Iowa lake · state assessment record
Nine Eagles Lake
Assessment decisions reported by Iowa to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle, a cycle that carries an interim EPA action.
- 63
- Assessed acres
- Lake
- Water type
- Mesotrophic
- Reported trophic class
This waterbody in one line
Nine Eagles Lake, a lake in Iowa, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2024), a cycle that carries an interim EPA action. By assessed acreage it sits above the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (2 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as fully supporting.
- Not Supporting
- overall status
- P60
- Assessed size nationally
- P10
- Shorter cause list
- Fully 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.
Where Nine Eagles Lake stands in the filed 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: 2 listed impairment causes, a longer list than 80% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
The uses disagree
This record splits: Not Supporting on recreation, Fully Supporting on aquatic life. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Nine Eagles Lake: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Nine Eagles Lake. 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 Nine Eagles Lake is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Mid-pack assessed size
63 acres lands in the middle tercile of units with an area filed. Acreage is not what distinguishes this record from its peers.
According to the U.S. Environmental Protection Agency's ATTAINS program, Iowa carries 371 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Nine Eagles 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.
| Designated use | Group | Verdict |
|---|---|---|
| Aquatic Life - Lakes and Wetlands Warmwater | Aquatic-life or related | Fully Supporting |
| Drinking Water | Drinking-water supply designation | Fully Supporting |
| Human Health | Recreation | Not Supporting |
| Primary Contact Recreation | Recreation | Not Supporting |
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 |
|---|---|---|---|
| Escherichia coli (E. coli) | Primary Contact Recreation | 2006 | TMDL approved |
| Mercury - Fish Consumption Advisory | Human Health | 2006 | TMDL priority: Low |
Probable sources named by the state
Each source below is listed under the cause the state filed it against, and carries the word the state filed with it — confirmed, or suspected.
- Mercury - Fish Consumption Advisory
- Agriculture (suspected)
Iowa also recorded the source of at least one listing here as unknown, including for Escherichia coli (E. coli).
Reading the record
Where Nine Eagles Lake sits among peers
7 of 9 Iowa lakes assessed this deeply also came out mixed
Iowa ruled definitively on 4 designated uses at Nine Eagles Lake and found 2 of 4 not supported. The dataset shows 9 Iowa lakes judged to that same depth.
Iowa's assessed lakes are most often judged on 2 uses; this one was judged on 4.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 27 | 27 | 10 | 2 | 0 |
| Mixed | Not possible | 38 | 31 | 7 (this record) | 0 |
| None supported | 45 | 12 | 4 | 0 | 0 |
Ringed cell: Nine Eagles Lake. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Nine Eagles Lake is one of 371 lake-type waterbodies reported to EPA from Iowa, and one of 167 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 63 assessed acres it ranks 15,507th 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 15,506 lakes with a larger one.
Open in the register
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
Mesotrophic 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 Nine Eagles 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
63 Top 40% larger than 60% 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 Nine Eagles Lake. Hover or tap any bar for its full count and share.
In context
Iowa context
ATTAINS carries 371 lake-type waterbodies in Iowa, 137 assessed as not supporting at least one use and 66 fully supporting. Among the 167 indexed units there, Nine Eagles Lake ranks 63rd by listed-cause count (2 listed causes) and 100th by assessed size among the 167 with an area filed; it sits in the not-supporting set (137 statewide) . Its listed causes include Escherichia coli (E. coli), which also appears among Iowa's most-filed impairment causes (led by Chlorophyll-a). It also lists Mercury - Fish Consumption Advisory, outside that top-five list.
| Other large assessed lakes in Iowa | Assessed acres |
|---|---|
| Red Rock Reservoir Not Supporting | 19,000 |
| Rathbun Reservoir - Main Basin Fully Supporting | 6,330 |
| Saylorville Reservoir Not Supporting | 5,950 |
| Coralville Reservoir Not Supporting | 4,900 |
| Big Spirit Lake Fully Supporting | 4,169 |
| Clear Lake Not Supporting | 3,684 |
Peers near Nine Eagles Lake's size or cause load
Similar assessed acres
Nearest filed extents (63 acres here).
- Adams Lake · 63 acres · OK
- Breakneck Pond · 63 acres · NY
- Horse Pond · 63 acres · MA
- Lake Erie-04120200 · 63 acres · PA
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 IA 05-GRA-1361. 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.