By Mary Manning

Published Wednesday, July 9, 2008 | 10:39 a.m.

Updated Tuesday, Oct. 28, 2008 | 10:15 a.m.

The National Park Service plans to temporarily close a small part of the River Mountains Loop Trail beginning Monday and lasting for four weeks.

The half-mile trail segment scheduled to be closed runs from the former site of Lake Mead Cruises, just north of Boulder Harbor on Lakeshore Road, up to the Nevada Department of Wildlife Fish Hatchery.

The trail closure is necessary because the Southern Nevada Water Authority is adding a third intake, called the "third straw," to supplement its current two pipelines operating on Saddle Island and serving the Las Vegas Valley with drinking water, said Roxanne Dey, a park service spokeswoman. As Lake Mead continues to drop in the ongoing drought, the water authority plans to add the third intake. The Bureau of Reclamation, which operates the Colorado River feeding Lake Mead, forecasts further drops in the lake level, requiring a deep-water intake to ensure continued water supplied to Southern Nevada, Dey said.

While the trail is closed, the park service plans to improve it, including a culvert that will route the trail below Saddle Cove Road. The culvert will protect the trail from construction traffic as the pipeline is built, Dey said.

The rest of the 14-mile-long River Mountain Loop Trail will not be affected by the closure or the pipeline project, Dey said.