Borah Lake
Richland County, IllinoisView mapDirections
Nutrients and algae run above the regional average.
↑ up from F at the last regrade
- Eutrophic
- Impaired · Mercury
- #3 of 3 in the county
- 31 ft max depth
- Public access
- Limited data
Borah Lake in Richland County, Illinois has a water quality grade of D (Nutrient-rich). Water clarity: 2.2 ft visibility. Phosphorus: 153.5 µg/L. Chlorophyll-a (algae): 29 µg/L.
- Clarity
- 2.2 ft
- Typical in August
- 79°F
- Max depth
- ~31 ft est.
- Type
- Eutrophic
- Phosphorus
- 153.5 µg/L
- Chlorophyll-a
- 29 µg/L
- Public access
- Yes
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Stays near Borah Lake
Compare lakeside cabins, hotels, and vacation rentals near Borah Lake in Richland 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 Borah Lake are listed below.
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Borah Lake is a productive, nutrient-rich eutrophic lake in Richland County, Illinois with an estimated average depth of about 31 feet. Water quality is graded D based on 2 sampling years through 2022. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Richland County, Borah Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-10-13. Grade methodology: LakeQuality methodology.
What Borah Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
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 D is nutrients and algae, not a swimming clearance. Borah Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.2 ft of visibility. Phosphorus 153.5 µg/L. Chlorophyll-a 29 µg/L. TSI 69. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.2 ft | Not graded |
| Phosphorus | 153.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 29 µg/L | Poor |
| Trophic State Index (TSI) | 69 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Borah Lake typically sits around 79°F at the surface in August. Summer average is about 77°F. Usually warmest in Aug (about 79°F) and coldest in Apr (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 209 field readings (2014–2022) via the EPA Water Quality Portal. See the full Borah Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~31 ft est. |
| Average Depth | ~6 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 Borah 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.
Recreation & Access
- Borah LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Borah Lake
Reservoir Info (USACE NID)
Borah Lake is a man-made reservoir impounded by the M. D. Borah Lake Dam (completed 1953), built primarily for recreation on the TRIB FOX RIVER; earth-type dam, 36 ft tall and 960 ft long.
- Normal storage
- 2,060 ac-ft
- Max storage
- 4,720 ac-ft
- Hazard class
- High
- Owner
- CITY OF OLNEY
All listed purposes: Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID IL00331 · Operator website · Matched by proximity (0.87 km)
EPA Impairment Status
Borah 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_RCB · Official waterbody report · Matched by proximity (0.17 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Borah Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- West Liberty - Dundas Sanitary District StpDundas · 4.1 mi away · NPDES IL0077879Recent violation
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 #3 of 3 lakes in Richland County
Nearby Lakes in Richland County
Frequently asked questions about Borah Lake
Where is Borah Lake?
- Borah Lake is a lake in Richland County, Illinois. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Borah Lake?
- Borah Lake in Richland County, Illinois has a water quality grade of D (Nutrient-rich). Water clarity: 2.2 ft visibility. Phosphorus: 153.5 µg/L. Chlorophyll-a (algae): 29 µg/L.
Is Borah Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Borah Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Borah Lake?
- Borah Lake typically sits around 79°F at the surface in August, from 209 EPA Water Quality Portal field readings (2014–2022). That is a typical value for the month, not a live reading.
How deep is Borah Lake?
- No published bathymetric survey covers Borah Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 31 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Borah Lake?
- Borah Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Borah Lake. Public access is listed as yes.
Explore Borah Lake across LakeQuality
More Illinois Lake Rankings
Other Grade D Lakes in Illinois
Eutrophic Lakes in Illinois
Where this data comes from
42 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_WQX42 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)
Named boat-access points from the USGS National Boat Ramps inventory