Arrowrock Reservoir is a productive, nutrient-rich eutrophic lake in Elmore County, Idaho. Water quality is graded C based on 3 sampling years through 2015. Compared to the 7 other monitored lakes in Elmore County, Arrowrock Reservoir ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Idaho DNR, last sampled 2015-02-11. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 9.5 ft. Phosphorus level: 55.5 µg/L. Chlorophyll-a: 6.8 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | C |
| Phosphorus | 55.5 µg/L | C |
| Chlorophyll-a (Algae) | 6.8 µg/L | B |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Arrowrock Reservoir
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Fishing Arrowrock Reservoir
Location
County Ranking
Ranked #7 of 8 lakes in Elmore County
Cleaner Lakes Within 30 Miles
Arrowrock Reservoir holds Grade C. 2 nearby lakes hold higher grades.
- ACat Creek LakeElmore County · 27.6 mi · Two grade letters higher (C → A)
- BArrowrock ReservoirElmore County · 2.5 mi · Higher grade (C → B)
Nearby Lakes in Elmore County
Explore Arrowrock Reservoir across LakeGrade
More Idaho Lake Rankings
Other Grade C Lakes in Idaho
Eutrophic Lakes in Idaho
More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2015-02-11
Monitoring stations: 1