Crane Creek IA 01-TRK-211

Assessment Comments

Assessment is based on results of (1) 1995 IDNR stream use assessment and (2) a 1994 IDNR/UHL biocriteria sampling (Fish IBI= 57(good), BM-IBI= 64(good)).

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses are assessed (evaluated) as "fully supported/ threatened" due to results of (1) IDNR/UHL biological monitoring in 1994 and (2) to 1995 IDNR stream use assessment.   Previous assessments were based on occurrence of  a fish kill in September 1997.   A review of this assessment shows that (1) the kill occurred more than three years ago, thus suggesting that any kill-related water quality impacts have dissiated and (2) the kill occurred in a tributary of Crane Creek and did not directly affect Crane Creek.   Thus, this assessment is based on results of biological monitoring in 1994 and 1995.    Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream segment.

EXPLANATION:  The previous (2000 and 2002) assessment of the aquatic life uses was based on the occurrence of a fish kill in 1997.   Bot the age of the kill (more than three years ago) and the fact that the kill did not affect Crane Creek suggest that the assessment is more appropriately based on results of IDNR biological monitoring in 1994 and 1995.   This monitoring suggests that the aquatic life uses are "fully supported / threatened."  As stated in the assessment developed for the 1998 reporting cycle:  

"A review of the field sheet from the September 1995 DNR stream use assessment, and the results of the September 1994 DNR biocriteria sampling near the same locations, suggests that the Class B(WW) aquatic life uses are fully supported due to (1) presence of a very diverse fish community (species/families:  1994, 26/6; 1995, 24/5) for streams in the Iowan Surface subecoregion (47c), including several environmentally sensitive species (American brook lamprey, rosyface shiner, northern hogsucker, black redhorse, rock bass, smallmouth bass, and banded darter), (2) presence of all, or nearly all the expected fish taxa (1994:  11 of 11; 1995, 10 of 11) for streams in this subregion, (3) presence of the expected game fish species (smallmouth bass), and (4) indications of above average habitat quality.   An updated interpretation of the results of the IDNR/UHL biocriteria sampling of fish and benthic macroinvertebrates in 1994 continues to suggest that the aquatic life uses are "fully supported / threatened."  That is, based on a comparison to results of ecoregion reference site sampling, the fish community was rated "good" (Fish IBI=57) and the benthic macroinvertebrate community was also rated "good" (MB IBI=64).   These results suggest that the Class B(WW) uses are 'fully supported / threatened.'"

Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream segment.