Vallee Aurelie

1
THE ORGE RIVERpolluted during wet weather
2
Situation of the basin

• The basin of the Orge river belongs to the
  parisian basin.
• The river is above Paris and its a tributary of
  the Seine river.
• It flows out for 52 km and goes through urbanized
  areas.
• The basin is a 950 km² area.

3
Sources of pollution in this riverduring wet
weather

• Overloaded of purification stations

• Wrong connections in the treatment plant

• Saturation of the waste waters pipes

• Urbanized running water carries away metals,
• hydrocarbons, weedkillers and others pollutants

4
Impacts on the environment

• Gas exchanged inhibited by hydrocarbons
• Destruction of ecosystems caused by toxicity
• Increase of the turbidity of water,
• flora cannot do photosynthesis any more
• Stop of oxygenation of the water
• Decrease of the biodiversity
• Evapotranspiration restricted by urbanization

5
Solutions against the pollution of the Orge river

• Installation of decant stations
• 10 desanding pools and deoilers
• Surveillance in continue to monitor the quality
  of the water
• All the data is sent to a central database
  management.
• Each year hydrobiologists make a report
• In the case of accidental pollutions
• Samples taken to be analyzed in labs
• Floating waterblocks to stop and absorb pollution
• Pumping trucks can be used in specific case

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Example of machine to clean the water
http//step.ouvaton.org/tech3.htm
7
Evolution of Orge water quality

• Improvement until the beginning of the 80s
• Then stagnation of the quality for 10 years
• About flora fauna status quo
• Poor biological quality water
• But the downstream section where the
  deterioration has been curbed, shows the
  improvements in cleaning up rainwater and
  restoring the vegetation of riversides.

8
Evolution of the basin
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References

• http//www.sivoa.fr
• http//step.ouvaton.org/tech3.htm