Alabama reservoir · state assessment record
Little Cahaba River (Lake Purdy)
Assessment decisions reported by Alabama Department of Environmental Management to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle.
- 962
- Assessed acres
- Reservoir
- Water type
This waterbody in one line
Little Cahaba River (Lake Purdy), a reservoir in Alabama, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2022). By assessed acreage it sits among the largest 10% by assessed acreage nationally (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. Alabama assesses fishing as not supported; it reported no verdict on fish consumption itself.
- Not Supporting
- overall status
- P94
- 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 Little Cahaba River (Lake Purdy)'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
The number that most separates Little Cahaba River (Lake Purdy) nationally is assessed size: 962 acres, larger than 94% of the 38,628 lake-type units with an area on file.
The uses disagree
This record splits: Not Supporting on fish consumption, Fully Supporting on recreation, aquatic life. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Little Cahaba River (Lake Purdy): Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Little Cahaba River (Lake Purdy). 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 Little Cahaba River (Lake Purdy) 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, Alabama carries 304 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Little Cahaba River (Lake Purdy) 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 |
|---|---|---|
| Contact Recreation | Recreation | Fully Supporting |
| Drinking and Food Processing | Drinking-water supply designation | Fully Supporting |
| Fishing | Fish-consumption or fishery | Not Supporting |
| Industrial and Agriculture Uses | Other | Fully Supporting |
| Propagation of Fish and Wildlife | Aquatic-life or related | Fully 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 | Fishing | 2018 | 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
- Atmospheric Deposition (suspected)
Reading the record
Where Little Cahaba River (Lake Purdy) sits among peers
38% of Alabama's lakes assessed this deeply also came out mixed
Alabama ruled definitively on 5 designated uses at Little Cahaba River (Lake Purdy) and found 1 of 5 not supported. The dataset shows 94 Alabama lakes judged to that same depth.
Alabama's assessed lakes are most often judged on 4 uses; this one was judged on 5.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 0 | 5 | 8 | 70 | 47 |
| Mixed | Not possible | 0 | 4 | 71 | 36 (this record) |
| None supported | 8 | 1 | 1 | 11 | 11 |
Ringed cell: Little Cahaba River (Lake Purdy). Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Little Cahaba River (Lake Purdy) is one of 304 lake-type waterbodies reported to EPA from Alabama, and one of 263 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 962 assessed acres it ranks 2,330th 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 2,329 lakes with a larger one.
In context
Where Little Cahaba River (Lake Purdy) 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
962 Top 6% larger than 94% 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 Little Cahaba River (Lake Purdy). Hover or tap any bar for its full count and share.
In context
Alabama context
ATTAINS carries 304 lake-type waterbodies in Alabama, 143 assessed as not supporting at least one use and 130 fully supporting. Among the 263 indexed units there, Little Cahaba River (Lake Purdy) ranks 87th by listed-cause count (one listed cause) and 95th by assessed size among the 263 with an area filed; it sits in the not-supporting set (143 statewide) . Its listed causes include Mercury, which also appears among Alabama's most-filed impairment causes (led by Mercury).
| Other large assessed lakes in Alabama | Assessed acres |
|---|---|
| Tennessee River (Lake Guntersville) Fully Supporting | 20,440 |
| Wheeler Lake Not Supporting | 18,705 |
| Tallapoosa River (Lake Martin) Fully Supporting | 15,867 |
| Coosa River (Weiss Lake) Not Supporting | 15,066 |
| Tennessee River (Wheeler Lake) Not Supporting | 13,441 |
| Tennessee River (Wilson Lake) Not Supporting | 13,363 |
Peers near Little Cahaba River (Lake Purdy)'s size or cause load
Similar assessed acres
Nearest filed extents (962 acres here).
- Whitney Reservoir · 962 acres · NE
- Florence Lake · 962 acres · CA
- Reedy Fork(including Lake Brandt and Lake Townsend below nor · 964 acres · NC
- Boca Reservoir · 964 acres · CA
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
- The listing here is on a fishery use, not on fish consumption, and this state reported no consumption verdict for this reservoir. Your state fish-advisory program is the source for whether the catch is safe to eat. 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 AL03150202-0103-102. 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.