Friday, March 29, 2024

Lake Chelan water levels

How low can you go?

Posted

CHELAN – Those who can call Lake Chelan home, as well as frequent vacationers, may have noticed and even commented on the low lake levels earlier this year. Kimberlee Craig, Public Information Officer with Chelan County P.U.D., answered some lingering questions last week, regarding the lake level, spill, and water runoff.
According to Craig, an average year of water flow expected from remaining snow on the mountain ranges is standardized as 100 percent runoff. This standard is an average based off 80 years of data collected from snow and runoff. What was unusual about this year? “We issue a forecast for the runoff period April 1 through July 31, and just to tell you about this year, there was a lot of concern about it being a dry year … and our first April 1 estimate was for 106 percent …, so that just means six percent more than average,” Craig then continued by stating, “what we found was that 85 percent of the runoff happened before the end of June, which makes it an early year”. With an abundance of rain, cold weather, and even some snow, the estimated runoff of 106 percent ended up being a drastically larger 130 percent runoff. “Usually we are plus or minus six percent of our original estimate” Craig said, “from 106 percent to 130 (percent) it was a lot more … so it’s just a reminder that Mother Nature really has the trump card.”
February 1, March 1, and April 1 Chelan County P.U.D. flies by helicopter out to four different SNOTEL sites. Although these sites automatically send out informational readings electronically, the data is manually checked to ensure the accuracy of the readings. After landing at each site, borings of snow are collected and weighed for water content. The density readings of the snow are then used to estimate the water remaining in the mountains, and the lake level is adjusted accordingly, to allow the estimated runoff room needed in the lake.
“It’s counterintuitive”, said Craig, “the more runoff, the lower we have to take the lake in the spring to make room for it. The dryer the year, the less we take the lake down, and we manage that both by spill and generation.” The community verbalized a desire for keeping the lake levels up higher through September when prompted by Chelan County P.U.D. staff in 2006, while considering license changes for the hydro project. Craig stated that while the voices within the community hold great weight, other aspects and factors are taken into consideration and some are a requirement with the new licensure in 2006. One of the aspects that are heavily considered, and rank over recreational activities, is the creek levels needed for fish activity, health and spawning. The runoff and spill amounts are important for the tributary creeks and natural spawning. Drawing the lake down washes out sediment buildup in the streams, preventing the buildup of sediment bars and allowing fish to swim up and spawn successfully.
For more information on lake levels, visit the Parks and Recreation tab at chelanpud.org to view a real-time graph and 10-day lake levels chart, along with other pertinent information.

Chelan, PUD, water levels

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