Thursday, August 19, 2010

CUTBACKS WELCOME - FOR ONCE

This year, efforts are being made to reduce the amount of summer weed clogging the Ancholme through Brigg, to make life easier for boaters and anglers and make the river more attractive to onlookers, visitors and tourists. Litter-picks are also been carried out to remove the rubbish tossed in by uncaring passers-by.
A further cut/litter sweep will be carried out by the Environment Agency in the very near future - probably prior to the forthcoming August Bank Holiday weekend.
The Agency will cut the central channel of the river, but not close to the banks. There's some sort of regulation in place about that.
Brigg Town Council is chipping in to the cost of this welcome scheme, and a brief update on the situation was given to councillors serving on the planning and environment committee during last night's meeting in the Angel Suite.
Coun Ann Eardley wondered whether it might be possible for the relevant powers-that-be to install under-bridge netting to catch some of the river-bound litter discarded by the public. However, Town Mayor Coun Ben Nobbs pointed out litter in the river accumulated from a very wide area.
Coun Tom Glossop said the cuts would tackle the main infestation of weed but not what he described as the chickweed, which would be dispersed naturally by the flow of the river once heavy rains were experienced.

1 comment:

Ken Harrison said...

In my opinion there are at least 3 causes of 'debris' in the Ancholme.

1. The natural summer growth of river weed species. These can be mechanically cutback, but unless the entire plants are removed, the problem will occur in subsequent years. Removal of weed plants can obvious affect the micro-system of the river.
But I believe there is a type of carp that easts river weed and helps to control weed expansion.

2. Algal Bloom - this is the green filamous matting seen on the Ancholme. Growth is accelerated by sunlight and certain chemical - such as (excessively rich) run-off phosphorus from agricultural fertilzers.
However, is a naturally occuring element and is an essential nutrient to life.
As the Ancholme is essentially a body of stagnant water, phosphorus may have created its own mini-cycle in certain parts of the river.
For example, phosphorus is ground based (ie doesn't normally float about as a gas),and high concentrations may be found in certain parts of the river bed soils. When climatic conditions are right, the phosphates feed the algal bloom - when decay occurs phosphorus is returned to the river bed. So unless one treats the real cause, the algal bloom problem will, also dependent on sunlight and temp, will re-cycle.
Possible treatments -
1. Shade water from direct sunlight by river-bank trees.
2. Encourage farmers not to use excessive amounts of fertilzers - run-off is however inevitable.
3. Employ biological measures - such as barley straw. Barley traw breaks the composition of phosphtes as it decays and reduces concentration level.
Is it possible to put barley straw, to act as biological filtering, in the dykes to catch some of the run-off, or float straw on the river itself to gradually reduce concentration levels?
3. Litter - often identified as the remnants of fast-food outlet. A boom across the river would catch an accumulation of floating rubbish, but the Ancholme is navigitable and this would affect boat-users. Anyway, it does not resolve problem.
Possible solutions:
1. More litter bins
2. Making fast-food outlets responsible to encourage patrons to dispose of packaging sensibly.
3. General education - notices - and emphasising the adverse affects on the micro-systems - animal and plant life.
4. Ban the habit of feeding the swans and ducks bread and other food - This is related to excessively increasing concentrations of nutrients in specific areas of the Anchome - and thus feeding algal bloom and river weed.
Offer alternative, environmental friendly bird food

What we have to be on the lookout for is PENNYWORT - a dense floating weed. This is a highly aggressive plant that has grossly affected parts of the River Cam - around Cambridge, another slow moving river and is already moving northwards - such as the Soar and etc.