We have recently installed a pumped ‘up and over’ eel pass at Kidds Mill sluice, Isleworth, which will allow eel and elver migration between the tidal Thames and the Duke of Northumberland’s River. The site was previously a complete barrier to eel migration due to the high velocities in the over-shot sluice channel and a vertical head drop on the sluice in excess of 2 m. The eel pass has been strategically located away from the highly energised flows below the sluice structure, passing over a disused pen-stock and discharging any eels or elvers that use the pass safely upstream away from the sluice gates.
As the site is tidal, the eel pass accounts for varying downstream water levels with multiple entry points enabling the pass to be functional over all tide states. The eel pass has been fabricated from a marine grade aluminium channel, with bristles boards installed in the channel to act as a climbing substrate for the eels.
