City Reservoir
Park County, Wyoming12 acresView mapDirections
Wyoming DEQ publishes the water-quality measurements for City Reservoir. Here is what has been measured.
- Eutrophic
- Limited data
City Reservoir in Park County, Wyoming has water-quality measurements published by Wyoming DEQ, shown here as reported. Phosphorus: 65 µg/L. Surface area: 12 acres.
City Reservoir is a 12-acre productive, nutrient-rich eutrophic lake in Park County, Wyoming. Overall water quality is improving over recent sampling years. Compared to the 4 other monitored lakes in Park County, City Reservoir ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Wyoming DEQ, last sampled 2016-09-20. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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. Check local advisories before you swim.
Whether City Reservoir 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 City Reservoir
These are the measurements Wyoming DEQ publishes for City 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 65 µg/L. TSI 64.
| 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 | 65µg/L | Fair GoodFairPoor |
| 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. | 64 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about City Reservoir
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Lake Details
Surface area
12 acres
No bathymetric survey has been published for City Reservoir, so its depth is not documented here.
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Stays near City Reservoir
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Fishing City Reservoir
Water quality readings over time
3 seasons of samples on record (2014–2016). Calling a direction takes at least 4 years of the same measurement.
Phosphorus
Improving-25 µg/L/yr3 years
Reservoir Info (USACE NID)
City Reservoir is a man-made reservoir impounded by the Markham (completed 1929), built primarily for water supply on the S Fork Shoshone Offstream; earth-type dam, 11 ft tall and 2,500 ft long.
- Surface area
- 12 ac
- Normal storage
- 67 ac-ft
- Max storage
- 730 ac-ft
- Drainage area
- 0.1 sq mi
- Hazard class
- Significant
- Owner
- CITY OF CODY
All listed purposes: Water Supply;Irrigation.
Source: USACE National Inventory of Dams, NID ID WY01101 · Operator website · Matched by proximity (0.24 km)
Nearby Lakes in Park County
Frequently asked questions about City Reservoir
Where is City Reservoir?
- City Reservoir is a lake in Park County, Wyoming. Its water-quality measurements are published by Wyoming DEQ and shown on this page as reported.
What is the water quality of City Reservoir?
- City Reservoir in Park County, Wyoming has water-quality measurements published by Wyoming DEQ, shown here as reported. Phosphorus: 65 µg/L. Surface area: 12 acres.
Is City Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore City Reservoir across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
6 measurements from 1 monitoring station, 2015–2016. 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 · 2015–2016
Analytical methods
- 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.