Monthly Flow Duration Curve Model for Ungauged River Basins

Hafzullah Aksoy,Halil Ibrahim Burgan

doi:10.3390/w12020338

Hafzullah Aksoy, Halil Ibrahim Burgan

Open Access

https://doi.org/10.3390/w12020338

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Journal: Water	Publication Date: Jan 24, 2020
Citations: 21	License type: CC BY 4.0

Affiliation: Istanbul Technical University, Istanbul Kültür University

Abstract

Flow duration curve (FDC) is widely used in hydrology to assess streamflow in a river basin. In this study, a simple FDC model is developed for monthly streamflow data. The model consists of several steps including the nondimensionalization and then normalization in case the monthly streamflow data do not fit the normal probability distribution function. The normalized quantiles are calculated after which a back transformation is applied to the normalized quantiles to return back to the original dimensional streamflow data. In order to calculate annual streamflow of the river basin, an empirical regression equation is proposed using the drainage area and the annual total precipitation only as the input. As the final step of the model, dimensional quantiles of FDC are calculated. Ceyhan River basin in southern Turkey is chosen for the case study. Forty-two streamflow gauging stations are considered; two thirds of the gauging stations are used for the model calibration, and one third for validation. The modeled FDCs are compared to the observation and assessed with a number of performance metrics. They are found similar to the observed ones with a relatively good performance; they are good in the mid and high flow parts particularly while the low flow part of FDCs might require further detailed analysis.

Highlights

In the planning and management practices of water resources, there are many computational tools available to the researchers and engineers
This study aims at contributing research on flow duration curve (FDC) of ungauged river basins by using hydrometeorological and topographical data of the surrounding basins
In order to prove that the model is applicable to ungauged river basins, a monthly streamflow data set composed of 42 hydrometric stations was chosen from the Ceyhan River basin streamflow data set composed of 42 hydrometric stations was chosen from the Ceyhan River basin in southern Turkey as detailed above

Summary

Introduction

In the planning and management practices of water resources, there are many computational tools available to the researchers and engineers. The flow duration curve (FDC) is used to characterize the regime of the hydrological watershed. It is obtained from the observed streamflow time series listed in the ascending order and plotted against the corresponding duration of exceedance [1]. By the use of FDC, discharges of certain time percentages (quantiles) are determined;. I.e., the upper and lower extreme events (floods and low flows) are calculated [2,3,4,5,6]. It is possible to model the urban stormwater [7], determine the environmental flow allocation [8] and calculate the hydropower potential and water availability at hydrological watersheds [9,10,11].

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