Скачать или смотреть How monsoons affect Lake Mead’s water level

Did the recent monsoonal downpours help Lake Mead’s diminished water level? The short answer is, not much.

Even with some areas of the Las Vegas Valley and the other regions around the lake receiving 1 to 2 inches of rain over the last couple of days, Lake Mead’s water level has barely budged. It has not risen or dropped any more than in the previous days.Currently, Lake Mead holds approximately 10 million acre-feet of water or about 3,259,000,000,000 gallons. Most of this water has come from melting snow in the Colorado Rockies.

According to Bureau of Reclamation Public Affairs Officer Michelle Helms, “At current elevation, an increase of one vertical foot at Lake Mead is equivalent to (approximately) 68,000 acre-feet [of water].” As of 5 Thursday night, the official water level at Lake Mead was 1,040.7 feet above sea level. Jump ahead almost 20 hours and the water level did go up, but only .04 inches to 1,040.74.Nearly 90% of Southern Nevada’s water comes from the Colorado River. The remaining 10% comes from Las Vegas valley groundwater. This graphic illustrates how water gets from the rain and snowmelt in the Colorado Rocky Mountains to Lake Mead.Lake Mead is fed by the Colorado River and three smaller tributaries: the Virgin and Muddy Rivers and Las Vegas Wash. Gregg Basin and Temple Basin are fed by the mainstream of the Colorado River, which now enters Lake Mead at the northern end of the Gregg Basin, nearly 60 miles upstream of Hoover Dam. The Virgin and Muddy Rivers flow into the Overton Arm, and then travel 25 miles under current conditions to merge with Colorado River water in the Virgin Basin. The combined flows from the upper end of the lake enter the east end of Boulder Basin at the Narrows. Las Vegas Wash enters Las Vegas Bay at the west end of Boulder Basin.Currently, Lake Mead is only 27% full by volume and the water level is 188.21 feet below its maximum capacity, or full pool.