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The Class A1 (primary contact recreation) uses of this lake remain “not assessed” due to the lack of water quality data or other information upon which to base an assessment.   This lake is not part of the IDNR/ISU statewide survey of Iowa lakes, nor has this lake been monitored as part of the IDNR/UHL 2005-2008 ambient lake monitoring program.  

The Class B(LW) uses of Binder Lake are assessed (monitored) as “fully supported” due improvements in the lake’s water quality and fish populations.   The impairment history of this lake is as follows.  

--U.S.  EPA added this lake to Iowa’s 1998 Section 303(d) list due to siltation impacts.   A TMDL for siltation at Binder Lake was prepared by IDNR and approved by EPA in 2001; thus, this lake was placed into IR Category 4a (TMDL approved) for the 2004 assessment/listing cycle.   To better define the impairments at Binder Lake, the IDNR Fisheries Bureau sampled the fish population of Binder Lake on September 8, 10, and 17, 2003.   Night electro-fishing was used on September 8 with daytime electrofishing and fyke nets on the 10th and 17th, respectively.   Based on the analysis of the fish populations at this lake performed by IDNR Fisheries Biologists (i.e., length/frequency analysis, growth rates (relative weight analysis, and population estimates), the fish population of Binder Lake appeared to be below expectations, thus suggesting an impairment of the Class B(LW) aquatic life use.   Based on their 2003 sampling and analysis, IDNR biologists suggested that both common carp and yellow bass were adversely impacting the sport fish populations of Binder Lake.  

--The common carp population was adversely affecting the lake’s water clarity through feeding activities that destroyed rooted plants and that increased the amount of suspended sediment in the water column.   The lack of rooted plants allowed excess nitrogen and phosphorus to be available thus causing extensive algae blooms that further reduced water clarity.   An additional factor affecting the fisheries this lake was the presence of yellow bass.   Based on the results of the 2003 sampling, the yellow bass population of Binder Lake was quite dense.   At high densities, yellow bass fail to grow to a harvestable size (stunting).   In addition, yellow bass are known to feed on eggs and the larval stage of nest-building sport fish species such as bluegill and largemouth bass, thus suppressing reproduction of those species.   In the presence of high densities of yellow bass, successive year classes of desirable sport fish species cannot reproduce at levels required to maintain their populations.   Over the long-term, the impacts of yellow bass typically include a dramatic reduction or elimination of sport fish species and a decline of the lake’s sport fishery.  

--Thus, the 2003 IDNR Fisheries investigation identified the primary cause of impairments of impairments of the Class B(LW) uses of Binder Lake as impacts of invasive/exotic species (common carp) and introduced species (yellow bass) on the fish populations and water quality of this lake.   According to IDNR's assessment/listing methodology, exotic species such as common carp or nuisance aquatic species such as yellow bass are considered "non-pollutant stressors".   Based on this information, this waterbody was moved from IR Category 4a (impaired; TMDL approved) to Category 4c (impaired by non-pollutant stressor; TMDL not required) for the 2006 assessment/listing cycle.   Binder Lake remained in IR Category 4c for the 2008 and 2010 assessment/listing cycles.  

Binder Lake’s fishery was renovated in late 2004:  the entire fish population was removed with a fish toxicant (rotenone).   According to the IDNR Fisheries Bureau, the years since the renovation have brought vastly improved water clarity, and the rooted plant community has expanded dramatically.   Prior to the renovation the lake had small areas of lotus and curly leaf pondweed present.   Since the renovation both plant species have expanded at least 10-fold in coverage area.   The curly leaf coverage could be as much as 30% of the lake’s surface during its peak.   Very little free floating algae is present.   Fish growth is normal or faster than most other southern Iowa lakes.   Water clarity no longer suppresses the sport-fish population of Binder Lake.   The IDNR Fisheries Bureau anticipates that, as long as common carp can be prevented from re-entering the lake, the sport fish populations and water quality conditions will remain good.  

Based on this information and the improvements in water quality conditions and sport fish populations, the assessment of the Class B(LW) aquatic life uses of Binder Lake is changed from “partially supporting/impaired” (Integrated Report Category 4c) to “fully supporting [not impaired]” (IR Category 2a).  

The Class C (drinking water) uses remain “not assessed” due to the lack of recent monitoring data upon which to base an assessment.   In previous 305(b) assessment cycles, the Class C uses were assessed  as "fully supported/threatened” (not impaired) based on results of sampling conducted by UHL in January 1995.   These data, however, are greater than 10 years old and are thus considered too old to accurately characterize current water quality conditions.

Fish consumption uses remain “not assessed” due to the lack of fish contaminant monitoring at this lake.