Brown water

nik · 20 February 2007, 13:15

I was on the fishbourne-portsmouth ferry on sunday, and about halfway across, near the shipping lane, I saw large patches of brown water.
I have seen the same thing on other days.
Is this sewage? if not, does anyone have any ideas what it could be.

Nick

Downhilldai · 22 February 2007, 00:15

Were you standing near the outlet valve of the ferry's holding tank?

Stoo · 22 February 2007, 01:32

It could possibly be an algae bloom of some sort, especially if it was a reddish-brown... The old "sniff test" can go a long way in determining the source!

nik · 22 February 2007, 08:15

Quote:

It could possibly be an algae bloom of some sort, especially if it was a reddish-brown... The old "sniff test" can go a long way in determining the source!

It could be. Its a bit hard to sniff the water from 50 feet up.
I would have thought algal bloom would be a summer thing.
At a first glance it looks as if you are running into shallow water.

Mark Halliday · 22 February 2007, 10:22

Hi Nik
Brown patches are not uncommon in the solent.
I used to watch out for them when yot racing. They usually occur when the tide is changing and I think they are caused by the change of flow stiring up the bottom.

nik · 22 February 2007, 18:38

Thanks, that seems very plausible.
There were several patches, each one being quite large, (a football pitch or two)

Jack h · 22 February 2007, 22:17

it's just sediment being kicked up, in the mersey where the tide is normally around 2-5kts where we sail the water is always brown, it only goes clear at slacks.