What is the water quality grade for Shepard Mountain Lake Intake?

Shepard Mountain Lake Intake in Iron County, Wisconsin received a water quality grade of D (Poor). Water clarity: 2.8 ft visibility. Phosphorus: 37 µg/L. Chlorophyll-a (algae): 18.3 µg/L. Surface area: 21 acres.

Is Shepard Mountain Lake Intake safe to swim in?

Swimming not recommended, poor water quality with high algae risk. Shepard Mountain Lake Intake has an overall water quality grade of D. Algae concentration (chlorophyll-a) is 18.3 µg/L. Always check local health department advisories before swimming.

Shepard Mountain Lake Intake

Iron County, WisconsinEutrophic

Shepard Mountain Lake Intake is a 21-acre productive, nutrient-rich eutrophic lake in Iron County, MO. Water quality is graded D based on 3 sampling years through 2020. Compared to the 1 other monitored lakes in Iron County, Shepard Mountain Lake Intake ranks #2 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2020-09-01. Grade methodology: LakeGrade methodology.

Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Very murky, less than 2.8 ft of visibility. Phosphorus level: 37 µg/L. Chlorophyll-a: 18.3 µg/L. Trophic State Index: 59.

Metric	Value	Grade
Water Clarity (Secchi Depth)	2.8 ft	F
Phosphorus	37 µg/L	C
Chlorophyll-a (Algae)	18.3 µg/L	C
Trophic State Index (TSI)	59	Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

Characteristic	Value
Surface Area	21 acres

Location

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County Ranking

Ranked #2 of 2 lakes in Iron County

Cleaner Lakes Within 30 Miles

Shepard Mountain Lake Intake holds Grade D. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Iron County

Lake Marseilles-Terre du Lac Lakes

St. Francois County

Lake Shayne-Terre du Lac Lakes

More Wisconsin Lake Rankings

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Top 25 by overall water quality score

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Grade A/B + low algae filter

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Panfish-rich, public access

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Other Grade D Lakes in Wisconsin

Boathouse Lake

St. Louis city County · Clarity: 2.3 ft

Hunnewell Lake

Shelby County · Clarity: 3.2 ft

Long Branch Lk. Lake

Macon County · Clarity: 1.8 ft

Harrison County Lake Intake

Harrison County · Clarity: 1.7 ft

Table Rock L. Bl. Hwy. 173 Lake

Stone County · Clarity: 2.3 ft

Henry Sever Lake

Knox County · Clarity: 2.1 ft

Eutrophic Lakes in Wisconsin

Aspen Lake Along Southern Arm Boathouse Lake Hunnewell Lake Long Branch Lk. Lake

Reservoir Info (USACE NID)

Shepard Mountain Lake Intake is a man-made reservoir impounded by the Shepard Mountain Dam (completed 1955), built primarily for recreation on the TR-STOUTS CREEK; gravity-type dam, 33 ft tall.

Surface area: 21 ac
Normal storage: 168 ac-ft
Max storage: 371 ac-ft
Drainage area: 4,525 sq mi
Hazard class: High
Owner: CITY OF IRONTON

All listed purposes: Recreation;Water Supply.

Source: USACE National Inventory of Dams, NID ID MO30324 · Operator website · Matched by proximity (0.04 km)

EPA Impairment Status

Shepard Mountain Lake Intake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).

Causes of impairment

Algal growth

Source: EPA ATTAINS assessment unit MO_7333.00 · Official waterbody report · Matched by proximity (0.33 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Most recent sample: 2020-09-01

Monitoring stations: 1