What is the water quality grade for Portage Lake Southwest Basin; Mendon Township?

Portage Lake Southwest Basin; Mendon Township in St. Joseph County, Wisconsin received a water quality grade of D (Poor). Water clarity: 5 ft visibility.

Is Portage Lake Southwest Basin; Mendon Township safe to swim in?

Swimming not recommended, poor water quality with high algae risk. Portage Lake Southwest Basin; Mendon Township has an overall water quality grade of D. Always check local health department advisories before swimming.

What fish are in Portage Lake Southwest Basin; Mendon Township?

Fish species found in Portage Lake Southwest Basin; Mendon Township include Chestnut lamprey, Common shiner, Rainbow darter. Portage Lake Southwest Basin; Mendon Township is located in St. Joseph County, Wisconsin.

Portage Lake Southwest Basin; Mendon Township

St. Joseph County, WisconsinLimited DataEutrophic

Portage Lake Southwest Basin; Mendon Township is a productive, nutrient-rich eutrophic lake in St. Joseph County, MI. Water quality is graded D based on 1 sampling years through 2023. The lake supports 3 documented fish species including Chestnut lamprey, Common shiner, and Rainbow darter. Compared to the 12 other monitored lakes in St. Joseph County, Portage Lake Southwest Basin; Mendon Township ranks #9 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2023-09-10. Grade methodology: LakeGrade methodology.

Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Murky, only visible to about 5 ft. Trophic State Index: 54.

Metric	Value	Grade
Water Clarity (Secchi Depth)	5 ft	D
Phosphorus	No data
Chlorophyll-a (Algae)	No data
Trophic State Index (TSI)	54	Eutrophic

High nutrients, frequent algae, reduced clarity

Fish Species

Chestnut lamprey Common shiner Rainbow darter

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Portage Lake Southwest Basin; Mendon Township (14-day solunar calendar)

→ Is it safe to eat fish from Portage Lake Southwest Basin; Mendon Township? (mercury & PFAS guide)

→ Portage Lake Southwest Basin; Mendon Township fishing regulations (limits, seasons, special rules)

Location

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County Ranking

Ranked #9 of 13 lakes in St. Joseph County

Cleaner Lakes Within 30 Miles

Portage Lake Southwest Basin; Mendon Township holds Grade D. 4 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in St. Joseph County

Corey Lake

St. Joseph County

Corey Lake Southeastern Basin; Fabius Township

St. Joseph County

Klinger Lake Central Basin; White Pigeon Township Section 1

St. Joseph County

Fishers Lake North Central Basin; Park Township

More Wisconsin Lake Rankings

Cleanest lakes in Wisconsin

Top 25 by overall water quality score

Best swimming lakes in Wisconsin

Grade A/B + low algae filter

Family fishing lakes in Wisconsin

Panfish-rich, public access

All Wisconsin lakes

Full state directory

Other Grade D Lakes in Wisconsin

Kimball Lake

Newaygo County · Clarity: 4.5 ft

Community College Pond

Chippewa County · Clarity: 1.5 ft

Little Beaver Lake

Alger County · Clarity: 6.2 ft

Van Etten Lake

Iosco County · Clarity: 5.5 ft

South Pond

Chippewa County · Clarity: 1.3 ft

Eagle Lake

Cass County · Clarity: 6 ft

Eutrophic Lakes in Wisconsin

Kimball Lake Van Etten Lake North Central Basin; Oscoda Township Community College Pond Pentwater Lake Northwest Basin; Pentwater Township

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2023-09-10

Monitoring stations: 1