Las Vegas is rightfully proud to be the doorway to thousands of tourists who travel to Grand Canyon National Park and the Colorado River. As our economy matures, we are becoming a destination for those seeking unique outdoor experiences. And of course, Southern Nevada has another inseparable tie to the Colorado River: The river gives us a safe, reliable water supply, providing more than 90 percent of our water needs.

Millions more downstream depend on the Colorado, but ours is the only big city whose needs are so closely intertwined with the fate of the river. So when it comes to people messing about with the river, regardless of their intentions, we take the issue seriously. Simply put, we have a very big dog in that hunt.

Several years ago, local elected officials and government agencies, including the Southern Nevada Water Authority, successfully pushed to clean up uranium mining tailings that were leaching toxic and radioactive chemicals into our water supply. Further, Southern Nevada lawmakers in Washington wisely opposed efforts to open more uranium mines near the river and supported a moratorium on new mining until the issue could be studied in detail by the Obama administration. That gave us a timeout in 2009.

As a Las Vegas city councilman for 14 years, and since 2009 a Clark County commissioner and member of the board of the Las Vegas Valley Water District, I, too, have a vested interest in protecting our water supply. More importantly, my family, like so many Southern Nevada families, drinks and enjoys the water from the Colorado River, so this is a personal issue.

Unfortunately, some lawmakers from Arizona and Utah recently introduced a bill that would open more than 1 million acres of federal land on the Arizona Strip, northeast of Las Vegas and alongside the Colorado River, to new uranium mining.

Those lawmakers don’t get their own water downstream of those operations, but they dismiss our legitimate concerns about effects to water quality in the river and Lake Mead. Officials from Mohave County in Arizona and Washington County in Utah, among others, insist they need to open up the Arizona Strip to uranium mining to boost the local economy. But the historical record is littered with incidents of contamination to the Colorado River, and there are ongoing examples of the modern mining industry contaminating water supplies and refusing to clean up the mess. Until agreeing to a deal with regulators, the Cotter Corp., a subsidiary of General Atomics, had long balked at a Colorado demand to clean up a defunct mine leaking into a Denver drinking water reservoir, according to the Denver Post.

Modern mining uses and pumps a lot of water out of mine sites. That water has to go somewhere. If it is near the river, a lot can go wrong. Abandoned mining and milling operations are already implicated in pollution of the river with toxic and radioactive waste products, including uranium, selenium, ammonia, arsenic and other metals. And once in the river, those elements can contaminate aquatic ecosystems for hundreds of years.

Our delegation in Congress from both sides of the aisle should once again oppose opening up land near the river to uranium mining. Meanwhile, the Obama administration’s Interior Department is supporting a 20-year moratorium on new uranium mines on the Arizona Strip. In fact, the bill introduced by Arizona and Utah Republicans is a response to a long-lasting moratorium. The administration’s environmental impact study on the issue, now in its third year, has included 15 cooperating agencies and 300,000 public comments. And the final decision announced this month by Interior Secretary Ken Salazar reflects those comments and study.

We need to keep industrial mining operations away from one of the great tourist destinations of the American West. We certainly can’t afford to gamble with our water supply.

Larry Brown is a member of the Clark County Commission.