In my local river, a lot of filmentous weed has formed on the bottom and I wonder is this due to agricultural fertiliser? I would really love to get rid of this weed because it screams (to me, at least) "LACK OF WATER QUALITY." Can anybody tell me what's going on here?

If it has suddenly appeared where it hasn't been in the past it can be a sign of fertiliser in the water. Trying to trace the source would be a nightmare I'd guess, part of the 'diffuse pollution' issue.

I don't think suddenly appeared, but it seems to be a bad sign and I feel so jealous when I see photos of rivers with nice clean gravel, sand or stone beds.
The river also has a lot of flowering ranunculus weed which is a good sign I hope. It does seem to be more of this diffuse pollution that's causing the filamentous weed though.

Definitely a sign of nutrient enrichment, but this could be from a sewage works discharge to the river; to run-off from land carrying agricultural nutrients and from road run-off or any combination thereof. This seems to be more of a problem in low flows.

we seem to be suffering it bad this year too, it ( filament algae) usually builds up during the year and then is flushed out of the the system with winter floods.
It is a combination of nitrogen enrichment and light levels that spur its growth on.
We can only theorise for our water.
Most of our (water comes from) field run off and ground water. The winter was so incredibly wet this year that the water levels are holding up despite no real rain for ages. Nitrogen as a nutrient is not 'held' by the soil and is suseptable to leeching out over winter, carried out by the water and as we are still getting plenty of field water coming down drainage chanels still and topping up levels, I suspect that this is very rich.

What i am trying to say is that you may not have had some single 'Event' that caused this, but just an unfortunate set of circumstances like us.
Are you monitoring your insect life regularly? It is one of the best ways of seeing if anything is amiss in the system.

I would love to monitor insect levels, can you advise me on what I should do or where I might find out?

sorry i didnt get back to you, look up the River Fly partnership and look up the entymology for anglers courses or Riverfly monitoring courses. We (like many other clubs on the forum) do 3 minute kick samples once a month and monitor the occurence of 8 groups of flys nymphs and shrimps, in out water. The training and equip was supplied by EA grants orginised by the RFP.
Riverfly - Partnership You can call them and talk to the totaly wonderful bridget Peacock, she'll help you get the wheels in motion.

by the way I was wrong about Nitrates ...in this case its phosphates that cause the problem!

My local River Ribble is choked with this nasty stuff at the moment - it always is if the water falls low for a prolonged period in summer. It's a product of the intensive agriculture which prevails in the middle and lower valley.

That said, when I did my kick sample at the weekend, although it took an age to sort the inverts out of the weedy mush which got washed into my net, the sample scored a healthy 14 with every group present barring ephemeridae....and no surprises there as mayflies are very seldom seen on the Ribble system.

Still, it would be nice to get some rain and flush the stinky stuff out.

__________________
The sun pushed dark spokes of melt and sparkle
Across the fields of hoar. And the river steamed -
Flint-olive.


http://northcountryangler.blogspot.com

Thanks for the info guys. I'd love to get those fertilisers out of the river's catchment area but that'll have to be a long term plan!

I would love it if someone who actually knew these plants came on here. We have so many different species from the truly awful to the indespensible in terms of trout habitat and everything in between. It is there as part of a balanced healthy system, and sometimes its an indicator that things are either out of balance or badly amiss.
I wlked parts of out strem with a retired EA man yeterday, who has worked throughtout the world on projects, he put me right on the phosphates, which I should, and did know, but years of people saying nitrates had muddled me. And was not too surprised or upset about our heavy algae cover this year seeing it as part of the natural cycle in a modern landscape we share with many other people, most of whom , including the farmers, have an interest in having a pristine clean waterway. Our main enemy with these problems is ignorance, and the first place to combat it is with ourselves.