NEPA--Environmental Assessment

ENVIRONMENTAL CONSEQUENCES
Alternative 1
Under this alternative, the visible trails from the high number of sheep grazed in the early 1900’s
would eventually revegetate, though it would be very slow, and use from deer and elk would hinder
this revegetation. This would reduce soil movement from uplands into streams.
Under this alternative any contribution of nitrate or fecal coliform from sheep manure would be
discontinued, though the existence or amount of any current impacts is unknown.
Under this alternative, heavy metals contributed to streams from sheep grazing on mineralized soils
would be eliminated. It is likely that extensive sheep grazing in the past has decreased the vegetative
ground cover in mineralized areas and accelerated erosion and exposure of oxygen and water to
metal sulfide bearing substrates. This weathering and erosion of metal-bearing rock and soil is a
portion of the undifferentiated background metal load documented in the Use Attainability Analysis
(Simon, 2001). Under a “no grazing” alternative, whatever portion is attributable to grazing would be
eliminated.
Alternative 2
Under this alternative, natural revegetation of historic sheep trails would continue, but at a slower
rate than in Alternative 1. Sheep use on historic trails likely keeps them from recovering as quickly
as they would if there were no sheep.
The existence or amount of nitrate or fecal coliform from sheep grazing is currently unknown,
though it would continue at a similar amount with the continuation of current grazing
Continued contribution of metals in streams from grazing on mineralized areas may continue.
About 119 acres on the Gladstone allotment and 687 acres on the Red Mountain allotment are in
areas suitable for sheep grazing overlapping with highly mineralized areas (Bove, 2007).
Additionally, 635 acres of the West Lime allotment overlap with mineralized areas and would remain
available for possible future re-stocking, for a total, of approximately 1,441 acres of overlap. In the
past, most of these areas were grazed, though recently not as much use has been made of the
mineralized areas.
Alternative 3
Under this alternative, natural revegetation of historic sheep trails would continue, at a slower rate
than in Alternative 1, but a faster rate than in Alternative 2. . The heavily used area and new trails
between Spencer Basin and Highland Mary Lakes would be improved because of the actions
specified for the Deer Park Allotment.
Any impacts from nitrates or fecal coliform would be similar to Alternative 2, because there is no
need for particular actions to address these constituents.
Under this alternative, impacts of grazing on mineralized soils would be reduced almost to the level
of Alternative 1. The proposed action of “excluding grazing south of Ohio Peak on the Red
Mountain allotment and excluding grazing south of Ohio Gulch west of Cement Creek and south of
Hancock Gulch east of Cement Creek on the Gladstone allotment” significantly reduces the acreage
of mineralized soil available for grazing. This reduces the amount of mineralized soil likely to be
grazed in the Red Mountain allotment from 687 to 93 (an 86% reduction) This also reduces the
amount of mineralized soil likely to be grazed in the Gladstone allotment from 119 to 76 (a 36%
reduction). Since the West Lime Allotment would be closed, this removes an additional 635 acres of
mineralized soil in suitable grazing from areas that have been grazed at some time in the past, for a
total of approximately 169 acres of overlap. The proposed action in this document removes a total
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