If you plan on visiting Lake Powell during the July 4 holiday, or anytime this summer, plan your visit so you don't arrive at a major launch ramp between 10 p.m. and 5:30 a.m. If you arrive during those hours, you won't be able to launch your boat.

The National Park Service has closed the ramps from 10 p.m. to 5:30 a.m. Utah time (9 p.m. to 4:30 a.m. in Arizona).

The nighttime ramp closure is part of a continuing effort to keep quagga and zebra mussels out of the lake.

Starting June 29, NPS personnel will be at the lake's major launch ramps from 5:30 a.m. to 10 p.m. every day. Every boater will be asked a series of questions before they launch their boat.

Boats that have been on waters infested with quagga or zebra mussels must be decontaminated before they're launched.