Timberline Lakes
St. Francois County, Missouri42 acresView mapDirections
Missouri DNR publishes the water-quality measurements for Timberline Lakes. Here is what has been measured.
- Oligotrophic
- Impaired · Nutrients (phosphorus, nitrogen)
Timberline Lakes in St. Francois County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 14.3 ft visibility. Phosphorus: 5.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 42 acres.
Timberline Lakes is a 42-acre cold, clear oligotrophic lake in St. Francois County, Missouri. Overall water quality is declining over recent sampling years. Compared to the 3 other monitored lakes in St. Francois County, Timberline Lakes ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-09-21. Methodology: how these readings are compared.
Timberline Lakes covers about 42 acres in St. Francois County. For a place on the water, look through cabin and lake-house rentals near Timberline Lakes on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Timberline Lakes is good for
From access and monitoring records, not editorial picks.
- Clear water14.3 ft of visibility
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Timberline Lakes is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Timberline Lakes is safe to swim in today is a call for the Missouri Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Timberline Lakes
These are the measurements Missouri DNR publishes for Timberline Lakes, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 14.3 ft. Phosphorus 5.5 µg/L. Chlorophyll-a 1.6 µg/L. TSI 34.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 14.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 5.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.6µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 34 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Timberline Lakes
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Timberline Lakes typically sits around 77°F at the surface in September. Summer average is about 82°F. Usually warmest in Jul (about 84°F) and coldest in Apr (about 62°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (62°F) to its warmest (84°F).
Typical surface water temperature by month, from 52 field readings (2010–2024) via the EPA Water Quality Portal. See the full Timberline Lakes water temperature breakdown →
Lake Details
Surface area
42 acres
No bathymetric survey has been published for Timberline Lakes, so its depth is not documented here.
Stays via Stay22
Stays near Timberline Lakes
Compare lakeside cabins, hotels, and vacation rentals near Timberline Lakes in St. Francois County, Missouri — 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.
Top-rated places to stay near Timberline Lakes
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Fishing Timberline Lakes
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Worsening5 years
Phosphorus
Worsening+0.45 µg/L/yr5 years
Chlorophyll-a
Improving-0.13 µg/L/yr5 years
Reservoir Info (USACE NID)
Timberline Lakes is a man-made reservoir impounded by the Lake Timberline Dam (completed 1963), built primarily for recreation on the BEE RUN CREEK; earth-type dam, 79 ft tall and 760 ft long.
- Surface area
- 42 ac
- Normal storage
- 1,083 ac-ft
- Max storage
- 1,464 ac-ft
- Drainage area
- 1.95 sq mi
- Hazard class
- High
- Owner
- LAKE TIMBERLINE BOARD OF TRUST
Source: USACE National Inventory of Dams, NID ID MO30156 · Operator website · Matched by proximity (0.06 km)
EPA Impairment Status
Timberline Lakes is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life.
Source: EPA ATTAINS assessment unit MO_7304.00 · Official waterbody report
Regulated Pollution Sources Nearby
5 EPA-permitted facilities operate within about 5 miles of Timberline Lakes under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Eagle Estates WwtpBonne Terre · 0.5 mi away · NPDES MO0120260Recent violation
- Stone Park ResortBonne Terre · 1.7 mi away · NPDES MO0137464Recent violation
- Bonne Terre Nw WwtpBonne Terre · 3.9 mi away · NPDES MO0100706Recent violation
- Boopers WwtfValles Mines · 2.4 mi away · NPDES MO0127388
- Bonne Terre Northeast WwtpBonne Terre · 4.8 mi away · NPDES MO0121321
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.
Nearby Lakes in St. Francois County
Frequently asked questions about Timberline Lakes
Where is Timberline Lakes?
- Timberline Lakes is a lake in St. Francois County, Missouri. Its water-quality measurements are published by Missouri DNR and shown on this page as reported.
What is the water quality of Timberline Lakes?
- Timberline Lakes in St. Francois County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 14.3 ft visibility. Phosphorus: 5.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Surface area: 42 acres.
Is Timberline Lakes safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Timberline Lakes is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Timberline Lakes?
- Timberline Lakes typically sits around 77°F at the surface in September, from 52 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
Explore Timberline Lakes across LakeQuality
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Where this data comes from
117 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC117 samples · 2020–2024
Analytical methods
- Depth, Secchi disk in meters
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)