T89 Karst Hydrology and Hydrogeology

Monday, 10 October 2022
8:00 AM - 12:00 PM
406

A PRELIMINARY CLASSIFICATION OF KARSTIC SPRINGS OF LEBANON

Paper number: T89-6
Program: Technical Sessions
Time: 9:10 AM – 9:25 AM

Authors

  • Issam Bou Jaoude Presenting Author
    National Cave and Karst Research Institute, currently at Morrison Hershfield, Ottawa, ON
  • Ziad Khayat
    United Nations Economic and Social Commission for Western Asia (ESCWA), Beirut

Abstract

Lebanon is a small Eastern Mediterranean country with a surface area of 10,425 km2. It is a coastal mountainous country with 65% of its surface land covered with karstic carbonate rocks. It relies heavily on karst groundwater. More than 80% of Lebanon’s fresh water comes from karst, mostly through springs. A total of around 5,050 springs are known in Lebanon, of which 40% (2,058 springs) are karstic in nature. Analyses of the structural and stratigraphic controls of those karstic springs from site visits and consultation of available previous work resulted in the identification of 11 different conceptual types including drainage overflow, combination between drainage and overflow, artesian and semi-artesian.

Only 331 of those karstic springs had reliable discharge measurements. Due to the lack of continuous measurements of springs, Meizer’s classification of springs based on discharge rate was used to classify them. From this, the minimum average discharge was used because it was more frequently reported and it is more reliable than the reported maximum discharge. None of the springs identified belonged to Class I and only five springs had a minimum discharge rate to be in Class II. Those five springs are: Ain ez Zarqa (South Bekaa) spring located at the axis of a syncline and is a drainage-overflow spring with a lower stratigraphic barrier. Chekka Submarines springs are artesian springs with upper stratigraphic control and fracturing allowing outflow. Ain el Zarka (North Bekaa) and Jeita springs are mainly overflow springs with a frontal barrier of steep dipping beds. Nabaa el Aarbine is dominantly an overflow spring located in a pull-apart basin with a frontal barrier made up of a major faulting zone. There are also 57 in Class III and 78 in Class IV. The rest are in Class V and VI.

This preliminary classification of Lebanese springs is the first step in understanding them, defining their static and dynamic reserves, and identifying those in need for further analyses and future protection measures.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-377787

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