Long Branch Lk. Lake is a 2,430-acre productive, nutrient-rich eutrophic lake in Macon County, Missouri. Water quality is graded D based on 3 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 3 other monitored lakes in Macon County, Long Branch Lk. Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-09-15. Grade methodology: LakeGrade methodology.
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Swimming Safety
Based on E. coli testing, Long Branch Lk. Lake rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 4.6% of 282 samples across 8 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Missouri’s current beach and health-department advisories before swimming.
Water Quality Grade: D, Poor
Very murky, less than 1.8 ft of visibility. Phosphorus level: 43.5 µg/L. Chlorophyll-a: 16.1 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.8 ft | F |
| Phosphorus | 43.5 µg/L | C |
| Chlorophyll-a (Algae) | 16.1 µg/L | C |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 2,430 acres |
Where to stay near Long Branch Lk. Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Branch Lk. Lake in Macon 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.
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Fishing Long Branch Lk. Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.008 m/yr | 5 |
| Phosphorus | → Stable | +0.1 µg/L/yr | 5 |
| Chlorophyll-a | ↑ Improving | -0.84 µg/L/yr | 5 |
Current Conditions
Latest reading Jul 6, 2026, 4:45 AM from USGS gauge 06906190. See live data ↗ — readings update every 15–60 minutes; this page refreshes on each build.
Water Temperature
Long Branch Lk. Lake averages about 79°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in Apr (about 54°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 92 field readings (2010–2024) via the EPA Water Quality Portal. See the full Long Branch Lk. Lake water temperature breakdown →
Location
County Ranking
Ranked #3 of 4 lakes in Macon County
Cleaner Lakes Within 30 Miles
Long Branch Lk. Lake holds Grade D. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Macon County
Explore Long Branch Lk. Lake across LakeGrade
More Missouri Lake Rankings
Other Grade D Lakes in Missouri
Randolph County · Clarity: 2.3 ft
Randolph County · Clarity: 1.6 ft
Randolph County · Clarity: 2.5 ft
Randolph County · Clarity: 2.5 ft
Randolph County · Clarity: 2.7 ft
Adair County · Clarity: 2.6 ft
Eutrophic Lakes in Missouri
Compare Long Branch Lk. Lake With Nearby Lakes
More records, surveys & data sources
Reservoir Info (USACE NID)
Long Branch Lk. Lake is a man-made reservoir impounded by the Long Branch Dam (completed 1978), built primarily for flood risk reduction on the EAST FORK LITTLE CHARITON; earth-type dam, 80 ft tall and 3,800 ft long.
- Surface area
- 2,430 ac
- Normal storage
- 35,000 ac-ft
- Max storage
- 98,000 ac-ft
- Drainage area
- 109 sq mi
- Hazard class
- High
- Owner
- USACE - Kansas City District
All listed purposes: Flood Risk Reduction;Other;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID MO11176 · Operator website
EPA Impairment Status
Long Branch Lk. Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MO_7168.00 · Official waterbody report · Matched by proximity (2.02 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Long Branch Lk. Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Mdnr, Long Branch State Park WwtfMacon · 1.2 mi away · NPDES MO0136212Recent violation
- Maple Hill LandfillMacon · 1.7 mi away · NPDES MO0117471Recent violation
- Bevier WwtfBevier · 3.3 mi away · NPDES MO0095214Recent 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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-15
Monitoring stations: 1