water Article Spatiotemporal Characteristics and Trends of Meteorological Droughts in the Wadi Mina Basin, Northwest Algeria Mohammed Achite 1,2 , Andrzej Wal˛ ega 3, * , Abderrezak Kamel Toubal 1 , Hamidi Mansour 2 and Nir Krakauer 4   Citation: Achite, M.; Wal˛ ega, A.; Toubal, A.K.; Mansour, H.; Krakauer, N. Spatiotemporal Characteristics and Trends of Meteorological Droughts in the Wadi Mina Basin, Northwest Algeria. Water 2021, 13, 3103. https://doi.org/10.3390/ w13213103 Academic Editor: Athanasios Loukas Received: 14 September 2021 Accepted: 31 October 2021 Published: 4 November 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Laboratory of Water & Environment, Faculty of Nature and Life Sciences, University Hassiba Benbouali of Chlef, Chlef 02180, Algeria; m.achite@univ-chlef.dz (M.A.); toubalabderrezak@gmail.com (A.K.T.) 2 Georessources, Environment and Natural Risks Laboratory, University of Oran, 2 Mohamed Ben Ahmed, P.O. Box 1015, El M’naouer, Oran 31000, Algeria; l_mansou_l@yahoo.fr 3 Department of Sanitary Engineering and Water Management, University of Agriculture in Krakow, Mickiewicza 24/28 Street, 30-059 Krakow, Poland 4 Department of Civil Engineering, The City College of New York, New York, NY 10031, USA; nkrakauer@ccny.cuny.edu * Correspondence: andrzej.walega@urk.edu.pl Abstract: Drought has become a recurrent phenomenon in Algeria in the last few decades. Significant drought conditions were observed during the late 1980s and late 1990s. The agricultural sector and water resources have been under severe constraints from the recurrent droughts. In this study, spatial and temporal dimensions of meteorological droughts in the Wadi Mina basin (4900 km 2 ) were investigated to assess vulnerability. The Standardized Precipitation Index (SPI) method and GIS were used to detail temporal and geographical variations in drought based on monthly records for the period 1970–2010 at 16 rainfall stations located in the Wadi Mina basin. Trends in annual SPI for stations in the basin were analyzed using the Mann–Kendall test and Sen’s slope estimator. Results showed that the SPI was able to detect historical droughts in 1982/83, 1983/84, 1989/90, 1992/93, 1993/94, 1996/97, 1998/99, 1999/00, 2004/05 and 2006/07. Wet years were observed in 1971/72, 1972/73, 1995/96, 2008/09 and 2009/10. Six out of 16 stations had significant decreasing precipitation trends (at 95% confidence), whereas no stations had significant increasing precipitation trends. Based on these findings, measures to ameliorate and mitigate the effects of droughts, especially the dominant intensity types, on the people, community and environment are suggested. Keywords: drought; trends; SPI; mina basin; Algeria 1. Introduction Drought is a recurring phenomenon that affects a wide variety of sectors, making it difficult to develop a single definition of it. According to a water-resource-oriented definition, which takes into account the water requirements related to biological, economic and social characteristics of a region, drought refers to a condition of severe reduction of water supply availability (compared to a normal value), extending along a significant period of time over a large region [1]. Drought is a complex phenomenon that involves different human and natural factors that determine the risk and vulnerability to it [2]. The particularly strong influence of drought on many sectors is visible in arid and semiarid regions, where water is scarce [3]. Water scarcity can strongly impact the agricul- tural sector in such regions [4]. In the case of the Mediterranean Basin, much of which is arid or semiarid, the extremely variable precipitation across temporal and spatial scales is influenced by geographical position of the region between two contrasting masses of water: the Atlantic Ocean and the Mediterranean Sea [5–7]. An additional feature determining high variability of precipitation in this region is the presence of various mountain ranges distributed along the coastal areas from east to west [7]. To avoid water scarcity, increased Water 2021, 13, 3103. https://doi.org/10.3390/w13213103 https://www.mdpi.com/journal/water