Cylinder Creek IA 04-UDM-1297

Assessment Comments

Assessment remains based on 2000 Fisheries data: FIBI = 37 (fair). Non-riffle FIBI BIC = 32.

Basis for Assessment

[Note:  Prior to the 2008 Section 305(b) cycle, this stream segment was designated only for Class B(LR) aquatic life uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008, this segment is now presumptively designated for Class A1 (primary contact recreation) uses.   The stream remains designated for aquatic life uses (now termed Class B(WW2) aquatic life uses).   Thus, for the current (2012) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]

SUMMARY/EXPLANATION:  The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment.   The assessment of the Class B(WW2) aquatic life uses is changed from “fully supporting/evaluated” to “not assessed” due to the lack of recent monitoring data upon which to base an assessment.  

EXPLANATION:  The previous (2010) assessment of the Class B(WW2) aquatic life uses was based on biological data collected in 2000 as part of an IDNR Fisheries stream sampling project: Manchester research station.   The results of this monitoring suggested that the Class B(WW) uses were “fully supported.”  Because the data upon which these assessment were based are now more than ten years old, the Class B(WW2) uses are now considered “not assessed.”  As water quality data age, they are less able to represent current water quality conditions.   As data age beyond ten years, their ability to represent current water quality conditions is increasing suspect.   Additional monitoring is needed in this assessment segment to update status of its aquatic communities.