The Three Lakes
What is the difference between a lake and a reservoir?:
A lake is a natural body of water formed by geological processes such as glaciation, volcanic activity, or tectonic movements. Lakes are integral parts of their ecosystems, supporting diverse flora and fauna and maintaining their water levels primarily through natural hydrological cycles, including precipitation, inflow from rivers and streams, and evaporation. They often serve as vital habitats for wildlife and are important for recreational activities and natural beauty.
A reservoir is an artificial body of water created by constructing dams or other barriers across rivers or streams. Reservoirs are engineered to meet specific human needs, such as water storage, flood control, irrigation, and hydroelectric power generation. Their water levels are actively managed and controlled to fulfill these operational purposes. While reservoirs can also support recreational activities and wildlife habitats, their primary function is to regulate and store water to serve human requirements. This distinction makes reservoirs fundamentally different from natural lakes, both in origin and purpose.
Three Lakes Stats:
Grand Lake
Type: Natural Lake
Description: Grand Lake is the largest and deepest natural lake in Colorado, covering approximately 507 acres with a maximum depth of about 265 feet. It was formed by glacial activity and has been a natural feature of the landscape for thousands of years.
Shadow Mountain Reservoir
Type: Reservoir
Created: 1947
Description: Shadow Mountain Lake is an artificial reservoir created as part of the C-BT Project. It covers about 1,346 acres with a maximum depth of approximately 24 feet.
Granby Reservoir
Type: Reservoir
Created: 1950
Description: Granby is the largest of the three lakes, covering about 7,256 acres with a maximum depth of 221 feet. It is an artificial reservoir created by the construction of Granby Dam.
The Three “Lakes” in the Grand Lake Area
Grand Lake is the largest and deepest natural lake in Colorado, covering approximately 507 acres with a maximum depth of about 265 feet. Formed by glacial activity, it has been a natural feature of the landscape for thousands of years. Historically, Grand Lake has played a vital role in the local ecosystem and served as an important cultural and recreational site for indigenous peoples and later settlers. Today, it serves primarily recreational purposes, including boating, fishing, and tourism, while also playing a critical role in the Colorado-Big Thompson (C-BT) Project as the natural storage basin that connects with the project's water diversion infrastructure.
Shadow Mountain Lake, an artificial reservoir created in 1947 as part of the C-BT Project, covers about 1,346 acres with a maximum depth of approximately 24 feet. Before its creation, the area consisted of meadows and wetlands. The reservoir was constructed to regulate and store water diverted from the Colorado River for agricultural and municipal use on Colorado's Eastern Slope. In addition to its primary function in water management, Shadow Mountain Lake supports recreational activities such as fishing, boating, and camping.
Lake Granby, the largest of the three lakes, spans about 7,256 acres with a maximum depth of 221 feet. Created in 1950 by the construction of Granby Dam, it transformed the area, which previously featured forests, meadows, and streams, into a reservoir to meet the water storage needs of the C-BT Project. Lake Granby serves as a major storage reservoir, holding water diverted from the Colorado River before it is transported to the Eastern Slope. It also offers various recreational opportunities, including fishing, boating, and camping.