Climate change, one of the major environmental challenges facing mankind, has caused intermittent droughts in many regions resulting in reduced water resources. This study investigated the impact of climate change on the characteristics (occurrence, duration, and severity) of meteorological drought across Ankara, Turkey. To this end, the observed monthly rainfall series from five meteorology stations scattered across Ankara Province as well as dynamically downscaled outputs of three global climate models that run under RCP 4.5 and RCP 8.5 scenarios was used to attain the well-known SPI series during the reference period of 1986–2018 and the future period of 2018–2050, respectively. Analyzing drought features in two time periods generally indicated the higher probability of occurrence of drought in the future period. The results showed that the duration of mild droughts may increase, and extreme droughts will occur with longer durations and larger severities. Moreover, joint return period analysis through different copula functions revealed that the return period of mild droughts will remain the same in the near future, while it declines by 12% over extreme droughts in the near future.

This study aims to investigate the effectiveness of the low impact development (LID) practices on sustainable urban flood storm water management. We applied three LID techniques, i.e. green roof, permeable pavements and bioretention cells, on a highly urbanized watershed in Istanbul, Turkey. The EPA-SWMM was used as a hydrologic-hydraulic model and the model calibration was performed by the well-known Parameter ESTimation (PEST) tool. The rainfall-runoff events occurred between 2012 and 2020. A sensitivity analysis on the parameter selection was applied to reduce the computational cost. The Nash-Sutcliffe efficiency coefficient (NSE) was used as the objective function and it was calculated as 0.809 in the model calibration. The simulations were conducted for six different return periods of a storm event, i.e. 2, 5, 10, 25, 50 and 100 years, in which the synthetic storm event hyetographs were produced by means of the alternating block method. The results revealed that the combination of green roof and permeable pavements have the major impact on both the peak flood reduction and runoff volume reduction compared to the single LIDs. The maximum runoff reduction percentage was obtained as 56.02% for a 10 years return period of a storm event in the combination scenario.

Spatial and temporal linkages between large‐scale atmospheric oscillations, namely, North Atlantic Oscillation (NAO), Southern Oscillation (SO) and North Sea–Caspian Pattern (NCP), and meteorological droughts in Turkey were investigated in this study. The corresponding oscillation indexes (NAOI, SOI and NCPI) were considered as monthly time indicators of the oscillations while the Standard Precipitation Index (SPI) obtained from 148 stations was used to define meteorological droughts. The suitability of various probability distributions was evaluated to obtain precise estimations of SPI values. Correlation analyses were then conducted to assess spatial and temporal distribution of the relationship between the oscillation and drought indexes. The linkages between the NAOI, NCPI and SPI were found to be more significant at the lag‐0, while the SOI had significant positive and negative correlations with SPI series at lag‐1–2. Moreover, our results revealed that the NAO is more dominant in the west and in the central Anatolia regions while the NCP has more influence on the northern and eastern regions.