Tipton Creek IA 02-IOW-755

Assessment Comments

Stream use assessments and recent fishkills.

Basis for Assessment

[Waterbody subsegment created in 1998 due to diffences in channel forms in Tipton Creek upstream from Hwy 65 (extensively channelized) versus downstream from Hwy 65 (primary meandered).  Repeated occurrence of fish kills upstream from Hwy 65 also a factor in the decision to create subsegments.]  

Used results of the May 1992 DNR stream use assessment as well as records of recent fish kills to develop the assessment of support of the Class B(LR) aquatic life uses.   The May 1992 stream use assessments suggest that this reach of Tipton Creek is extensively channelized with relatively diverse substrates with side pools and undercut banks providing the best aquatic habitats.   Nine species of fish from three families were captured, with a majority of the species typical of Class B(LR) streams occurring.   Although results of this assessment suggests that the Class B(LR) aquatic life uses are supported, the occurrence of recent fish kills suggests an impairment.   Fish kills occurred in this reach of Tipton Creek in August 1996 (46,000 fish estimated killed) and July 1998 (93,000 fish estimated killed over a 12-mile reach).   Both fish kills were caused by discharge of animal waste from animal feeding operations located near Williams, IA (the problems with repeated fish kills in Tipton Creek were highlighted in the August 1, 1998 Des Moines Register).   Thus, due to reoccurring fish kills, the Class B(LR) aquatic life uses of this reach of Tipton Creek were assessed as "partially supported" due to toxic levels of ammonia from animal feeding operations.   Follow-up monitoring is needed to determine the degree to which the Class B(LR) uses may be impaired by the residual effects of the accidental/illegal discharge of animal waste to this stream.