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LakeQuality
D

Tappan Lake

Harrison County, WisconsinLimited DataEutrophic

Tappan Lake is a 2,350-acre productive, nutrient-rich eutrophic lake in Harrison County, OH. Water quality is graded D based on 1 sampling years through 2020. Compared to the 1 other monitored lakes in Harrison County, Tappan Lake ranks #1 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2020-12-01. Grade methodology: LakeGrade methodology.

Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

No clarity data. Phosphorus level: 77 µg/L. Trophic State Index: 67.

MetricValueGrade
Water Clarity (Secchi Depth)No data
Phosphorus77 µg/LD
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)67Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Surface Area2.4K acres

Location

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County Ranking

Ranked #1 of 2 lakes in Harrison County

Nearby Lakes in Harrison County

Reservoir Info (USACE NID)

Tappan Lake is a man-made reservoir impounded by the Tappan Dam (completed 1936), built primarily for flood risk reduction on the LITTLE STILLWATER CREEK; earth-type dam, 52 ft tall and 1,550 ft long.

Surface area
2,350 ac
Normal storage
35,100 ac-ft
Max storage
61,600 ac-ft
Drainage area
71 sq mi
Hazard class
High
Owner
USACE - Huntington District

All listed purposes: Flood Risk Reduction;Fish and Wildlife Pond;Recreation.

Source: USACE National Inventory of Dams, NID ID OH00010 · Operator website

EPA Impairment Status

Tappan Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Algal growth

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit OH050400011503 · Official waterbody report · Matched by proximity (2.08 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: 2020-12-01

Monitoring stations: 1