History of Rim Drive, Crater Lake National Park
Segment 7-D (Kerr Notch to Sun Notch)
Aside from the belated paving of this road segment in 1960, only one project during the Mission 66 period took place in this road segment. It came in response to rockfall that repeatedly damaged, and in some cases, destroyed masonry guardrail along a section of road along Dutton Cliff in 7-D1. After considering construction of “rock sheds” to alleviate this problem during the first part of Mission 66, the NPS let a contract in 1966 to repair some of the guardrail and retaining wall, in conjunction with establishing some additional cross drainage in this section of road. Work also involved replacing damaged sections of the original guardrail with removable metal posts, a measure dependent upon annual installation by maintenance crews and one destined to last no more than a few years.
On the other side of Dutton Cliff, along 7-D2, continual slides and rock fall resulted in an attempt to cut the slope back similar to Anderson Point in the early 1970s. Repairing and rebuilding masonry guardrail along this so-called “Sun Grade” section followed in 1985. The park employed day labor rather than contractors for the latter job, which included rebuilding portions of guardrail that were located across the road from the slopes composed of glacial material. Cuts made as part of the original grading contract remained subject to erosion and raveling, particularly where the slope face remained wet.