Missouri reservoir · state assessment record
Wyaconda Lake
Assessment decisions reported by Missouri to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle. The cleanup plan below was established by EPA rather than by Missouri.
- 9.00
- Assessed acres
- Reservoir
- Water type
This waterbody in one line
Wyaconda Lake, a reservoir in Missouri, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2026). By assessed acreage it sits among the smaller assessed lakes nationally (38,628 lakes with a filed area); 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
- P17
- 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.
Reading Wyaconda 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: assessed size
What stands out first is how small the assessed unit is: 9 acres, smaller than 83% of the 38,628 lake-type units carrying an area.
Wyaconda Lake: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Wyaconda Lake. The remaining work is implementation and tracking, read the cleanup-standing and cause rows for what the state already committed to address.
Every ruled-on use is fully supporting
The filed use determinations for aquatic life are all Fully Supporting. Where an overall IR category still flags the unit, look at the cause list and report standing rather than treating the use row as empty.
Overall status: not supporting
The filer's overall status for Wyaconda Lake is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Typical cause-list length
1 listed cause is a middle-tercile list length among assessed lake-type units. Look to IR category and use outcomes for the distinctive reading.
According to the U.S. Environmental Protection Agency's ATTAINS program, Missouri carries 623 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Wyaconda Lake without modification. See our methodology for reporting-unit limits and gauge linking rules.
The record
Assessment entries
Fully Supporting and Not Supporting are the state's definitive verdicts; other entries mean the use was not conclusively assessed in this cycle.
| Assessment entry | Group | Verdict |
|---|---|---|
| Drinking Water Supply | Drinking-water supply designation | Not Supporting |
| Warm Water Habitat | Aquatic-life or related | Fully Supporting |
| Human Health Protection | Fish-consumption or fishery | Insufficient Information |
| Irrigation | Other | Insufficient Information |
| Livestock and Wildlife Protection | Aquatic-life or related | Insufficient Information |
| Secondary Contact Recreation | Recreation | Insufficient Information |
| Unclassified with General Criteria Protections | Other | Insufficient Information |
| Whole Body Contact Recreation - Category B | Recreation | Insufficient Information |
Not every entry above is a designated use: Unclassified with General Criteria Protections is a record that the water carries no classified designated use. The state files it in the ATTAINS use column, so it carries whatever verdict the state recorded against it.
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 |
|---|---|---|---|
| Atrazine | Drinking Water Supply | 1998 | TMDL established by EPA |
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.
- Atrazine
- Crop Production with Subsurface Drainage (suspected)
Reading the record
Wyaconda Lake: Category 4A reading
4A Category 4A: impaired, TMDL completed
Missouri filed this assessment unit as Category 4A: impaired, with a pollutant-budget TMDL already completed under 303(d). The listing remains an impairment finding; the plan is on file rather than still awaiting write-up.
Scale and rank
Wyaconda Lake is one of 623 lake-type waterbodies reported to EPA from Missouri, and one of 170 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 9.00 assessed acres it ranks 31,856th 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 31,855 lakes with a larger one.
Open in the register
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.
In context
Where Wyaconda 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
9 Top 83% larger than 17% 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 Wyaconda Lake. Hover or tap any bar for its full count and share.
In context
Missouri context
ATTAINS carries 623 lake-type waterbodies in Missouri, 151 assessed as not supporting at least one use and 118 fully supporting. Among the 170 indexed units there, Wyaconda Lake ranks 140th by listed-cause count (one listed cause) and 159th by assessed size among the 170 with an area filed; it sits in the not-supporting set (151 statewide) . Its listed causes (Atrazine) sit outside Missouri's top-five list, which is led by Chlorophyll-a.
| Other large assessed lakes in Missouri | Assessed acres |
|---|---|
| Lake of the Ozarks Not Supporting | 59,520 |
| Harry S Truman Reservoir Not Supporting | 55,600 |
| Table Rock Lake Not Supporting | 41,747 |
| Stockton Lake Fully Supporting | 23,680 |
| Mark Twain Lake Not Supporting | 20,100 |
| Bull Shoals Lake Not Supporting | 9,000 |
Peers near Wyaconda Lake's size or cause load
Similar assessed acres
Nearest filed extents (9.00 acres here).
- Abner Pond · 9.00 acres · MA
- Anderson Ditch - Unnamed Lake · 9.00 acres · IN
- Axel Lake · 9.00 acres · IN
- Baldwin · 9.00 acres · VT
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 MO_7009.00. 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.