What separates the best students is their ability apply the theory that they learnt in real life, so having examples will allow to you demonstrate a good understanding of the theory.
Introduction
The river Exe is 82.7-kilometre-long river which has a maximum elevation of 514 metres and a low of 19 metres, passing through the areas of Devon and Exeter. The geology that it passes through is the Devonian sandstone.
Human intervention
- Wimbleball reservoir- this is 150-hectare reservoir built in 1972 which was meant to improve to the sustainable water supply and controlled drainage levels in the river exe to reduce the risk of flooding. However, this is ineffective as it’s only has control over the Hadeo tributary, so during storm events, it is hard to control discharge levels in the river exe which control a single tributary.
- Abstraction points-further down the river axes where abstraction points are found which abstract water from the river exe, philtres it before being pumped to the towns of Exeter and Devon for utilisation. Since the water quality is so high in the river, not much infiltration work is needed which is an economic benefit for the abstraction points. However, the discharge levels beyond the abstraction points decreases which can be harmful for aquatic ecosystems further down the river.
- Drainage of peat- surrounding the river exe is Moorland which has her high level of peat. This is soil, which is concentrated with carbon, thus makes it an ideal source of fuel to burn. Therefore, people have drained the Moreland, to dry out the peat before it’s harvested. This creates artificial tributaries as the ditch is a field of water but by precipitation and increases channel flow. Since the soil is susceptible to erosion, the channel flow contains sediment which ends up entering the river as surface run off, reducing the quality of the water and creating greater costs for the obstruction points as they have to filter the muddy water.
Outcomes of intervention
The Exmoor mires project had wanted to restore 2000 hectares of Moorland back to its boggy condition. By 2015, they had restored 1000 hectares of it, which has increased infiltration rates by 66%, by blocking the ditch’s with organic material like hay bales and peat bought in from other parts of the county.