New Jersey multi-water assessment unit · state assessment record
Spruce Run Reservior / Willoughby Brook
Assessment decisions reported by New Jersey to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle.
- 35
- Acres of lake water
- Lake
- Water type
This waterbody in one line
Spruce Run Reservior / Willoughby Brook, a multi-water assessment unit in New Jersey, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2022). By assessed acreage it sits below the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (3 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting. Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P46
- Assessed size nationally
- P5
- Shorter cause list
- Not Supporting
- aquatic life
The state agency files this as one assessment unit spanning 35.18 acres of lake water and 15.46 miles of stream and river. The verdicts and listed causes below are reported for the whole unit, not for the lake water alone. 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 Spruce Run Reservior / Willoughby Brook 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: cause-list length
The standout filed fact is cause-list length: 3 listed impairment causes, a longer list than 90% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
Every ruled-on use is not supporting
On the uses this filer ruled on, fish consumption, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Spruce Run Reservior / Willoughby Brook: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Spruce Run Reservior / Willoughby Brook. 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 Spruce Run Reservior / Willoughby Brook is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Mid-pack inside New Jersey
Size rank 231 of 588 inside New Jersey is mid-pack; the national percentile is the better scale comparison for this unit.
According to the U.S. Environmental Protection Agency's ATTAINS program, New Jersey carries 611 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Spruce Run Reservior / Willoughby Brook 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 | Aquatic-life or related | Not Supporting |
| Aquatic Life - Trout | Aquatic-life or related | Not Supporting |
| Fish Consumption | Fish-consumption or fishery | Not Supporting |
| Public Water Supply | Drinking-water supply designation | Fully Supporting |
| Primary Contact Recreation | Recreation | Insufficient Information |
| Secondary Contact Recreation | Recreation | Not Assessed |
| Shellfish Harvesting | Fish-consumption or fishery | Not Assessed |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this multi-water assessment unit, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Temperature | Aquatic Life - Trout Also assessed as meeting: Aquatic Life | 2002 | TMDL priority: Medium |
| pH | Aquatic Life, Aquatic Life - Trout | 2002 | TMDL priority: Medium |
| Mercury in Fish Tissue | Fish Consumption | 2008 | TMDL approved |
Reading the record
What this co-filed unit covers
15.46 miles of stream and river co-filed on this unit
The state agency files this as one assessment unit spanning 35.18 acres of lake water and 15.46 miles of stream and river. The verdicts and listed causes below are reported for the whole unit, not for the lake water alone.
This page is about the lake water in the unit; counts and verdicts below cover the whole multi-water assessment unit. How multi-water units are filed.
Scale and rank
Spruce Run Reservior / Willoughby Brook is one of 611 lake-type waterbodies reported to EPA from New Jersey, and one of 588 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 35 assessed acres it ranks 20,805th 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 20,804 lakes with a larger one.
Awaiting a filing
The state has not yet filed a definitive recreation verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
In context
Where Spruce Run Reservior / Willoughby Brook 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
35 Top 54% larger than 46% 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
3 Longer than most more listed causes than 90% 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 Spruce Run Reservior / Willoughby Brook. Hover or tap any bar for its full count and share.
In context
New Jersey context
ATTAINS carries 611 lake-type waterbodies in New Jersey, 583 assessed as not supporting at least one use and 21 fully supporting. Among the 588 indexed units there, Spruce Run Reservior / Willoughby Brook ranks 300th by listed-cause count (3 listed causes) and 231st by assessed size among the 588 with an area filed; it sits in the not-supporting set (583 statewide) . Its listed causes include Mercury in Fish Tissue, which also appears among New Jersey's most-filed impairment causes (led by Arsenic). It also lists Temperature and pH, outside that top-five list.
| Other large assessed lakes in New Jersey | Assessed acres |
|---|---|
| Wanaque Reservior (below Monks gage) Not Supporting | 2,599 |
| Lake Hopatcong Not Supporting | 2,583 |
| Prescott Brook / Round Valley Reservior Not Supporting | 2,297 |
| Merrill Creek Not Supporting | 1,298 |
| Wallkill R / Lake Mohawk(above Sparta Sta) Not Supporting | 975 |
| Wanaque R/Greenwood Lk(aboveMonks gage) Not Supporting | 881 |
Peers near Spruce Run Reservior / Willoughby Brook's size or cause load
Similar assessed acres
Nearest filed extents (35 acres here).
- Carlson · 35 acres · MN
- Smith Lake · 35 acres · WI
- Sphinx Lakes (Tulare County) · 35 acres · CA
- Williams · 35 acres · MN
Similar cause load
Nearest listed-cause counts (3 here). Peers already in the acreage column are omitted.
- 67th St. Beach · 3 causes · IL
- Abiquiu Reservoir · 3 causes · NM
- Agate Reservoir · 3 causes · OR
- Agnes · 3 causes · MN
What to do with this record
- The fish-consumption use is assessed as not supporting. Before eating fish from this multi-water assessment unit, check your state fish-advisory program for species-specific meal limits. 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 NJ02030105020040-01. 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.