Status : Verified
| Personal Name | Iracta, Rodney James A. |
|---|---|
| Resource Title | Non-stationary Extreme Value Analysis of Annual Maximum Streamflow in Cagayan De Oro River Basin |
| Date Issued | 28 June 2024 |
| Abstract | Floods in the Philippines constitute about 23% of the hazards that have occurred during the past decades. Flood risk management strategies are usually developed from statistical models to derive return levels from flood frequency analysis. Traditional analysis relies on the concept of stationarity, which assumes that there are no shifts in the key statistical properties of the data over time, i.e., design flood levels will fall within the distribution characterized by historical data. Several studies, however, revealed that streamflow records indicate some kind of non-stationarity in the form of changing trends and shifts associated with climate change and urbanization; thus, there is a need to consider non-stationary analysis. This research conducted a non-stationary analysis of the annual maximum daily streamflow of the Cagayan De Oro River Basin, which is one of the areas in the country significantly affected by floods in the past. Streamflow data was fitted to generalized extreme value distributions under stationary and non-stationary assumptions using the maximum likelihood estimation method, incorporating time, annual rainfall mean, and percentage of impervious area as covariates. Twelve non-stationary models were developed and compared using the Akaike Information Criterion. The model with impervious area as a covariate was deemed as the best model. Model results show that flood magnitudes having 25-, 50-, and 100-year return periods under the stationary assumption correspond to 20-, 30-, and 48-year return periods, respectively, under the non-stationary assumption. Implications on risk of failure show consistently higher risk throughout the project life of the structure under non-stationary conditions, particularly on longer return periods. Projected water level estimates also indicate that expected levels are generally higher under the non-stationary assumption. These results suggest that flood structures designed under stationary assumption are bound to fa |
| Degree Course | MS Civil Engineering |
| Language | English |
| Keyword | flood frequency analysis; non-stationary analysis; generalized extreme value distribution |
| Material Type | Thesis/Dissertation |
Preliminary Pages
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Category : F - Regular work, i.e., it has no patentable invention or creation, the author does not wish for personal publication, there is no confidential information.
Access Permission : Open Access