From the beginning, the founders of the City of Boise had to consider the nearby Boise River when planning the future capital city. Organizers of Boise designed the town site so that main street ran parallel, though not too close, to the erratic waterway. They wanted the city to be far enough away to avoid any flooding, yet close enough to take advantage of the abundant water supply. As years passed, the unpredictability of the water’s path and level kept development to a minimum alongside the river.       

Boise River, leveed and channelized, flowed under Oregon Trail Memorial Bridge through Julia Davis Park, about 1932. Idaho State Historical Society.

For many decades, locals built levees on each side of the river, slowly narrowing and straightening the stream. This allowed development nearer the river though occasional flooding still kept serious growth to a minimum. Finally, in 1955, the construction of Lucky Peak Dam upstream gave Boise citizens the confidence to invest in significant development and urban expansion moved toward the riverbanks.