Eightmile Lake

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Eightmile Lake
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Eightmile Lake Mosaic Burn
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Eightmile Lake
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Red pog.svg
Eightmile Lake
Location Chelan County, Washington, United States
Coordinates 47°31′13.1″N120°51′55.1″W / 47.520306°N 120.865306°W / 47.520306; -120.865306
Primary inflows Eightmile creek
Primary outflows Eightmile creek
Basin  countriesUnited States
Water volume76.6 acres (31.0 ha)
Surface elevation4,641 ft (1,415 m) [1]

Eightmile Lake is a reservoir lake located on the eastern slope of Eightmile Mountain, in Chelan County in Washington. It is a reservoir lake formed along the beginning route of Eightmile Creek as it exits Jack Ridge.

Contents

The lake is located approximately 10 miles from the city of Leavenworth, Washington. It is accessed by a 3.5-mile trail (USFS Trail No. 1552) that starts at USFS Road 7601 as it crosses over Eighmile Creek and makes a turn towards the Stuart and Culchuck Lake Trailhead where the road ends. [2] Self-issued Alpine Lake Wilderness permit required for transit within the Eightmile Lake area. [3]

Geography

Geology

Eighmile lake sits in a basing consisting of rocky soils and igneous tonalite geology. The bedrock is about 3 feet from the surface. There is a large landslide area with boulders and other mass-wasting deposits located at the northeast shore of the lake. The trail to the lake consists of sandy loam and boulders. Eightmile Lake sits on a highly glaciated and semibarren alpine basin, surrounded by heather and other wildflowers and a coniferous presence primarily larch pines. [4]

Climate

Eightmile lake has a hemiboreal climate. [5] The average temperature is 2 °C. The warmest month is August, with an average temperature of 17 °C, and the coldest month is January, at an average of −10 °C. [6] The average rainfall is 705 millimeters per year. The wettest month is December, with 111 millimeters of rain, and the least in July, with 16 millimeters of rain.

Eightmile Lake
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
 
 
94
 
 
−8
−11
 
 
85
 
 
−6
−11
 
 
74
 
 
−2
−10
 
 
50
 
 
1
−7
 
 
30
 
 
8
−1
 
 
25
 
 
14
3
 
 
16
 
 
23
9
 
 
23
 
 
22
12
 
 
39
 
 
16
7
 
 
68
 
 
7
0
 
 
90
 
 
−4
−6
 
 
111
 
 
−8
−12
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: [6]
Imperial conversion
JFMAMJJASOND
 
 
3.7
 
 
18
12
 
 
3.3
 
 
21
12
 
 
2.9
 
 
28
14
 
 
2
 
 
34
19
 
 
1.2
 
 
46
30
 
 
1
 
 
57
37
 
 
0.6
 
 
73
48
 
 
0.9
 
 
72
54
 
 
1.5
 
 
61
45
 
 
2.7
 
 
45
32
 
 
3.5
 
 
25
21
 
 
4.4
 
 
18
10
Average max. and min. temperatures in °F
Precipitation totals in inches

Uses

Eightmile Lake is managed by the Icicle and Peshastin Irrigation Districts (IPID) to provide water storage for irrigation. The lake captures water runoff from a 3,800-acre drainage basin which gives the lake a high potential for refill, even during dry years. The reservoir is contained by a small dam consisting of a rock and masonry structure with stop logs and an earthen embankment section that extends from the rock-masonry/concrete structure to the hillside north of the dam. The dam is fitted with a low-level outlet pipeline and a slide gate at the outlet of the lake. Stop logs were first placed in a notch in the concrete portion of the dam up to the spillway crest to allow the lake to fill to an elevation of approximately 4,671 feet. [7]

This infrastructure allows for controlled releases of stored water to supplement flows into Icicle Creek and increase the water supply available during low flow periods, which typically occur during the late summer. [7]

2017 fire

Jack Creek Forest Fire and Eightmile Lake 2017 09 05-11.33.07.029-CDT.jpg
Jack Creek Forest Fire and Eightmile Lake

On August 11, 2017 lightning caused by a cold frontal passage that tracked through the Alpine Lakes Wilderness started a fire about 15 miles southwest of Leavenworth, Washington. [8] The fire expanded into the Stuart Lake and Eightmile drainages burning to the shoreline of Eightmile Lake damaging a large percentage of the lake's watershed. The fire has caused a potential change in runoff into the lake. [7]

Restoration

In 2016, Chelan County and the Washington State Department of Ecology had proposed the Icicle Strategy plan to resolve the shortage of water supply that threatened irrigation, fish habitat and passage, and tribal and non-tribal fisheries in the Icicle Creek subbasin region. [9] The plan also managed to improve streamflow and water availability into the subbasin affected by the subsequent 2017 forest fires. In 2018, the plan was approved by the Washington State Department of Ecology. The Icicle Strategy also restored the dam infrastructure at Eightmile Lake, permitting higher levels of water storage. [9] Although there were concerns for flooding in and around the areas surrounding the lake and the possibility of damaging trails and vegetation, the positive impacts outweighed the risks; habitat protection, fish passage, fish screening, and water conservation efficiencies. [10]

The earthen embankment portion of the dam was restored to reposition from erosion around the north side of the rock-masonry dam which had reduced its capacity of impounding water to the full level for which it was designed and at which it historically operated. Restorations raised the water level to an elevation of approximately 4,667 feet. [7]

See also

Related Research Articles

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<span class="mw-page-title-main">Eightmile Mountain</span> Mountain in Washington (state), United States

Eightmile Mountain is a 7,996-foot (2,437-metre) mountain summit located in Chelan County of Washington state. Eightmile Mountain is situated within the Alpine Lakes Wilderness, on land managed by the Okanogan–Wenatchee National Forest. It is part of the Wenatchee Mountains which are a subset of the Cascade Range. Its nearest higher neighbor is Cashmere Mountain, 3 mi (4.8 km) to the northeast, and Mount Stuart rises 4 mi (6.4 km) to the south. Precipitation runoff from the mountain drains into Trout Creek and Eightmile Creek, both tributaries of Icicle Creek, which in turn is a tributary of the Wenatchee River. This mountain is known for its spring skiing and excellent view of the Stuart Range.

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Snow Lakes are a system of freshwater reservoir lakes made by Upper Snow Lake and Lower Snow Lake, approximately a mile long. They are located on the eastern slope of The Enchantments, in Chelan County, Washington. The Snow Lakes are one of the most heavily used destination in the Forest Service wildernesses in Oregon and Washington. Self-issued Alpine Lakes Wilderness permits are required for transit within the Snow Lakes area.

Nada Lake is a freshwater reservoir lakes located on the eastern slope of The Enchantments, in Chelan County, Washington. Self-issued Alpine Lakes Wilderness permits are required for transit within the Snow Lakes area.

Lake Alice is a freshwater lakes located on the north slope of the Grindstone Mountain, in Chelan County, Washington. The lake is a popular area for hiking, swimming, and fishing. Self-issued Alpine Lake Wilderness permit required for transit within the Lake Alice area.

Lake Sylvester is a freshwater lake located on the north slope of the Grindstone Mountain, in Chelan County, Washington. The lake is a popular area for hiking, swimming, and fishing. Lake Sylvester is located approximately 15 miles west of the city of Leavenworth and access is obtained by Chatter Creek Trail #1580. Self-issued Alpine Lake Wilderness permit required for transit within the Grindstone Mountain area.

Lower Florence Lake is a freshwater lake located on the west skirt of Ladies Peak and Cape Horn, and North of Grindstone Mountain, in Chelan County, Washington. The lake is a popular area for hiking, swimming, and fishing cutthroat trout. Lower Florence Lake is located further down the slope from Upper Florence Lake, approximately 15 miles west of the city of Leavenworth. Self-issued Alpine Lake Wilderness permit is required for transit within the Lake Alice area.

<span class="mw-page-title-main">Upper Florence Lake</span> Lake in Washington, United States

Upper Florence Lake is a freshwater lake located on the west skirt of Ladies Peak and Cape Horn, and North of Grindstone Mountain, in Chelan County, Washington. The lake is a popular area for hiking, swimming, and fishing, especially for rainbow trout. Lower Florence Lake is located further down the slope of Mary Pass from Upper Florence Lake, approximately 15 miles west of the city of Leavenworth. Self-issued Alpine Lake Wilderness permit required for transit within the Lake Alice area.

Lake Augusta is a freshwater lake located on the southwest skirt of Big Jim Mountain, East of Icicle Ridge, in Chelan County, Washington. Because of its close proximity to Icicle Ridge Trail, the lake is a popular area for hiking, swimming, and fishing cutthroat trout. Smaller Lake Ida is a short distance on the opposite side of Icicle Ridge and Big Jim Mountain Lakes or on the northeast slope of the mountain. Lake Augusta is located approximately 15 miles west of the city of Leavenworth. Self-issued Alpine Lake Wilderness permit required for transit within the Lake Augusta area.

Lake Ida is a freshwater lake located along Icicle Ridge, approximately 10 miles west of the city of Leavenworth in Chelan County, Washington. Because of its close proximity to Icicle Ridge Trail, the lake is a popular area for hiking, swimming, and fishing cutthroat trout. Lake Augusta is a short distance on the opposite side of Icicle Ridge. Lake Ida sits on a highly glaciated alpine cirque, surrounded by a coniferous forest primarily larch pines and outflows into Ida Creek, a tributary of Icicle Creek. At least one unrated waterfall is found downstream as Ida Creek runs the south slope of Icicle Ridge. Self-issued Alpine Lake Wilderness permit required for transit within the Lake Ida and Augusta area.

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Lake Edna is a freshwater lake located along Icicle Ridge, approximately 10 miles west of the city of Leavenworth in Chelan County, Washington. Because of its close proximity to Icicle Ridge Trail, the lake is a popular area for hiking, swimming, and fishing. Lake Alice is a short distance in a prominent cirque on the opposite side of Icicle Ridge.

<span class="mw-page-title-main">Icicle Ridge</span> Mountain ridge in Alpine Lakes Wilderness, Washington state, USA

Icicle Ridge is a mountain ridge located in the eastern border of the Alpine Lakes Wilderness, in the Washington state, United States. Several trails lead to Icicle Ridge which borders several prominent mountains, peaks, and lakes. Icicle Ridge is located at the western edge of the city of Leavenworth on land managed by the Okanogan–Wenatchee National Forest.

Josephine Lake is a natural lake and reservoir near Stevens Pass in Chelan County, Washington, United States. At the south skirt of Big Chief Mountain, Josephine Lake is the source of the Icicle Creek. Because Josephine Lake is at the heart of the Alpine Lakes Wilderness, the lake is a popular area for hiking, swimming, and fishing golden trout.

References

  1. Geological Survey (U.S.). Branch of Geographic Names (1981). Washington Geographic Names, Book 1. U.S.G.S. Topographic Division, Office of Research & Technical Standards. p. 127.
  2. Peterson, Ken. "Eightmile Lake". Washington Trails Association. Retrieved 9 March 2021.
  3. "Eightmile Lake Trail #1552". United States Department of Agriculture. Retrieved 11 March 2021.
  4. Day Hiking Central Cascades. Mountaineers Books. 2019. p. 186. ISBN   9781594854378.
  5. Peel, M C; Finlayson, B L. "Updated world map of the Köppen-Geiger climate classification" (PDF). Hydrology and Earth System Sciences. 11: 1639–1640. doi: 10.5194/hess-11-1633-2007 . Retrieved 19 March 2021.
  6. 1 2 "NASA Earth Observations Data Set Index". NASA. Archived from the original on 28 November 2017. Retrieved 19 March 2021.
  7. 1 2 3 4 Icicle and Peshastin Irrigation Districts (April 2018). "Eightmile Lake Storage Restoration Feasibility Study" (PDF). Chelan County Natural Resources Department. Retrieved 9 March 2021.
  8. "Post-Fire BAER Assessment Burned Area Emergency Response (BAER) Information Brief" (PDF). Central Washington Fire Recovery. United States Forest Service. Archived from the original (PDF) on 2018-05-16. Retrieved 16 May 2018.
  9. 1 2 "Icicle Creek strategy - Washington State Department of Ecology". ecology.wa.gov. Retrieved 2020-10-17.
  10. "Chelan County Natural Resources - Environmental Review". www.co.chelan.wa.us. Retrieved 2020-10-17.