The U.S. Army Corps of Engineers, Jacksonville District and the Big Cypress National Preserve partnered to place additional culverts under US 41, better known as Tamiami Trial, to help restore the ecosystem and promote a more natural pattern of water sheet flow from the Big Cypress National Preserve southward within the Everglades.
As a subconsultant, Moffatt & Nichol provided hydraulics and hydrology analysis and design as well as conducted a field condition assessment of the existing culverts and canal plugs while also surveying differential water surface elevations across US 41 (upstream vs. downstream). These were combined with watershed delineations to guide locations for additional culvert and canal plug placement. Based on the results, Moffatt & Nichol reviewed potential sites as candidates to receive repairs or new culverts and canal plugs and made recommendations to the agencies with supporting calculations and maps. The firm's use of the differential water surface elevation survey as a check of where water would like to flow under natural conditions was lauded by the agencies as an elegant, cost-effective solution in absence of detailed modeling. The survey also supported the results from the watershed delineations which are very difficult in such a flat terrain.