Rock Lake
Platte County, Wyoming37 acresView mapDirections
Wyoming DEQ publishes the water-quality measurements for Rock Lake. Here is what has been measured.
- 26 ft max depth
- Limited data
Rock Lake in Platte County, Wyoming has water-quality measurements published by Wyoming DEQ, shown here as reported. Water clarity: 3.8 ft visibility. Phosphorus: 12.4 µg/L. Surface area: 37 acres.
Rock Lake is a 37-acre lake in Platte County, Wyoming with an estimated average depth of about 26 feet. Water clarity is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Wyoming DEQ, last sampled 2015-09-03. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Rock Lake is safe to swim in today is a call for the Wyoming Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Rock Lake
These are the measurements Wyoming DEQ publishes for Rock Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.8 ft. Phosphorus 12.4 µg/L. TSI 49.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12.4µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Rock Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~26 ft est.
Surface area
37 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wyoming has not published bathymetry for Rock Lake.
Lake Size & Watershed
Watershed (drainage) area
0 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1 mi
HydroLAKES / HydroSHEDS
Elevation
4,974 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.
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Fishing Rock Lake
Water quality readings over time
2 seasons of samples on record (2015–2018). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Worsening+2.5 µg/L/yr2 years
Reservoir Info (USACE NID)
Rock Lake is a man-made reservoir impounded by the Rock Lake (completed 1930), built primarily for irrigation on the North Wheatland Creek; earth-type dam, 15 ft tall and 660 ft long.
- Surface area
- 37 ac
- Normal storage
- 250 ac-ft
- Max storage
- 334 ac-ft
- Drainage area
- 0 sq mi
- Hazard class
- Low
- Owner
- WHEATLAND IRRIGATION DISTRICT
Source: USACE National Inventory of Dams, NID ID WY00033 · Operator website
Nearby Lakes in Platte County
Frequently asked questions about Rock Lake
Where is Rock Lake?
- Rock Lake is a lake in Platte County, Wyoming. Its water-quality measurements are published by Wyoming DEQ and shown on this page as reported.
What is the water quality of Rock Lake?
- Rock Lake in Platte County, Wyoming has water-quality measurements published by Wyoming DEQ, shown here as reported. Water clarity: 3.8 ft visibility. Phosphorus: 12.4 µg/L. Surface area: 37 acres.
Is Rock Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Rock Lake?
- No published bathymetric survey covers Rock Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 26 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 37 acres.
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Where this data comes from
6 measurements from 1 monitoring station, 2015. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- State of Wyoming Department of Environmental Quality Watershed Program
WYDEQ_WATERSHED6 samples · 2015
Analytical methods
- Secchi
- Total Phosphorus After Block Digestion
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
Lake size & watershed from HydroLAKES (HydroSHEDS)