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Water resource situation of the Republic
of Djibouti
Omar ASSOWE DABAR
Integrating Groundwater Management within River Basins
15-17 January 2019 Nairobi, Kenya
Regional Training Workshop on Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
Introduction
❖ The Republic of Djibouti (23 000 km2) is localized in the Horn Africa.
❖70% of the population live in urban areas, 58% live in the capital (Djibouti city).
2
❖ Djibouti is an arid country which receives, on
average, 150 mm of rain annually and has no
permanent source of surface water.
❖Access to water in Djibouti is a major
challenge for the development of socio-
economic activities.
❖ Harnessing surface and groundwater to
improve access to drinking water for vulnerable
populations is a Government priority
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
Geological situations
❑ Geological Setting
3
❖ The republic of Djibouti is one of several African
countries located on the East African Rift System
(EARS).
❖ About 90% of the geological formations are
volcanic rocks and 10% are sedimentary formations.
❖ The groundwater in Djibouti is controlled by
volcanic and sedimentary aquifers. Volcanic
aquifers systems are mainly represented by the
Dalha basalts, the stratoid basalts and the Mabla
rhyolites.
Dalha basalts sequence Coastal plain sediments
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
Climatological conditions
❖ The Republic of Djibouti is characterized by arid to semiarid climate. Two seasons
predominate :
- Cool season (winter) from October to April (20 °C and 30 °C )
- Hot season (summer) from May to September (30 °C and 45 °C) with high rate of
Evapotranspiration amounting to 2000 mm per year
4
Pré
cipitation (m
m)
HOLL HOLL
DIKHIL
Précipitation trends (1960 – 1990)
200
250
300
350
1960 1965 1970 1975 1980 1985 1990
130
140
150
160
170
180
1960 1965 1970 1975 1980 1985 1990
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
➢ Decrease in rainfall can be observed in different
location.
➢This could strongly impact groundwater recharge
conditions and deteriorate the quantity and quality.
Groundwater situation
5
❖Water resources demands
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
!(
!(
!(
!(
!(
!(
ARTA
OBOCK
DIKHIL
DJIBOUTI
TADJOURAH
ALI SABIEH
Annual pumping rate millions m3/an
0
0.01 à 0.1
0.1 à 0.5
0.5 à 1
1 à 2
plus de 10
1.7 2.6 3.2
15.2
22.9
28.5
12.5 15.2 1
9.3
29.4
40.8
51.0
0
20
40
60
2005 2010 2015
Vo
lum
e a
nn
uel.
Millio
n m
3
Rural (population+bétail)
Urbain
Agriculture
Total
1.7 2.6 3.2
15.2
22.9
28.5
12.5 15.2 1
9.3
29.4
40.8
51.0
0
20
40
60
2005 2010 2015
Vo
lum
e a
nn
uel.
Millio
n m
3
Rural (population+bétail)
Urbain
Agriculture
Total
❖ The extreme climate condition explains
the lack of permanent rivers, and has
led the country to exploit the only
available water resources, which are
represented by groundwater in the
basaltic aquifer.
➢ The population of Djibouti relies
heavily on groundwater resources for
drinking water and irrigation purposes.
Groundwater situation
6
❖Groundwater degradations
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
0
10
20
30
40
1960 1970 1980 1990 2000
Cl-
(mm
ol/l
)
70
80
90
100
1984 1986 1988 1990 1992 1994
Wate
r le
vel m
➢ The continuous and severe increase of water demands, due to the rapid
population growth, have led to overexploitation of groundwater, and have
severely depleted its quantity and quality.
Djibouti
Mouloud
Groundwater monitoring
7
❖Surface water mobilisation : Surface water hydrology monitoring-early warning system-Ambouli
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
Limnigraph
➢With the arid climatic regime, most watercourses in the Republic of Djibouti are temporary and
run for only a few days after any rain event (wadis).
Geochemical characterization of the Bara volcano-sedimentary
aquifer (Republic of Djibouti) : Case study
8
❖ The UNDP is financial supported a program
for developing agro-pastoral as a climate change
adaptation strategy for poor rural communities in
the south-eastern part of the republic of Djibouti
(Bara area).
❖The context of this project is based on the
settlement of a hundred families in this area. All
boreholes are used for drinking purpose.
❖The study area is located in the south-eastern
part of the country. The Petit Bara and Grand
Bara zones correspond to sedimentary basins
limited to the East by the Dalha basalts (8.3–
4.3Ma) and to theWest by the Stratoid basalts (3–
1 Ma).
❖ Twenty two borehole waters were collected in
this area and analysed.
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
Geochemical characterization of the Bara volcano-sedimentary
aquifer (Republic of Djibouti) : Case study
9
❖Groundwater Classification
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
➢The groundwater have moderate to
high EC values (from 957 to 4846
S/cm), temperature values between
27 and 43C, and moderately alkaline
pH ranging from 7.31 to 8.38.
➢The Depth of the boreholes in this
area ranges between 80 and 200 m
➢Most of sampled groundwaters are
brackish (10 g/L TDS 1 g/L) with
the exception of several fresh waters
(TDS 1 g/L) from North of Petit
Bara (#1–#4), Grand Bara (Hambocto
F1) and Dadin3.
Samples T
(°C)
Depth
(m)
pH EC
(µS/cm)
TDS
(mg/l)
Hydrochemical types
Petit Bara Zone
PK48 36 133 7.75 956.9 666Na-HCO3-Cl
PK50 38 90 7.97 1127 795Na-HCO3-Cl
PK51 39 135 7.75 1204 811Na-HCO3-Cl
Didjander 28 170 7.96 2876 1617Na-Cl
Omar Jakka 38 161 7.79 2958 2015Na-Cl
Naheel 39 155 6564 3668 Na-Cl-Ca
Kourtimaley 37 165 7.8 7731 3254 Na-Cl-Ca
Grand Bara Zone
Awraoussa 1 36 195 7.81 2692 1842Na-Cl-Mg-Ca-SO4
Iskoutir 32 181 7.81 3258 2363Na-Cl-Ca-SO4
Gabla-galan 27 156 8.38 2200 1519Na-Cl-HCO3-SO4
Hambocto F2 35 190 7.26 1896 1329Na-Cl-Mg-Ca-HCO3
Hambocto F1 38 150 7.31 1464 988Na-Cl-Mg-Ca-HCO3
Doudoub Bololé F2 36 103 7.62 2337 1576Na-Cl-Mg-SO4
Doudoub Bololé F1 41 93 7.48 4143 3173Na-Cl-Mg-SO4
Dagandalol 43 113 7.8 2871 1879 Na-Cl-SO4
Dagaah-damere 39 170 7.71 4846 3484Na-Cl-Mg-Ca-SO4
Mouloud-Dadin Zone
Mindil 36 80 7.46 2630 1824Na-Cl-Mg-SO4
Mouloud C 39 115 7.49 3035 2075Na-Cl-Mg-SO4
Mouloud 4 39 140 7.33 2880 1965Na-Cl-Mg-SO4
Dadin 3 34 139 7.43 1388 980Na-Cl-HCO3
Geochemical characterization of the Bara volcano-sedimentary
aquifer (Republic of Djibouti) : Case study
10
❖Groundwater Classification
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
➢ Using statistical method (PCA and HCA) The geochemical data were classified into distinct groups according to the
common variables they share using 13 variables (pH, EC, TDS, Ca2 +, Mg2 +, Na +, K +, HCO3-, Cl-, SO4
-, F-, NO3- , Br-).
Site
Ca
(mg/l)
Mg
(mg/l)
Na
(mg/l)
K
(mg/l)
Li
(mg/l)
NH4
(mg/l)
HCO3
(mg/l)
Cl
(mg/l)
SO4
(mg/l)
NO3
(mg/l)
F
(mg/l)
Br
(mg/l)
NO2
(mg/l)
Petit Bara Zone
PK48 26.75 22.74 151.6 4.1 0.017 0.01 347.84 100.09 65.65 12.43 0.825 0.41 0.006
PK50 24.9 22.19 187.66 4.36 0.04 ≤ DL 352.87 146.99 77.92 17.73 0.705 0.715 ≤ DL
PK51 23.1 21.07 222.9 4.34 0.01 ≤ DL 307.88 189.05 88.86 14.81 0.78 0.85 0.003
Didjander 88 63.18 383.99 18.45 0.9 0.13 237.09 609.5 197.62 32.49 0.01 2.88 0.033
Omar Jakka 89.95 68.86 435.67 8.45 0.022 ≤ DL 218.97 697.75 234 54.31 0.425 2.69 0.002
Naheel 215 231 852 11 0.2 0.43 95 1987 608 119 0.9 1.74 0.08
Kourtimaley 368 165 1080 32 ≤ DL ≤ DL 61 2410 572 122 0.245 1.78 0.008
Grand Bara Zone
Awraoussa 1 116.96 65.9 321.24 11.65 0.041 ≤ DL 140.76 519 295 71 0.64 2.59 ≤ DL
Iskoutir 145.73 65.19 440.13 8.165 0.015 ≤ DL 100.94 818.47 319.19 50.76 0.28 3.5 0.009
Gabla-galan 36.17 50.32 382.5 7.94 0.037 0.13 235.06 356 192.93 247.48 0.385 2.26 ≤ DL
Hambocto F2 115 66.78 169.53 4.98 0.0103 ≤ DL 209.68 269.19 131.17 255.67 0.595 2.35 ≤ DL
Hambocto F1 58.37 38.69 185.97 4.08 0.01 ≤ DL 239.72 249.78 112.53 49.83 1.01 1.27 ≤ DL
Doudoub Bololeh F2 70.97 61.92 327.53 7.65 0.0175 ≤ DL 166.09 517.22 240.18 55.075 0.675 2.085 ≤ DL
Doudoub Bololeh F1 165 134.78 507.45 13.13 0.03 ≤ DL 107.71 1120.4 418.7 59.11 0.61 4.125 ≤ DL
Dagandalol 88.54 57.43 453 8.26 0.037 ≤ DL 213.31 572.09 334 142.02 0.885 2.5 ≤ DL
Daagah-damere 199.28 123.44 653 15.30 ≤ DL 0.8 95 1271.5 486.5 62 0.09 5.29 0.21
Mouloud Zone
Mindil 55.11 92.56 361.21 9.75 0.015 ≤ DL 283.67 481.35 301.09 47.3 0.52 2.51 ≤ DL
Mouloud C 82.15 79.79 442.92 10.94 0.015 ≤ DL 188.86 686.89 336.51 79.6 0.425 2.73 ≤ DL
Mouloud 4 96.52 92.21 377.29 8.31 0.028 ≤ DL 177.47 625.53 329.03 75.78 0.615 2.56 ≤ DL
Dadin 3 46.96 26.37 217.5 5.07 0.03 ≤ DL 443.57 157.32 102.89 33.82 1.51 0.4 0.07
Cluster 1
Cluster 1 contains six samples that
characterize waters with low
mineralization (805 ≤ EC (μS / cm)
≤1464). This group corresponds to Na-
Cl-HCO3 water type. (South petit Bara
and Dadin)
Cluster 2
Cluster 2 contains twelve different water
samples characterized by moderate
mineralization. (Grand Bara-Mouloud)
Cluster 3
Cluster 3 contains four different water
samples characterized by very high
mineralization (4143≤ EC (μS / cm)
≤7731). This group correspond to Na-Mg-
Cl-SO4 water type (between GB and PB).
Geochemical characterization of the Bara volcano-sedimentary
aquifer (Republic of Djibouti) : Case study
11
❖Groundwater Contaminations
Integrating Groundwater Management : 15-17 January 2019, Nairobi, Kenya
➢Some of the groundwater analyzed present
high nitrate concentration (up to 50 ppm ;
WHO).
➢The lowest values are found in Petit Bara and
Dadin , while the highest values are found in Grand
Bara (up to 250mg/L in alluvium groundwaters from
boreholes #13 and #18; up to 150 mg/L in basalt
groundwaters from #11 and #12) and in the central
area (up to 120 ppm in #7 and #8).
➢It should be noted that people living in the
Republic of Djibouti are mostly nomad, and hence
have no agricultural tradition. The local nomads, who
raise goats and cheeps, do not have a fixed
settlement, hence not septic tanks.
➢Therefore, in many cases, natural soil might
contribute mainly for nitrate concentrations in the
study area as observed in some semi-arid or arid
regions over the world.
Thank you