Split-leaf gates: Automate your stoplogs

Stoplogs are commonly used at small dams to maintain reservoir levels, allow crest flow, and provide flood discharge capacity. During normal flow conditions, the reservoir is maintained at or slightly above the stoplog crest. Minor discharge fluctuations require no special attention if the reservoir is allowed to fluctuate slightly. During high flows, the stoplogs may be incrementally removed to provide added discharge capacity. Stoplogs were historically constructed of wood, a common and inexpensive material. However, stoplogs can often be difficult or dangerous to remove during high flow events. Various lifting mechanisms have been developed to allow the stoplogs to be lifted from the spillway. Examples include manually operated lifting poles or hooks and overhead trolleys and chain hoists. These stoplog removal systems can be time-consuming, unreliable, and dangerous. Consequently, stoplogs often are not completely removed and full spillway capacity is not achieved. Split-leaf gates were developed as an alternative to stoplogs. The gates are functionally similar to stoplogs, but provide the reliability and ease of operation offered by gates. This paper will discuss how the split-leaf gate was developed, how it functions, where the gate is applicable, and where the gate has been installed. Several examples are included to show its application, design concept, installation, function, and operation. 11 pp.