Water and carbon cycles
Drainage basin
- Eden
- In north-west England between the mountains of the Lake District and the Pennines.
- Source in Pennine hills in Cumbria.
- Flows north-west through Appleby-in-Westmorland and Carlisle.
- Mouth in Solway Firth at the Scottish border.
- Basin is largely rural, although the river does through through the city of Carlisle.
- Upland areas experience extreme weather that can cause flooding downstream. Carlisle is
particularly vulnerable as it’s at the confluence of Eden, Petteril and Caldew rivers, and it is
fairly low-lying.
- Rainfall is higher than the national average. Relief on the mountains encourages orographic
rainfall. High rainfall means that lots of water enters the river channels.
- Long and relatively narrow, which increases lag time.
- Slopes within the basin are steep. Reduces lag time and increases peak discharge.
- Made up of different types of rock. Highest ground in the west of the basin made of igneous
rocks which are impermeable - infiltration is very slow and surface runoff is high, reducing lag
time. Much of the basin is made up of limestone and sandstone which are permeable -
infiltration is quick and little surface runoff, increasing lag time. The amount of water in ground
stores increases.
- Between 2000 and 2009, there was a 30% increase in the number of cattle in the Eden Valley.
- Eden Gate development to the north of the city. Plans to build a huge ‘garden village’ to the
south of the city including up to 10,000 new homes.
- Flood defences to protect homes.
- Parts of western UK could get up to 35% more winter rainfall by 2080.
- Storm Desmond in 2015.
- In Shap, 262.2mm of rain fell in 48 hours between the 4th and 6th December. 50mm more than
the average rainfall for the whole of December.
- 2000 properties were flooded in Carlisle.
- River Exe
- Characteristics of upper course (near Simonsbath): Land use - town, hotel, housing (concrete).
Little vegetation (few areas of forest). Steep sloping land around the river - average 350m.
- Characteristics of middle course (near Dulverton): lots of vegetation (large areas of forest), rural
- not many buildings (caravan park, castle, farmland). Not as steep as upper course - average
250m.
- Characteristics of lower course (near Exeter): high density buildings, barely any vegetation (only
on golf course), low lying land (approx. 40m).
- Characteristics of Wimbleball reservoir: the dam impounds water from the river haddeo to form
a reservoir with a net storage of 21,320 megalitres and surface area of 150 hectares.
- Job of Wimbleball reservoir is to supply Exeter and parts of east Devon by releasing water into
the river exe. the water is then abstracted at Tiverton and Exeter. water also supplied by
pipeline to Wessex waters Maundown water treatment works.
- Impact of WImbleball reservoir: peak discharge lowered, regulates and controls discharge
throughout the year, helps meet demand and decreases likelihood of flooding.
- Causes of problems of Exmoor mires: drainage ditches dug and peat cutting. this causes the
mires to dry out, which reduces the water capacity of the moors.
- As a result of drying on the moors, oxidation of exposed peat bogs, releasing large quantities of
carbon into the atmosphere.
- Exmoor mires project - blocking drainage ditches using sustainable methods, local materials,
contractors in order to rewet the bog, enabling it to retain water and carbon.
- Re-wetted peat bogs slow down the run-off of water from land before steadily releasing it.
, - Floods less likely, reduced soil erosion and the amount of silt entering the rivers.
- Peat cuttings reduce surges after storm event, minimising flood damage - 1/3 less water in
storms.
- Water naturally filtered through the vegetated peat.
- Slower flow of water gives suspended particles in water more time to settle = reduction of
suspended particles and dissolved organic carbon (DOC) - 30% less.
- Reduced amount of silt entering rivers means water is 20% less expensive to treat.
- Exeter and Exmouth - 2,000 to 5,000 properties at risk from flooding.
- Cowley and Bampton - 100 to 250 properties at risk from flooding.
Carbon sequestration
- Boundary Dam, Saskatchewan
- In 2014 became the first power station in the world to successfully use Carbon Capture and
Storage (CCS) technology.
- Produces 115 megawatts (MW) of power—enough to power about 100,000 Saskatchewan
homes.
- Capable of reducing the SO2 emissions from the coal process by up to 100 per cent and the
CO2 by up to 90 per cent.
- It is expected to result in a 90 percent (1 million tonnes/year) reduction in CO2 emissions and
will also reduce the output of Unit 3 from 139 MW to 110 MW. only about a half of this CO2 will
be actually be permanently stored.
- In 2015, internal documents from SaskPower revealed that there were "serious design issues"
in the carbon capture system, resulting in regular breakdowns and maintenance problems that
led the unit to only be operational 40% of the time.
- The low productivity of the plant had in turn meant that SaskPower was only able to sell half of
the 800,000 tonnes of captured carbon dioxide that it had contracted to sell.
Links between water and carbon cycles
- Amazon rainforest
- World’s largest tropical rainforest.
- Covers 40% of the South American landmass.
- Has a hot, very wet climate and vegetation is very dense.
- Many groups of indigenous people.
- Home to up to 1 million plant species, over 500 species of mammals and over 2000
species of fish.
- Home to many endangered species, including the Amazonian manatee (an aquatic
mammal), black caiman (a reptile) and the pirarucu (a fish).
- Water cycles cause the Amazon to be very wet - lots of evaporation over the Atlantic
ocean, and the wet air is blown towards the Amazon. Contributes to very high rainfall.
- Warm temperatures mean that evaporation is high → increases precipitation.
- Rainforest has a dense canopy - high interception, so less water flows into rivers that
might do otherwise and it does so more slowly.
- Species are adapted to high humidity and frequent rainfall.
- Amazon rainforest stores lots of carbon it is vegetation and soil, so it’s a carbon sink.
- Increasing concentration of CO2 in the atmosphere has led to increased productivity
because vegetation is able to access more CO2 for photosynthesis - amount of biomass
increasing.
- Amount of CO2 sequestered by the Amazon has increased.
- Although trees are growing more quickly, they’re also dying younger.
- Deforestation.
- Climate change.
- Amazon had severe droughts in 2005 and 2010.
- Scientists predict that a 4oC temperature rise could kill 85% of the Amazon rainforest.
