Recent hydrographic surveys indicate a slight overall improvement in the depths between Kew Road Bridge and Oliver's Ait from those shown on the most recently published PLA chart No. 307. The chartlet on the reverse of this Notice to Mariners shows the result of the latest survey.
Attention is also drawn to Port of London Permanent Notice to Mariners Number 28 that states:
REDUCED UPRIVER DEPTHS
Mariners are reminded that depths in the upper reaches of the tidal Thames are greatly affected over the low water period by the amount of land water flowing over Teddington Weir.
The area particularly affected lies between Kew Railway Bridge and Richmond half-tide lock.
Under low flow conditions water levels in the above area will remain at or less than chart datum between three hours before and one hour after the time of predicted low water at Richmond Lock. Low water levels of 0.5 metres below Chart Datum are to be expected.
During such periods of reduced depths, Masters of vessels navigating upriver of Putney should only do so with caution and should also make every effort to avoid impeding the passage of commercial vessels, which are highly constrained in their ability to manoeuvre in such conditions.
In order to assist passage planning upriver of Putney, London VTS broadcasts the height of tide at Richmond as part of the half-hourly broadcast on VHF Channel 14.
The Port of London Authority publishes a comprehensive folio of hydrographic charts showing surveys of the tidal river from Teddington to the outer limits of the Port of London. Copies of the charts, at the current fee, may be obtained from:
The Port Hydrographer
Port of London Authority
London River House
Royal Pier Road
Gravesend
Kent DA12 2BG
