Penton Hook Lock
Penton Hook Lock is the sixth lowest lock of forty four on the non-tidal reaches of the River Thames in England. It faces an island which was until its construction a pronounced meander and is on the site of its seasonal cutoff. It is against the left bank marking the church parish medieval border of Laleham and Staines upon Thames in Surrey for many centuries. Until 1965 their county was Middlesex. At it is the third longest lock on the river.
A bend 1000 yards upstream of the lock, Silvery Sands, hosts Staines Regatta in the sport of rowing annually. On the opposite bank in Thorpe is Penton Hook Marina which occupies lakes once land used for gravel extraction.
History
Problems were long caused in erosion and to navigation by floodwaters topping the neck of the meander. The Corporation promoted the funding of the lock with formalised weirs in 1809, and Parliament passed its enabling act 1814. The lock was completed in 1815, two years after Chertsey Lock, as the Thames lock furthest upstream controlled by the City of London Corporation, whose arms appear on the Lock Cottage built in 1814. It soon became the sixth lock proceeding upstream, as it is today.The main weir was built in 1846 when positioned below the offtake of the Abbey River, a medieval-established leat and so sited for the benefit of watermill power; the grain mills were by the end of that century superseded by large industrial granaries. Horse, cattle and crop farming tenants had conflicting interest of reducing its flow; in spate, the weirs elsewhere reduced the flow of the main river for a mile or more. For a few years the leat was sourced above the main weir thus increasing the flooding of Laleham Burway and other fields of northern Chertsey; its shallow course has banks without bundings and few sluices. These interests outweighing those of the outdated mill led to start of the Abbey River being moved to below the main weir of Penton Hook, reducing the enhanced flows along the Abbey River. To resume additional flood relief channels, as of the early 2020s, the Environment Agency proposes new instances of channels below this lock and that below to act in the same way as the Jubilee River upstream which fast tracks flows from above Maidenhead to below Windsor.
The lock was rebuilt in 1909.
Access and location
The lock is accessible on foot or bicycle along the towpath from Blacksmiths Lane and its spur Riverside or Penton Hook Road.The lock is against the left bank marking the Church parish medieval border of Laleham and Staines upon Thames in Surrey since at least the Norman Conquest. By boat the lock can be accessed from Thorpe on the right bank.