This little monument is in O.K. Anderson City Park, a beautiful verdant patch on mostly dusty Main Street in Green River, Utah (population about 1,000). The primary commercial activity I saw during my 30 minutes here in August 2017 was melons. There were big melon stands, watermelons mostly, near the Interstate 70 ramps on both ends of town. Green River is also known for, or at least hosts, a melon festival each September. It's not all that far from Moab if you happen to be in that area.
As to the monument, the text reads:
Born July 31, 1869, at Bowling Green, Missouri. Died July 8, 1949, in the vastness of the Grand Canyon, the land of the blue horizons and the desert mesas that he loved so well.
"I belong to the wonderous West, and the West belongs to me."
Reading the memorial, you think, "Gee -- there's a biography in that." And there actually is a recent one: "The Very Hard Way: Bert Loper and the Colorado River." If you're not up for 456 pages "that never once bog down," here's a brief summary of Loper's life by way of the Grand Canyon River Heritage Coalition. The denouement: