Green Lakes (Deschutes)

Reachcode: 17070301005181 | Area: 86.3 acres | Shoreline: 1.8 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985) The Green Lakes are a group of three glacial lakes in the northern section of the Three Sisters Wilderness nestled directly between South Sister and Broken Top. The reason for the name is obvious when they are viewed from above: the color is a lovely, deep green. Middle Green Lake, the larger of the three, is 83 acres in size and lies at an elevation of 6505 feet above sea level. Upper Green Lake, the second largest of the group, is about 10 acres in size, and lies directly north of the main lake. Lower Green Lake is the smallest, about three acres, and is the first one seen by hikers who approach the area via the Fall Creek Trail from the Cascade Lakes Highway. The Green Lakes area is one of the most popular destinations for hikers in the Central Oregon Cascades, and tents are scattered around the lakes throughout the short summer season. The area serves as a base for climbers on their way to the top of South Sister or Broken Top. Anglers find both native brook trout and rainbow trout in Middle Green Lake, and mostly the former in the smaller lakes. The wilderness quality of the area is now assured, but in 1915 the Green Lakes were investigated as a possible source of irrigation water for use on land east of Sisters. A dam, 20 feet high, would have stored 7500 acre feet of water. However, nothing ever came of the plan. An extensive lava field, the Newberry Flow on the lower southeast slope of South Sister, is responsible for the formation of the lakes, having blocked drainage from snowmelt runoff. Two streams off the slopes of South Sister contribute to Middle Green Lake. Fall Creek, the outlet stream, has cut a channel around the east side of the lava flow, and drops 1000 feet in five miles before discharging into Sparks Lake. The drainage basin of Middle Green Lake is about 2.7 square miles and has extensive areas of white pumice supporting a sparse cover of alpine vegetation, low grasses, and wildflowers. Clusters of mountain hemlock and fir are found on the higher ridges. Middle Green Lake consists of a single deep central basin. There are shoal areas at the ends of the lake and in the vicinity of several small tributaries. Because of the high elevation of this lake, the water remains unusually cool, with temperatures seldom exceeding 550 Fahrenheit (120 Celsius), even at the surface. The water has a very low concentration of minerals; the concentrations of ions, alkalinity and conductivity are low. The concentrations of chlorophyl and phosphorus are also low, and the water is very transparent. The lake is oligotrophic.