Citation

Reich BM, Davis DR. Transp. Res. Rec. 1985; 1017: 1-8.

Copyright

(Copyright © 1985, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Various statistical tests indicate that a significant increase in flood magnitude has occurred on Arizona's semiarid Santa Cruz River throughout its 70 years of stream gauging. Inspection of field conditions, aerial photographs, and historical reports confirms that increased conveyance and reduced overbank flooding onto wide upstream floodplains could have produced this nonstationarity. The most recent 27 years of statistical data is therefore used as a first approximation to present hydrologic conditions. Uncertainties associated with this short subrecord and progressive deterioration of the river system are considered in a systems analysis. Because of the extensive expense of rebuilding many bridges within this rapidly expanding community, it is recommended that consideration be given to confidence bands, safety factors, distributions other than the Log Pearson III, and floods observed on other Arizona watersheds within the past century in an attempt to establish a new 100-year estimate for this 2,222 square mile semiarid watershed. It is hoped that this new design parameter can be used for a reasonable planning horizon of approximately 30 years. Highway concerns include enlargement of openings for new and existing bridges, revised calculation of pier and abutment scour, general widening of the main channel that occurred during the 1983 flood, and endangerment of roadways by the river's lateral migration.

Language: en

Keywords

BRIDGES, HIGHWAY; STATISTICAL METHODS; HIGHWAY ENGINEERING; HIGHWAY SYSTEMS - Design; FLOODS - Arizona; HYDROLOGY