Johnson Lake
Gosper County, NebraskaView mapDirections
Nebraska DEE publishes the water-quality measurements for Johnson Lake. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- 30 ft max depth
- Public access
Johnson Lake in Gosper County, Nebraska has water-quality measurements published by Nebraska DEE, shown here as reported. Water clarity: 2.8 ft visibility. Phosphorus: 62.3 µg/L. Chlorophyll-a (algae): 11.3 µg/L.
Johnson Lake is a productive, nutrient-rich eutrophic lake in Gosper County, Nebraska with an estimated average depth of about 30 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, NDEE, last sampled 2024-09-26. Methodology: how these readings are compared.
What Johnson Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Camping1 public campground nearby
Swimming conditions
Readings onlyElevated nutrients
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. Johnson Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Johnson 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 Johnson Lake
These are the measurements Nebraska DEE publishes for Johnson 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 2.8 ft of visibility. Phosphorus 62.3 µg/L. Chlorophyll-a 11.3 µg/L. TSI 60.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 62.3µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 11.3µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 60 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Johnson Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~30 ft est.
Public access
Yes
Listed by Nebraska DEE
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Nebraska has not published bathymetry for Johnson Lake.
Lake Size & Watershed
Watershed (drainage) area
7 sq mi
HydroLAKES / HydroSHEDS
Surface area
2,078 acres
HydroLAKES / HydroSHEDS
Shoreline
8.8 mi
HydroLAKES / HydroSHEDS
Elevation
2,615 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.
Recreation & Access
- Johnson Lake State Recreation Area InletPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Johnson Lake
- Johnson Lake State Recreation Area2.2 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Johnson Lake
Compare lakeside cabins, hotels, and vacation rentals near Johnson Lake in Gosper County, Nebraska — 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 Johnson Lake are listed below.
Top-rated places to stay near Johnson Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip? Cabins and lodging at Johnson Lake → · more Nebraska lake trips
Follow Johnson Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Johnson Lake
Water Quality Trend: Improving
Based on 13 years of monitoring (2012–2024).
Water clarity
Stable13 years
Phosphorus
Stable+0.35 µg/L/yr5 years
Chlorophyll-a
Improving-0.61 µg/L/yr12 years
Reservoir Info (USACE NID)
Johnson Lake is a man-made reservoir impounded by the Johnson Lake Dam (completed 1941), built primarily for hydroelectric; earth-type dam, 47 ft tall and 4,985 ft long.
- Normal storage
- 54,000 ac-ft
- Max storage
- 59,000 ac-ft
- Hazard class
- High
- Owner
- Central Nebraska Public Power & Irrigation District
All listed purposes: Hydroelectric;Irrigation.
Source: USACE National Inventory of Dams, NID ID NE01025 · Operator website
EPA Impairment Status
Johnson 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.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NE-MP2-L0520 · Official waterbody report
Nearby Lakes in Gosper County
Frequently asked questions about Johnson Lake
Where is Johnson Lake?
- Johnson Lake is a lake in Gosper County, Nebraska. Its water-quality measurements are published by Nebraska DEE and shown on this page as reported.
What is the water quality of Johnson Lake?
- Johnson Lake in Gosper County, Nebraska has water-quality measurements published by Nebraska DEE, shown here as reported. Water clarity: 2.8 ft visibility. Phosphorus: 62.3 µg/L. Chlorophyll-a (algae): 11.3 µg/L.
Is Johnson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Johnson Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Johnson Lake?
- No published bathymetric survey covers Johnson Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 30 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Johnson Lake?
- Johnson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Johnson Lake State Recreation Area Inlet. Public access is listed as yes.
Can I fish at Johnson Lake?
- Johnson 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.
Are there campgrounds on Johnson Lake?
- Johnson Lake has 1 public campground from USGS The National Map within 5 km, including Johnson Lake State Recreation Area. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Johnson Lake across LakeQuality
More lakes in Nebraska
Other Lakes in Nebraska
Eutrophic Lakes in Nebraska
Where this data comes from
161 measurements from 2 monitoring stations, 2012–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Nebraska Department of Environment and Energy
21NEB001_WQX161 samples · 2012–2024
Analytical methods
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- Total Phosphorus After Block Digestion
Monitoring station identifiers (2)
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)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles