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What is the Wash?
Channel Stabilization

Bed Stabilization

The purpose of channel bed stabilization is to reduce channel bed erosion by slowing stream flow to less erosive conditions while providing a stable platform for vegetation establishment. This will be accomplished through the construction of grade control structures (also known as weirs, or low height dams) along the Wash within the next several years.

Downstream from Pabco Weir
Downstream from Pabco Weir

Weirs prove mettle against heavy storms

Although recent storms brought more rainfall than Southern Nevada has seen in 15 to 25 years, weirs at the Las Vegas Wash stood up to the test and storm damage was minimal.

The storms challenged the weirs with 15- to 25-year rain events along the Wash (meaning we experienced an amount of rainfall only seen every 15 or 25 years). Because permanent weirs along the Wash are built to withstand up to 100-year events, there was little to no damage.

Water levels at the Nature Preserve reached two to three feet in depth and lasted two hours as it flowed into the Wash. More than 200 tons of decomposed granite will be needed to replace some of the trails that were washed away by storms. Although the flows deposited mud and rock onto the newly opened parking lot and equipment got wet, without weirs in place, it all would have been much, much worse.

The Nature Center during fall 2012 storms
The Nature Center during fall 2012 storms

Since the first permanent weir structure was placed in the Las Vegas Wash in 1998, 13 other structures have been constructed to control water flows making their way to Lake Mead. Eventually 22 weirs will be found along the Wash to deal with runoff, treated wastewater, shallow groundwater and stormwater.

Weirs are designed to withstand large storm events. The weirs at the Wash vary in construction and material type depending on where they are located. Some have a natural look and others are obviously man-made. Yet the goal is still to slow the flow of water as it travels down the Wash.

weir map
Printable map (PDF)

Completed Structures

  1. Upper Diversion Weir and Diversion Channel - completed 2008
  2. Monson Weir – completed 2002
  3. Visitor Center Weir – completed 2002
  4. DU Wetlands No. 2 Weir - completed 2009
  5. Pabco Weir – completed 2000
  6. Historic Lateral Weir – completed 2000
  7. Bostick Weir – completed 2003
  8. Calico Ridge Weir - completed 2004
  9. Demonstration Weir – completed 1999. However, the weir was moved and reconstructed in 2007
  10. Rainbow Gardens Weir – completed 2004
  11. Powerline Crossing Weir- completed 2006
  12. Fire Station Weir – completed 2000
  13. Homestead Weir - completed 2011
  14. Lower Narrows Weir - completed 2011

Planned Structures (with expected completion date)

Las Vegas Wash Project Coordination Team • 100 City Parkway, Suite 700 • Las Vegas, NV 89106 • (702) 822-3300