Las Vegas Wash trail to close next week for construction work

A popular hiking trail along the Las Vegas Wash will be closed starting next week to make way for construction related to erosion control on the wash and the ongoing cleanup of a decades-old industrial site at the edge of Henderson.

Contractors will be installing underground pipes to capture and treat groundwater contaminated with perchlorate and other pollutants that have been seeping into the wash from the Black Mountain Industrial complex for years.

The Pabco Trailhead, about two and half miles downstream from the Nature Center at Clark County Wetlands Park, will be closed from Monday through Sept. 20 to accommodate the work. Visitors also should expect temporary closures to portions of the South Loop Trail at the park during construction, county officials announced Thursday.

In separate but related work in the area, the Southern Nevada Water Authority is building a new flow-control structure called a weir upstream from the Pabco Trailhead and rebuilding an old weir downstream. The project is part of an ongoing effort by the authority and its partners to reduce erosion and improve wetland and riparian habitat along the Las Vegas Wash, which carries the valley’s treated wastewater and storm runoff to Lake Mead.

The underground pipes and treatment system also will keep groundwater out of the authority’s job site.

“To keep the construction area dry, the groundwater that runs into the wash there will be intercepted, pumped and treated by a dewatering ion-exchange system, then released into the wash at another location,” said JoAnn Kittrell, spokeswoman for the Nevada Division of Environmental Protection.

The cleanup at the Black Mountain Industrial complex began in 1999, after the site was identified as the source of perchlorate contamination in Lake Mead and the Colorado River below Hoover Dam.

Since then, perchlorate levels in the lake have been reduced by 95 percent by slowing the flow of groundwater from the BMI property into the wash and by cleaning up contaminated water at the industrial site.

The underground pipe installation is slated for completion in November.

The water authority’s weir work is expected to last until September 2019 and lead to other temporary closures on the South Loop Trail near the Pabco Trailhead in late September or early October.

Signs will be posted to notify visitors about the trail closures and detours. Updates on the work will be available on the Clark County Wetland Park’s website or by calling the park at (702) 455-7522.

Contact Henry Brean at hbrean@reviewjournal.com or 702-383-0350. Follow @RefriedBrean on Twitter.