Complex sentence: Unlike most dry lakes in the Basin and Range Province that have been dry for thousands of years, Owens held significant water until 1924, until much of the Owens River was diverted into the Los Angeles Aqueduct, causing it to desiccate.
Split into simpler sentences: Unlike most dry lakes in the Basin and Range Province that have been dry for thousands of years, Owens held significant water until 1924. Much of the Owens River was diverted into the Los Angeles Aqueduct, causing Owens Lake to desiccate.