[3] The lake basin receives more than 110 inches (2,800 mm) of rain annually due to its location in the Cascade Range, about 9 miles (14 km) west of Mount Hood.

Public access to the area has been controlled since June 17, 1892, with the creation of the Bull Run Reserve by President Benjamin Harrison.

President Theodore Roosevelt restricted entry to all but government agents and water company employees and banned stock grazing on April 28, 1904.

[2] In 1915 a new timber and rock fill dam raised the lake level about 10 feet (3.0 m).

Concrete pier blocks were installed to minimize the effect of water temperature shock on downstream aquatic life.