South Dakota reservoir · state assessment record
East Lemmon Lake
Perkins County. Assessment decisions reported by South Dakota to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle.
- 167
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
East Lemmon Lake, a reservoir in South Dakota, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2026). By assessed acreage it sits in the upper quartile by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (2 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P79
- Assessed size nationally
- P10
- Shorter cause list
- Not Supporting
- aquatic life
Assessment verdicts are the state agency's decisions as reported to EPA ATTAINS; PlainLakes renders them without modification.
A composite of this record's EPA ATTAINS designated-use verdicts, filed impairment count, and assessment currency, weighted and benchmarked against the national corpus of assessed active waterbodies. This is a water-quality standing, not a human-recreation or property-value judgment, and dimensions with no filed verdict drop out rather than count against the score.
Reading East Lemmon Lake's filed record
Paragraphs are selected by this unit's percentiles and use matrix: different lakes lead with different dimensions. Figures are ATTAINS / portal register arithmetic, not advice.
The signature stat: in-state cause rank
Inside South Dakota, cause-list rank is the local separator: East Lemmon Lake is 31 of 176 indexed units by listed-cause count, toward the top of that state's filed lists.
A split ruling across uses
This record splits: Not Supporting on aquatic life, Fully Supporting on recreation. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
East Lemmon Lake: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for East Lemmon Lake. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Longer than most cause lists
2 listed causes puts this unit above 80% of assessed lake-type records by list length. Treat that as a coding-and-sampling signal: states that split pollutants finely mint longer lists without proving worse water.
Overall status: not supporting
The filer's overall status for East Lemmon Lake is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
According to the U.S. Environmental Protection Agency's ATTAINS program, South Dakota carries 195 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to East Lemmon Lake without modification. See our methodology for reporting-unit limits and gauge linking rules.
The record
Designated-use assessments
Fully Supporting and Not Supporting are the state's definitive verdicts; other entries mean the use was not conclusively assessed in this cycle. South Dakota filed 2025 as the year this waterbody was last monitored.
| Designated use | Group | Verdict |
|---|---|---|
| Fish and Wildlife Propagation, Recreation, and Stock Watering Waters | Aquatic-life or related | Not Supporting |
| Immersion Recreation Waters | Recreation | Fully Supporting |
| Limited Contact Recreation Waters | Recreation | Fully Supporting |
| Warmwater Semipermanent Fish Life Propagation Waters | Aquatic-life or related | Not Supporting |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this reservoir, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Mercury in Fish Tissue | Warmwater Semipermanent Fish Life Propagation Waters; Fish and Wildlife Propagation, Recreation, and Stock Watering Waters | 2018 | TMDL approved |
| pH | Warmwater Semipermanent Fish Life Propagation Waters Also assessed as meeting: Fish and Wildlife Propagation, Recreation, and Stock Watering Waters | 2026 | TMDL priority: Low |
Reading the record
Where East Lemmon Lake sits among peers
67% of South Dakota's lakes assessed this deeply also came out mixed
South Dakota ruled definitively on 4 designated uses at East Lemmon Lake and found 2 of 4 not supported. The dataset shows 126 South Dakota lakes judged to that same depth.
South Dakota's assessed lakes are most often judged on 4 uses, as this one was.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 3 | 7 | 0 | 26 | 5 |
| Mixed | Not possible | 1 | 0 | 84 (this record) | 10 |
| None supported | 24 | 8 | 2 | 16 | 0 |
Ringed cell: East Lemmon Lake. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
East Lemmon Lake is one of 195 lake-type waterbodies reported to EPA from South Dakota, and one of 176 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 167 assessed acres it ranks 8,284th by assessed size among the 38,628 lakes the dataset carries an area for, counting a state’s repeated filings of one water once, behind 8,283 lakes with a larger one.
Awaiting a filing
The state has not yet filed a definitive fish-consumption verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
Reported trophic class
South Dakota carried the trophic field for this assessment unit and filed it as unclassified, which records that no class was determined rather than that the water is unenriched. What the trophic scale measures.
In context
Where East Lemmon Lake sits nationally
Assessed size among U.S. lakes
Distribution of assessed acreage across ATTAINS lakes filed with an area, counting a state’s repeated filings of one water once
167 Top 21% larger than 79% of 38,628 lakes
lakes the dataset carries an area for, counting a state’s repeated filings of one water once, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
Listed causes vs waterbodies carrying a verdict
How many impairment causes U.S. waterbodies with a reported verdict carry
2 Longer than most more listed causes than 80% of 23,610 waterbodies carrying a verdict
named waterbodies carrying a verdict, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
In both charts each bar is a band and taller bars hold more waterbodies; the dashed line and filled bar mark East Lemmon Lake. Hover or tap any bar for its full count and share.
In context
South Dakota context
ATTAINS carries 195 lake-type waterbodies in South Dakota, 145 assessed as not supporting at least one use and 41 fully supporting. Among the 176 indexed units there, East Lemmon Lake ranks 31st by listed-cause count (2 listed causes) and 103rd by assessed size among the 176 with an area filed; it sits in the not-supporting set (145 statewide) . Its listed causes include Mercury in Fish Tissue and pH, which also appear among South Dakota's most-filed impairment causes (led by Mercury in Fish Tissue).
| Other large assessed lakes in South Dakota | Assessed acres |
|---|---|
| Lake Thompson Not Supporting | 13,888 |
| Lake Poinsett Not Supporting | 9,795 |
| Waubay Lake Not Supporting | 9,531 |
| Bitter Lake Not Supporting | 7,865 |
| Dry Lake Number 2 Not Supporting | 6,442 |
| Orman Dam (Belle Fourche Reservoir) Not Supporting | 6,106 |
Peers near East Lemmon Lake's size or cause load
Similar assessed acres
Nearest filed extents (167 acres here).
- Lake Arlington · 167 acres · TX
- Browns Creek Lake · 167 acres · TN
- George (Rock Island) · 167 acres · IL
- Liberty Lake · 167 acres · OK
Similar cause load
Nearest listed-cause counts (2 here). Peers already in the acreage column are omitted.
- 12th St. Beach · 2 causes · IL
- 31st St. Beach · 2 causes · IL
- 49th St. Beach · 2 causes · IL
- 57th St. Beach · 2 causes · IL
What to do with this record
- Assessment verdicts are cycle-based, not real-time. For fish-consumption decisions, your state advisory program is the binding source. Consumption status guide
- Impairment listings follow the Clean Water Act 303(d) process; a listing is a regulatory finding, not a closure notice. 303(d) explained
PlainLakes renders state assessment decisions and federal gauge observations without modification. It does not issue advisories.
Assessment decisions on this page are rendered directly from state Integrated Report records in EPA's ATTAINS system; gauge figures are daily-value observations from the USGS National Water Information System, no number is typed in by an editor. Overall status, use verdicts, and causes are the state's reported decisions for assessment unit SD-GR-L-EAST_LEMMON_01. Counts and percentiles are computed across all lake-type records PlainLakes ingests from ATTAINS. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-17. Primary sources: EPA ATTAINS and USGS National Water Information System.