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RAGT90 - Percentage of stream corridor buffered to 90 meters classified as all agricultural use The percentage of all agricultural land cover 90 meters adjacent
to streams is calculated by summing the total number of pasture,
crop and orchard land cover cells underneath stream segments in
the 1 km grid cell reporting unit and within a three cell buffer
(90 meters) and dividing by the stream corridor’s total land
area (all cells 90 meters adjacent to streams minus those classified
as water). Cells inside the buffer zone but outside of the grid
cell boundary are ignored. Agricultural practices typically employ
fertilizers, pesticides and other chemicals that may be transported
to streams in water runoff. The closer agriculture is to a stream
the more likely related pollutants will enter the stream. Concentrations
of pollutants transported into streams are also more likely to be
higher when agriculture is closer to streams. Animals grazing in
pasture land may decrease vegetation cover possibly leading to increased
runoff. Livestock may also impair stream banks by trampling riparian
vegetation, which may cause increased sedimentation in the stream. |