After two consecutive years of dramatic declines in Lake Sawyer water levels during summer and early fall, current water level measurements put us pretty close back to "normal". Thanks again to Jack Sperry, following is a chart showing water levels over the last 8 years. 2017 data is shown in red.
Why such steep declines in 2015 and 2016? Three factors likely account for declines in lake water levels:
- Snowpack - The higher the snowpack, the greater the snowmelt lasting into summer. This means more water flowing longer through Ravensdale creek and Rock creek and less lake water flowing out as groundwater. 2017 has been a good year while 2015 and 2016 were years of low snowpack.
- Evaporation - During periods when no water flows into the lake from Ravensdale creek or Rock creek, evaporation can account for 10" to 15" of water level decline. This is close to the Mean Low Water Level of 14.7" shown in the above chart. For more about lake evaporation, read my earlier post Lake Evaporation - How Much of a Factor.
- Beaver Dams - During 2015 and 2016, water stopped flowing into Lake Sawyer from Rock Creek as early as April with Ravensdale Creek ceasing to flow a month or so later. This year, thanks to the hard work done by the Rock Creek Restoration Team, 30 beaver dams were removed along Rock Creek between Jones Lake and Lake Sawyer. Water flowed freely in this area for the first time in years and water levels and flooding behind the dams also declined appreciably. No doubt this action, taken by volunteers with permits for their work issued by the State Dept. of Fish & Wildlife, has had a major beneficial impact on lake water levels and lake water quality. Many thanks to our team of volunteers - more about them is a future post.
For those new to Lake Sawyer or for those who need to be reminded regularly, we have very tight water quality restrictions on the lake and "strictly enforced". Everyone is watching!
I hope that you are enjoying this summer as much as we are. Thanks again for the data Jack!
Comments