Colchuck Lake is a freshwater reservoir

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

located on the western slope of

The Enchantments The Enchantments is a region within the Alpine Lakes Wilderness area of Washington state's Cascade Mountain Range. At an elevation of 4,500 feet (1,372 m), it is home to over 700 alpine lakes and ponds surrounded by the vast peaks of Cashmere Cr ...

, in Chelan County,

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. The lake is located approximately 15 miles from the city of

Leavenworth, Washington Leavenworth is a city in Chelan County, Washington, United States. It is part of the Wenatchee− East Wenatchee Metropolitan Statistical Area. The population was 2,263 at the 2020 census. The entire town center is modeled on a German Bavarian ...

and sits on the southeast corner of the

Icicle Creek Icicle Creek is a nonNavigable stream in the U.S. state of Washington. It originates at Josephine Lake near the crest of the Cascade Range and flows generally east to join the Wenatchee River near Leavenworth. Icicle Creek's drainage basin is mo ...

subbasin. It is accessed by a 4-mile trail that starts at USFS Road 7601 as it crosses over Eightmile Creek and makes a turn towards the Stuart and Culchuck Lake Trailhead where the road ends. The origin of the word comes from Chinook Jargon ''kol'' + ''cak'' to mean ''cold waters''.

History

Icicle Irrigation District applied in 1926 for the right to divert water from Colchuck Lake at a rate of 50 cfs (cubic feet per second), 2,500 acre-feet per year for seasonal irrigation purposes. The State Supervisor of Hydraulics issued Permit Number 828 in January 1927 for the requested amount. The irrigation district also sought permission to raise the lake levels because of inadequate summer flows for irrigation. The Department of Public Lands approved this request in a 1927 order that allowed the irrigation district to inundate lakeshores on the lake.

Hydrology

Colchuck Lake has an area of approximately and a maximum surface elevation of 5,570 feet above

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...

, depending on the fluctuation of the depth of the lake. The lake has a tributary basin of acres, and an average storage capacity estimated at 1,570 acre-feet.

Dam

Colchuck Lake is contained by a masonry dam constructed in the late 1930s out of cement with a spillway opening at the center of the dam to control overflow. Operation of flow through the outlet is controlled by a valve located south of the spillway supported by a concrete pedestal that rises 2 feet above high water level. The depth to the gate from the top of the concrete pedestal is approximately . The gate allows for water discharge through the low-level outlet pipe to an unnamed creek, which flows into Mountaineer Creek, a tributary of

Geography

Colchuck Lake sits in a basin consisting of rocky soils and igneous

tonalite Tonalite is an igneous, plutonic ( intrusive) rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with alkali feldspar making up less than 10% of the total ...

geology. The

bedrock In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface mater ...

is about 3 feet from the surface and mapped as granites of the Mount Stuart Batholith (Mesozoic

intrusive rock Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''Igneous intrusion, intrusions'', such as batholiths, dike (geology), dikes, Sill (geology), sills, laccoliths, and volcanic necks.I ...

s) and

ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...

of the Ingalls Tectonic Complex (Mesozoic-Paleozoic ultramafic rocks). The trail to the lake consists of sandy

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...

the first half and boulders added in the second half of the trajectory.

Uses

Colchuck Lake is managed by the Icicle and Peshastin Irrigation Districts (IPID) to provide water storage for

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...

. The lake captures water runoff at the far southeast of a 3,800-acre

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, t ...

which gives the lake a high potential for refill, even during dry years. The reservoir is contained by a small

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

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. This infrastructure allows for controlled releases of stored water to supplement flows into

through its outflowing tributaries and increase the water supply available during low flow periods, which typically occur during the late summer.

2017 fire

On August 11, 2017 lightning caused by a cold frontal passage that tracked through the

Alpine Lakes Wilderness The Alpine Lakes Wilderness is a large wilderness area spanning the Central Cascades of Washington state in the United States. The wilderness is located in parts of Wenatchee National Forest and Snoqualmie National Forest, and is approximately b ...

started a fire about 15 miles southwest of

. The fire expanded into the

Eightmile Lake 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. The lake is located approx ...

, Stuart Lake and Colchuck drainages burning to the shoreline and damaging a large percentage of the lake's watershed.

Access

Lake Stuart-Colchuck Lake intersection - Flickr - brewbooks

The foot trail starts at the trailhead at the end of USFS Road 7601 becoming Stuart Lake Trail #1599. The trail eventually crosses over Mountaineer Creek about 1.5 miles from the trailhead by way of a wooden bridge. The trail will fork in two less than a mile from the bridge, to the right is the trail to Stuart Lake and to the left is Colchuck Lake Trail #1599.1 towards Colchuck Lake. The trail has a second bridge over Mountaineer Creek shortly after the split fork. Self-issued Alpine Lake Wilderness permit is required for transit within the Colchuck Lake area.

References

{{authority control Lakes of Chelan County, Washington Lakes of the Alpine Lakes Wilderness Okanogan National Forest