Hwy 62 – 79 ALTERNATIVE B: RESURFACING, RESTORATION, AND REHABILITATION Soils and Geology

Rehabilitation of Highway 62 West, Crater Lake National Park, Klamath County, Oregon

 ENVIRONMENTAL CONSEQUENCES

ALTERNATIVE B: RESURFACING, RESTORATION, AND REHABILITATION

This section evaluates the potential impacts of alternative B.

Soils and Geology

Roadway

The existing roadway covers approximately 26 acres (11 hectares). The total amount of previously undisturbed soil permanently affected by alternative B would be 0 acres (0 hectares) (FHWA, 30% design, 2002). About 0.2 acre (0.08 hectare) of previously disturbed ground (removed turnouts) would be restored and revegetated. Surface scarring, rehabilitation, and revegetation efforts would reduce loss of soil through erosion. Natural soil processes would be restored in rehabilitated areas only over the very long term, as soil structure slowly returned to a more natural condition. This would constitute a long-term, negligible, beneficial effect on soils.

No blasting activities should be required. Some moving, covering, trampling, and compaction of soils by equipment and workers within the construction zone is expected, but soils in much of the construction zone have been previously disturbed by road-related activities (e.g., construction and maintenance). Local soil compaction would temporarily decrease permeability, alter soil moisture content, and diminish the water storage capacity. This would constitute a negligible, long-term, adverse effect to soils.

Alternative B would not change geological conditions of the road.

Cumulative Impacts. Past, present, and reasonably foreseeable future actions that affect soils and geology within the park include the waterline replacement from Munson Springs to Garfield and the lagoon project at Munson Valley. The adverse effects of these projects would result in long-term, negligible, localized, adverse impacts. Alternative B would contribute a long-term and negligible beneficial cumulative effect on reclaimed sites, but a long-term, adverse, and negligible impact on roadside soils due to compaction.

Conclusion. There would no change to geology on the road corridor. Construction activities associated with alternative B would have a long-term, negligible, adverse effect on soils, but erosion controls, restoration, and revegetation would have a long-term, negligible beneficial effect on soils. Alternative B would contribute a long-term and negligible, beneficial, cumulative effect on reclaimed sites, but a long-term, adverse, and negligible impact on roadside soils due to compaction.

Because there would be no major adverse impacts to a resource or value whose conservation is (1) necessary to fulfill specific purposes identified in the park’s establishing legislation, (2) key to the natural or cultural integrity of the park or to opportunities for enjoyment of the park, or (3) identified as a goal in the park’s General Management Plan or other relevant National Park Service planning documents, there would be no impairment of park resources or values related to soils and geology at Crater Lake National Park.

 

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