Performance and Design of Labyrinth Weirs

The purpose of the labyrinth weir is to increase the discharge per unit width of channel beyond that usually obtained from a conventional weir under identical head conditions. This is achieved by compressing a large length of crest in concertina form into the space available on site. An increase of discharge ranging up to sixfold or more can be obtained. Described are the results of a program of research on labyrinth weirs that is aimed to provide comprehensive performance and design data. The experimental work covered the effects of all primary parameters affecting performance such as crest length magnification, plan geometry, number of cycles, etc. Parallel with the experimental work a mathematical model was constructed and a computer program developed which will predict performance to ± 4% accuracy or better over a wide range of operating conditions. Finally a simple design method is instilled from the experimental and theoretical results.