01490758

Monograph

http://www.trb.org/Main/Blurbs/169456.aspx

http://www.trb.org/Publications/Blurbs/169456.aspx

The results of a research study to develop practical procedures for estimating joint probabilities of coincident flows at stream confluences and guidelines for applying the procedures to design problems are documented in this report. The study was based on a database of 85 gage pairs located throughout the coterminous United States. Two practical design methods emerged from the study. The first method for determining a set of exceedance probability combinations associated with the desired joint probability for design is based on copulas. The Gumbel- Hougaard copula was selected as the most appropriate for this application. Use of the copula requires estimation of the Kendall’s τ rank correlation for an ungaged watershed pair. Tools for estimating this parameter based on watershed characteristics are also a product of the research. For a given Kendall’s τ, the appropriate combinations of events on the main and tributary streams for a desired joint exceedance probability are provided in tabular form. The second method is the use of the total probability method. Although the total probability method, based on the total probability theorem, is a well-documented procedure, this study provided recommended conditional probability matrices needed to apply the theorem. Both methods result in the design conditions representing the joint probability desired by the designer for analysis.

NCHRP Project 15-36

English

270p

2013-3

NCHRP Web-Only Document

Contractor's Final Report

Print

Appendices; Figures; Maps; References; Tables

Design methods; Drainage structures; Floods; Stream gages; Streamflow; Streams

Design; Highways; Hydraulics and Hydrology; I20: Design and Planning of Transport Infrastructure; I26: Water Run-off - Freeze-thaw

TRIS, TRB, ATRI

Aug 30 2013 10:56AM