il of
-339,
. GIS
1993.
t SIG
5 and
ation.
1a de
ques
THE CONTRIBUTION OF REMOTE SENSING AND GEOGRAPHIC INFORMATION
SYSTEMS IN THE PREDICTION OF WATER RISING AND FLOODING FIELD
Mohamed CHIKH
CENTRE NATIONAL DES TECHNIQUES SPATIALES
B.P 13- AZEW 31200 ALGERIE
Tél 213. 6. 47. 22. 17, Fax : 213.6 .47. 34. 54
ISPRS Commission VII Symposium, working group No:2
KEY WORDS: Watershed, G.LS, D.T.M, Remote
Sensing
ABSTRACT:
The conditions of an unexpected arrival of a flood depend
directly on the hydrological behaviour of a watershed. As a
consequence, the study of flooding fields involve — the
knowledge of certain meteorological and physiographic
characteristic of the zone of study.
The work shows the contribution of Remote Sensing, a
Digital Terrain Model (D.T.M) hydrologically consistent and
G.LS in the fields of water rising, the cartography of fields
and their integration in a coherent set.
Each time, an important rain falls on a given region of the
country, we expect floods. To apprehend these floods, it is
important to understand the water cycle and its various
interactions with the physical medium and to give bigger
importance to the rain water draining. This attention has
become obvious the ( past) years with the advent of a
number of rain simulation watershed models .
The spatio - temporal characterisation of a watershed with a
G.S with different resolutions, the suitability of a
deterministic hydrologic model of a conceptual type,
distributed and meshed and the height flow transformation
will be traited.
The visualisation of the affected zones by floods was reported
on D.T.M. The application was made on a watershed of 60
km? of " Oued El Mohgoun" which is situated on the upwards
the city of Arzew (ALGERIA).
RESUME:
les conditions de survenance d'une inondation dépendent
directement du comportement hydrologique d'un bassin
versant. Par conséquent, létude des champs d'inondation
implique la connaissance de certaines caractéristiques
météorologiques et physiographiques de la zone d'étude.
Ce travail montre l'apport de la télédétection, d'un modèle
Numérique du Terrain ( M.N.T) hydrologiquement consistant
et les systèmes d'information géographique (S.1.G) dans le
domaine de la prédiction des crues, la cartographie des
champs d'inondations et leur intégration dans un ensemble
cohérent.
A chaque fois qu'une pluie importante tombe sur une région
donnée du pays, on s'attend à des inondations. Afin
d'appréhender ces dernières, il est important de comprendre
le cycle de l'eau et ses diverses interactions avec le milieu
physique et d'accorder beaucoup d'attention aux ouvrages
d'évacuation des eaux pluviales. Cette attention s'est
manifesté ces dernières années par l'apparition d'un grand
nombre de modèle de simulation pluie- débit à l'exutoire d'un
bassin versant. La caractérisation spatio-temporelle d'un
bassin versant à l'aide d'un S.LG raster à différentes
résolutions, la convenance d'un modèle hydrologique
déterministe de type conceptuel, distribué et maillé et la
transformation des débits en hauteur d'eau seront abordés. La
visualisation des zones affectées par les inondations a été
reporté sur le modèle numérique du terrain. L'application s'est
faite sur le bassin versant de 60 km? de Oued El Mohgoun
qui se trouve à l'amont de la ville d'Arzew (Algérie).
1. INTRODUCTION
The conditions of existence of a flood depend directly on the
hvdrologic behavior of a watershed. Consequently the study
of flood fields implies the knowledge of some physiographic
and, meteorological characteristics of watershed and the
capacity of outlet evacuation that are the main factors of a
flood.
For this , we are interested in the spatio - temporal
characterization of a watershed with the help of a G.IS, the
convenience of a hydrologic model of mesh, with the
contribution of the new techniques (G.L.S, Remote sensing,
numerical cartography) , meteorological data (hyetogramme),
the hydrogramme simulated to the outlet of the watershed as
well as the transformation of max debit in height to the
endorsement of the watershed.
The application has been made on a no gauged watershed
with an area of 60 km2 of Oued El Mohgoun that is found in
the
uphill of the city of Arzew. It has been done according to a
mesh of 100 x 100 m.
2. ZONE Of STUDY
The choice of the site of study was guided by the existence
of a cartography to 1/25000 and a satellite image TM of 15
March 1995, the vegetation in phase of degradation, growing
urbanization and the appearance of flood fields for some
episodes pluvieus. We have opted for the topographic
watershed of the Oued El Mohgoun. It is situated in the
west of Arzew and is between 35° 47 and 35° 53 in latitude
and between 0°2' and 0°3 West in longitude. The barrage of
Arzew is considered as the watershed outlet.
The climate is typical Mediterranean: dryness in the Summer,
lessened sometimes by some storms, maximum of
International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 91
Ty
