Tappan Lake siteid=239 · OH
loading…
Water level & flow 2017-09-30 .. 2026-09-16 · SWOT depth track + USGS NWIS gauges · one linked timeline
current depth
21 ft
drawdown
1.7 ft
below full pool
water level (depth)
93%
21 of
23 ft deep
water stored (volume)
57%
est. from bathymetry
measured
Sep 16
nwis_stage
pipeline refresh
2026-09-17 21:56 UTC
zoom or pan either chart — the other follows
elevation trend: robust smoothing + outlier removal · raw value on hover
loading water-depth track…
Inflow / outflow USGS NWIS daily discharge · same timeline as above
loading gauge data…