Lake Lowell

Transforming Treasure Valley

The Reclamation Act of June 17, 1902, aimed to create proper irrigation systems that could provide water access for residents of western states. Lake Lowell was one of those projects.

Under the direction of the 1902 Reclamation Act—congressional legislation intended to irrigate western states and provide greater access to water—the Bureau of Reclamation approved and developed Lake Lowell, starting in 1902 and finishing in 1909. Three dams—the Upper, Middle, and Lower Embankments (embankments are walls of earth or stone built to prevent a river from flooding an area)—surround a natural depression southwest of Nampa, Idaho to form the lake. A fourth wall, called the East Embankment, was added later to protect farmsteads on the eastern end of the reservoir.

In the irrigation off-season, the Boise River Diversion Dam and New York Canal provide most of Lake Lowell’s volume, discharging water intp the upper end of the lake, where there is a capacity ranging from 12.7 feet on the Middle Embankment to 65 feet on the Upper. During the irrigation season, Lake Lowell becomes one of the major irrigation providers for Canyon County agriculture. With the capacity to irrigate over 200,000 acres of land, it is one of the American West’s largest off-stream reservoirs.

As with many other western irrigation projects, Lake Lowell presented a significant opportunity for economic growth and restructured the relationship between people and their environment. Along with other government investment projects that opened the area to construction and farming, irrigation attracted migrants from the Midwest who worked as laborers to develop the dam and as farmers to till the land. In 1900, the census counted 161,772 people living in Idaho; by the 1920 census, the population had more than doubled to 431,866 people. This growth was sharpest in southwestern Idaho, which grew by 130% during this twenty-year period as agricultural and ex-urban communities transformed Treasure Valley into fertile land. Lake Lowell made that change possible.

In addition to serving local farms, towns, and cities, Lake Lowell also plays a role in how people and other living things interact with the region’s nature. The lake hosts the Deer Flat Reservoir, one of the oldest refuges in the National Wildlife Refuge System. As for humans in nature, Lake Lowell is a popular destination for numerous outdoor activities, including boating, swimming, fishing, birdwatching, hiking, and hunting.


Building up
Building up Source: “The Deer Flat Reservoir During Construction.” 1906. Courtesy of the Idaho State Historical Society.
As above
As above A view of the Deer Flat Upper Embankment. Source: Courtesy of the United States Bureau of Reclamation.
Holding the center
Holding the center A view of the Deer Flat Middle Embankment. Source: Courtesy of the United States Bureau of Reclamation.
So below
So below A view of the Deer Flat Lower Embankment. Source: Courtesy of the United States Bureau of Reclamation.
Sky and sea
Sky and sea An aerial view of Lake Lowell. Source:

“Lake Lowell 2.” Drew Morris, April 17, 2014. Via Flickr (CC BY-NC-SA 2.0).


Legna Roximar Morales, College of Idaho, “Lake Lowell,” Intermountain Histories, accessed February 24, 2024,