Captain's Handbook ©

MARINE NOTICE, No. 88 of 2014

(Re-issued 14 Oct 2014)

All Navigations

Low Water Levels

Advisory Information

The extended period of dry weather has meant that water levels in the navigations are presently lower than normal for this time of year.
Masters and users are advised of the following:

Navigation
Where water levels fall below normal summer levels masters should be aware that their vessels may be at risk of grounding, particularly deep drafted vessels.
To reduce this risk masters should navigate where possible on or near the centreline of the channel and also avoid short cutting in dog-legged channels and navigating too close to navigation markers.
Proceeding at a slow speed will also reduce “squat” effect i.e. where the vessel tends to sit lower in the water as a consequence of higher speed.
Slipways
Low water levels will also impact on slipways with reduced slipway length available under the water surface and the possibility of launching trailers dropping off the end of the concrete apron onto the river /lake bed and causing damage to trailer, outboard motor or boat. More slipway surface will also be susceptible to weed growth requiring care while engaged in launching boats.
Bank Erosion
Very dry riverbanks are more susceptible to erosion from vessel wash. Please ensure you adhere to the speed limits and maintain a reduced wash.
Lock Share.
Where appropriate by maximising on the number of vessels in a lock the total volume of water moving downstream is decreased. This also reduces the volume of water used. Please be patient and wait for other boaters to share the lock with you rather than using locks for single passages.
Efficient Lock Use.
Make sure lock cycles are used for vessels travelling each way. Each lock cycle should take boats both up and down stream. Shut all sluice gates and paddles when leaving a lock.
Service Blocks
You are requested not to leave taps running at watering points or service blocks in the interest of water conservation.

Charles Lawn, Inspector of Navigation, 18 July 2014