GIS Application for Groundwater Vulnerability Assessment: Study Case

of Hammam-Bou-hadjar Area-NW of Algeria

Bouakkaz Khaled Salim

, Dehni Abdellatif

, Meguenni Bouhadjar

and Kessar Cherif

Department of S.I.R.S, Center of Space Techniques, Algerian Space Agency, Arzew, Algeria

Department of D.O.T, Center of Space Techniques, Algerian Space Agency, Arzew, Algeria

Keywords:

GIS, Vulnerability, GOD, Pollution, Hammam-Bou-hadjar.

Abstract:

This study deals with the vulnerability and pollution risk in the Hammam bouhdjar aquifer (Algeria). The

plain has been threatened by numerous pollution sources (urbanization, industry, farms, dumps, etc.) which

have unfortunately increased in the area, due to a lack of environmental protection measures, especially for

water resources. A map of groundwater vulnerability of the zone was carried out according to method (GOD)

using GIS processing. The obtained vulnerability map shows three zones of differing vulnerability degrees

accordingly to low, medium and high vulnerability which occupy respectively 51, 45 and 3 % of the total area.

1 INTRODUCTION

The socioeconomic development of a region predom-

inantly depends on the availability of good qual-

ity water .The evaluation of vulnerability is a mean

to gather complex hydrogeological data in a way

that can be used by non-specialist people such as

decision-makers (Hosseini M et al., 2018).The de-

velopment and sustainable management of ground-

water resources requires the application of modern

techniques.In recent years, vulnerability assessment

of groundwater aquifers considered as an essential

part for putting suitable plans to protect groundwa-

ter aquifers around the world (Al-Abadi A.M et al.,

2014). An integrated approach is implemented due

to the new geo-spatialization techniques and the geo-

graphical information system (GIS).

In the current context of the sustainable management

of water resources, the prediction of the risk of pol-

lution and the protection of these resources are of

paramount importance. For this, the medium and

long-term safeguarding of the quality of these re-

sources is necessary. This protection can be done, ﬁrst

by delimiting the areas likely to be affected by pollu-

tion (Amharref M et al., 2007). Groundwater reser-

voirs are easily affected by pollution. The process is

slow but its effects are very dreadful (Baghvand et al.,

2010).

In agricultural areas, in particular, an excessive use

of fertilizers has directly or indirectly affected the

groundwater quality (Huang et al., 2012). But beyond

the quantitative aspect, it is also advisable to remain

vigilant on the level of the water quality consumed

by the populations (Diodato et al., 2013). However,

the prevention against groundwater pollution consti-

tutes an important phase to which scientists are doing

their best notably in studying the vulnerability of the

groundwater. They therefore, created classical scien-

tiﬁc methods (Etienne et al., 2009)

2 THE STUDY AREA

In this study we focus on the Hammam-Bou-hadjar

aquifer which is situated between Latitudes 35.23

◦

to 35.46

◦

N and Longitudes 0.85

◦

to 1.09

◦

E in the

southwestern part of the Oran watershed Basin, lo-

cated in the Northern West of Algeria (Figure 1).

The area is generally gently sloping low-lying and is

characterized by dry and wet climatic seasons which

spans from April to October and wet season between

November and March. Occasional rainfalls are of-

ten witnessed within the dry season due to its prox-

imity to the Mediterranean Sea. Rainfall forms the

major source of groundwater recharge in the area;

mean annual rainfall is greater than 200 mm. The

mean monthly temperature ranges from 36

◦

C in July

to 20

◦

C in February. Because of its proximity to

the coast, the area is under the inﬂux of sea salt and

aerosols sprayed from the Mediterranean Sea; this can

potentially increase the salinity of the subsoil.

Salim, B., Abdellatif, D., Bouhadjar, M. and Cherif, K.

GIS Application for Groundwater Vulnerability Assessment: Study Case of Hammam-Bou-hadjar Area-NW of Algeria.

DOI: 10.5220/0007714002070211

In Proceedings of the 5th International Conference on Geographical Information Systems Theory, Applications and Management (GISTAM 2019), pages 207-211

ISBN: 978-989-758-371-1

207

Figure 1: Localization of Hammam-Bou-hadjar aquifer.

Figure 2: The Study area geological map.

3 MATERIALS AND METHODS

In this work, the GOD method was chosen based on

the encouraging results obtained in previous project

carried out in our department. to assess the vulner-

ability of groundwater to pollution (Knouz N et al,

2017) This system was developed by Foster in 1987,

it is illustrated by Figure 2 which presents the vul-

nerability of the aquifer to the vertical percolation of

pollutants through the unsaturated zone and does not

deal with the lateral migration of pollutants in the sat-

urated zone.

Table 1: Attribution of notes for GOD model parameters.

G (Groundwater occurrence)

Characteristic’s Note

None aquifer 0

Artesian 0.1

Conﬁned 0.2

Semi-conﬁned 0.3

Free with cover 0.4-0.6

Free with cover 0.7-1

O (Overall lithology of aquifer)

Characteristic’s Note

Residual soil 0.4

Limon alluvial, loess, shale, ﬁne limestone 0.5

Acolian sand, siltite, tuf, igneous, rock 0.6

Sand and gravel, sandstoe, tufa 0.7

Gravel 0.8

Limestone 0.9

Fracture or karstic limestone 1

D (Depth to water table)

Characteristic’s Note

< 2 1

2-5 0.9

5-10 0.8

10-20 0.7

20-50 0.6

50-100 0.5

> 100 0.4

This method is based on the identiﬁcation of three cri-

teria:

• Groundwater type.

• Type of aquifer in terms of lithological factors

(Overall aquifer class);

• Depth to groundwater table.

The necessary elements for the groundwater protec-

tion scheme and for the classiﬁcation of aquifer vul-

nerability are, according to this method; the soil type,

the geological formations of the unsaturated zone and

the depth of the aquifer.

The vulnerability index (I) is obtained according to

the following equation:

I = Ca ∗ Cl ∗ Cd (1)

Of which: Ca: Aquifer type rating, CI: Lithology rat-

ing and ﬁnally Cd: Depth of the water table.

The vulnerability increases with the index and the

classiﬁcation is made in ﬁve categories, ranging from

GISTAM 2019 - 5th International Conference on Geographical Information Systems Theory, Applications and Management

208

0 to 1. According to the table 1, the range of possi-

ble values varies minimum vulnerability (0 values) to

maximum vulnerability (1 value).

Figure 3: Procedure for developing the vulnerability map

using the GOD method.

4 RESULTS AND DISCUSSION

4.1 Groundwater Occurrence (G)

Figure 4: Groundwater occurrence map (parameter G).

The map of aquifer type was developed by inter-

preting using Inverse Distance Weighting IDW be-

tween 298 geoelectrics test of boreholes in the study

area.

Figure 4 shows different class according to the degree

of conﬁnement, a reclassiﬁcation by rate gave us the

map of the parameter groundwater occurrence.

Generally, the study area is characterized by two types

of groundwater occurrence, Aquifer with fairly per-

meable cover speciﬁcally in the Eastern zone and un-

conﬁned aquifer in the West of El Malah and the SW

of Hammam-Bou-hadjar.

4.2 Overall Lithology of Aquifer (O)

Using the results of geoelectric’s tests the lithology

for each point was classiﬁed and the rate was at-

tributed, the map was created after interpolation.

Figure 5: Overall lithology of aquifer map (parameter O).

According to the map, the study area is characterized

by several type of lithology, the map obtained from

the digitization of the geological map 1/50000 of the

study area and a conversion to raster mode (Enabling

the reclassiﬁcation according to the rating system of

the GOD method).

After reclassiﬁcation, the map obtained (Figure 5)

shows that the study area contains different classes of

lithology, in the West side of Hammam-Bou-hadjar

the majority of soils are alluvional composed by clay

and silt, in the West of Douar Sidi Belhadi and the

North of Hammam-Bou-hadjar the limestone soil was

characterized.

GIS Application for Groundwater Vulnerability Assessment: Study Case of Hammam-Bou-hadjar Area-NW of Algeria

209

4.3 Depth to Water Table (D)

Figure 6 shows the map of the depth to the water table

parameter, which was established from the interpola-

tion of the piezometric measurements using the IDW

method.

Figure 6: Depth to water table (parameter D).

After the interpolation of the water levels of the wa-

ter table, a reclassiﬁcation of each pixel was then car-

ried out according to the rating system of the GOD

method (Knouz N et al, 2017) The depth of the water

table decreases gradually from the SW and Est to the

north exactly in Hammam-Bou-hadjar area character-

ized by the lower depth between 2 and 5 meters.

5 THE VULNERABILITY MAP

The vulnerability map using (GOD) method has been

established after calculation the GOD index using

equation (1). The values of this index range from 0

to 0.7. They are reclassiﬁed according to the classiﬁ-

cation system of the GOD method shown in Table 2

below:

Table 2: Classes of GOD Vulnerability Index.

Vulnerability Index Class of vulnerability

0 No vulnerability

0-0.1 Negligible

0.1-0.3 Low

0.3-0.5 Medium

0.5-0.7 High

0.7-1 Very High

Figure 7: Vulnerability map using GOD method of

Hammam-Bou-hadjar zone.

The analysis of ﬁgure 7 reveals that low-vulnerability

areas account for 51% of the total study area, mod-

erately vulnerable occupy 45.76 %, while high-

vulnerability areas occupy 3.2%; the high vulner-

ability is located exactly in the North and around

Hammam-Bou-hadjar city, medium vulnerability is

the extension of the high class to the South in the West

of Sidi Boumediene and Douar Sidi Belhadi.

Figure 8: Spatial distribution of vulnerability class in per-

cent.

6 RESULT VALIDATION

Nitrate is one of the most common indicators of hu-

man impact on groundwater resources (White P and

al., 2013). Nitrate is not naturally present in ground-

water over concentration of 5-8 mg L-1 and higher

concentrations have obviously been attributed to an-

thropogenic pollution (Busico G and al., 2019).In the

study area, agriculture is the most common activity

between the populations; the crops are irrigated and

GISTAM 2019 - 5th International Conference on Geographical Information Systems Theory, Applications and Management

210

fertilized without monitoring the water quality and

fertilizer, speciﬁcally nitrogen. For this purpose we

have tried to validate the vulnerability map by the

GOD method by analyzing the distribution map of ni-

trates. The spatial analyst of nitrate distribution shows

according the map (Figure 9) that the area around

Hammam-Bou-hadjar is characterized by high con-

centration of nitrate, in the North very high concen-

tration are observed in Hassi El Ghella, the same case

in the SE in Sidi Boumediene zone.

Figure 9: Spatial distribution of nitrate concentration.

7 CONCLUSION

Vulnerability-study results of Hammam-Bou-hadjar

aquifer using GOD method show that the vulnera-

bility degree increases from South to the North and

N-E due to composition of unsaturated zone, 49%

of area is exposed to a medium to high vulnerabil-

ity. Lithological composition and type of aquifer

make Hammam-Bou-hadjar zone exposed to ground-

water pollution. intensive anthropogenic activity like

uncontrolled fertilization accelerate the groundwater

pollution. The protection of groundwater reservoir is

a priority to conserve the quality of water, this objec-

tive can be achieved by the protection of groundwa-

ter’s perimeters, monitoring of fertilization process in

agriculture and installing an evacuation plan of waste

water.

REFERENCES

l-Abadi A.M, Al-Shamma’a AM, Aljabbari MH.(2014).

A GIS-based DRASTIC model for assessing intrin-

sic groundwater vulnerability in northeastern Missan

governorate, southern Iraq. Applied Water Science:

7(1):89 - 101.

mharref M, Bernoussi A S (2007). Vulnerability and risk of

groundwater pollution, JSIRAUF actes.

aghvand A, Nasrabadi T, Nabibidhendi G, Vosoogh A, Kar-

bassi A, Mehradadi N (2010). Groundwater quality

degradation of an aquifer in Iran central desert. De-

salination 260(3):264-275.

oufekane A, SAIGHI O (2013). Assessment of groundwa-

ter pollution by nitrates using intrinsic vulnerability

methods: A case study of the Nil valley groundwater

(Jijel, North-East Algeria). African Journal of Envi-

ronmental Science and Technology. 7(10): 949-960.

usico G, Mastrocicco M, Cuoco E, Sirna M and Tedesco

D (2019). Protection from natural and anthropogenic

sources: a new rating methodology to delineate “Ni-

trate Vulnerable Zones”, Environmental Earth Sci-

ences 78:104.

iodato N, Esposito L, Bellocchi G, Vernacchia L, Fiorillo F,

Guadagno FM (2013). Assessment of the Spatial Un-

certainty of Nitrates in the Aquifers of the Campania

Plain (Italy). Am. J. Clim. Chang. 2:128-137.

tienne DK, Boyssoro H, Dibi B, Mahaman B, Biemi J

(2009). Contribution Methods Intrinsic Vulnerability

DRASTIC and GOD in The Study of Pollution by Ni-

trates in Bonoua Region (South-east of Ivory Coast).

Eur. J. Sci. Res. 31(1):157-171.

osseini M and Saremi A. (2018). Assessment and Estimat-

ing Groundwater Vulnerability to Pollution Using a

Modiﬁed DRASTIC and GODS Models (Case Study:

Malayer Plain of Iran), Civil Engineering Journal,

4(2): 433-434.

uang T, Pang Z, Edmunds WM (2012). Soil proﬁle evo-

lution following land-use change: Implications for

groundwater quantity and quality. Hydrol. Process

27(8):1238-1252.

nouz N, Bachaoui EM, Boudhar A (2017). Cartography of

intrinsic aquifer vulnerability to pollution using GOD

method: Case study Beni Amir groundwoter, Tadla,

Morocco JMES, 8 (3): 1046-1053

hite P, Ruble C.L, Lane M.E (2013). The effect of changes

in land use on nitrate concentration in water supply

wells in southern Chester County, Pennsylvania. Env-

iron Monit Assess 185:643–651.

GIS Application for Groundwater Vulnerability Assessment: Study Case of Hammam-Bou-hadjar Area-NW of Algeria

211