Colorado reservoir · state assessment record
Lake and reserviors tributary to the South Platte River
The assessment record reported by Colorado to EPA under Clean Water Act sections 303(d) and 305(b).
- 5,770
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
Lake and reserviors tributary to the South Platte River, a reservoir in Colorado, was reported but not assessed in the state's most recent Integrated Report. By assessed acreage it sits among the largest 1% of assessed lakes nationally (38,628 lakes with a filed area).
- Not Assessed
- overall status
- P99
- Assessed size nationally
Assessment verdicts are the state agency's decisions as reported to EPA ATTAINS; PlainLakes renders them without modification.
Reading Lake and reserviors tributary to the South Platte River'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 Lake and reserviors tributary to the South Platte River nationally is assessed size: 5,770 acres, larger than 99% of the 38,628 lake-type units with an area on file.
IR category 3 on Lake and reserviors tributary to the South Platte River
The Integrated Report category filed for Lake and reserviors tributary to the South Platte River is 3. PlainLakes renders EPA's code without remapping it into a consumer grade.
Overall status: Not Assessed
ATTAINS overall status on this unit is “Not Assessed”. PlainLakes does not rewrite that vocabulary into a consumer score.
According to the U.S. Environmental Protection Agency's ATTAINS program, Colorado carries 344 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Lake and reserviors tributary to the South Platte River 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 |
|---|---|---|
| Agriculture | Other | Not Assessed |
| Aquatic Life Warm Water-Class 2 | Aquatic-life or related | Not Assessed |
| Recreation | Recreation | Not Assessed |
| Water Supply | Drinking-water supply designation | Not Assessed |
The record
Listed impairment causes
The state reported this reservoir in its most recent Integrated Report but reached no assessment determination, so no causes are listed. The unit is recorded under EPA integrated-reporting Category 3: reviewed, with insufficient information to determine whether it meets water-quality standards. An undetermined waterbody is neither confirmed clean nor confirmed impaired.
Reading the record
What Lake and reserviors tributary to the South Platte River's record holds
Scale and rank
Lake and reserviors tributary to the South Platte River is one of 344 lake-type waterbodies reported to EPA from Colorado. It is not among the 122 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 5,770 assessed acres it ranks 542nd 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 541 lakes with a larger one.
What this record holds
Colorado filed this reservoir in its most recent Integrated Report but reached no determination, so the record holds that filing and its use rows, but no verdict, and with nothing judged, no impairment cause to track over time. The state has not yet filed a definitive fish-consumption verdict, a definitive recreation verdict, a definitive aquatic-life verdict, and 1 other for this record; those fields populate when it reports them in a future Integrated Report cycle.
In context
Where Lake and reserviors tributary to the South Platte River 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
5,770 Top 1% larger than 99% 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
In both charts each bar is a band and taller bars hold more waterbodies; the dashed line and filled bar mark Lake and reserviors tributary to the South Platte River. Hover or tap any bar for its full count and share.
In context
Colorado context
ATTAINS carries 344 lake-type waterbodies in Colorado, 89 assessed as not supporting at least one use and 74 fully supporting.
| Other large assessed lakes in Colorado | Assessed acres |
|---|---|
| John Martin Reservoir. Not Supporting | 17,147 |
| Blue Mesa Reservoir Fully Supporting | 8,957 |
| Lake Granby. Not Supporting | 7,036 |
| Two Buttes Reservoir, Two Buttes Pond, Hasty Lake, Holbrook Reservoir, Burchfield Lake, Nee-Skah (Queens) Reservoir, Neeso Pah Reservoir, Nee Noshe Reservoir. Fully Supporting | 6,123 |
| Lake Meredith. Not Supporting | 5,531 |
| Adobe Creek Reservoir. Not Supporting | 4,784 |
Lakes near Lake and reserviors tributary to the South Platte River's assessed acres
Similar assessed acres
Nearest filed extents (5,770 acres here).
- Lake Claiborne · 5,769 acres · LA
- Lake O' the Pines · 5,772 acres · TX
- Lake Buchanan · 5,768 acres · TX
- Jim L. Chapman Lake (formerly Cooper Lake) · 5,761 acres · TX
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 COSPLS04_B. 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.