Chalkrock Lake
Cedar County, Nebraska44 acresView mapDirections
Nebraska DEE publishes the water-quality measurements for Chalkrock Lake. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- Public access
- Limited data
Chalkrock Lake in Cedar County, Nebraska has water-quality measurements published by Nebraska DEE, shown here as reported. Water clarity: 3.3 ft visibility. Chlorophyll-a (algae): 9.3 µg/L. Surface area: 44 acres.
Chalkrock Lake is a 44-acre productive, nutrient-rich eutrophic lake in Cedar County, Nebraska. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Cedar County, Chalkrock Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, NDEE, last sampled 2016-09-21. Methodology: how these readings are compared.
What Chalkrock Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
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. Chalkrock Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Chalkrock Lake is safe to swim in today is a call for the Nebraska Department of Environment and Energy and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Chalkrock Lake
These are the measurements Nebraska DEE publishes for Chalkrock Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3.3 ft of visibility. Chlorophyll-a 9.3 µg/L. TSI 56.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 9.3µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 56 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Chalkrock Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
44 acres
Public access
Yes
Listed by Nebraska DEE
No bathymetric survey has been published for Chalkrock Lake, so its depth is not documented here.
Recreation & Access
- Chalkrock Wildlife Management AreaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Stays near Chalkrock Lake
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Fishing Chalkrock Lake
Reservoir Info (USACE NID)
Chalkrock Lake is a man-made reservoir impounded by the Menominee Dam (completed 1986), built primarily for flood risk reduction on the Antelope Creek; earth-type dam, 61 ft tall and 2,054 ft long.
- Surface area
- 44 ac
- Normal storage
- 291 ac-ft
- Max storage
- 3,198.1 ac-ft
- Drainage area
- 18 sq mi
- Hazard class
- Low
- Owner
- Lewis & Clark Natural Resources District
Source: USACE National Inventory of Dams, NID ID NE02258 · Operator website · Matched by proximity (0.17 km)
EPA Impairment Status
Chalkrock Lake 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: Aquatic life.
Source: EPA ATTAINS assessment unit NE-MT2-L0020 · Official waterbody report
Nearby Lakes in Cedar County
Frequently asked questions about Chalkrock Lake
Where is Chalkrock Lake?
- Chalkrock Lake is a lake in Cedar County, Nebraska. Its water-quality measurements are published by Nebraska DEE and shown on this page as reported.
What is the water quality of Chalkrock Lake?
- Chalkrock Lake in Cedar County, Nebraska has water-quality measurements published by Nebraska DEE, shown here as reported. Water clarity: 3.3 ft visibility. Chlorophyll-a (algae): 9.3 µg/L. Surface area: 44 acres.
Is Chalkrock Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Chalkrock Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Are there boat ramps on Chalkrock Lake?
- Chalkrock Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Chalkrock Wildlife Management Area. Public access is listed as yes.
Can I fish at Chalkrock Lake?
- Chalkrock Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Nebraska's fish and wildlife agency, so check its current regulations before you go.
Explore Chalkrock Lake across LakeQuality
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Where this data comes from
10 measurements from 1 monitoring station, 2016. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Nebraska Department of Environment and Energy
21NEB001_WQX10 samples · 2016
Analytical methods
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
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
Named boat-access points from the USGS National Boat Ramps inventory