Sedan City South Lake
Chautauqua County, Kansas75 acresView mapDirections
Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.
- Impaired · Nutrients (phosphorus, nitrogen)
- 22 ft max depth
- Limited data
Sedan City South Lake in Chautauqua County, Kansas is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.9 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Surface area: 75 acres.
- Clarity
- 4.9 ft
- Max depth
- ~22 ft est.
- Area
- 75 acres
- Phosphorus
- 20 µg/L
- Chlorophyll-a
- 8.5 µg/L
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Watch Sedan City South Lake’s letter
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Why Sedan City South Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Sedan City South Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by KDHE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Sedan City South Lake is a 75-acre lake in Chautauqua County, Kansas with an estimated average depth of about 22 feet.
Source: EPA Water Quality Portal sampling records, KDHE, last sampled 2015-08-31. Grade methodology: LakeQuality methodology.
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Sedan City South Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Water quality measurements for Sedan City South Lake
These readings exist but are not enough for an A–F grade — see why.
Murky, only visible to about 4.9 ft. Phosphorus 20 µg/L. Chlorophyll-a 8.5 µg/L. TSI 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | Not graded |
| Phosphorus | 20 µg/L | Not graded |
| Chlorophyll-a (Algae) | 8.5 µg/L | Not graded |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~22 ft est. |
| Average Depth | ~14 ft est. |
| Surface Area | 75 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 Sedan City South Lake.
Lake Size & Watershed
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.
Fishing Sedan City South Lake
Reservoir Info (USACE NID)
Sedan City South Lake is a man-made reservoir impounded by the Dd No 6-28 Lower Dam (Sedan City Lake) (completed 1965), built primarily for flood risk reduction on the Deer Creek; earth-type dam, 60 ft tall and 1,585 ft long.
- Surface area
- 75 ac
- Normal storage
- 780 ac-ft
- Max storage
- 3,250 ac-ft
- Drainage area
- 7.03 sq mi
- Hazard class
- High
- Owner
- SEDAN, CITY OF
All listed purposes: Flood Risk Reduction;Water Supply.
Source: USACE National Inventory of Dams, NID ID KS02451 · Operator website · Matched by proximity (0.17 km)
EPA Impairment Status
Sedan City South Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit KS-LM048601 · Official waterbody report · Matched by proximity (2.59 km)
Nearby Lakes in Chautauqua County
Frequently asked questions about Sedan City South Lake
Where is Sedan City South Lake?
- Sedan City South Lake is a lake in Chautauqua County, Kansas. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Sedan City South Lake?
- Sedan City South Lake in Chautauqua County, Kansas is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.9 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Surface area: 75 acres.
Is Sedan City South Lake safe to swim in?
- The letter is not a swimming clearance. Sedan City South Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Sedan City South Lake?
- No published bathymetric survey covers Sedan City South Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 22 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 75 acres.
Explore Sedan City South Lake across LakeQuality
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Where this data comes from
5 measurements from 1 monitoring station, 2015. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Kansas Department Of Health And Environment
21KAN001_WQX5 samples · 2015
Analytical methods
- Depth, Secchi disk depth
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)