Sweet Briar Dam-Mid Reservoir
Morton County, North DakotaView mapDirections
ND DEQ publishes the water-quality measurements for Sweet Briar Dam-Mid Reservoir. Here is what has been measured.
- Hypereutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- Public access
- Limited data
Sweet Briar Dam-Mid Reservoir in Morton County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 239.5 µg/L. Chlorophyll-a (algae): 36.9 µg/L.
Sweet Briar Dam-Mid Reservoir is a highly nutrient-loaded hypereutrophic lake in Morton County, North Dakota. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 3 other monitored lakes in Morton County, Sweet Briar Dam-Mid Reservoir ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2024-08-06. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Sweet Briar Dam-Mid Reservoir is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Sweet Briar Dam-Mid Reservoir is safe to swim in today is a call for the North Dakota Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Sweet Briar Dam-Mid Reservoir
These are the measurements ND DEQ publishes for Sweet Briar Dam-Mid Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3 ft of visibility. Phosphorus 239.5 µg/L. Chlorophyll-a 36.9 µg/L. TSI 70.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 240µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 36.9µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 70 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Sweet Briar Dam-Mid Reservoir
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Sweet Briar Dam-Mid Reservoir typically sits around 44°F at the surface in October. Summer average is about 64°F. Usually warmest in Jun (about 74°F) and coldest in Oct (about 44°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (44°F) to its warmest (74°F).
Typical surface water temperature by month, from 25 field readings (2022–2023) via the EPA Water Quality Portal. See the full Sweet Briar Dam-Mid Reservoir water temperature breakdown →
Stays via Stay22
Stays near Sweet Briar Dam-Mid Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Sweet Briar Dam-Mid Reservoir in Morton County, North Dakota — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Sweet Briar Dam-Mid Reservoir are listed below.
Top-rated places to stay near Sweet Briar Dam-Mid Reservoir
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at North Dakota’s top lakes →
Follow Sweet Briar Dam-Mid Reservoir’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Sweet Briar Dam-Mid Reservoir
Water quality readings over time
3 seasons of samples on record (2022–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Worsening+62.5 µg/L/yr3 years
Chlorophyll-a
Improving-29.3 µg/L/yr3 years
EPA Impairment Status
Sweet Briar Dam-Mid Reservoir 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
Nearby Lakes in Morton County
Frequently asked questions about Sweet Briar Dam-Mid Reservoir
Where is Sweet Briar Dam-Mid Reservoir?
- Sweet Briar Dam-Mid Reservoir is a lake in Morton County, North Dakota. Its water-quality measurements are published by ND DEQ and shown on this page as reported.
What is the water quality of Sweet Briar Dam-Mid Reservoir?
- Sweet Briar Dam-Mid Reservoir in Morton County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 239.5 µg/L. Chlorophyll-a (algae): 36.9 µg/L.
Is Sweet Briar Dam-Mid Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Sweet Briar Dam-Mid Reservoir is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Sweet Briar Dam-Mid Reservoir?
- Sweet Briar Dam-Mid Reservoir typically sits around 44°F at the surface in October, from 25 EPA Water Quality Portal field readings (2022–2023). That is a typical value for the month, not a live reading.
Can I fish at Sweet Briar Dam-Mid Reservoir?
- Public access to Sweet Briar Dam-Mid Reservoir is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by North Dakota's fish and wildlife agency, so check its current regulations before you go.
Explore Sweet Briar Dam-Mid Reservoir across LakeQuality
More lakes in North Dakota
Other Lakes in North Dakota
Hypereutrophic Lakes in North Dakota
Where this data comes from
45 measurements from 1 monitoring station, 2022–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX45 samples · 2022–2024
Analytical methods
- Phosphorus by Colorimetry
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 4500 NO3 E ~ Nitrate in Water- Cadmium Reduction
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database