Thermal – 04 III. Conclusions A. Congressional Criteria for Determining Significance

Report of the Sec. of the Interior under Sec. 7 of Public Law 100-443 on the Presence or Absence of Significant Thermal Features Within Crater Lake National Park, 1992

III. Conclusions Regarding Significance of the Hydrothermal Features of Crater Lake


A. Congressional Criteria for Determining Significance

As explained in the Introduction, Sections 2 and 6 of the Act includes Crater Lake National Park on the list of units of the National Park System containing significant thermal features. To some degree, the listing of Crater Lake National Park by the Congress supercedes this discussion of whether the hydrothermal features in Crater Lake “qualify” for significance under the criteria established by Congress under Section 6 of the Act. However, this chapter of the report addresses the significance of the hydrothermal features located in Crater Lake and will evaluate whether the hydrothermal features in Crater Lake would qualify for listing as if they were under consideration for the first time.

The Act requires the Secretary of the Interior to consider the following criteria in determining the significance of thermal features:

(1) Size, extent and uniqueness;

(2) Scientific and geologic significance;

(3) The extent to which such features remain in a natural, undisturbed condition;

(4) Significance of thermal features to the authorized purposes for which the National Park System unit was established.

The Department of the Interior provided an explanation of how these criteria would be applied to thermal features undergoing a determination of significance when it published the final list of significant thermal features in the Federal Register on August 3, 1987 (52 FR 28790). This discussion was revised to accommodate public comments received on the proposed notice published in the Federal Register in February 1987 (52 FR 4700). The Department’s final explanation of how it would apply the Congressional criteria is excerpted below:

“(1) Size, extent and uniqueness – Neither lower nor upper limits on the size or extent of a feature were established. Each feature is still identified according to its existing surface dimensions. In the proposed notice, a feature could be considered significant under this criterion as long as it was identified as unique to the park unit, as well as to Region, the Nation, or-in some cases, the World. Public comments received on the application of this criterion stated that it was applied too broadly. As a result of reevaluating the application of this criterion, the Department decided that unless a feature was identified as unique to at least the Region, it should not automatically qualify as a significant thermal feature.

“(2) Scientific and geologic significance – Under the proposed notice, a feature qualified as ‘significant’ if the feature contributed important information to scientific or geologic knowledge, to the understanding of thermal regimes, or to the history or origin of the feature within the park unit, the Region, or the Nation. Also, the proposal considered biological factors as important to the scientific significance of a feature. The Department decided to define ‘scientific significance’ so as to exclude consideration of biological factors because they are considered and protected under the provisions of other laws, such as the National Environmental Policy Act and the Endangered Species Act. Also, the Department decided to narrow the qualifiers of this criterion so that only those features that satisfy the following conditions would meet this criterion: a feature must contribute to geologic knowledge compared with similar features in other areas or must make a unique contribution to the understanding of similar systems.