AZ-UT Mile 143.8: Antelope Island

Next westbound: Lake Powell  Next eastbound: Navajo Mountain

On Antelope Island, Lake Powell, on the Arizona-Utah line through the high red desert, with Wahweap, Arizona in the distance. Here, Surveyor Brown’s 1934 Triangulation Station sits as a stolid witness to the subtle geological changes in the nearly-Martian desert surface while major climate upheavals pull on the theatre set backdrops: Lake Powell’s water level in 2018 is 107 feet below ‘full pool’, indicated on the 1985 map below. Brown’s triangulation station, placed before its location could be called an island, long before the Glen Canyon dam was built, faced the implacable rise of Lake Powell: in 1985 the monument sat on a peninsula; now the lake has ebbed away.

Brown’s triangulation station on Antelope Island, looking west.






Brown’s triangulation station. Antelope Island, looking east.



Brown’s  1934 monument

N 370 0.0940′ W 1110 27.1937′






Above: Brown’s Triangulation Station, in lower left corner of map, which also shows 1985 nominal water level in Lake Powell.

Google Earth image, above right, shows water level in 2018.

Looking east, from the east side of Antelope Island, toward Navajo Mountain, the blue hump on the horizon; the borderline passes over its southern flank. Near the right edge of the image, the Navajo Generation Station’s stack merges with the storm cloud above it.