Pima County Regional Flood Control District Monthly Brown Bag Series
Speaker: Ian Sharp, J.E. Fuller/Hydrology & Geomorphology, Inc.
Date: Wednesday, June 14, 2017
Time: 12:00 – 1:00
Location: 9th Floor Public Works Building, 201 N. Stone, Tucson AZ, 85701
Floodplain regulators and others have long suspected that the existing mapping of the Santa Cruz River floodplain is inaccurate and outdated due to geomorphic changes, floodplain development, and inherent difficulties in modeling a perched floodplain. Pima County has responded by entering a Cooperating Technical Partners (CTP) agreement with FEMA leading to the Upper Santa Cruz Risk Map project. This is a joint local/federal project seeking to provide flood mapping products that accurately reflect current flood risks using high quality mapping data and the best available modeling techniques. Under the direction of the District, JE Fuller is preparing HEC-RAS two-dimensional modeling and floodplain mapping of 23 miles of the upper Santa Cruz River from the Santa Cruz County / Pima County Line to 2 miles north of Pima Mine Road. Risk MAP products are being prepared for the 10-percent, 4-percent, 2-percent, 1-percent, and 0.5-percent flood events.
The presentation will give an overview of the project, including preliminary mapping and HEC-RAS model results. Other topics will include problems encountered with modeling the river in RAS 2D, benefits and shortcomings of RAS 2D, bridge modeling in 2D, comparison to other methods, and preparing regulatory products such as floodways, profiles, and BFEs.