With reference to a river catchment that you have
studied, assess the potential impact of human activity
upon the drainage basin.
The river exe flows for 82.7km from its source in Simonsbath to its
mouth in the English Channel and Lyme bay. The river starts in a rural
area and flows through urban areas like Exterior and Thorverton
further down the river. Humans have increased urbanisation in the
area which has consequently led to increased flooding and damage
in the drainage basin.
Most of the land is agricultural grassland (67%), the conversion from
what would have been woodland areas has reduced the slow flow of
stem flow and also means plants cant intercept water and the
ground will become saturated faster. The increase of grassland
means that surface runoff will increase and the lag time will decrease
during flooding. Drainage ditches have been dug for decades in the
peat bogs of Exmoor to make it more suitable for farming. Peat has
been dug as a fuel which leaves ugly scars in the landscape.
Furthermore, as peat surface has dried out decomposition has
occurred which releases carbon in the form of carbon dioxide and
methane from an important carbon store. This has also increased
the speed of water to flow to the Exe and reduces water quality as
increased silt is carried downstream. In 1979 the River Haddeo which
is an upland tributary of the River Exe was dammed to create the
Wimbleball reservoir. The reservoirs 160ft high and has a surface
area of 150 hectares providing a water storage capacity of 21,000
megalitres. The reservoir supplies water to Exeter and parts of East
Devon. It regulates water flow, ensuring a steady regime throughout
the year and prevents peaks and troughs of water discharge which
would make flooding and droughts more likely. Humans have a huge
impact on drainage basins but these impacts can be positive and also
negative.
studied, assess the potential impact of human activity
upon the drainage basin.
The river exe flows for 82.7km from its source in Simonsbath to its
mouth in the English Channel and Lyme bay. The river starts in a rural
area and flows through urban areas like Exterior and Thorverton
further down the river. Humans have increased urbanisation in the
area which has consequently led to increased flooding and damage
in the drainage basin.
Most of the land is agricultural grassland (67%), the conversion from
what would have been woodland areas has reduced the slow flow of
stem flow and also means plants cant intercept water and the
ground will become saturated faster. The increase of grassland
means that surface runoff will increase and the lag time will decrease
during flooding. Drainage ditches have been dug for decades in the
peat bogs of Exmoor to make it more suitable for farming. Peat has
been dug as a fuel which leaves ugly scars in the landscape.
Furthermore, as peat surface has dried out decomposition has
occurred which releases carbon in the form of carbon dioxide and
methane from an important carbon store. This has also increased
the speed of water to flow to the Exe and reduces water quality as
increased silt is carried downstream. In 1979 the River Haddeo which
is an upland tributary of the River Exe was dammed to create the
Wimbleball reservoir. The reservoirs 160ft high and has a surface
area of 150 hectares providing a water storage capacity of 21,000
megalitres. The reservoir supplies water to Exeter and parts of East
Devon. It regulates water flow, ensuring a steady regime throughout
the year and prevents peaks and troughs of water discharge which
would make flooding and droughts more likely. Humans have a huge
impact on drainage basins but these impacts can be positive and also
negative.
