LAS VEGAS — Only a few miles from the Las Vegas Strip, in the Mojave Desert, is an unlikely scene: A county park with walking trails and thick vegetation that circles a vibrant rush of flowing water.
Known as the Las Vegas Wash, the water running through this channel is a crucial part of how Nevada has managed to keep its net Colorado River use below its allocation, despite booming population growth and two decades of persistent drought, worsened by a changing climate.
Every time a shower or a faucet is turned on in Las Vegas, the water flowing down the drain is treated at wastewater plants and recycled. The treated water is discharged into the wash, which flows into Lake Mead, a declining Colorado River reservoir held back by the Hoover Dam. Once there, the water can be used for a second time, effectively increasing Nevada’s overall portfolio.
“It allows Las Vegas to exist in its present form,” said John Hiatt, a conservationist who sits on a coordination committee for the wash. “(Without it), we’d be half our size and really struggling.”
When the Colorado River Compact was negotiated in the early 1900s, only about 5,000 people lived in Clark County, home to Las Vegas. Few envisioned the massive growth that has turned the desert into a sprawling paved landscape of nearly 2.2 million people — and growing.
Accordingly, the compact gave Nevada the smallest cut of the Colorado River: 1.8 percent, or just 300,000 acre-feet (an acre foot is the amount of water needed to fill an acre to a depth of one foot). The small share has meant Nevada has long had to live on a tight water budget and rely on conservation measures that are only now being considered by other Western states.
Unlike other states, Nevada has one main river user: Las Vegas. It is responsible for more than 90 percent of the state’s diversions, with additional water going to the Fort Mojave Indian Tribe, whose rights were recognized in a 1963 Supreme Court case, and other small water users.
For decades, Las Vegas has relied on wastewater recycling and removing water-guzzling lawns to stretch and conserve its small Colorado River share. But even with proactive management, it could face significant challenges and uncertainties when it comes to future population growth.
“We still have some room with the water resources we have today,” said Assemblyman Howard Watts, a Democrat who has worked on water issues for years, including in the Legislature. “But eventually we’re going to reach a point where we’re going to go past that limit and that’s when we really have to consider what a sustainable path is for Southern Nevada moving forward.”
Many of the Southern Nevada Water Authority’s future planning scenarios are premised on an ability to collaborate with other states to augment Las Vegas’s current supply. Yet negotiations over the Colorado River have become increasingly difficult for the seven states that rely on the shrinking river and its reservoirs, including Lake Mead, which is dropping to critically low levels.
Nevada, even though it has a small slice of the Colorado River, has a huge stake in those talks. Las Vegas is reliant on the Colorado River. It’s the source of about 90 percent of the city’s water supply. The remainder comes from a local groundwater aquifer, which was historically overused.
Any other water in Nevada is far away. For years, Las Vegas had looked to import rural eastern Nevada groundwater hundreds of miles away as a potential supply. But local water managers shelved the controversial plan in 2020 amid legal challenges and concerns about environmental impacts. While it still owns ranches in eastern Nevada, the water authority has said its focus is on supplementing its supply through collaboration, including a recycling project in California.
How Southern Nevada has managed to…