Final answer:
It is true that since the year 2000, Lake Mead has experienced a 33% reduction in water levels, reaching lows not seen since before the Hoover Dam's construction. Factors include drought, water demand, and sedimentation, posing a risk to long-term water supply and dam operation.
Step-by-step explanation:
The statement that water levels in Lake Mead have dropped by 33% since the year 2000 and are now at the lowest levels since the 1930s before the Hoover Dam was built is true. This decline in water levels can be attributed to a combination of prolonged droughts and high water demand, particularly from urban areas such as Las Vegas. Despite Las Vegas's efforts in reducing water consumption and recycling water efficiently, the water crisis remains a grave concern.
Sedimentation is also a factor affecting Lake Mead. The Colorado River carries a significant amount of sediment which, over time, accumulates in the lake and contributes to decreasing its volume. The Hoover Dam itself, constructed between 1931 and 1935, was a monumental engineering project meant to provide hydroelectric power and aid in water management. However, sediment buildup and receding water levels pose challenges to its long-term functionality.