East Hottes Lake IA 06-LSR-6602
Along west shore of Big Spirit Lake in NW1/4 Sec. 17 T100N R36W Dickinson Co.
- Cycle
- 2018
- Release Status
- Final
- Overall IR
- 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
- Trend
- Unknown
- Created
- 6/13/2019 1:06:39 PM
- Updated
- 6/13/2019 1:06:55 PM
The Class B(LW) aquatic life uses remain assessed (evaluated) as "fully supported." The fish consumption uses remain "not assessed" due to the lack of water quality information upon which to base an assessment. Sources of data for this assessment include results of water quality, aquatic vegetation, and fish monitoring conducted by the IDNR shallow lakes and wetlands monitoring program in 2010 and information from the IDNR Wildlife Bureau. This is the same assessment used in the previous assessment cycle. No new sampling occurred during the 2012 - 2014 assessment period.
Results of water quality monitoring conducted at EastHottes Lake indicate that the aquatic life uses should be assessed (evaluated) as "fully supported." This remains an "evaluated" assessment because of the number of samples collected during the current assessment.According to DNR methodology, 9 samples from the most recent assessment period are required to constitute a "monitored" assessment.
Guidelines for wetland assessment from the Upper Mississippi River Conservation Committee’s Water Quality Technical Section (2003) state that an average total suspended solids concentration during the growing season of less than 30 mg/L is necessary to provide sufficient water clarity to support the growth of submersed aquatic vegetation in wetlands and shallow lakes. High levels of total suspended solids impede the growth of submersed aquatic vegetation (SAV). Submersed aquatic vegetation is critical to the health of wetland and shallow lake ecosystems. The elimination of SAV can degrade habitat quality such that undesirable aquatic species such as cyanobacteria, common carp and fathead minnows dominate. As such, the suppression of SAV constitutes a violation of Iowa’s narrative water quality criteria protecting against undesirable or nuisance aquatic life.
Using the overall median values from the DNR shallow lakes and wetlands monitoring program from 2010 (approximately 2 samples), the median growing season total suspended solids concentration was 3 mg/L; this median value is well below the UMRCC guideline and therefore does not suggest impairment of the aquatic life uses.
The level of algae suggests full support of the aquatic life uses at Hottes Lake. The Carlson’s (1977) trophic state index value for chlorophyll a was 50.According to Carlson (1977), the index value for chlorophyll a places West Hottes Lake in the eutorphic category and suggests moderately high levels of chlorophyll a and suspended algae in the water.
NOTE:The TSI value for Secchi depth is not used to evaluate the attainment of aquatic life goals in shallow lakes. Due to the depth of these shallow lakes, TSI values for Secchi depth can be misleading. In some instances the Secchi disk remains visible at the bottom of the lake and the depth of the lake is recorded as the Secchi depth. In these instance, water clarity may be sufficient to support the Class B(LW) uses, but the index value is limited by the depth of the lake. Thus the combination of total suspended solids and chlorophyll a will be used to determine whether or not the Class B(LW) uses are impaired in these shallow systems.