Port Perry Lake South Arm
Perry County, Missouri187 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
↑ up from B at the last regrade
- Mesotrophic
- #2 of 3 in the county
- Limited data
Port Perry Lake South Arm in Perry County, Missouri has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 8.3 µg/L. Chlorophyll-a (algae): 2.3 µg/L. Surface area: 187 acres.
- Clarity
- 9.5 ft
- Area
- 187 acres
- Type
- Mesotrophic
- Phosphorus
- 8.3 µg/L
- Chlorophyll-a
- 2.3 µg/L
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Watch Port Perry Lake South Arm’s letter
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Port Perry Lake South Arm is a 187-acre mesotrophic lake in Perry County, Missouri. Water quality is graded A based on 2 sampling years through 2024. Compared to the 2 other monitored lakes in Perry County, Port Perry Lake South Arm ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-09-17. 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 A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 9.5 ft. Phosphorus 8.3 µg/L. Chlorophyll-a 2.3 µg/L. TSI 39. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | Not graded |
| Phosphorus | 8.3 µg/L | Good |
| Chlorophyll-a (Algae) | 2.3 µg/L | Good |
| Trophic State Index (TSI) | 39 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 187 acres |
No bathymetric survey has been published for Port Perry Lake South Arm, so its depth is not documented here.
Fishing Port Perry Lake South Arm
Reservoir Info (USACE NID)
Port Perry Lake South Arm is a man-made reservoir impounded by the Port Perry Dam (completed 1973), built primarily for recreation on the TR NATIONS CREEK; earth-type dam, 70 ft tall and 900 ft long.
- Surface area
- 187 ac
- Normal storage
- 828 ac-ft
- Max storage
- 6,506 ac-ft
- Drainage area
- 3.11 sq mi
- Hazard class
- High
Source: USACE National Inventory of Dams, NID ID MO30030 · Operator website · Matched by proximity (0.73 km)
County Ranking
Ranked #2 of 3 lakes in Perry County
Nearby Lakes in Perry County
Frequently asked questions about Port Perry Lake South Arm
Where is Port Perry Lake South Arm?
- Port Perry Lake South Arm is a lake in Perry County, Missouri. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Port Perry Lake South Arm?
- Port Perry Lake South Arm in Perry County, Missouri has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 8.3 µg/L. Chlorophyll-a (algae): 2.3 µg/L. Surface area: 187 acres.
Is Port Perry Lake South Arm safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Port Perry Lake South Arm across LakeQuality
More Missouri Lake Rankings
Other Grade A Lakes in Missouri
Mesotrophic Lakes in Missouri
Where this data comes from
21 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC21 samples · 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)
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.