Margin of Safety Based Flood Reliability Evaluation of Wastewater Treatment Plants: Part 1 – Basic Concepts and Statistical Settings.

Low-lying coastal urban areas are vulnerable to frequent and chronic flooding due to population growth, urbanization, and accelerated sea level rise originating from climate change. This paper is part one of a 2 paper series, however a detailed literature review on the concept and the technical aspects of both papers is presented. In the 2nd paper, the application of the concepts and the proposed methodology are utilized to set the mitigation strategies for quantification of reliability attributes. The case study is the Hunts Point wastewater treatment plant and its sewershed in Bronx, New York City. The suitability of two major rainfall stations of Central Park and LaGuardia airport in the vicinity of the case study is tested. The copula-based non-stationary 100–year flood frequency analysis of rainfall and storm surge is analyzed to obtain the design values of surge and rainfall. A differential evaluation Markov Chain with Bayesian interface is used in this paper for parameter estimation. In this study, the likelihood of joint probability of co-occurring heavy rainfall and storm surge is determined to illustrate the risk of joint events. Therefore, the copula-based non-stationary 100–year flood frequency analysis of rainfall and storm surge are performed to obtain the design values of surge and rainfall. A multi-criteria decision-making (MCDM) approach that incorporates the load-resistance concept is presented in Part 2 paper to assess the Margin of Safety flood reliability of a wastewater treatment plant (WWTP). The framework presented in this paper is applicable to other coastal sewersheds. [ABSTRACT FROM AUTHOR]