Teddington Weir is a man-made structure which has changed enormously over time (Figs. 1a and 1b). In our designs we have sought to capture and improve upon the essence of the weir. We hope that, over time, our hydro scheme will become as familiar and loved as Teddington footbridge is today.
A weir was in place on the Thames at Teddington by 1345, although it was destroyed about 1535. A new lock was opened in 1811. Since 1811, the weir has marked the end of the tidal reach of the river. Prior to 1811, the tide used to go as far upriver as Walton, and occasionally even to Staines.
Teddington Lock is a complex of three locks and a weir on the River Thames, and consists of a conventional launch lock, a very large barge lock and a small skiff lock.
The lock was rebuilt in 1858, and the barge lock added in 1904. The weir itself has had to be rebuilt several times following floods. The section nearest the Middlesex bank (the proposed location of the hydro scheme) used to have a roof over the walkway, as seen in Fig. 2 (photo circa 1960) and Fig. 3 (the engineering drawing of that section of the weir prior to its demolition and reconstruction in 1991/2). Teddington footbridge was built in 1889: the funds for its construction were raised by public subscription – a very similar mechanism to the financing plan for our scheme.
The section of the weir to be used for the hydroelectric scheme was reconstructed in 1991-92 (Fig. 5) and now incorporates two sluice gates, two overspills and two fish passes between the roller sluices and the river wall. The small brick and pitched roof gauge house on the bank, adjacent to the Lensbury Club, was built at the same time. Demolition of this section of weir and the introduction of the hydro power scheme and replacement fish pass and sluice should be seen as the latest incremental change at this site. The proposal effectively replaces one engineering structure with another, of appropriate scale and enhanced appearance.
The scheme is designed to keep it consistent with the range of existing engineering structures forming Teddington Weir. The overall scale of the structure is comparable with the adjoining large roller sluice gates. Three 4 metre wide Archimedian screws will be mainly below the top of the river wall, although the shafts will extend up to a higher generator platform (above the projected maximum flood level) and maintenance walkway. These are flanked on one side by a wider fish pass next to the river wall and a new sluice gate on the other. A small plant room for inverters and electrical switchgear is located on this platform above the sluice. None of the components of the scheme exceed the height of the existing roller sluice structure.