Assessment Comments
Assessment based on results of (1) IDNR/UHL biological (biocriteria) monitoring in 1999 (Fish IBI= 29(fair), BM-IBI= 78(excellent)) and in 2001 (Fish IBI=19(poor),18(poor), BM-IBI= 44(fair), 57(good)) and (2) ambient water quality monitoring conducted in 2001 in support of TMDL development.
Basis for Assessment
SUMMARY: The Class B(LR) aquatic life uses were assessed (monitored) as "partially supported" based on results of biological monitoring conducted in 1999 and 2001 as part of the IDNR/UHL stream biocriteria project. Sources of data for this assessment also include the results of ambient monthly water quality monitoring conducted by IDNR/UHL at two locations on Camp Creek from March to November 2001 as part of monitoring in support of TMDL development: (1) approximately 3 miles SE of Runnells (lower site--STORET station 11770001) and (2) 1.5 miles downstream from Mitchell Park (upper site--STORET station 11770002). This assessment is the same as that developed for the 2002 report.
EXPLANATION: The previous assessment of support for the general beneficial uses of this stream ("partially supported") was based on the results of IDNR biological monitoring in November 1990 that suggested lower than expected diversity of aquatic life in this stream segment (see assessment developed for the 1998 report). Results of follow-up biological and chemical monitoring conducted during the 2000-2001 biennial period suggest that, despite relatively good chemical water quality, the status of the biological community continues to suggest an impairment of the Class B(LR) aquatic life uses. Results TMDL-related (chemical) monitoring in 2001 suggest that Camp Creek has relatively good water quality. None of the nine samples collected between March and November 2001 violated the Class B(LR) chronic water quality criterion for dissolved oxygen, pH, or ammonia nitrogen. The samples collected on March 7, 2001 at both sites, however, relatively high levels of ammonia-nitrogen: the sample from the upper site contained 1.2 mg/l, and the sample from the lower site contained 1.8 mg/l of ammonia-nitrogen. Although these levels do not exceed the Class B(LR) chronic criteria for ammonia-nitrogen, these levels are nonetheless relatively high, and the level from the lower site does exceed the Class B(WW) chronic criterion for ammonia-nitrogen.
Results of biological monitoring conducted in 1999 and 2001 as part of Section 305(b) follow-up activities continue to suggest "partial support" of the Class B(LR) uses. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biocriteria sampling data. The biological metrics are based on the numbers and types of benthic macroinvertebrate taxa and fish species that were collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (F-IBI) and a benthic macroinvertebrate index (BM-IBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 1999 and 2001 Fish IBI score were 29 (fair), 19 (poor), and 18 (poor) and the BM-IBI scores were 78 (excellent), 44 (fair), 57 (good). The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2002 Section 305(b) report. The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.
