El Dorado Lake
Butler County, Kansas8,400 acresView mapDirections
KDHE publishes the water-quality measurements for El Dorado Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 80 ft max depth
- Public access
- Limited data
El Dorado Lake in Butler County, Kansas has water-quality measurements published by KDHE, shown here as reported. Water clarity: 2.8 ft visibility. Phosphorus: 34 µg/L. Chlorophyll-a (algae): 14.3 µg/L. Surface area: 8400 acres.
El Dorado Lake is a 8,400-acre productive, nutrient-rich eutrophic lake in Butler County, Kansas with an estimated average depth of about 80 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 9 public boat landings. Compared to the 2 other monitored lakes in Butler County, El Dorado Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, KDHE, last sampled 2017-07-17. Methodology: how these readings are compared.
What El Dorado Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch9 documented ramps
- Big water8,400 acres
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. El Dorado Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), sediment / turbidity. Check local advisories before you swim.
Whether El Dorado 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 El Dorado Lake
These are the measurements KDHE publishes for El Dorado 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 34 µg/L. Chlorophyll-a 14.3 µg/L. TSI 58.
| 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 | 34µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 14.3µg/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. | 58 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about El Dorado Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~80 ft est.
Surface area
8,400 acres
Public access
Yes
Listed by KDHE
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Kansas has not published bathymetry for El Dorado Lake.
Lake Size & Watershed
Watershed (drainage) area
265 sq mi
HydroLAKES / HydroSHEDS
Shoreline
48.1 mi
HydroLAKES / HydroSHEDS
Elevation
1,342 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
- El Dorado-Walnut RiverPublic
- El Dorado-NE 60th StreetPublic
- El Dorado-NE Cole CreekPublic
- El Dorado-Area 1Public
- El Dorado-Goose CovePublic
- El Dorado-Quail RunPublic
Showing 6 of 9 documented landings from the USGS National Boat Ramps inventory.
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near El Dorado Lake
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Fishing El Dorado Lake
Water quality readings over time
2 seasons of samples on record (2014–2017). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Phosphorus
Worsening+4.5 µg/L/yr2 years
Chlorophyll-a
Worsening+4.13 µg/L/yr2 years
Reservoir Info (USACE NID)
El Dorado Lake is a man-made reservoir impounded by the El Dorado Dam (completed 1981), built primarily for flood risk reduction on the Walnut River; earth-type dam, 99 ft tall and 20,930 ft long.
- Surface area
- 8,400 ac
- Normal storage
- 161,928 ac-ft
- Max storage
- 246,882 ac-ft
- Drainage area
- 234 sq mi
- Hazard class
- High
- Owner
- USACE - Tulsa District
All listed purposes: Flood Risk Reduction;Other;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID KS00027 · Operator website
EPA Impairment Status
El Dorado 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-LM033001 · Official waterbody report
Nearby Lakes in Butler County
Frequently asked questions about El Dorado Lake
Where is El Dorado Lake?
- El Dorado Lake is a lake in Butler County, Kansas. Its water-quality measurements are published by KDHE and shown on this page as reported.
What is the water quality of El Dorado Lake?
- El Dorado Lake in Butler County, Kansas has water-quality measurements published by KDHE, shown here as reported. Water clarity: 2.8 ft visibility. Phosphorus: 34 µg/L. Chlorophyll-a (algae): 14.3 µg/L. Surface area: 8400 acres.
Is El Dorado Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. El Dorado Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), sediment / turbidity. Check local advisories before you swim.
How deep is El Dorado Lake?
- No published bathymetric survey covers El Dorado Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 80 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 8400 acres.
Are there boat ramps on El Dorado Lake?
- El Dorado Lake has 9 documented boat landings in the USGS National Boat Ramps inventory. Named access points include El Dorado-Walnut River, El Dorado-NE 60th Street, El Dorado-NE Cole Creek, El Dorado-Area 1, among others. Public access is listed as yes.
Can I fish at El Dorado Lake?
- El Dorado Lake has 9 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Kansas's fish and wildlife agency, so check its current regulations before you go.
Explore El Dorado Lake across LakeQuality
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Where this data comes from
11 measurements from 1 monitoring station, 2014–2017. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Kansas Department Of Health And Environment
21KAN001_WQX11 samples · 2014–2017
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)
Named boat-access points from the USGS National Boat Ramps inventory