Five sets of sluices and two weirs are used to control the canal's depth. Bedford also benefits from the presence of weirs and sluices, creating white water opportunities. The basic elements of a barrage are caissons, embankments, sluices, turbines, and ship locks. Natural ponds were augmented with sluices and causeways. The inhabitants controlled the lake with a sophisticated system of dikes, canals and sluices. This reservoir complex has facilitated with a stone made spillway and three main sluices. Mining equipment such as sluices, flumes, wheels and derricks were carried away across the state. The use of sluices, dredges, or other machinery is forbidden. The sluices in the culvert at the west end were also opened. The extremely high pressure stream was used to wash entire hillsides through enormous sluices. It is tidal below the sluices at New Clyce Bridge in Highbridge. The basin is filled through the sluices until high tide. The minerals are then concentrated using sluices or jigs. The canal stretches for ; its granite sluices date from 1836. Improvements to assist navigation began in 1618, with the construction of sluices and locks.