Water + Carbon Case Studies

• Amazon Rainforest - Background

  • Largest area of rainforest in world.
  • 300 billion trees, 15000 species - store 1/5 of all carbon in planets biomass. 
  • 1500 mm and 3000 mm of rainfall/yr. Half from recycling - convectional rainfall. 
  • Amazon basin - 1/5 of fresh water running over Earth's surface.
  • Amazon river - largest volume. 
  • 25 and 30 degrees all year → rapid evaporation, increases humidity levels. 
  • Brazil has the most carbon stored on land and the most extensive deforested area.
• Amazon Rainforest - Deforestation

  • Less rainfall (convectional) and increased runoff as less interception. Drought.
  • Less moisture in wind - rainfall levels fall at larger scale. 
  • Temperature increase up to 40% (reduction in cloud cover + evapotranspiration). 
  • Carbon source rather than sink. Reduced carbon absorption. 
  • Rain (formed over intact rainforest) - fall over deforested land and cause soil erosion.
  • 2019 held 76 billion tonnes of carbon.
  • 90s - absorbed 2 bil tonnes of CO2 per year. 2019 - only 600 mil tonnes per yr.
  • 4 yrs of Bolsonaro - area larger than Denmark deforested (increased)
• Amazon Rainforest - Management

  • Brazilian Forest Code - Amazon landowners should maintain 80%.
  • Minimal incentives + repercussions to stop deforestation
  • Required reforestation - cost high and no real punishment. 6% of farmers. 3/4 said would only if made to do so. 
• Amazon Rainforest - Management

  Lula’s Government - wants to eliminate deforestation in the Amazon by 2030. 

  • Track criminal activity - Satellite imaging for illegal loggers and cattle ranching
  • Rural registry to monitor forest management
  • Degraded forests recovered, economic incentives for conservation and sustainable forest management
  • Track cash movements to pay for chainsaws, excavators etc.
  • Tracing system for wood, livestock and other products from Amazon (ensure not from deforested land)
• The River Exe, Devon - Background

  • 82.7km
  • High drainage density, many tributaries.
  • 84% underlain by impermeable rocks (sandstones).
  • 67% (most) land agricultural, 15% woodland, 3% moors and peat bogs (Exmoor).

  High runoff = 65% of water balance due to:

  • impermeable bedrock (reduced percolation)
  • drainage ditches on Exmoor (reduce water storage)

  Discharge recedes slowly. 

  1979 River Haddeo (upland tributary) dammed to create reservoir - 150 ha. Supplies water to Exeter and East Devon. Regulates water flow to prevent flooding. 
• The River Exe - Peat Bogs

  Drainage ditches dug in peat bogs of Exmoor for farming. Peat also dug as fuel.

  • Releases CO2 + methane. Peat is carbon store - dry peat releases CO2 as organic matter no longer preserved in water and decomposes.
  • Reduced water storage - increases runoff and speed of water flow to Exe. Reduces water quality as silt carried. 
• River Exe - Management

  Exmoor Mires Project - restore peat bogs by blocking drainage ditches with peat blocks and bales.

  Aim to restore 2000ha of Exmoor. 

  • Increases water content and reinstates saturated conditions. 
  • Increase water storage (larger storage capacity - decreases runoff).
  • Increases carbon storage - rewetting peat 

  2015 - 1000 ha restored, 100km ditches blocked, reduced amount of water that drains by 2/3.