# University of Twente Student Theses

## Search for the Optimal Selection Formulas When Calibrating Separately for Flood and Dry Season

Post, T.M.I. (2013) Search for the Optimal Selection Formulas When Calibrating Separately for Flood and Dry Season.

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 Abstract: This research has calibrated the Xinanjiang model with the Genetic Algorithm using different selection formulas. The Xinanjiang model is a rainfall-runoff model which requires precipitation and evaporation as input and generates the river discharge in cubic meters per second at a certain location and for a certain moment in time. The Genetic Algorithm was used in combination with collected data in the Qingjiang river basin in China. Using the precipitation, evaporation and river discharge, the proper settings (parameter values) were found for the Xinanjiang model so it would function in the Qingjiang river basin. Performing this multiple times with different selection formulas means that it was possible to make a comparison between these formulas in order to find which one works best. Because the model could not function accurately for an entire year with one set of parameters, different parameter values were needed for the wet season and the dry season which has shown in other research (Muleta, 2012) to increase the accuracy of the predictions. Therefore, the goal of the research is to find the selection formulas, which are used in the Genetic Algorithm, that perform best for each season. The conclusion drawn is that for the flood seasons the Nash-Sutcliffe formula should be used. The Relative Mean Absolute Error has performed satisfactory as well, but there seems to be no reason to prefer this formula over the Nash-Sutcliffe. For the dry season, the best selection formula is the Relative Mean Absolute Error. On a close second place is the RSR formula, which is the Nash-Sutcliffe formula with a square root in the numerator and denominator. This research has been performed as a bachelor thesis which is requirement for finishing the bachelor study in Civil Engineering at the University of Twente. The research has mostly taken place at the China Three Gorges University in Yichang between the end of 2012 and early 2013. The data of the Qingjiang river basin was already available at the university of which the years 1990 and 1991 were used. Item Type: Essay (Bachelor) Faculty: ET: Engineering Technology Subject: 56 civil engineering Programme: Civil Engineering BSc (56952) Link to this item: https://purl.utwente.nl/essays/66664 Export this item as: BibTeXEndNoteHTML CitationReference Manager

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