On Thu, 16 Mar 2006 12:43:35 +0000 (GMT), "Dave Liquorice"
wrote:

On Wed, 15 Mar 2006 23:03:59 GMT, Mark wrote:

Agreed, the Environment Agency recommend when the bottom silt content
reaches 25% of volume.

How does one measure the bottom silt content?

Scuba gear and great bravery?