SEA

MEDITERRANEAN Akoura Roueiss Yenouh Mzarib Yahshoush Janneh Afqa

Outlet

1600 Afqa 1200 Mzarib Roueiss 800 Yahshoush Outlet 400 Janneh Yenouh 0 Altitude (m) Altitude 0 5 10 15 20 25 30 35 Distance from sea (km)

Figure 1: Geographic and geological setting of the Nahr Ibrahim watershed. The bold blue line represents the Nahr Ibrahim River. The yellow diamonds indicate the location of sampling sites. The Red triangle represents the Akoura meteorological station. The river profile is given below the geological map. 0 Figure 2: (a) Precipitation at Akoura Meteorological 25 station. (b) Nahr Ibrahim discharge at Afqa gauging station and at Outlet. (c) Snow cover area in the Nahr 50 Ibrahim watershed.

75 Precipitation [mm] Precipitation 2013-2014 2014-2015 2015-2016 100 60 Flow Outlet 45 Flow Afqa

30

15 Discharge [m3/s] Discharge 0 300 ] 2 250 200 150 100 50 Snow Cover Area [Km Area Snow Cover 0 01/09 01/09 01/12 01/03 01/06 01/09 01/12 01/03 01/06 01/09 01/12 01/03 01/06 9 500 (a) (b)

8.5 400 S/cm) μ

8 300 pH

7.5 200 Conductivity (

7 100 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 Distance to the sea (Km) Distance to the sea (Km)

Figure 3: (a) pH and (b) electrical conductivity measurements at different sampling sites. ˜ Afqa; ¢ Roueiss; £ Yenouh; ™ Mzarib; r Janneh; Ú Yahshoush; ¯ Outlet. Samples collected during the wet season in blue, during the dry season in red. ˜ Afqa; ¢ Roueiss; £ Yenouh; ™ Mzarib; r Janneh; ¶ Yahshoush; Ê Outlet

Figure 4: Piper trilinear diagram for the Nahr Ibrahim water samples. Wet season samples are in blue, dry season samples are in red. (¶ corresponds to Ú in the other graphs, and Ê corresponds to ¯) δ18O (‰) -9 -8.5 -8 -7.5 -7 -6.5 -32

-36 D (‰)

-40 δ

™ Mzarib -44 ˜ Afqa r Janneh

LMWL ¢ Roueiss Ú Yahshoush £ Yenouh ¯ Outlet -48

Figure 5: Plot of δ18O vs. δD for the Nahr Ibrahim water samples. Samples taken during the wet season are in blue, whereas samples taken during dry season are in red. The solid line shows the Lebanese Meteoric Water Line (δD=7.135*δ18O+15.979). 2.5 2 (a) (b) =1 2+

) 2 1.5 /Ca

) 2+ 0.75 mM Mg ( 1.5 mM ] ( 1 2+ ] 0.5

1 2+ 1:2 0.33 +Mg Mg

[ 0.5 2+ 0.5 0.1 Ca [ 0 0 0 1 2 3 4 5 0 0.5 1 1.5 2 - 2+ [HCO3 ] (mM) [Ca ] (mM)

2+ 2+ - 2+ Figure 6: (a) Plot of Ca +Mg versus HCO3 for the Nahr Ibrahim watershed. The solid line shows the (Ca + 2+ - 2+ 2+ Mg ) : 2HCO3 relationship. (b) Mg versus Ca for the Nahr Ibrahim watershed. The solid lines shows various Mg2+/Ca2+ ratios that characterize dolomite and/or calcite dissolution. ˜ Afqa; ¢ Roueiss; £ Yenouh; ™ Mzarib; r Janneh; Ú Yahshoush; ¯ Outlet. Wet season samples are in blue, dry season samples are in red. 0.3 0.3 (a) (b) 0.25 1.012* 0.25 0.2 0.2 ) ) Figure 7: (a) Plot of Na+ versus Cl-. The 0.15 0.15 + -

mM solid line shows the Na /Cl ratio in local mM ( (

] precipitations (Saad et al., 2000). (b) ] + 0.1 - 0.1 2 2- - + 4 Plot of SO4 versus Cl . (c) Plot of K Na [ versus Cl-. (d) Plot of K+ versus SO 2-.

0.05 SO 0.05 4 [ ˜ Afqa; ¢ Roueiss; £ Yenouh; 0 0 ™ Mzarib; r Janneh; Ú Yahshoush; 0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 0.4 0.5 ¯ Outlet. Samples collected during the [Cl-] (mM) [Cl-] (mM) wet season samples are in blue, samples 0.04 0.04 collected during the dry season are in red. (c) (d) 0.03 0.03 ) ) mM

mM 0.02 0.02 ( ( ] ] + + K K [ [ 0.01 0.01

0 0 0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 - 2- [Cl ] (mM) [SO4 ] (mM) 1.6 1 4.5 (a) (b) (c) 0.8 ) ) 1.2 ) 0.6 mM mM (

mM 3 ( ( ] - ] ] 0.4 3 2+ 0.8 2+ Ca [ Mg

0.2 HCO [ [ 0.4 0 1.5 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 Distance (km) Distance (km) Distance (km)

0.3 0.3 0.04 (d) (e) (f)

) 0.03 ) 0.2 0.2 ) mM ( mM mM ( ( ] 0.02 - ] 2 ] + 4 +

0.1 0.1 K Na [ SO [

[ 0.01

0 0 0 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 Distance (km) Distance (km) Distance (km)

2+ 2+ - + 2- + Figure 8: Downstream evolution of (a) Ca ; (b) Mg ; (c) HCO3 (d) Na ; (e) SO4 and (f) K . The distance is from the outlet of the Nahr Ibrahim River in the . ˜ Afqa; ¢ Roueiss; £ Yenouh; ™ Mzarib; r Janneh; Ú Yahshoush; ¯ Outlet. Wet season samples are in blue, dry season samples are in red. -30 1250

1000

750

-34 500 Altitude (m) Altitude 250

0 -30 -34 -38 -42 -46 δD (‰) -38 D (‰) δ

-42 ™ Mzarib ˜ Afqa r Janneh ¢ Roueiss Ú Yahshoush £ Yenouh ¯ Outlet -46 0 150 300 450 600

[Cl-] (μM)

Figure 9: Plot of δD versus Cl- for the Nahr Ibrahim water samples. The inset gives the variation of δD with the altitude of the sampling site. Wet season samples are in blue, dry season samples are in red. 1.2 2.5 (a) (b) 2

0.8 1.5

Dolomite 1 SI calcite

SI 0.4 0.5

0

0 -0.5 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 Distance (km) Distance (km)

Figure 10: Downstream evolution of (a) calcite saturation index SICalcite and (b) dolomite saturation index SIDolomite for the Nahr Ibrahim water samples. ˜ Afqa; ¢ Roueiss; £ Yenouh; ™ Mzarib; r Janneh; Ú Yahshoush; ¯ Outlet. Wet season samples are in blue, dry season samples are in red.