Highland Silver Lake
Madison County, IllinoisView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Mercury
- #2 of 2 in the county
- 49 ft max depth
- Public access
- Limited data
Highland Silver Lake in Madison County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 123 µg/L. Chlorophyll-a (algae): 57.3 µg/L.
- Clarity
- 1.3 ft
- Typical in August
- 81°F
- Max depth
- ~49 ft est.
- Type
- Hypereutrophic
- Public access
- Yes
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Stays near Highland Silver Lake
Compare lakeside cabins, hotels, and vacation rentals near Highland Silver Lake in Madison County, Illinois — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Highland Silver Lake are listed below.
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Highland Silver Lake is a highly nutrient-loaded hypereutrophic lake in Madison County, Illinois with an estimated average depth of about 49 feet. Water quality is graded F based on 2 sampling years through 2022. Limited fish-species data available. Public access is available. Compared to the 1 other monitored lakes in Madison County, Highland Silver Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-10-26. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The F is nutrients and algae, not a swimming clearance. Highland Silver Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.3 ft of visibility. Phosphorus 123 µg/L. Chlorophyll-a 57.3 µg/L. TSI 72. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 ft | Not graded |
| Phosphorus | 123 µg/L | Poor |
| Chlorophyll-a (Algae) | 57.3 µg/L | Poor |
| Trophic State Index (TSI) | 72 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Highland Silver Lake typically sits around 81°F at the surface in August. Summer average is about 82°F. Usually warmest in Jul (about 85°F) and coldest in Apr (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 36 field readings (2014–2022) via the EPA Water Quality Portal. See the full Highland Silver Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~49 ft est. |
| Average Depth | ~16 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Highland Silver Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Highland Silver Lake
Reservoir Info (USACE NID)
Highland Silver Lake is a man-made reservoir impounded by the Silver Lake Dam (completed 1962), built primarily for water supply on the EAST FORK SILVER CREEK; earth-type dam, 29 ft tall and 2,780 ft long.
- Normal storage
- 4,224 ac-ft
- Max storage
- 9,945 ac-ft
- Hazard class
- Significant
- Owner
- CITY OF HIGHLAND
Source: USACE National Inventory of Dams, NID ID IL00178 · Operator website
EPA Impairment Status
Highland Silver Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_ROZA · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Highland Silver Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Highland Stp, City OfHighland · 4.9 mi away · NPDES IL0029173MajorRecent violation
- Munie Trucking Co.-HighlandHighland · 1.7 mi away · NPDES IL0068861
- Transcanada Keystone Pipeline, L.P.Wood River · 2.1 mi away · NPDES IL0078956
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #2 of 2 lakes in Madison County
Nearby Lakes in Madison County
Frequently asked questions about Highland Silver Lake
Where is Highland Silver Lake?
- Highland Silver Lake is a lake in Madison County, Illinois. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Highland Silver Lake?
- Highland Silver Lake in Madison County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 123 µg/L. Chlorophyll-a (algae): 57.3 µg/L.
Is Highland Silver Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Highland Silver Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides. Check local advisories before you swim.
What is the water temperature of Highland Silver Lake?
- Highland Silver Lake typically sits around 81°F at the surface in August, from 36 EPA Water Quality Portal field readings (2014–2022). That is a typical value for the month, not a live reading.
How deep is Highland Silver Lake?
- No published bathymetric survey covers Highland Silver Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 49 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Highland Silver Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Illinois's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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Planning a trip around Gateway Arch?
Highland Silver Lake is about 30 miles from Gateway Arch National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Gateway Arch →More Illinois Lake Rankings
Other Grade F Lakes in Illinois
Hypereutrophic Lakes in Illinois
Where this data comes from
40 measurements from 3 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX40 samples · 2022
Analytical methods
- MEASURED IN FIELD
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (3)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)