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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 8 - CLIMATE CHANGE AND HAZARD MITIGATION : Effects of Climate Change on Design Discharges
Effects of Climate Change on Design Discharges
Author : Joyce Bello, Javier Aparicio and Polioptro Martínez
Waterworks are designed using probability distribution functions accepting the hypothesis that climatic and hydrological variables are stationary, meaning that their statistical properties are constant over time. However, climate change is manifested in the increase in air temperature, rising ocean levels and other physical changes which significantly modify the hydrological cycle and thus statistical properties of hydrological variables.This paper aims to analyze the effects of climate change in the probability distribution functions in two basins in Mexico, through rainfall projections produced by the Earth Model, developed by the Meteorological Research Institute of the Japan Meteorological Agency whose horizontal resolution is equivalent to about 20 km, one of the more detailed resolutions in the models approved by the Intergovernmental Panel on Climate Change (IPCC). This model provides precipitation scenarios for three periods: present (1979-2003), near future (2015-2039) and end of the century (2075-2099).Using registered runoff in both basins, unit hydrographs were obtained for each annual maximum flood, yielding a single average unit hydrograph for each basin. In order to track soil moisture variations and using measured average daily rainfall, an Antecedent Precipitation Index vs. Average Infiltration Index ???? curve was built, fitting a function to the curve in order to later obtain the average infiltration index for the years projected by the model. This curve was used to calculate effective rainfall and runoff hydrographs were computed using the corresponding unit hydrographs. Maximum annual discharges were then computed for the present period scenario (which was used as the control period) by means of the Earth Model precipitation and such discharges were compared to those measured. A correction algorithm for the Earth Model discharges was found and later applied to discharges computed for the near future and end of the century periods. Probability Distribution Functions were adjusted to the corrected discharges thus computed and design discharges for several return periods were found for each period. Results In a basin shows a significant increase for different return periods considering climate change, while for the other basin, some return periods there is an increase and others a decrease. This methodology can be used to review the design of existing waterworks and to include the possible effects of climate change in the design of new works.
File Size : 571,054 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Article : THEME 8 - CLIMATE CHANGE AND HAZARD MITIGATION
Date Published : 19/07/2016
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