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Open AccessEditor’s ChoiceArticle

by Radu Drobot, Aurelian Florentin Draghia, Nicolai Sîrbu and Cristian Dinu

Hydrology 2023, 10(1), 10; https://doi.org/10.3390/hydrology10010010 - 30 Dec 2022

Cited by 2 | Viewed by 3101

Droughts are natural disasters with a significant impact on the economy and social life. Prolonged droughts can cause even more damage than floods. The novelty of this work lies in the definition of a synthetic drought hydrograph (SDH) which can be derived at each gaging station of a river network. Based on drought hydrographs (DHs) recorded for a selected gaging station, the SDH is statistically characterized and provides valuable information to water managers regarding available water resources during the drought period. The following parameters of the registered drought hydrograph (DH) are proposed: minimum drought discharge

Q_{D}^{m i n}

, drought duration

D_{D}

and deficit volume

V_{D}

. All these parameters depend on the drought threshold

Q_{T}

, which is chosen based on either pure hydrological considerations or on socio-economic consequences. For the same statistical parameters of the drought, different shapes of the synthetic drought hydrograph (SDH) can be considered. In addition, the SDH varies according to the probabilities of exceedance of the minimum drought discharge and deficit volume. Full article

(This article belongs to the Special Issue Stochastic and Deterministic Modelling of Hydrologic Variables)

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23 pages, 6024 KiB

Open AccessArticle

Risk Analysis of Reservoir Operations Considering Short-Term Flood Control and Long-Term Water Supply: A Case Study for the Da-Han Creek Basin in Taiwan

by Wen-Ming Cheng, Chien-Lin Huang, Nien-Sheng Hsu and Chih-Chiang Wei

Water 2017, 9(6), 424; https://doi.org/10.3390/w9060424 - 12 Jun 2017

Cited by 22 | Viewed by 7096

Abstract

This study applies an integrated methodology to assess short-term over-levee risk and long-term water shortage risk in the Da-Han Creek basin, which is the most important flood control and water storage system in northern Taiwan. An optimization model for reservoir flood control and water supply is adopted, to determine reservoir releases based on synthetic inflow hydrographs during typhoons, which are generated by Monte Carlo simulations. The release is then used to calculate the water level at a downstream control point using a novel developed back-propagation neural network-based model, to reduce computational complexity and achieve automatic-efficient risk evaluation. The calculated downstream water levels and final reservoir water levels after a typhoon event are used to evaluate the mapped over-levee risk and water shortage risk, respectively. The results showed that the different upper limit settings for the reservoir have a significant influence on the variation of 1.19 × 10⁻⁵% to 75.6% of the water shortage risk. This occurs because of the insufficient inflow and narrow storage capacity of the Shih-Men Reservoir during drought periods. However, the upper limit settings have a minor influence (with a variation of only 0.149% to 0.157%) on the over-levee risk in typhoon periods, because of the high protection standards for the downstream embankment. Full article

(This article belongs to the Special Issue Innovative Aspects in Flood Risk Evaluation, Mapping and Communication)

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