Banks Lake is a 27 miles (43.5 km) long reservoir

Reservoir

A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

 in central Washington in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

Part of the Columbia Basin Project

Columbia Basin Project

The Columbia Basin Project in Central Washington, USA, is the irrigation network that the Grand Coulee Dam makes possible. It is the largest water reclamation project in the United States, supplying irrigation water to over of the large project area, all of which was originally intended to be...

, Banks Lake occupies the northern portion of the Grand Coulee

Grand Coulee

The Grand Coulee is an ancient river bed in the U.S. state of Washington. This National Natural Landmark stretches for about sixty miles southwest from Grand Coulee Dam to Soap Lake, being bisected by Dry Falls into the Upper and Lower Grand Coulee....

, a formerly dry coulee

Coulee

Coulee is applied rather loosely to different landforms, all of which refer to a kind of valley or drainage zone.The word coulee comes from the Canadian French coulée, from French word couler meaning "to flow"....

 near the Columbia River

Columbia River

The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

, formed by the Missoula Floods

Missoula Floods

The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s...

 during the Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 epoch. Grand Coulee Dam

Grand Coulee Dam

Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...

, built by the United States Bureau of Reclamation on the Columbia River created Franklin D. Roosevelt Lake

Franklin D. Roosevelt Lake

Franklin D. Roosevelt Lake is the reservoir created in 1941 by the impoundment of the Columbia River by the Grand Coulee Dam in Washington state. It is named for Franklin D. Roosevelt, who was President during the construction of the dam...

, the reservoir on the river behind the dam. The surface of Lake Roosevelt is several hundred feet above the original Columbia River, making it easier to pump water 280 feet (85.3 m) up and out of the river's canyon into the adjacent Grand Coulee. Two low earth-fill dams, Dry Falls Dam

Dry Falls Dam

Dry Falls Dam is a rockfaced earthfill-type dam in the U.S. state of Washington. Located in Grant County near Coulee City, it was built as part of the Bureau of Reclamation's Columbia Basin Project. Water from the Columbia River, impounded by Grand Coulee Dam, is pumped into Grand Coulee, a...

 and North Dam, keep the water in the Grand Coulee, thus creating the reservoir named Banks Lake. It is named after Frank A. Banks, the construction supervisor at Grand Coulee Dam.

At the north end of Banks Lake the city of Grand Coulee

Grand Coulee, Washington

Grand Coulee is a city in Grant County, Washington, United States. The population was 897 at the 2000 census.-History:Grand Coulee was officially incorporated on November 6, 1935...

 and the town of Electric City

Electric City, Washington

Electric City is a town in Grant County, Washington, United States. The population was 922 at the 2000 census. The community was named for its proximity to the power source at Grand Coulee Dam.-Geography:Electric City is located at ....

 are located. Steamboat Rock State Park

Steamboat Rock State Park

Steamboat Rock State Park is a state park in the state of Washington in the United States. It is located near the north end of Banks Lake in the Grand Coulee. It covers , has of freshwater shoreline, and is open year-round for camping and day use...

 is in the north-central portion. The town of Coulee City

Coulee City, Washington

Coulee City is a town in Grant County, Washington, United States. The population was 600 at the 2000 census.-Geography:Coulee City is located at ....

 is at the south end of the lake. From the south end, the water stored in Banks Lake is distributed over a large region for irrigation of the Columbia Basin Project

Columbia Basin Project

The Columbia Basin Project in Central Washington, USA, is the irrigation network that the Grand Coulee Dam makes possible. It is the largest water reclamation project in the United States, supplying irrigation water to over of the large project area, all of which was originally intended to be...

.

Satellite photo

In this summertime photo, the land appears in shades of beige, brown, and green. In contrast to the rugged, irregular contours of local peaks, cultivated land appears as a network of rectangles, some deep green, others beige or tan. Bright green dots reveal fields watered with center-pivot irrigation systems. The greatest concentration of agricultural fields occurs south of the dam. North of the reservoir, vegetated hills predominate. Flatter terrain not under cultivation appears gray-beige, likely resulting from sparse vegetation, especially in the northwest.