1. NEW APPROACH FOR GROUNDWATER DETECTION MONITORING AT LINED LANDFILLS N. Buket YENiGüL1,a, Amro M.M. ELFEKI 2,c and Cees van den AKKER 1,b 1 Faculty of Civil Engineering and Geosciences, Water Resources Section, TU Delft, P.O. Box 5048, 2600 GA Delft, The Netherlands. Fax:+31-15-2785915 a Corresponding author. e- mail address: n.b.yenigul@citg.tudelft.nl b e- mail address: j.m.dejong@citg.tudelft.nl 2Department of Hydrology and Water Resources Management, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, P.O. Box 80208, Jeddah 21589, Kingdom of Saudi Arabia. e-mail address: aelfeki@kaau.edu.sa c On leave from Irrigation and Hydraulics Dept., Faculty of Engneering, Mansoura University, Mansoura, Egypt.1a2cb 1 an.b.yenigul@citg.tudelft.nl bj.m.dejong@citg.tudelft.nlaelfeki@kaau.edu.sa c

7. System reliability as a function of distance from the source for selected monitoring systems for conventional monitoring approach: (a) homogenous medium, and (b) heterogeneous medium.

8. Average contaminated area as a function of distance from the source for selected monitoring systems for conventional monitoring approach: (a) homogenous medium and (b) heterogeneous medium.

9. System reliability as a function of distance from the source for a 3-well monitoring system for the proposed monitoring approach (pumping rate is 100 l/day).

10. Average contaminated area as a function of distance from the source for a 3-well monitoring system for the proposed monitoring approach (pumping rate is 100 l/day).

11. Influence of the pumping rate on (a) detection probability of a 3-well system

12. Influence of the pumping rate on (b) average contaminated area.

13. Comparison of the conventional and the proposed monitoring approaches (pumping rate = 100 l/day) in terms of reliability “in heterogeneous medium”: (a) transverse dispersivity,  T = 0.01 m, and (b) transverse dispersivity,  T = 0.03 m.

14. Comparison of the conventional and the proposed monitoring approaches (pumping rate = 100 l/day) in terms of the average contaminated area “in homogenous medium”: (a) transverse dispersivity,  T = 0.01 m and (b) transverse dispersivity,  T = 0.03 m.

16. Comparison of the conventional and the proposed monitoring approaches (pumping rate = 100 l/day) in terms of the average contaminated area “in heterogeneous medium”: (a) transverse dispersivity,  T = 0.01 m and (b) transverse dispersivity,  T = 0.03 m.

18. Expected cost as a function of number of wells in a monitoring system for transverse dispersivity,  T = 0.03 m: (a) homogenous medium and (b) heterogeneous medium.