The Delavan plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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75° on Nov. 11, 2022, the hottest reading for this week of the year since 1945. Next is 71° in 1964.
Delavan’s center stands about 940 ft above sea level. Within three miles the land runs from 870 ft to 1,010 ft, a difference of 140 ft: gently rolling country.
Under the town center the state geologic map shows Sinnipee Group (dolostone), from the Ordovician, 445 to 487 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 59×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone. Age: Ordovician, 445 to 487 million years old. About 18 mi of the line.
Shale, dolostone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Dolostone. Age: Silurian, 422 to 445 million years old. About 2 mi of the line.
Dolostone, limestone. Age: Silurian, 422 to 445 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Delavan reaches the Gulf of America by way of Turtle Creek, the Rock River and the Mississippi: about 1,660 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Delavan; river miles along the main stem, rounded.
Delavan has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 15° in January. A normal year brings about 40 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 Delavan normally reaches 48° and falls to 31°. The record high is 70°, in 1971; the record low 8°, in 1959. The most rain on this date, 1.13 in, fell in 1957.
Normals 1991–2020 and records since 1945 at Lake Geneva Wwtp, 11 miles east-southeast. NOAA, through RCC-ACIS.
