Cumulative drought effect on Figeh karstic spring discharge (Damascus basin, Syria)

• Published in: Environmental earth sciences 2016, Vol.75 (2), p.1-17, Article 125
• Main Authors: Zakhem, Boulos Abou, Kattaa, Bassam
• Format: Article
• Language: English
• Subjects: Biogeosciences; Climate change; Climate effects; Drought; Earth and Environmental Science; Earth Sciences; Environmental risk; Environmental Science and Engineering; Geochemistry; Geology; Groundwater discharge; Groundwater management; Hydrology/Water Resources; Karst; Original Article; Precipitation; Sustainability management; Sustainable development; Terrestrial Pollution; Water resources
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-015-5013-3

The effects of climate changes are being strongly perceived in the studied area as in the rest of the Mediterranean basin, and groundwater resources are obviously affected. In this paper, Figeh karst spring discharge and precipitation in Damascus basin were analyzed by normalized methods on a yearly time scale. Trends and fluctuations have been highlighted by moving average and the time series are transformed by the rescaled adjusted partial sum (RAPS). Cumulative drought analyses were carried out using SPI30 and SQI30. Finally, the decreasing trends of the spring discharge due the decrease in rainfall were analyzed. The main results reveal that moving averages and linear trends of SPI and SQI delineate very well the drought periods and exhibit clear decrease of precipitation and spring discharge. The RAPS method identifies a consecutive drought that lasted for 8–9 years separated by 2–3 years of wet periods, during the last three decades. The cumulative droughts using SPI30 and SQI30 reveal that wet period (1970–1983) with positive SPI30 and SQI30 was characterized by high precipitation and spring discharge, followed by transition period (1984–1997) with around zero values, was affected by the beginning of successive severe and extended droughts. Finally, dry period (1998–2013) with negative indexes values distinguished by the effect of severe and extended droughts. The decreasing trends analysis using DPI and DQI showed annual decreasing rates of −0.36 % and of −0.63 %, respectively. Thus, the results reveal that precipitation will be decreased to about DPI = −27 % and the discharge decline of about −47 % by 2050. Consequently, Figeh karstic system is affected by severe extended hydrological droughts during the past three decades especially where the SPI30 and SQI30 values decrease below −10. Accordingly, it requires the development of sustainable groundwater management to reduce long-terms drought risks.