and his directors are satisfied, he would write a letter indicating he can certify the project will not interfere with levee certification; his directors would then vote. The engineers told council members they are prioritizing the review to limit further rounds of questions.
Council role and context: speakers repeatedly emphasized that the primary objective is to avoid any outcome that would jeopardize the levee's certification. Several council members asked for clarifications about whether prior structures (a 1996 gangway and an event center cited in earlier reviews) had been evaluated; engineers said older approvals had not been reexamined in the current review and that connection points on the new plans are being redesigned as part of the current set.
Ending: engineers said they will continue reviewing the most recent submittal and that they expect many comments to be straightforward to resolve; the Corps will complete its final review after local concerns are addressed. Council members were told they would be updated after the conservancy and engineers finish the review and coordinate with the Corps.
