What is dredging?

Britain has been hit by the most severe flooding in 90 years and water levels are still rising.

It's the Environment Agency's job to manage flood risks and reduce the impact of flooding but some say the organisation has not done enough.

Farmers in Somerset claim a lack of river dredging has made the impact of the flooding in their area worse.

But the issue of whether rivers should be dredged is not straight forward.

The Environment Agency says that dredging can improve drainage, but cannot prevent rivers from flooding, due to the huge amount of water involved during major floods.

What is dredging?

The basic aim of dredging is to remove silt (a material made of fine sand), clay and small particles of rock from the river's bed.

Silt builds up on the river bed over time

During heavy rain the river floods

The process to remove it usually involves an excavator, or vacuum pump, stationed on a barge or on the riverbank.

Dredging clears the bottom and sides of the river to enable the waterways to flow freely.

Blockages can also be caused by trees, shrubs and weeds. River banks as well as river beds need to be maintained.

Problems with dredging

Dredging is expensive and the Environment Agency say that it is harmful to the environment.

They believe that it and can weaken riverbanks as well as the foundations of bridges and weirs.

The agency also say that dredging can lead to the loss of grounds for fish to breed and can cause loss of some species and destroy the habitat of river bank wildlife such as otters and water voles.

From CBBC newsround

Click for less

Princes Charles and William launch wildlife campaign

They are seated side by side, looking straight into camera - two future British kings with a message that matters deeply to them.

Prince Charles and Prince William have launched a campaign calling for an end to the illegal trade in elephant tusks and rhino horns.

They say it has reached unprecedented levels, placing the animals at risk of extinction.

It comes a day after Prince William was reported to be hunting deer and wild boar in Spain.

Both Charles and William are passionate in their support for the world's endangered wildlife, and increasingly exercised by the threat posed to that wildlife by organised criminal gangs which slaughter animals for their tusks or horns or other body parts.

As Charles says in the unprecedented video message which launches their anti-poaching campaign, the numbers being killed are "staggering": nearly 100 elephants killed every day - a rhinoceros killed every 11 hours - a wild tiger population which, a century ago, numbered around 100,000 and which, today, has been reduced to an estimated 3,200.

There is, he says, an apparently "insatiable" demand, much of it from Asia, which is driving this trade and which is giving rise to levels of killing and related violence which has not been witnessed before.

Father's footsteps

For the British royal family, a commitment to the cause of conservation is a long-standing one.

Charles's father, Prince Philip - the husband of the Queen - was one of the original founding fathers of the World Wildlife Fund, now the World Wide Fund for Nature.

Half a century ago, he travelled the world urging audiences to pay greater attention to the needs of the natural world.

And just as Charles followed in his father's footsteps, William has done the same - three generations of royals each of whom has been drawn to the African bush and the majesty of its wildlife.

From BBC News

READ MORE