Sweetbriar Dam Lake is a 278-acre productive, nutrient-rich eutrophic lake in Morton County, North Dakota with a maximum depth of 30 feet (10-foot average). Water quality is graded F based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. The lake supports 8 documented fish species including Walleye, Yellow Perch, and Black Crappie. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Morton County, Sweetbriar Dam Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, North Dakota DNR, last sampled 2024-08-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 3 ft of visibility. Chlorophyll-a: 54 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 54 µg/L | F |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 29.9 ft |
| Average Depth | 10 ft |
| Surface Area | 278 acres |
| Shoreline Length | 10.5 mi |
| Public Access | Yes |
Where to stay near Sweetbriar Dam Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Sweetbriar Dam Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.32 m/yr | 2 |
| Chlorophyll-a | ↑ Improving | -29.3 µg/L/yr | 3 |
Recreation & Access
Location
County Ranking
Ranked #2 of 4 lakes in Morton County
Cleaner Lakes Within 30 Miles
Sweetbriar Dam Lake holds Grade F. 4 nearby lakes hold higher grades.
- BArroda LakeOliver County · 25.1 mi · Two grade letters higher (F → B)
- CEast Arroda LakeOliver County · 25.2 mi · Two grade letters higher (F → C)
- DNelson LakeOliver County · 13.8 mi · Higher grade (F → D)
- DNygren Dam LakeMorton County · 19.9 mi · Higher grade (F → D)
Nearby Lakes in Morton County
Explore Sweetbriar Dam Lake across LakeGrade
Fish species and top-graded lakes across North Dakota
Fish species and best lakes in Morton County
Species activity outlook by water temperature and season
Where to stay at North Dakota's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
North Dakota's cleanest and most-polluted lakes, ranked
More North Dakota Lake Rankings
Other Grade F Lakes in North Dakota
Eutrophic Lakes in North Dakota
More records, surveys & data sources
EPA Impairment Status
Sweetbriar Dam Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit ND-10130203-005-L_00 · Official waterbody report · Matched by proximity (0.16 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Depth, fish, and access data from North Dakota Game & Fish
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-08-06
Monitoring stations: 2