Chimney Reservoir West Lobe North
Humboldt County, NevadaView mapDirections
Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.
- Impaired · Mercury
- Limited data
Chimney Reservoir West Lobe North in Humboldt County, Nevada is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 480 µg/L. Chlorophyll-a (algae): 13 µg/L.
- Phosphorus
- 480 µg/L
- Chlorophyll-a
- 13 µg/L
- Trend
- ↑ Improving
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Watch Chimney Reservoir West Lobe North’s letter
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Why Chimney Reservoir West Lobe North has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Chimney Reservoir West Lobe North, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded phosphorus and algae (chlorophyll-a), but not water clarity.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by NDEP and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Chimney Reservoir West Lobe North is a lake in Humboldt County, Nevada. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, NDEP, last sampled 2014-06-11. Grade methodology: LakeQuality methodology.
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Chimney Reservoir West Lobe North is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), nutrients (phosphorus, nitrogen), temperature, toxic inorganics, turbidity. Check local advisories before you swim.
Water quality measurements for Chimney Reservoir West Lobe North
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Phosphorus 480 µg/L. Chlorophyll-a 13 µg/L. TSI 74.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 480 µg/L | Not graded |
| Chlorophyll-a (Algae) | 13 µg/L | Not graded |
| Trophic State Index (TSI) | 74 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Fishing Chimney Reservoir West Lobe North
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↑ Improving | -20.9 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.89 µg/L/yr | 2 |
EPA Impairment Status
Chimney Reservoir West Lobe North is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NV04-LH-95-B_00 · Official waterbody report · Matched by proximity (0.97 km)
Graded lakes near Chimney Reservoir West Lobe North
Chimney Reservoir West Lobe North has no grade, but these lakes within a short drive do.
Nearby Lakes in Humboldt County
Frequently asked questions about Chimney Reservoir West Lobe North
Where is Chimney Reservoir West Lobe North?
- Chimney Reservoir West Lobe North is a lake in Humboldt County, Nevada. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Chimney Reservoir West Lobe North?
- Chimney Reservoir West Lobe North in Humboldt County, Nevada is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 480 µg/L. Chlorophyll-a (algae): 13 µg/L.
Is Chimney Reservoir West Lobe North safe to swim in?
- The letter is not a swimming clearance. Chimney Reservoir West Lobe North is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), nutrients (phosphorus, nitrogen), temperature, toxic inorganics, turbidity. Check local advisories before you swim.
Explore Chimney Reservoir West Lobe North across LakeQuality
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Where this data comes from
11 measurements from 2 monitoring stations, 2012–2014. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Nevada Division of Environmental Protection
21NEV1_WQX11 samples · 2012–2014
Analytical methods
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database