rivers and waste
The waste products from both
livestock and arable farming can lead to the pollution of rivers
and fisheries if farmers are not very careful. Dairy farming, keeping
pigs, sheep and chickens or growing crops such as wheat, maize,
potatoes and other root vegetables can all cause pollution in rivers
and streams. Pollution like this is often unintentional, but is
nevertheless a real problem of agricultural land use.
Free range chickens
Miscanthus, a modern alternative crop
Sheep in a barn
Waste: The process that involves the rotting or break down
of waste organic materials, such as plants and animal dung, can
lead to the pollution of water. This is called organic pollution.
On farms there might be manure heaps and slurry lagoons (W07d)
that leak or silage clamps (W07f)
with liquids slowly trickling out. If these liquids run into ditches
or channels that lead to rivers or streams they will pollute the
Roadside muck heap
Cattle in a river
Fertilisers are applied to the soil or plants to help the plants
grow. Most fertilisers are made of a mixture of chemicals such as
nitrates and phosphates (W07b).Any
fertiliser not taken up by the plants in growing will find its way
eventually to a river or stream and will then affect the plants
that grow there. A small amount of fertiliser will help the aquatic
plants to grow, but too much will destroy the delicate balance of
and Pesticides (G1):
Some chemicals that are used in farming practices can cause serious
pollution problems more directly. Chemicals are used to kill weeds
(called herbicides or weed-killers) and pests (called pesticides
or insecticides). If these chemicals find their way into the water
cycle the effects can be disastrous. Plants and animals that live
in or close to the river (B09)
could be killed and fisheries ruined.
Soil, fine sand and clays can be washed off the fields and riverbanks
and pollute the river by filling the water with particles and covering
the spawning gravel with sediment so that young fish cannot survive.
Farm animals can churn up soils in the fields or damage riverbanks
so that soil is eroded (worn down) and carried away in the water.
farm waste: Black plastic silage wraps or fertiliser bags,
empty medicine, pesticide or sheep dip containers, unused animal
feed, rusty barbed wire, fence posts and broken gates are all agricultural
waste that needs to be disposed of carefully.
Pollution of rivers can be caused
by accident. For instance, pesticides or fertilisers might be blown
by the wind or washed off the fields by rain and into the river.
By taking precautions some pollution incidents can be avoided, such
as a farmer building a dyke or bank around a slurry lagoon in case
it overflows or leaving a wide margin beside a river when he is
spraying crops in a field.
Don’t despair, there are
solutions to pollution problems, but to find them the source of
the pollution has to be found, and where and why it happened has
to be understood. Some pollution problems are easier to solve than
others. To learn more click on the key words below.
Some examples of these waste issues can be found on the Trust’s
Demonstration Sites – visit the WRT website for information
on Demonstration sites currently available for visits – www.wrt.org.uk