Levee Lowering of the North Bank Levee along the Salt River in Tempe, Arizona

A Study was conducted to determine the feasibility of lowering a levee certified by the Federal Emergency Management Agency located along the north bank of the Salt River in Tempe, Arizona. The Salt River was channelized in the early 1990s with protective levees to contain flooding through the city. Funding to accomplish the design and construction was through a combination of Arizona Department of Transportation (ADOT), Flood Control District of Maricopa County (FCDMC), and City of Tempe funds. The levee reach studied is 579 meters (1900 feet) long and adjacent to the Tempe Town Lake (Town Lake) project. A bike path on the landward side of the levee had a vertical profile such that no site view of the Town Lake was possible for most of this reach. The Town Lake recreational area draws tens of thousands of visitors each year that come to enjoy views available along its entire frontage. This study evaluated whether the levee could be lowered, thus improving site view, yet still be approvable by local government and federal regulatory agencies. The proposed new levee lowering would result in a significant impact to years of planning, design and construction required for the existing levee. Alternatives to lowering the levee were considered. In addition to ADOT and the FCDMC, concept approvals were required from FEMA, the Salt River Project (SRP), and the Union Pacific Railroad (UPRR). Upon concept approval only, the preparation of construction documents could commence.