Aspen Lake Along Southern Arm
Warren County, Missouri146 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
↑ up from C at the last regrade
- Mesotrophic
- #7 of 16 in the county
Aspen Lake Along Southern Arm in Warren County, Missouri has a water quality grade of A (Excellent). Water clarity: 3.8 ft visibility. Phosphorus: 20.8 µg/L. Chlorophyll-a (algae): 5.3 µg/L. Surface area: 146 acres.
- Clarity
- 3.8 ft
- Typical in September
- 79°F
- Area
- 146 acres
- Type
- Mesotrophic
- Phosphorus
- 20.8 µg/L
- Chlorophyll-a
- 5.3 µg/L
- Trend
- ↓ Declining
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Watch Aspen Lake Along Southern Arm’s letter
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Aspen Lake Along Southern Arm is a 146-acre mesotrophic lake in Warren County, Missouri. Water quality is graded A based on 2 sampling years through 2021. Overall water quality is declining over recent sampling years. Compared to the 15 other monitored lakes in Warren County, Aspen Lake Along Southern Arm ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2021-09-27. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLow algae
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 A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Murky, only visible to about 3.8 ft. Phosphorus 20.8 µg/L. Chlorophyll-a 5.3 µg/L. TSI 51. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.8 ft | Not graded |
| Phosphorus | 20.8 µg/L | Good |
| Chlorophyll-a (Algae) | 5.3 µg/L | Good |
| Trophic State Index (TSI) | 51 | Mesotrophic |
Moderate nutrients, good water quality
Water Temperature
Aspen Lake Along Southern Arm typically sits around 79°F at the surface in September. Summer average is about 83°F. Usually warmest in Jul (about 87°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 87 field readings (2010–2021) via the EPA Water Quality Portal. See the full Aspen Lake Along Southern Arm water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 146 acres |
No bathymetric survey has been published for Aspen Lake Along Southern Arm, so its depth is not documented here.
Fishing Aspen Lake Along Southern Arm
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.035 m/yr | 5 |
| Phosphorus | ↓ Declining | +0.88 µg/L/yr | 5 |
| Chlorophyll-a | ↓ Declining | +0.33 µg/L/yr | 5 |
Reservoir Info (USACE NID)
Aspen Lake Along Southern Arm is a man-made reservoir impounded by the Lake Aspen Dam (completed 1979), built primarily for recreation on the TRIB CHARRETTE CREEK; earth-type dam, 53 ft tall and 650 ft long.
- Surface area
- 146 ac
- Normal storage
- 2,167 ac-ft
- Max storage
- 4,540 ac-ft
- Drainage area
- 7.46 sq mi
- Hazard class
- High
- Owner
- INNSBROOK OWNERS ASSOCIATION
Source: USACE National Inventory of Dams, NID ID MO31714 · Operator website · Matched by proximity (0.3 km)
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Aspen Lake Along Southern Arm under Clean Water Act (NPDES) discharge permits. 4 facilities have a reported Clean Water Act violation in the past three years.
- Innsbrook Estates WwtpWright City · 0.3 mi away · NPDES MO0098906Recent violation
- Oakview Estates WwtpWright City · 0.9 mi away · NPDES MO0125181Recent violation
- Odom WwtfWright City · 1.4 mi away · NPDES MO0120898Recent violation
- Wildwood Hills Subdivision WwtfWright City · 1.5 mi away · NPDES MO0087955Recent 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 #7 of 16 lakes in Warren County
Nearby Lakes in Warren County
Frequently asked questions about Aspen Lake Along Southern Arm
Where is Aspen Lake Along Southern Arm?
- Aspen Lake Along Southern Arm is a lake in Warren County, Missouri. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Aspen Lake Along Southern Arm?
- Aspen Lake Along Southern Arm in Warren County, Missouri has a water quality grade of A (Excellent). Water clarity: 3.8 ft visibility. Phosphorus: 20.8 µg/L. Chlorophyll-a (algae): 5.3 µg/L. Surface area: 146 acres.
Is Aspen Lake Along Southern Arm safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Aspen Lake Along Southern Arm?
- Aspen Lake Along Southern Arm typically sits around 79°F at the surface in September, from 87 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.
Explore Aspen Lake Along Southern Arm across LakeQuality
More Missouri Lake Rankings
Other Grade A Lakes in Missouri
Mesotrophic Lakes in Missouri
Where this data comes from
32 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC32 samples · 2020–2021
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)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)