Iowa lake · state assessment record
Blue Heron 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.
- 25
- Assessed acres
- Lake
- Water type
- Eutrophic
- Reported trophic class
This waterbody in one line
Blue Heron Lake, a lake in Iowa, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2024), a cycle that carries an interim EPA action. By assessed acreage it sits below the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes). Aquatic life is assessed as fully supporting.
- Not Supporting
- overall status
- P38
- Assessed size nationally
- P20
- 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.
How Blue Heron Lake reads against 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: in-state cause rank
Inside Iowa, cause-list rank 123 of 167 is mid-pack, the state peer table is not driven by an extreme list length here.
A split ruling across uses
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.
Blue Heron Lake: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Blue Heron 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 Blue Heron Lake is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Small within Iowa
State size rank 136 of 167 puts Blue Heron Lake toward the small end of Iowa's indexed lake-type units with an area.
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 Blue Heron 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 |
| Human Health | Recreation | Fully 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 |
|---|---|---|---|
| Secchi Disk Transparency | Primary Contact Recreation | 2024 | TMDL priority: Medium |
Reading the record
Where Blue Heron Lake sits among peers
69% of Iowa's lakes assessed this deeply also came out mixed
Iowa ruled definitively on 3 designated uses at Blue Heron Lake and found 1 of 3 not supported. The dataset shows 45 Iowa lakes judged to that same depth.
Iowa's assessed lakes are most often judged on 2 uses; this one was judged on 3.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 27 | 27 | 10 | 2 | 0 |
| Mixed | Not possible | 38 | 31 (this record) | 7 | 0 |
| None supported | 45 | 12 | 4 | 0 | 0 |
Ringed cell: Blue Heron Lake. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Blue Heron 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 25 assessed acres it ranks 24,028th 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 24,027 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
Eutrophic 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 Blue Heron 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
25 Top 62% larger than 38% 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
1 Longer than most more listed causes than 49% 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 Blue Heron 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, Blue Heron Lake ranks 123rd by listed-cause count (one listed cause) and 136th by assessed size among the 167 with an area filed; it sits in the not-supporting set (137 statewide) . Its listed causes include Secchi Disk Transparency, which also appears among Iowa's most-filed impairment causes (led by Chlorophyll-a).
| 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 Blue Heron Lake's size or cause load
Similar assessed acres
Nearest filed extents (25 acres here).
- Airline Lake (Put & Take Trout) · 25 acres · IN
- Arnolds Pit · 25 acres · IN
- Batemans Pond · 25 acres · MA
- Big Bear · 25 acres · IL
Similar cause load
Nearest listed-cause counts (1 here). Peers already in the acreage column are omitted.
- Aaron · 1 causes · MN
- Aaron River Reservoir · 1 causes · MA
- Abbotts Creek (including Lexington-Thomasville Water Supply Reservoir at normal reservoir elevation, Tom-A-Lex Lake) · 1 causes · NC
- Abeniki Lake · 1 causes · NH
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 04-RAC-3105. 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.