Rush Lake IA 06-LSR-1773
Osceola County S36T100NR40W 1 mi NE of Ocheyedan.
- Cycle
- 2024
- Release Status
- Final
- Overall IR
- 3 - Insufficient data exist to determine whether any designated uses are met.
- Trophic
- Hypereutrophic
- Trend
- Unknown
- Created
- 11/14/2023 3:30:06 PM
- Updated
- 1/4/2024 10:54:58 AM
The Class BLW use was assessed (evaluated) as "WINOFI" due to high levels of total suspended solids that leads to an impairment of the narrative criteria protecting against undesirable or nuisance aquatic life. High levels of algae at this shallow lake also suggest (evaluated) impairment "WINOFI" due to aesthetically objectionable conditions. All other designated uses were “not assessed.”
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2021-2021 14000360 Rush
Lake
Class BLW – Shallow Lake TSI: Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Median Value Median TSI Violation? Assessment Type Support Level 14000360 6 Chlorophyll a TSI 5 / 1 73 80 76 YES Evaluated WINOFI The TSI value for Secchi depth is not used to evaluate the
attainment of the aquatic life use 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 instances, water
clarity may be sufficient to support the Class BLW use, but the index value is
limited by the depth of the lake. Thus, the combination of total suspended
solids and chlorophyll a was used to determine whether or not the Class BLW use
was impaired in these shallow systems. Class BLW - Protection of Submerged Aquatic Vegetation: Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Median Value Median Value >= SAV Assessment Type Support Level 14000360 6 Total suspended solids 5 / 1 29 140 65 YES Evaluated WINOFI Guidelines for wetland assessment from the Upper Mississippi
River Conservation Committee’s Water Quality Technical Section (2003) state
that a median 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 (SAV) in wetlands and shallow lakes.
High levels of total suspended solids impede the growth of SAV. SAV 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.
Class HH - No Data