From the Proceedings of the 1984 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona-Nevada Academy of Science - April 7, 1984, Flagstaff, Arizona

From the Proceedings of the 1984 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona-Nevada Academy of Science - April 7, 1984, Flagstaff, Arizona

From the Proceedings of the 1984 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona-Nevada Academy of Science - April 7, 1984, Flagstaff, Arizona

From the Proceedings of the 1984 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona-Nevada Academy of Science - April 7, 1984, Flagstaff, Arizona / Post-disaster studies of the October 1983 flood lead to serious questions concerning the applicability to southern Arizona of nationally standardized procedures for flood hazard evaluation. When the U.S. Water Resources Council method of determining flood flow frequency is applied to the Santa Cruz River annual peak flow record at Tucson for the period 1915-1982, the 1983 flood discharge is predicted to have an exceedence probability of less than 0.001. Hydro-climatological considerations suggest that such large floods occur much more frequently. The standard procedure for flood hazard zonation utilizes step-backwater calculations for the extant channel and valley floor geometry to route the discharges obtained from the standard flood flow frequency analysis. This procedure, as used in the Federal Emergency Management Agency flood insurance study, greatly overestimated the areas of overbank flooding along the Santa Cruz River as experienced in the 1983 flood. A detailed post-flood study was performed to assess channel change for reaches of Pantano Wash, Tanque Verde Creek, the Rillito, and the Santa Cruz River in the Tucson Basin. Bank erosion occurred as cutbank recession of actively migrating meander bends except where local areas of bank were preserved by revetments. Where revetments remained intact during the flooding they served to concentrate and enhance bank erosion in the unprotected reaches immediately downstream. From an overall river management perspective, piecemeal bank protection generates greater channel instability than does no protection at all.

From the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada

From the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada / Hydrologic and hydraulic design procedures developed by the Pima County Department of Transportation and Flood Control District were proposed for use by the Department of Transportation, Engineering Division of the City of Tucson, Arizona. These procedures were evaluated with respect to their reasonableness of approach and in comparison with other methods and existing data used to derive similar methodology and standards. The proposed criteria/methodology were found to be consistent with procedures used in other cities in the Southwest, and with the current state of the art in urban hydrology and hydraulic engineering practices and procedures. However, locally derived rainfall intensity -duration relationships were found to be superior to regionally based relationships, and minor modifications were suggested for channel design procedures.

From the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada

From the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada

From the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada

From the Proceedings of the 1986 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 19, 1986, Glendale Community College, Glendale, Arizona