Assess the extent to which changes in the water cycle have affected flood risk or sustainable
water supply in a drainage basin you have studied. [20 marks]
Changes in the water cycle can have a significant impact on flood risk in the drainage basin
of the river Exe. The river Exe covers an area of 601km 2 and runs from the hills of Exmoor to
the South coast of Devon. It has 11,000 properties at risk of floods, as a result of changes in
the water cycle. Human activity, such as water abstraction, agricultural land use and the
peatland restoration project have all affected flood risk to some extent. Physical factors, such
as relief, also have an impact on flood risk from in the drainage basin of the river Exe.
Land use change for agriculture can significantly impact the water cycle, increasing flood
risks as a result. 57% of the land around the river Exe is agricultural grassland, meaning that
it is having a significant impact on the water cycle and flood risks in the area. Pastoral
farming of cattle and sheep are the primary use of this agricultural land. The weight from
these animals compact the soil, reducing the size of the pores and therefore reducing the
amount of water that the soil can hold. Rates of infiltration drop as a result, which means that
there is more surface runoff entering the river at a faster rate. This increases the amount of
flooding in the area as the river is unable to hold all the water from this surface runoff. This
shows that agricultural land use can significantly impact the water cycle and increase flood
risk to a great extent.
One physical factor that has an impact on the water cycle and affects flood risk in the
drainage basin of the river Exe is relief. The drainage basin has steep river valleys to the
north, and gently sloping river valleys to the South. Relief rainfall in the north means that
there is a large input of water towards the steep slopes. This results in low infiltration and
fast runoff down the hillslopes, straight into the river channels. As a result, there is more
water in the river and decreased storage in the lithosphere, so flood risk increases. This
water supply in a drainage basin you have studied. [20 marks]
Changes in the water cycle can have a significant impact on flood risk in the drainage basin
of the river Exe. The river Exe covers an area of 601km 2 and runs from the hills of Exmoor to
the South coast of Devon. It has 11,000 properties at risk of floods, as a result of changes in
the water cycle. Human activity, such as water abstraction, agricultural land use and the
peatland restoration project have all affected flood risk to some extent. Physical factors, such
as relief, also have an impact on flood risk from in the drainage basin of the river Exe.
Land use change for agriculture can significantly impact the water cycle, increasing flood
risks as a result. 57% of the land around the river Exe is agricultural grassland, meaning that
it is having a significant impact on the water cycle and flood risks in the area. Pastoral
farming of cattle and sheep are the primary use of this agricultural land. The weight from
these animals compact the soil, reducing the size of the pores and therefore reducing the
amount of water that the soil can hold. Rates of infiltration drop as a result, which means that
there is more surface runoff entering the river at a faster rate. This increases the amount of
flooding in the area as the river is unable to hold all the water from this surface runoff. This
shows that agricultural land use can significantly impact the water cycle and increase flood
risk to a great extent.
One physical factor that has an impact on the water cycle and affects flood risk in the
drainage basin of the river Exe is relief. The drainage basin has steep river valleys to the
north, and gently sloping river valleys to the South. Relief rainfall in the north means that
there is a large input of water towards the steep slopes. This results in low infiltration and
fast runoff down the hillslopes, straight into the river channels. As a result, there is more
water in the river and decreased storage in the lithosphere, so flood risk increases. This
