Thorpe Park Wetland IA 02-IOW-3126
5 miles west of Forest City (T98N R25W S35 Winnebago County)
- Cycle
- 2022
- Release Status
- Final
- Overall IR
- 3 - Insufficient data exist to determine whether any designated uses are met.
- Trend
- Unknown
- Created
- 12/22/2021 9:53:58 AM
- Updated
- 2/1/2022 6:39:03 AM
The Class BLW use was assessed (evaluated) as "WINOFI" due to dissolved oxygen standard violations and due to high levels of total suspended solids that lead to an impairment of the narrative criteria protecting against undesirable or nuisance aquatic life. High levels of chlorophyll a (algae) at this wetland also suggest potential impairment "WINOFI" due to aesthetically objectionable conditions that lead to adverse impacts on plant/animal communities.
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2016-2019 23950019 Wetland
201
Class BLW - TSI's Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Median Value Median TSI Violation? Assessment Type Support Level 23950019 6 Chlorophyll a TSI 6 / 2 67 93 83 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 will be used to determine whether or not the Class
BLW use is impaired in these shallow systems. Class BLW - Conventional Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Mean Value # Violations # Acute / Chronic Violations Violations needed for impairment Violates Significantly >10% Rule? Assessment Type Support Level 23950019 6 Ammonia 5 / 2 0.0003 0.06 0.03 NA 0 / 0 2 NO Evaluated Full 23950019 6 Dissolved Oxygen 5 / 2 1.26 12.36 6.64 2 NA / NA 2 YES Evaluated WINOFI 23950019 6 pH 5 / 2 7.33 8.36 7.77 0 NA / NA 2 NO Evaluated Full 23950019 6 Temperature 5 / 2 15.4 27.6 22.2 0 NA / NA 2 NO Evaluated Full 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 23950019 6 Total suspended solids 6 / 2 25.5 318.5 121 Yes Evaluated WINOFI 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 (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 In general, Iowa wetlands are not managed for recreational fisheries; thus, fish contaminant monitoring is not typically conducted at these waterbodies.