Knott Creek Reservoir
Humboldt County, Nevada10 acresView mapDirections
NDEP publishes the water-quality measurements for Knott Creek Reservoir. Here is what has been measured.
- Hypereutrophic
- Impaired · Metals (other than mercury)
- 24 ft max depth
Knott Creek Reservoir in Humboldt County, Nevada has water-quality measurements published by NDEP, shown here as reported. Phosphorus: 145 µg/L. Chlorophyll-a (algae): 59 µg/L. Surface area: 10 acres.
Knott Creek Reservoir is a 10-acre highly nutrient-loaded hypereutrophic lake in Humboldt County, Nevada with an estimated average depth of about 24 feet. Phosphorus level is declining over recent sampling years. Compared to the 3 other monitored lakes in Humboldt County, Knott Creek Reservoir ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, NDEP, last sampled 2021-10-05. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Knott Creek Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
Whether Knott Creek Reservoir is safe to swim in today is a call for the Nevada Division of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Knott Creek Reservoir
These are the measurements NDEP publishes for Knott Creek Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 145 µg/L. Chlorophyll-a 59 µg/L. TSI 73.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 145µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 59µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 73 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Knott Creek Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~24 ft est.
Surface area
10 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Nevada has not published bathymetry for Knott Creek Reservoir.
Lake Size & Watershed
Watershed (drainage) area
6 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.2 mi
HydroLAKES / HydroSHEDS
Elevation
6,467 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Knott Creek Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Knott Creek Reservoir in Humboldt County, Nevada — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Knott Creek Reservoir are listed below.
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Fishing Knott Creek Reservoir
Water Quality Trend: Stable
Based on 6 years of monitoring (2016–2021).
Phosphorus
Worsening+17.57 µg/L/yr6 years
Chlorophyll-a
Improving-18.19 µg/L/yr3 years
Reservoir Info (USACE NID)
Knott Creek Reservoir is a man-made reservoir impounded by the Knott Creek Reservoir Dam, built primarily for irrigation on the Knott Creek; masonry-type dam, 28 ft tall and 100 ft long.
- Surface area
- 10 ac
- Normal storage
- 2,000 ac-ft
- Max storage
- 3,860 ac-ft
- Drainage area
- 6.2 sq mi
- Hazard class
- Significant
- Owner
- RDD INC
All listed purposes: Irrigation;Fire Protection, Stock, Or Small Fish Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID NV00004 · Operator website
EPA Impairment Status
Knott Creek Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Drinking water, Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit NV01-NW-05-B_00 · Official waterbody report
Nearby Lakes in Humboldt County
Frequently asked questions about Knott Creek Reservoir
Where is Knott Creek Reservoir?
- Knott Creek Reservoir is a lake in Humboldt County, Nevada. Its water-quality measurements are published by NDEP and shown on this page as reported.
What is the water quality of Knott Creek Reservoir?
- Knott Creek Reservoir in Humboldt County, Nevada has water-quality measurements published by NDEP, shown here as reported. Phosphorus: 145 µg/L. Chlorophyll-a (algae): 59 µg/L. Surface area: 10 acres.
Is Knott Creek Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Knott Creek Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
How deep is Knott Creek Reservoir?
- No published bathymetric survey covers Knott Creek Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 24 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 10 acres.
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Where this data comes from
20 measurements from 1 monitoring station, 2016–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Nevada Division of Environmental Protection
21NEV1_WQX20 samples · 2016–2021
Analytical methods
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 4500 P E ~ Phosphorus by Ascorbic Acid
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)