Regarding the lake…it’s an endorheic lake in a high-evaporation environment. Levels can fluctuate greatly in basins like that. The lake was at similarly low levels in the 1960s, and record highs in the 1980s. Pretty much the entire northwestern portion of Utah was a huge lake in prehistoric times (Lake Bonneville). SLC’s water is mostly groundwater….that being said, large growing cities in arid locations makes managing water resources challenging.