FLAGSTAFF, Ariz. — Lake Powell has reached its lowest level since 2005, the year of its historical low.

The National Park Service is capitalizing on the low water as a prime time to resume its digging work at the Castle Rock Cut, a popular shortcut for boaters. The channel has been closed since February 2013 due to low water. It is closed when the shortcut's water depth drops below 5 feet.

"Because of the lower lake levels, it's an opportune time to be doing the excavation," said Denise Shultz, a spokesperson for Glen Canyon National Recreation Area.

The Park Service hopes that deepening the cut will allow for longer periods of use during the season in the future. The cut saves about 10 miles of boating.

"This not only saves time and gas for boaters," stated NPS Project Manager Carl Elleard, "but it also provides for a safer boating experience."

Lake levels typically drop in winter and rise again following spring and the inflow of snowmelt. Despite a heavy monsoon season in northern Arizona, a depleted snowpack upriver from Lake Powell left the lake lower this year than it was last January.

"Right now we haven't been able to use (Castle Rock Cut) all season because the lake level has been too low," Shultz said.

"As the lake comes back up again, it will fill that cut and, depending on the draft of your boat, people will be able to use it," Shultz added.

Dredging work began on Tuesday and will take about four months to complete. Approximately 70,000 cubic yards of material must be removed at a cost of $1.6 million. Once completed, the digging will lower the elevation of the cut to approximately 3,580 feet.

The work is being done by Brown Brothers Construction of Loa, Utah.