Tennessee reservoir · state assessment record
City Lake Portland
Assessment decisions reported by Tennessee to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle.
- 34
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
City Lake Portland, a reservoir in Tennessee, is assessed as not supporting one or more designated uses, with 4 listed impairment causes in the state's most recent Integrated Report cycle (2024). By assessed acreage it sits below the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (4 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P45
- Assessed size nationally
- P3
- 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.
City Lake Portland 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: 4 listed impairment causes, a longer list than 95% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
No ruled-on use clears the bar
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.
City Lake Portland: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for City Lake Portland. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Small within Tennessee
State size rank 72 of 73 puts City Lake Portland toward the small end of Tennessee's indexed lake-type units with an area.
Overall status: not supporting
The filer's overall status for City Lake Portland is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
According to the U.S. Environmental Protection Agency's ATTAINS program, Tennessee carries 117 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to City Lake Portland 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. Tennessee filed its own confidence on the 4 definitive verdicts it rated: Fair and 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 |
|---|---|---|
| Domestic Water Supply | Drinking-water supply designation | Not Supporting Filer confidence: Fair |
| Fish and Aquatic Life | Aquatic-life or related | Not Supporting Filer confidence: Fair |
| Irrigation | Other | Fully Supporting Filer confidence: Good |
| Livestock Watering and Wildlife | Other | Fully Supporting Filer confidence: Good |
| Recreation | Recreation | Not Assessed |
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 |
|---|---|---|---|
| Dissolved Oxygen | Fish and Aquatic Life | 1998 | TMDL priority: Low |
| Nutrients | Fish and Aquatic Life | 1998 | TMDL priority: Low |
| Sedimentation/Siltation | Fish and Aquatic Life | 1998 | TMDL priority: Low |
| Taste | Domestic Water Supply | 1998 | 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.
- Dissolved Oxygen
- Municipal (Urbanized High Density Area) (suspected) Animal Feeding Operations (NPS) (suspected)
- Nutrients
- Municipal (Urbanized High Density Area) (suspected) Animal Feeding Operations (NPS) (suspected)
- Sedimentation/Siltation
- Municipal (Urbanized High Density Area) (suspected) Animal Feeding Operations (NPS) (suspected)
- Taste
- Animal Feeding Operations (NPS) (suspected)
Reading the record
Where City Lake Portland sits among peers
11 of 16 Tennessee lakes assessed this deeply also came out mixed
Tennessee ruled definitively on 4 designated uses at City Lake Portland and found 2 of 4 not supported. The dataset shows 16 Tennessee lakes judged to that same depth.
Tennessee's assessed lakes are most often judged on 5 or more uses; this one was judged on 4.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 0 | 0 | 0 | 5 | 13 |
| Mixed | Not possible | 0 | 3 | 11 (this record) | 31 |
| None supported | 10 | 2 | 1 | 0 | 0 |
Ringed cell: City Lake Portland. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
City Lake Portland is one of 117 lake-type waterbodies reported to EPA from Tennessee, and one of 73 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 34 assessed acres it ranks 21,134th 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 21,133 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 City Lake Portland 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
34 Top 55% larger than 45% 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
4 Longer than most more listed causes than 95% 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 City Lake Portland. Hover or tap any bar for its full count and share.
In context
Tennessee context
ATTAINS carries 117 lake-type waterbodies in Tennessee, 60 assessed as not supporting at least one use and 16 fully supporting. Among the 73 indexed units there, City Lake Portland ranks 9th by listed-cause count (4 listed causes) and 72nd by assessed size among the 73 with an area filed; it sits in the not-supporting set (60 statewide) . Its listed causes include Dissolved Oxygen; Nutrients; and Sedimentation/Siltation, which also appear among Tennessee's most-filed impairment causes (led by Mercury in Fish Tissue). It also lists Taste, outside that top-five list.
| Other large assessed lakes in Tennessee | Assessed acres |
|---|---|
| Kentucky Reservoir Fully Supporting | 99,500 |
| Chickamauga Reservoir Fully Supporting | 35,400 |
| Watts Bar Reservoir Not Supporting | 34,075 |
| Douglas Reservoir Fully Supporting | 30,400 |
| Old Hickory Reservoir Fully Supporting | 27,439 |
| Cherokee Reservoir Not Supporting | 25,964 |
Peers near City Lake Portland's size or cause load
Similar assessed acres
Nearest filed extents (34 acres here).
- Ashuelot River Dam Pond · 34 acres · NH
- August A Busch Lake Number 34 · 34 acres · MO
- Bar-Dew Lake · 34 acres · OK
- Bartley Lake · 34 acres · IN
Similar cause load
Nearest listed-cause counts (4 here). Peers already in the acreage column are omitted.
- Agency Lake · 4 causes · OR
- Alachua Sink · 4 causes · FL
- Aldrich Pond · 4 causes · MA
- American Falls Reservoir (Snake River) · 4 causes · ID
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 TN05110002CITYLKPO_1000. 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.