Detroit Lake
Marion County, Oregon3,490 acresView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
- Mesotrophic
- Impaired · Algal growth
- #1 of 1 in the county
- 90 ft max depth
- Public access
- Limited data
Detroit Lake in Marion County, Oregon has a water quality grade of B (Good). Phosphorus: 15 µg/L. Surface area: 3490 acres.
- Max depth
- ~90 ft est.
- Area
- 3,490 acres
- Type
- Mesotrophic
- Phosphorus
- 15 µg/L
- Public access
- Yes
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Detroit Lake is a 3,490-acre mesotrophic lake in Marion County, Oregon with an estimated average depth of about 90 feet. Water quality is graded B based on 1 sampling years through 2023. Limited fish-species data available. Public access is available with 4 public boat landings.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2023-08-15. Grade methodology: LakeQuality methodology.
What Detroit Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch4 documented ramps
- Big water3,490 acres
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. Detroit Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
Water Quality Grade: B (Good)
No clarity data. Phosphorus 15 µg/L. TSI 43. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Current Conditions
USGS snapshot Sep 7, 2026, 3:45 PM from gauge 14180500 (DETROIT LAKE NEAR DETROIT, OR). Station page ↗ — a live reading replaces this snapshot when the gauge responds. Missing live data is not an all-clear.
→ Detroit Lake water level: the live USGS gauge reading
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~90 ft est. |
| Surface Area | 3,490 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Oregon has not published bathymetry for Detroit Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Detroit Lake State Park - D RampPublic
- Big CliffPublic
- Mongold State ParkPublic
- Detroit Lake State Park - G RampPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Detroit Lake
Reservoir Info (USACE NID)
Detroit Lake is a man-made reservoir impounded by the Detroit Dam (completed 1953), built primarily for flood risk reduction on the North Santiam River; gravity-type dam, 463 ft tall and 1,580 ft long.
- Surface area
- 3,490 ac
- Normal storage
- 155,000 ac-ft
- Max storage
- 455,000 ac-ft
- Drainage area
- 438 sq mi
- Hazard class
- High
- Owner
- USACE - Portland District
All listed purposes: Flood Risk Reduction;Other;Irrigation;Navigation;Recreation;Hydroelectric.
Source: USACE National Inventory of Dams, NID ID OR00004 · Operator website
EPA Impairment Status
Detroit Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit OR_LK_1709000503_02_100768 · Official waterbody report
County Ranking
Ranked #1 of 1 lakes in Marion County
Nearby Lakes in Marion County
Frequently asked questions about Detroit Lake
Where is Detroit Lake?
- Detroit Lake is a lake in Marion County, Oregon. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Detroit Lake?
- Detroit Lake in Marion County, Oregon has a water quality grade of B (Good). Phosphorus: 15 µg/L. Surface area: 3490 acres.
Is Detroit Lake safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Detroit Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
How deep is Detroit Lake?
- No published bathymetric survey covers Detroit Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 90 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 3490 acres.
What is the water level at Detroit Lake?
- The USGS snapshot on this page for Detroit Lake is 1524.53 ft of water-surface elevation, recorded Sep 7, 2026, 3:45 PM at gauge 14180500. Current Conditions hydrates a live NWIS reading from that same station when the gauge responds. A missed live fetch is not an all-clear.
Are there boat ramps on Detroit Lake?
- Detroit Lake has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Detroit Lake State Park - D Ramp, Big Cliff, Mongold State Park, Detroit Lake State Park - G Ramp. Public access is listed as yes.
Explore Detroit Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
4 documented falls within 22.5 mi, nearest Henline Falls
3 thermal springs within 23.9 mi, nearest Breitenbush Hot Springs
Species activity outlook by water temperature and season
Where to stay at Oregon's top lakes, each with its grade
Moderate nutrients, good water quality
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Other Grade B Lakes in Oregon
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Where this data comes from
12 measurements from 4 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Oregon Water Science Center
USGS-OR12 samples · 2023
Analytical methods
- Nutrients, wu, WCA,persulfate,CF
Monitoring station identifiers (4)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory