Tappan Lake is managed by U.S. Army Corps of Engineers / Muskingum Watershed Conservancy District. Lake Insights displays its latest available elevation from U.S. Geological Survey. Published reference elevations are listed below.
Lake Status
0.35 feet above full pool
+0.35 ft vs full pool
- 7-day trend
- Stable
- 7-day change
- Up 0.01 ft
- 30-day change
- Down 0.43 ft
- Last updated
- 5 hours ago
Tappan Lake is currently 0.35 feet above full pool and has remained relatively stable over the past seven days. Readings have been steady over the past week while the lake remains above full pool.
Key Facts
Managing authority
Waterbody / project type
Official purposes
Full pool
Winter pool
Datum
Current-level source
Project / NID identifier
Dam / watershed (NID design values)
Static design values from a confidently matched National Inventory of Dams record — not live gage readings.
- Normal storage
- 35,100 acre-ft
- Max storage
- 61,600 acre-ft
- Surface area at normal pool
- 2,350 acres
- Drainage area
- 71 sq mi
- Spillway capacity (design)
- 23,700 cfs
- Dam structure
- Earth · 52 ft high · completed 1936
- Hazard classification
- High
- Safety & inspection
- last inspection Apr 4, 2024 · EAP yes
National Inventory of Dams · matched record: Tappan Dam (OH00010)
How this lake is operated
- Documented project purposes (National Inventory of Dams): Flood Risk Reduction, Fish and Wildlife Pond, Recreation.
Why the level can change
General factors for reservoirs like this
These are common influences for this type of lake. They do not identify the cause of a specific current change unless an operator update confirms it.
Rainfall & inflows
Rain and upstream river inflows can raise reservoir levels, especially after storms.
Downstream releases
When an operator releases water through a dam, reservoir storage can fall and downstream flows can rise.
Flood-risk operations
Some projects store or release water under flood-risk rules when conditions require it.
Water supply
Some reservoirs support municipal, industrial, irrigation, or regional water-supply needs.
Hydropower
Hydropower projects may pass water through turbines when generating electricity.
Seasonal weather
Dry periods, heat, evaporation, and seasonal rainfall patterns can affect storage over weeks and months.
Published reference elevations
- Full pool
- 899.00 ft
- Winter / seasonal pool
- 894.00 ft
Published reference elevation. Not necessarily a fixed year-round target for every project.
A winter / seasonal pool elevation is published, but Lake Insights does not have verified seasonal operating dates for this lake.
Current data source
Managing authority: U.S. Army Corps of Engineers / Muskingum Watershed Conservancy District
Observation source used by Lake Insights: U.S. Geological Survey
Who manages the lake and who publishes the reading Lake Insights displays can differ. Lake Insights does not invent a source label from the managing authority alone.
General education
Shared background — not lake-specific facts
Lake Insights aggregates water level information from authoritative public sources such as the U.S. Army Corps of Engineers, NOAA, TVA, Bureau of Reclamation, power utilities, and other official lake operators. We preserve historical observations, calculate trends, and present lake conditions in a consistent format. For U.S. Geological Survey, we link to the official source whenever it is available. Lake Insights does not predict future lake levels unless an official forecast has been published by the managing authority.
Common questions about Tappan Lake
- Who manages Tappan Lake?
- Tappan Lake is managed by U.S. Army Corps of Engineers / Muskingum Watershed Conservancy District. Lake Insights reports published gauge readings; it does not operate the waterbody.
- What is full pool at Tappan Lake?
- The published full-pool elevation for Tappan Lake is 899.00 ft (NGVD29). Full pool is a published reference elevation — not a prediction of today’s level.
- Does Tappan Lake have a published winter pool?
- Tappan Lake has a published winter / seasonal pool elevation of 894.00 ft. Lake Insights does not currently have verified seasonal operating dates for this lake.
- Where does Lake Insights get the level reading for Tappan Lake?
- Lake Insights displays the latest available elevation for Tappan Lake from U.S. Geological Survey. The managing authority (U.S. Army Corps of Engineers / Muskingum Watershed Conservancy District) may differ from the agency that publishes the observation used on this page.
- What datum is used for Tappan Lake?
- Elevations for Tappan Lake are referenced to NGVD29 (MSL).
- What are the documented purposes of Tappan Lake?
- Documented purposes for Tappan Lake (National Inventory of Dams): Flood Risk Reduction, Fish and Wildlife Pond, Recreation.