Sources of Pollution


You can tell something about the land use in an area by examining its aerial photograph. For example, Agriculture shows as large rectangular fields of cropland. Flow alteration shows as straight channels made when canals are dredged, and square ponds made when fields that are surrounded to control water level become flooded. Urban areas that contribute runoff show as jigsaw puzzle looking features with multiple colors located along waters bodies in this watershed.

When people talk about nonpoint source pollution, they talk about watersheds. A watershed is an area of land in which all water that falls as rain drains to a single water body at the lowest elevation. Nonpoint source pollution only occurs during rainfall runoff. When it rains the water runs from higher elevations in the watershed (watershed boundaries) to the lowest elevations in the watershed (swamps, bayous, lakes, bays) out to the ocean. Rainfall runoff carries pollutants from sources that vary with the watershed.

In order to determine the source of a nonpoint source pollutant within a watershed you must know the type of land use that is going on in the watershed. The land use determines the source of the pollution.

Land Uses & Sources of Pollution in the Barataria & Terrebonne Basins include:

  • Urban Runoff
  • Agriculture
  • Untreated Sewage
  • Natural Sources
  • Sediment Resuspension
  • Boat Dumping
  • Flow Alteration
  • Wildlife & Waterfowl
  • Drought
  • Forestry
  • Construction


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