Gardner Lake
Johnson County, Kansas130 acresView mapDirections
KDHE publishes the water-quality measurements for Gardner Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 42 ft max depth
- Limited data
Gardner Lake in Johnson County, Kansas has water-quality measurements published by KDHE, shown here as reported. Water clarity: 2.3 ft visibility. Phosphorus: 37 µg/L. Chlorophyll-a (algae): 43.5 µg/L. Surface area: 130 acres.
Gardner Lake is a 130-acre highly nutrient-loaded hypereutrophic lake in Johnson County, Kansas with an estimated average depth of about 42 feet. Overall water quality is declining over recent sampling years. Compared to the 12 other monitored lakes in Johnson County, Gardner Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, KDHE, last sampled 2018-08-06. Methodology: how these readings are compared.
Gardner Lake covers about 130 acres in Johnson County. Vrbo is where to look for cabins and lake homes around Gardner Lake, and Booking.com and Expedia search hotels near the lake for your dates.
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. Gardner Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Whether Gardner Lake is safe to swim in today is a call for the Kansas Department of Health and Environment and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Gardner Lake
These are the measurements KDHE publishes for Gardner 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 2.3 ft of visibility. Phosphorus 37 µg/L. Chlorophyll-a 43.5 µg/L. TSI 63.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 37µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 43.5µg/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. | 63 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Gardner Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~42 ft est.
Surface area
130 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Kansas has not published bathymetry for Gardner Lake.
Lake Size & Watershed
Watershed (drainage) area
6 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.9 mi
HydroLAKES / HydroSHEDS
Elevation
1,007 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 Gardner Lake
Compare lakeside cabins, hotels, and vacation rentals near Gardner Lake in Johnson County, Kansas — 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 Gardner Lake are listed below.
Top-rated places to stay near Gardner 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 whole trip? See where to stay at Kansas’s top lakes →
Follow Gardner Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Gardner Lake
Water quality readings over time
2 seasons of samples on record (2012–2018). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Phosphorus
Worsening+3.17 µg/L/yr2 years
Chlorophyll-a
Worsening+1.83 µg/L/yr2 years
Reservoir Info (USACE NID)
Gardner Lake is a man-made reservoir impounded by the Gardner Lake Dam (completed 1940), built primarily for water supply on the Kill Creek; other-type dam, 61 ft tall and 1,550 ft long.
- Surface area
- 130 ac
- Normal storage
- 2,060 ac-ft
- Max storage
- 3,618 ac-ft
- Drainage area
- 5.34 sq mi
- Hazard class
- High
- Owner
- GARDNER, CITY OF
All listed purposes: Water Supply;Recreation.
Source: USACE National Inventory of Dams, NID ID KS02488 · Operator website
EPA Impairment Status
Gardner Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Drinking water, Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit KS-LM040401 · Official waterbody report
Nearby Lakes in Johnson County
Frequently asked questions about Gardner Lake
Where is Gardner Lake?
- Gardner Lake is a lake in Johnson County, Kansas. Its water-quality measurements are published by KDHE and shown on this page as reported.
What is the water quality of Gardner Lake?
- Gardner Lake in Johnson County, Kansas has water-quality measurements published by KDHE, shown here as reported. Water clarity: 2.3 ft visibility. Phosphorus: 37 µg/L. Chlorophyll-a (algae): 43.5 µg/L. Surface area: 130 acres.
Is Gardner Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Gardner Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
How deep is Gardner Lake?
- No published bathymetric survey covers Gardner Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 42 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 130 acres.
Explore Gardner Lake across LakeQuality
More lakes in Kansas
Other Lakes in Kansas
Hypereutrophic Lakes in Kansas
Where this data comes from
8 measurements from 1 monitoring station, 2012–2018. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Kansas Department Of Health And Environment
21KAN001_WQX8 samples · 2012–2018
Analytical methods
- Depth, Secchi disk depth
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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)