Unnamed Tributary to Pierson Creek IA 06-LSR-1912
from mouth in S20 T89N R42W Woodbury Co. to headwaters in SE1/4 S24 T90N R43W Plymouth Co.
- Cycle
- 2018
- Release Status
- Final
- Overall IR
- 3 - Insufficient data exist to determine whether any designated uses are met.
- Trend
- Unknown
- Created
- 7/29/2019 9:33:46 AM
- Updated
- 7/29/2019 9:35:04 AM
The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to a lack of water quality information upon which to base an assessment. The presumptive Class B(WW1) aquatic life uses of this stream remain assessed as “partially supported” due to a fish kill in November 2004.
This kill occurred on or before November 13, 2004 in Section 2 of T89N, R43W, Plymouth County. The cause of the kill was attributed to fertilizer. An ammonia nurse tank reportedly came unhooked when a truck crossed a bridge on 340th St. in Plymouth County around 10 PM Saturday, November 13, releasing approximately 25 pounds of ammonia into the creek. The DNR investigation showed that ammonia levels in the creek were near 50 parts per million (ppm). Ammonia levels of about 8 to 10 ppm can cause a fish kill, depending on stream temperature and pH. The kill affected approximately 3 miles of this tributary. An estimated 7,323 fish were killed with an estimated value of $782. The responsible party was identified and restitution was sought.
According to DNR's assessment methodology for Section 305(b) reporting, occurrence of a single pollution-caused fish kill during an assessment period indicates "partial support" of the aquatic life uses. If, however, a consent order has been issued to the party responsible for the kill and if monetary restitution has been sought for the fish killed, the affected waterbody should be placed in IR Category 4d (impaired but TMDL not required). Thus, this assessment segment was placed into Category 4d of Iowa's 2006 Integrated Report. If no additional fish kills have occurred over at least a five-year period, the assessment of impairment should be considered “evaluated” (i.e., of lower confidence), and the waterbody segment should be moved from IR Category 4d to IR Category 3b (list of waters in need of further investigation). Thus, because this kill occurred more than five years ago and because no subsequent kills have been reported, this impairment was moved to Category 3b of the Integrated Report and was added to Iowa’s list of waters in need of further investigation. This impairment remains in IR Category 3b.