Drought intensity–duration–frequency curves based on deficit in precipitation and streamflow for water resources management

Abstract

Abstract. Drought estimates in terms of physically measurable variables such as precipitation deficit or streamflow deficit are key knowledge for an effective water management. How these deficits vary with the drought event severity indicated by commonly used standardized indices is often unclear. Drought severity calculated from the drought index does not necessarily correspond to the same amount of deficit in precipitation or streamflow at different regions, and it is different for each month in the same region. We investigate drought to remove this disadvantage of the index-based drought intensity–duration–frequency (IDF) curves and develop IDF curves in terms of the associated deficit. In order to study the variation of deficits, we use the link between precipitation and streamflow and the associated indices, the Standardized Precipitation Index (SPI) and the Standardized Streamflow Index (SSI). More specifically, the analysis relies on frequency analysis combined with the total probability theorem applied to the critical drought severity. The critical drought has varying durations, and it is extracted from dry periods. IDF curves in terms of precipitation and streamflow deficits for the most severe drought of each drought duration in each year are then subject to comparison of statistical characteristics of droughts for different return periods. Precipitation and streamflow data from two catchments, the Seyhan River (Türkiye) and the Kocher River (Germany), provide examples for two climatically and hydrologically different cases. A comparison of the two cases allows a similar method to be tested in different hydrological conditions. We found that precipitation and streamflow deficits vary systematically, reflecting seasonality and the magnitude of precipitation and streamflow characteristics of the catchments. Deficits change from one month to another at a given station. Higher precipitation deficits were observed in winter months compared to summer months. Additionally, we assessed observed past major droughts experienced in both catchments on the IDF curves, which show that the major droughts have return periods at the order of 100 years at short durations. This coincides with the observation in the catchments and shows the applicability of the IDF curves. The IDF curves can be considered a tool for using in a range of specific activities of agriculture, ecology, industry, energy and water supply, etc. This is particularly important to end users and decision-makers to act against the drought quickly and precisely in a more physically understandable manner.

Formative drought rate to quantify propagation from meteorological to hydrological drought

“…In Step 1 of the experiment, monthly precipitation data were transformed into standardized drought indices, which are probabilistic transformation of physical variables with a known distribution to the standard normal distribution (Aksoy & Cavus, 2022;Erhardt & Czado, 2018). As drought indices are widely known in the literature (Cavus et al, 2023;Hong et al, 2015;Tabari et al, 2013), we provide no detail about their formulation but explain how we treated them in this study. Among the standardized drought indices, we used SPI of McKee et al (1993) and SDI of Nalbantis and Tsakiris (2009), to identify periods of precipitation and streamflow deficits, respectively.…”

“…Monthly and seasonal timescales are considered short while other timescales are considered long (Vicente-Serrano et al, 2013). In its practical meaning, the term timescale refers to the lag from the starting of a deficit in precipitation or in streamflow to the time when its consequences are identified on water resources, engineering activities, ecology, economy or society (Cavus et al, 2023). The timescale to consider differs depending on the purpose of the problem practiced.…”

From Cut-in to Qanats - Ancient Groundwater Extraction Techniques

“…With increasing concern on the global climate change and the local asymmetrical balance between water demand and supply, drought remained one of the unsolved problems of hydrological extremes [1]. This is the fundamental reason for the bloomed interest about the drought not only to better understand its technical context at local, regional or larger scales, and to develop methodologies [2][3][4][5][6] but also to link the drought with its social aspects due to the direct impact on economy, ecology and society [7][8]. As it is for today, the drought has affected on the society in the ancient time.…”