Lake Profile and Channels

"We're not moving"

The Lake's cross sectional profile varies around its shore due to the deposition of silt from incoming flood water and the scouring action of the wind either directly to the Lake floor when dry or via water movement when wet.

The northern two thirds of Lake Eyre North has what must be one of the gentlest gradients on Earth - about 3 metres in 75km!

The three main navigation basins have gradients of around 5 metres in 10km.

Wind and water scoured channels along north south aligned shores, and along the sandspits that tend to form at the end of these shores, can be extremely steep sided in Lake terms. Gradients of 1.5m in as little as 50metres. The Silcrete and Jackboot Spit Channels have been sounded by LEYC members at depths equal to the deepest parts of the Lake.

Areas of shallow water between points and headlands (as distinct from sandspits) extend outwards in a curve rather than the expected concave curve to match the shoreline. This makes it necessary to take a "great circle" course between points. A direct route between such points would lead to a stranding.

Strong winds or their recent conclusion can cause strong currents in the Lakes channels. These currents have been reported at up to 5km/hr and thus can seriously hamper navigation. Furthermore they may be hard to detect as the whole volume of water is moving at the same rate with no sign of eddies.