Heavy rains help hydro

Recent heavy rains likely mean Juneau will have plenty of water to produce hydroelectric power this winter.

“Our fuel is rain and snow, so even though we all like sunshine and nice weather, we need the rain,” says Alaska Electric Light and Power generation engineer Scott Willis.

He watches water levels in the lakes that produce electricity for Snettisham, Lake Dorothy and Salmon Creek hydro projects. He says it’s been a dry two years.

“Prior to this weekend, our lakes were lower this year than last year at this time. And last year we didn’t fill any of our lakes,” Willis says. “But just this three-day storm put us ahead of last year.”

The Snettisham area got nine inches of rain between Friday and Monday. Crater and Long lakes provide the energy for the turbines. Crater Lake rose 21 feet and Long Lake rose 15 feet over the weekend. Prior to the rain storm, Long Lake had been rising only six to eight inches a day.

“Snettisham gets about three times more precipitation than we do in town. So if we get an inch and a half in town that’s four or five inches out at Snettisham,” Willis says.

Snettisham is the workhorse of A-E-L & P’s generation system, and provides most of Juneau’s electricity. The rest comes from Lake Dorothy and Salmon Creek hydro projects. Lake Dorothy grew seven feet, and Salmon Creek rose 10 feet over the weekend.

While none of the lakes have filled, Willis says he expects there’ll be plenty of water to run Juneau’s hydro this fall and winter, especially since September and October are usually wet months. When lake levels are low, the company has to supplement hydro with expensive diesel fuel.

A graph of lake levels is at www.aelp.com.