The Knippa 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.
Mostly cloudy
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Mostly cloudy; cooler
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Partly cloudy
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Knippa’s center stands about 980 ft above sea level. Within three miles the land runs from 930 ft to 1,100 ft, a difference of 170 ft: gently rolling country. The highest named summit within 15 miles is Davenport Hill, about 1,760 ft, 15 miles northwest.
Under the town center the state geologic map shows Leona Formation (coarse-detrital, fine-detrital), from the Pleistocene, less than 2.6 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 26×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Coarse-detrital, fine-detrital. Age: Pleistocene, less than 2.6 million years old. About 15 mi of the line.
Limestone. Age: Early Cretaceous, 100 to 145 million years old. About 6 mi of the line.
Limestone. Age: Late Cretaceous, 66 to 100 million years old. About 1 mi of the line.
Sandstone-mudstone. Age: Late Paleocene to Early Eocene, 48 to 59 million years old. About 0.9 mi of the line.
Sand. Age: Pleistocene to Holocene, less than 2.6 million years old. About 0.5 mi of the line.
Limestone. Age: Early Cretaceous, 100 to 145 million years old. About 0.4 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 Knippa reaches Corpus Christi Bay and the Gulf of America by way of the Frio and the Nueces: about 280 river miles.
Lakes on the way: Horseshoe Tank and Lake Corpus Christi.
130 miles of the trip are on the Frio.
Often dry. About 30% of the way is mapped as streams that run only after rain or snowmelt; the water makes the whole trip in floods.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Knippa; river miles along the main stem, rounded.
