The effect of irrigation on the city of Boise is unmistakable as intricate canal systems, along with diversion dams, enabled locals to transport water from the Boise River to farms on the Boise Bench and other remote areas. Before significant irrigation in the valley, farmers had to locate their farmstead within close proximity to a substantial water source, usually the Boise River. Tom Davis, for example, settled alongside the river in current day Julia Davis Park where he dug a ditch from the river to his orchard. In fact, farmers utilized much of the land along the Boise River in the early years of Boise history as few deemed it worthy of little else due to flooding. As county population grew, however, citizens realized the need for irrigable land beyond the riverbanks. Many looked to the large expanse of land south of Boise just below the Boise Bench as well as downstream to the west.
Though progress was painfully slow between 1890 and 1912, the promise of irrigation brought new development to the Boise Valley with brisk growth commencing after 1909. As part of the plan, now called the Boise Project, workers built a reservoir near Nampa named Deer Flat for storage and a diversion dam east of Boise to carry the water above the Boise Bench. With the construction of Arrowrock Dam upstream a few years later, the valley had a surplus of water allowing for year around irrigation.
With the increase in irrigable property, the city of Boise grew toward the hinterlands absorbing some smaller urban communities and creating others. The abundance of irrigable land brought new inhabitants and development to Boise and the surrounding valley. It is difficult today to imagine the landscape of the Boise without the influence of irrigation. Irrigation allowed Boise to grow in all directions and at elevations previously inaccessible to any substantial amount of Boise River water. Between 1880 and 1910, the Boise City population increased from 1,899 to 17,358 a large portion of that due to irrigation related development.
Remote agricultural communities were not the only places experiencing growth. The city of Boise reaped the rewards of having water available above the Bench with the development of residential and commercial districts south of the city. Few Boise area maps before around 1910 even acknowledge the existence of inhabitants south of the Boise River and on the Boise Bench. As indicated on a 1917 map of Boise by the Intermountain Map Company, just a few years after the completion of the Boise Project, various agricultural, commercial, and residential developments covered the Boise Bench. Whereas other factors played a part in this development, irrigation provided the foundation for them to build upon.
