Lake Alva Mid-Lake Deep
Missoula County, MontanaView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
↓ down from A at the last regrade
- Oligotrophic
- #7 of 40 in the county
- Limited data
Lake Alva Mid-Lake Deep in Missoula County, Montana has a water quality grade of B (Good). Water clarity: 21.6 ft visibility.
- Clarity
- 21.6 ft
- Type
- Oligotrophic
- Trend
- ↑ Improving
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Stays near Lake Alva Mid-Lake Deep
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Watch Lake Alva Mid-Lake Deep’s letter
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Lake Alva Mid-Lake Deep is a cold, clear oligotrophic lake in Missoula County, Montana. Water quality is graded B based on 1 sampling years through 2021. Overall water quality is improving over recent sampling years. Compared to the 39 other monitored lakes in Missoula County, Lake Alva Mid-Lake Deep ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2021-09-17. Grade methodology: LakeQuality methodology.
What Lake Alva Mid-Lake Deep is good for
From access and monitoring records, not editorial picks.
- Clear water21.6 ft of visibility
- Camping3 public campgrounds nearby
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 B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: B (Good)
Crystal clear, you can see 21.6 ft down. TSI 33. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 21.6 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 33 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Recreation & Access
Public campgrounds near Lake Alva Mid-Lake Deep
- Lake Alva Campground Complex1.0 km
- Lake Alva Cg Complex1.0 km
- Lakeside Cg (old Alva)2.1 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fishing Lake Alva Mid-Lake Deep
Water Quality Trend: ↑ Improving
Based on 12 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.046 m/yr | 8 |
| Phosphorus | → Stable | +0.11 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.4 µg/L/yr | 2 |
County Ranking
Ranked #7 of 40 lakes in Missoula County
Nearby Lakes With Higher Grades
Lake Alva Mid-Lake Deep holds Grade B. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Missoula County
Frequently asked questions about Lake Alva Mid-Lake Deep
Where is Lake Alva Mid-Lake Deep?
- Lake Alva Mid-Lake Deep is a lake in Missoula County, Montana. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Alva Mid-Lake Deep?
- Lake Alva Mid-Lake Deep in Missoula County, Montana has a water quality grade of B (Good). Water clarity: 21.6 ft visibility.
Is Lake Alva Mid-Lake Deep safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Are there campgrounds on Lake Alva Mid-Lake Deep?
- Lake Alva Mid-Lake Deep has 3 public campgrounds from USGS The National Map within 5 km, including Lake Alva Campground Complex, Lake Alva Cg Complex, Lakeside Cg (old Alva). This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Lake Alva Mid-Lake Deep across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Montana's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
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Other Grade B Lakes in Montana
Oligotrophic Lakes in Montana
Where this data comes from
66 measurements from 1 monitoring station, 2012–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Montana Volunteer Water Quality Monitoring
MTVOLWQM_WQX66 samples · 2012–2021
Analytical methods
- 4500 N C ~ Persufate Method for Total Nitrogen
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
Public campgrounds from USGS The National Map Structures, within about 3 miles