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Table 1. Stressors and Receptors Chosen for the Study
Stressor
Valued ResourcesFish
Water Quality
Waterfow l
Forest
Road construction x
x x
Pipeline breaks x
x x
Oil spray x
x
Road construction may affect all of the resources through either direct habitat destruction or by indirect effects
such as increased ponding, flood alteration, and the release of sediments into the water. Increased sedimentation may degrade water quality by decreasing the amount of light penetrating the water column, filling the interstitial spaces in the
gravel of the stream bottom, or directly smothering fish eggs. These actions may directly affect population levels of fish or may affect the habitat of important food resources. Waterfowl may be impacted indirectly through a reduction of food sources or by impairment of their ability to find food because of increases in turbidity.
Pipeline breaks may release large quantities of oil directly into the water if a break occurs at a stream crossing. If a break occurs on land or in a buried section of pipe, impacts will depend on terrain features and whether or not the released oil reaches the water. There are several routes of exposure of waterfowl to the spilled oil. The birds may directly contact the spray and ingest oil while preening their feathers to remove it, or they may be impacted through the ingestion of oil while feeding. Death of the birds may result from direct toxicity of the oil or by secondary effects caused by the loss of body heat because the feathers lose their insulation property. If the
oil spill reaches water bodies, fish may be impacted through direct toxicity of the water-soluble fraction of the oil, by impact to the respiratory surfaces of their gills, or indirectly by a reduction in the availability of food.
With respect to water quality, severe impacts often occur when heavy equipment is brought in during the cleanup operations and allowed to operate in the stream channel.
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Oil spray from the production wells and oil/water separators coats the surfaces of the forest trees, inhibiting oxygen transfer and retarding growth. Coating during bud or seed production times is especially harmful. Oil spray may have direct effects on water quality if the oil enters the water directly or is washed off the land surface into the water.
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