The Granite Reef Watershed is located in the southeast part of the City of Scottsdale. The south part of the watershed includes a 100-year FEMA floodplain for Granite Reef Wash. Approximately 700 homes are within this floodplain. The current concepts for the related drainage improvement project include: the addition of inlets and lateral pipes to existing storm drain pipes that convey stormwater westward into Indian Bend Wash, two detention basins to attenuate stormwater flows, and various improvements to provide a stormwater outfall to the Salt River. The project improvements are expected to greatly reduce the floodplain. The City of Scottsdale is the lead agency for the project and is partnering with the Flood Control District of Maricopa County. The City is also coordinating and partnering with the Salt River Pima Maricopa Indian Community (SRPMIC) for the outfall segment of the project that lies within the SRPMIC.
The construction of the storm drain lateral systems at Jackrabbit Road, Chaparral Road, and Camelback Road (comprising Phase I-A) was completed in October 2018. Phase I-B-1 (storm drains and inlets at Indian School Road and Pima Road) was completed in Nov 2018. Phase I-B-2 (Indian School Road lateral storm drains) construction is expected to start in approx. April 2019.