Determination of a reasonable/accurate tailwater elevation is important in locations such as central, southern, and coastal Florida where the terrain is predominately flat, low-lying, and includes areas of high groundwater. In these areas, a few tenths of a foot difference in water surface elevation on the upstream side of a hydraulic structure (headwater) can be the determining factor in whether a project gets a stormwater permit from the applicable regulatory agency, because of the potential to adversely impact adjacent properties. That same relatively small difference in water surface elevation can also lead to larger pipe sizes for culvert and storm drain systems, larger stormwater ponds, and has a direct impact on the amount of fill needed for projects.
Hydraulic structures in these areas typically flow under "Outlet" control for the design event. The downstream water surface elevation at the discharge point, or tailwater elevation, while a significant component in hydraulic calculations is often given the least amount of attention during design.
This course is of interest to a wide variety of engineers that work on both public and private infrastructure and site development projects. This course discusses those less than ideal, yet typical tailwater conditions encountered during actual practice. It addresses typical agency design requirements as well as some of the more common pitfalls encountered in estimating tailwater elevations. The course discusses the impacts of over and underestimated tailwater elevations and identifies things the designer should consider during the design to avoid the more common pitfalls.