Flatwoods Citrus Best Management Practice: Riser-Board Structures

Figure 2. Typical riser-board structure within a citrus grove drainage system. Water discharge structures are used to control water table levels and surface water levels in drainage and irrigation ditches within flatwoods citrus groves. The type of structure selected can significantly influence the quality of water discharged. With flashboard risers, water is forced to flow over the top board. This flow path creates a low current area toward the bottom, which facilitates the deposition of sediments and their accompanying nutrients or pesticides, essentially removing them from the discharges. Conversely, screw-gate structures do not create this dead-current zone. Since they open from the bottom, sediments are swept out along with the discharge water. Written by Chris Wilson, Liberta Scotto, Brian Boman, and Tim Gaver. Original publication date February 2002. Revised April 2012 and August 2015.