Illinois lake · state assessment record
Churchill Lagoon
Assessment decisions reported by Illinois to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2004 reporting cycle.
- 21
- Assessed acres
- Lake, Freshwater
- Water type
- Hypereutrophic
- Reported trophic class
This waterbody in one line
Churchill Lagoon, a lake in Illinois, is assessed as not supporting one or more designated uses, with 5 listed impairment causes in the state's most recent Integrated Report cycle (2004). By assessed acreage it sits below the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (5 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P34
- Assessed size nationally
- P1
- 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.
Churchill Lagoon against the ATTAINS register
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: cause-list length
The standout filed fact is cause-list length: 5 listed impairment causes, a longer list than 97% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
Every ruled-on use is not supporting
On the uses this filer ruled on, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Churchill Lagoon: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Churchill Lagoon. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Overall status: not supporting
The filer's overall status for Churchill Lagoon is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Small within Illinois
State size rank 291 of 388 puts Churchill Lagoon toward the small end of Illinois's indexed lake-type units with an area.
According to the U.S. Environmental Protection Agency's ATTAINS program, Illinois carries 783 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Churchill Lagoon 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. Illinois filed its own confidence on the 2 definitive verdicts it rated: Good. That rating is the filer's, in EPA's own field, and EPA publishes no definition of the four words it offers.
| Designated use | Group | Verdict |
|---|---|---|
| Aesthetic Quality | Other | Not Supporting Filer confidence: Good |
| Aquatic Life | Aquatic-life or related | Not Supporting Filer confidence: Good |
| Fish Consumption | Fish-consumption or fishery | Not Assessed |
| Primary Contact | Recreation | Not Assessed |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this lake, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Aldrin | Aquatic Life | 2004 | TMDL priority: Medium |
| Phosphorus, Total | Aquatic Life, Aesthetic Quality | 2004 | TMDL priority: Low |
| Silver | Aquatic Life | 2004 | TMDL priority: Medium |
| Total Suspended Solids (TSS) | Aquatic Life, Aesthetic Quality | 2004 | TMDL priority: Low |
| Algae | Aquatic Life | 2016 | None reported |
Reading the record
Where Churchill Lagoon sits among peers
19% of Illinois's lakes assessed this deeply also had no use supported
Illinois ruled definitively on 2 designated uses at Churchill Lagoon and found none of them supported. The dataset shows 289 Illinois lakes judged to that same depth.
Illinois's assessed lakes are most often judged on 2 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 | 8 | 43 | 12 | 0 | 0 |
| Mixed | Not possible | 192 | 107 | 44 | 1 |
| None supported | 27 | 54 (this record) | 6 | 3 | 0 |
Ringed cell: Churchill Lagoon. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Churchill Lagoon is one of 783 lake-type waterbodies reported to EPA from Illinois, and one of 439 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 21 assessed acres it ranks 25,669th 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 25,668 lakes with a larger one.
Still unfiled
The state has not yet filed a definitive fish-consumption verdict and a definitive recreation verdict for this record; those fields populate when it reports them in a future Integrated Report cycle.
Reported trophic class
Hypereutrophic is the trophic class the filing agency reported to EPA ATTAINS for this assessment unit. It describes nutrient enrichment, not whether the water is safe, and it is not a PlainLakes inference. What the trophic scale measures.
In context
Where Churchill Lagoon 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
21 Top 66% larger than 34% 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
5 Longer than most more listed causes than 97% 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 Churchill Lagoon. Hover or tap any bar for its full count and share.
In context
Illinois context
ATTAINS carries 783 lake-type waterbodies in Illinois, 434 assessed as not supporting at least one use and 63 fully supporting. Among the 439 indexed units there, Churchill Lagoon ranks 42nd by listed-cause count (5 listed causes) and 291st by assessed size among the 388 with an area filed; it sits in the not-supporting set (434 statewide) . Its listed causes include Phosphorus, Total; and Total Suspended Solids (TSS), which also appear among Illinois's most-filed impairment causes (led by Phosphorus, Total). It also lists Aldrin, Silver, and Algae, outside that top-five list.
| Other large assessed lakes in Illinois | Assessed acres |
|---|---|
| Lake Michigan Nearshore Not Supporting | 125,440 |
| Carlyle Not Supporting | 24,580 |
| Rend Not Supporting | 18,900 |
| Shelbyville Not Supporting | 11,000 |
| Crab Orchard Not Supporting | 6,965 |
| Clinton Not Supporting | 4,895 |
Peers near Churchill Lagoon's size or cause load
Similar assessed acres
Nearest filed extents (21 acres here).
- Adams (Woodfd) · 21 acres · VT
- Anderson Ditch - Unnamed Lake · 21 acres · IN
- Athens · 21 acres · VT
- Austin Community Lake · 21 acres · MO
Similar cause load
Nearest listed-cause counts (5 here). Peers already in the acreage column are omitted.
- Alexandria Lake No. 3 · 5 causes · NE
- Alexauken Ck (above 74d 55m) · 5 causes · NJ
- Alexauken Ck (below 74d 55m to 11BA06) · 5 causes · NJ
- Alloway Ck (Quinton to Alloway-WdstwnRd) · 5 causes · NJ
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 IL_RGG. 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.