Assessment Comments
Assessment is based on: (1) results of chemical/physical monitoring from April to September 2005 at two DNR/UHL TMDL monitoring stations: station 30 NE of New Vienna (STORET station 11310003) and station 28 north of Dyersville (STORET station 11310004), (2) results of USGS monitoring at Dyersville on November 22, 2004, (3) IDNR/UHL biological monitoring in 2005, and (4) the occurrence of two fish kills in 2004, one fish kill in 2006, and one fish kill in 2007.
Basis for Assessment
[Note: Prior to the current (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 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), 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 (2008) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]
SUMMARY: The Class A1 primary contact recreation uses are not assessed. The Class B(WW2) aquatic life uses remain assessed (monitored) as “not supporting” due to (1) results of DNR/UHL biological monitoring in 2005 that show regionally poor biological integrity and (2) occurrence of two fish kills in July 2004 and one fish kill in July 2006. A TMDL for this impairment was approved by U.S. EPA in April 2007 (see http://www.iowadnr.gov/water/watershed/tmdl/files/final/northforkmaq.pdf). Fish consumption uses are not assessed due to lack of fish contaminant monitoring in this assessment segment. Sources of data used for this assessment include (1) results of chemical/physical monitoring from April to September 2005 at two DNR/UHL TMDL monitoring stations: station 30 NE of New Vienna (STORET station 11310003) and station 28 north of Dyersville (STORET station 11310004), (2) results of USGS monitoring at Dyersville on November 22, 2004, (3) IDNR/UHL biological monitoring in 2005, and occurrence of two fish kills in 2004 and one fish kill in 2006.
EXPLANATION: The Class A1 (primary contact recreation) uses were “not assessed” due to the lack of sufficient data upon which to base an assessment. Only two samples were collected and analyzed for indicator bacteria in this assessment segment during the 2004-2006 period: both samples were collected on July 7, 2005 at IDNR/UHL TMDL monitoring stations NE of New Vienna (STORET station 11310003) (2,300 orgs/100 ml) and north of Dyersville (STORET station 11310004) (2,100 orgs/100ml). This small amount of data neither meets IDNR guidelines for developing Section 305(b) water quality assessments nor allows calculation of summary statistics (i.e., geometric mean) needed to develop such an assessment.
The Class B(WW2) aquatic life used are assessed as “not supported” due to results of 2005 biological monitoring showing poor biotic integrity and due to occurrence of fish kills in 2004 and 2006. Results of chemical/physical monitoring conducted at the IDNR/UHL TMDL stations, however, suggest relatively good water quality in this assessment segment. None of the combined 26 samples collected at these stations in 2005 exceeded Class B(WW2) criteria for pH or dissolved oxygen. None of the combined 22 samples contained violations of the Class B(WW2) chronic criteria for ammonia nitrogen. Only one sample was collected at the USGS monitoring station at Dyersville; all analytes met Class B(WW2) criteria (i.e., pH, dissolved oxygen, ammonia, DDE, and dieldrin).
The Class B(WW2) aquatic life uses remain assessed (monitored) as “not supported” based, in part, on data collected in 2005 as part of the DNR/UHL stream biocriteria and TMDL development projects. 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 (FIBI) and a benthic macroinvertebrate index (BMIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2005 FIBI scores were 37, 36(fair), and the BMIBI scores were 25 (poor), 47 (fair). The FIBI average was 36.5 and the BMIBI average was 36. The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The non-riffle site FIBI BIC for this ecoregion is 44 and the natural substrate BMIBI BIC for this ecoregion is 70.
In addition to results of IDNR/UHL biological monitoring that suggest impairment of the Class B(WW2) uses, one fish kill in January 2007, one fish kill in July 2006, and two fish kills occurred in July 2004 that also suggest impairment of these uses. The most recent kill occurred on January 29, 2007 and was attributed to a spill of liquid nitrogen fertilizer. The fertilizer was discharged to a storm drain that emptied into the North Fork of the Maquoketa River. The kill began on the north edge of Dyersville and continued at least 9.5 miles downstream, where there was no access to the stream for the investigation and 100% ice cover prevented the observation of dead fish. However, ammonia levels were over 3.0 ppm at the bridge above Cascade (29.3 miles downstream of the spill location). Approximately 56,542 fish were killed. The estimated value of these fish was $13507.92. At the time of this assessment there are no records that IDNR has sought/received restitution for this fish kill.
The kill in 2006 occurred on or before July 25, 2006 and was attributed overflow from a manure pit and runoff from an open feedlot caused by heavy rain on July 25. Approximately 54,208 fish were killed along a 5.7 mile stretch of the stream. The value of the fish was estimated to be $10738.46. At the time of this assessment there are no records that IDNR has sought/received restitution for this fish kill.
The first kill in 2004 occurred on or before July 6, 2004; no cause of the kill was identified (cause “unknown”). An estimated 200 non-game fish (“minnows” and “suckers”) were killed over approximately 1.5 miles of stream. No estimate of the value of the fish killed was provided. The kill occurred in New Wine Park and upstream in Section 6 of T89N, R2W, Dubuque County. According to the IDNR investigation, the fish had been dead for a few days when they were discovered. The party responsible for the kill was not identified. This segment of the North Fork Maquoketa River has been affected by a number of fish kills over the 1995-2005 period.
A second kill in 2004 that affected this assessment segment occurred on or before July 15, 2004. The kill was caused by a release of manure from an open feedlot dairy operation to an unnamed tributary to the North Fork Maquoketa River. An estimated 200 fish (“minnows”) were killed. Approximately 1 mile of stream was affected. This kill primarily affected the unnamed tributary (location information was not provided for this tributary). The IDNR investigation, however, suggested that the kill could affect the North Fork Maquoketa River [segment IA 01-NMQ-0020-2] as well. According to the IDNR investigation, a plywood stop in a manure control structure failed, releasing an estimated several thousand gallons of manure into the unnamed tributary. The owner of the farm worked quickly to address the spill, constructing an earthen dam, keeping most of the manure contained in the stream and out of the North Fork of the Maquoketa River. The collected manure was applied to cornfields. The manure caused a complete fish kill in the tributary, killing a few hundred creek chubs, stonerollers and minnows. The party responsible for the kill was not identified; IDNR records indicate no attempt to seek restitution for the value of the fish killed.
According to IDNR’s assessment and listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period (2004-2007) indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired.” If a cause of the kill is identified, and the cause is either known, or suspected, to be a “pollutant”, the assessment type is considered “monitored” and the affected waterbody is a candidate for Section 303(d) listing. Fish kills attributed to a pollutant, but where a source of the pollutant was not identified and/or where enforcement actions were not taken against the responsible party, will be placed into Integrated Report subcategory 5b. The intent of placing these waterbodies into Category 5 is not to necessarily require a TMDL but to keep the impairment highlighted due to the potential for similar future kills from the unaddressed causes and/or sources. Since a TMDL was completed for the biological impairment in this stream segment, this assessment will be placed in Category 4a for the 2008 assessment/listing cycle.
Fish consumption uses are not assessed due to lack of fish contaminant monitoring in this assessment segment.
