Mariposa Lake IA 03-NSK-867
Jasper County S32T81NR18W 6 mi. NE of Newton.
Assessment Comments
Assessment is based on results of water quality monitoring and surveys by IDNR Fisheries Bureau.
Basis for Assessment
Fishable uses were assessed as PS for the following reasons: (1) BPJ of DNR Fisheries; (2) results of monitoring in 1990 show that averages levels of secchi depth, chl-a, total-P, and TSS are worse than overall averages of the 116 SPOLs sampled in 1990 and 1992; averages of total-P and TSS both approach the overall average +/- 1 SD; (3) Bachmann et al. (1994) report a relatively high sedimentation rate (4.2 cm/yr) and a relatively short life expectancy (53 years); they also report no swimming activity for the lake. Thus, lake appears to be impaired by sediment and nutrients eroded from agricultural land. Due to lack of use for swimming, swimmable uses not assessed.
Assessment Key Dates
Methods
| 340 | Primary producer surveys (phytoplankton/periphyton/macrophyton) |
| 120 | Surveys of fish and game biologists/other professionals |
| 222 | Non-fixed-station monitoring (conventional during key seasons and flows) |
Monitoring Levels
| Biological | 0 |
| Habitat | 0 |
| Physical Chemistry | 2 |
| Toxic | 0 |
| Pathogen Indicators | 0 |
| Other Health Indicators | 0 |
| Other Aquatic Life Indicators | 0 |
| # of Bio Sites | 0 |
| BioIntegrity | N/A |
| Causes | Use Support | Cause Magnitude | Sources | Source Magnitude |
|---|---|---|---|---|
| Algal Grwth/Chlorophyll a | Overall Use Support | Moderate |
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| Algal Grwth/Chlorophyll a | Aquatic Life Support | Moderate |
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| Algal Grwth/Chlorophyll a | Primary Contact Recreation | Moderate |
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| Siltation | Overall Use Support | Moderate |
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| Siltation | Aquatic Life Support | Moderate |
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| Nutrients | Overall Use Support | Slight |
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| Nutrients | Aquatic Life Support | Slight |
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| Nutrients | Primary Contact Recreation | Slight |
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