Spatial Drought Characterization for Seyhan River Basin in the Mediterranean Region of Turkey

Abstract

Drought is a natural phenomenon that has great impacts on the economy, society and environment. Therefore, the determination, monitoring and characterization of droughts are of great significance in water resources planning and management. The purpose of this study is to investigate the spatial drought characterizations of Seyhan River basin in the Eastern Mediterranean region of Turkey. The standardized precipitation index (SPI) was calculated from monthly precipitation data at 12-month time scale for 19 meteorological stations scattered over the river basin. Drought with the largest severity in each year is defined as the critical drought of the year. Frequency analysis was applied on the critical drought to determine the best-fit probability distribution function by utilizing the total probability theorem. The sole frequency analysis is insufficient in drought studies unless it is numerically related to other factors such as the severity, duration and intensity. Also, SPI is a technical tool and thus difficult to understand at first glance by end-users and decision-makers. Precipitation deficit defined as the difference between precipitation threshold at SPI = 0 and critical precipitation is therefore more preferable due to its usefulness and for being physically more meaningful to the users. Precipitation deficit is calculated and mapped for 1-, 3-, 6- and 12-month drought durations and 2-, 5-, 10-, 25-, 50- and 100-year return periods at 12-month time scale from the frequency analysis of the critical drought severity. The inverse distance weighted (IDW) interpolation technique is used for the spatial distribution of precipitation deficit over the Seyhan River basin. The spatial and temporal characteristics of drought suggest that the Seyhan River Basin in the Eastern Mediterranean region of Turkey experiences quite mild and severe droughts in terms of precipitation deficit. The spatial distribution would alter greatly with increasing return period and drought duration. While the coastal part of the basin is vulnerable to droughts at all return periods and drought durations, the northern part of the basin would be expected to be less affected by the drought. Another result reached in this study is that it could be common for one point in the basin to suffer dry conditions, whilst surrounding points in the same basin experience normal or even humid conditions. This reinforces the importance of spatial analysis over the basin under investigation instead of the point-scale temporal analysis made in each of the meteorological stations. With the use of spatial mapping of drought, it is expected that the destructive and irreversible effects of hydrological droughts can be realized in a more physical sense.

Location Suitability for Small Reservoirs at the Bodri-Kuto River Basin Based on Spatial Monthly SPI

“…(3) Spatial interpolation was performed based on the SPI at 25 rainfall stations. The spatial interpolation throughout the river basin was performed using multi-dimension inverse distance weighting (IDW) in ArcMap by Environmental Systems Research Institute (ESRI) [21] to obtain the spatial distribution of SPI [22]. Other approaches to define spatial distribution include using principle component analysis for clustering homogenous regions based on SPI [23].…”

Special Issue “Multiscale Impacts of Anthropogenic and Climate Changes on Tropical and Mediterranean Hydrology”

“…Many of them deal with the study of time series variability, rainfall [16], discharges [19,20], sediment transport [11][12][13]21], recession coefficient [22,23], climate change impacts [17,24], or anthropogenic impacts [2,11,20,21]. Drought is also a topic of notable interest in Mediterranean and tropical areas [23][24][25].…”

“…Cavus and Aksoy [25] study the spatial drought characterization for the Seyhan River in Turkey, investigating the spatial and temporal characteristics of drought using standardized precipitation index and different spatialization techniques. They primarily use the standardized precipitation index (SPI) from monthly precipitation data at a 12-month time scale for 19 meteorological stations scattered over the river basin.…”

Drought and Ecological Flows in the Lower Guadiana River Basin (Southwest Iberian Peninsula)

“…A management strategy in the hydrological plans is the characterization and modelization of the seasonal and interannual variability of droughts that have occurred in past periods in these basins with Mediterranean climate conditions. This knowledge will be fundamental for the establishment of medium-term and long-term governance guidelines that guarantee the availability of water resources and the compatibility of the different uses and the environmental flows in the case of future drought events [5,6]. Several indicators can be used for the description of drought events [7] and, among them, one of the most widely used worldwide is the Standardized Precipitation Index (SPI) developed by McKee et al [8].…”