M. ZEGGANE Houari

The current experimental study conducted in Ouled Sidi Brahim (Algeria) seeks to understand how the direction of the walls affects their temperature in the summer. A small red brick house of 20×20×20 cm 3 was used for the test, and throughout the experiment, the temperature was recorded every minute at the center of each wall facing the four cardinal points (East, West, North, and South) for 24 h (day and night). A digital acquisition device based on an Arduino board was realized to record the temperature on different days at the end of June, July, August, and the beginning of September. Only when solar radiation is present during the day can the influence of the walls' orientation be detected. The temperature of the walls remains nearly constant at night and drops from sunset to daybreak. The wall facing east is the hottest in the morning during the summer. The west-facing wall, on the other hand, is the coolest …

The problems of water quality and quantity have the potential to affect users of the
resource at the watershed scale. Watershed management is considered as an effective
approach that brings together all water users around the core related issues in order to
develop planned and concerted actions in a consensual manner to serve the general
interest. In the central region of northern Algeria, there has been a severe and persistent
drought in recent years due to a recurring problem, in time and space, of the availability
of this resource. The spatial and temporal variability study remains one of the first tools
of water resources manager. At the first stage, the study of spatial variability of the
average monthly precipitation in central-northern Algeria, by a synthetic visualization of
similarities between the response profiles of the seventy measuring stations, highlighted
two rainfall gradients: a strong gradient between the northeastern and the southwestern
regions of the study area, and a small gradient between regions of low and high altitudes.
The link between the variables revealed three synthetic indicators; a big wet season where
almost all precipitations are recorded, a short spring and a dry summer. At the second
stage of this study, a temporal analysis of annual rainfall series recorded from 11 rain
gauging stations, through trends, ruptures and the standardized precipitation index
showed a trend towards precipitation decrease over the whole study area with an average
of 20% over the observation period 1910-2010. The analysis of the standardized rainfall
index shows that the drought that rages on this region of Algeria is a consequence of the
rate of years with mildly dry which is 44% and that of severe dry represent 9%. The
persistence and severity of the drought in recent years in the study area is reflected in the
increase in the rates of years with mildly dry in the order of 13%, on one hand, and by
decreasing year rates of the mildly wet of 12%, 4.5% for the moderate wet, 3% for the
very wet and 5% for the extremely wet, on the other hand.
Keywords: Spatiotemporal variability, precipitation, response profiles, variables links,
dry, Algeria.

The value of water evaporation is a key data in establishing the water balance of lakes
and reservoir dams. In general, the evaporation of water bodies is assessed either from
observation data from evaporation pan (Colorado pan and class A pan), or by analogy
with other reservoir dams for which these data are available. In frequent cases, the
evaluation of the evaporation of water bodies becomes impossible by applying the two
methods mentioned because of the reduced number of weather stations or the absence of
evaporation pans among their equipment. Applying the analogy with other reservoir
dams, it can lead to considerable errors. In order to eliminate the difficulty of
determining the evaporation of water, often encountered by engineers and operators of
reservoir dams, the development of a calculation method simulating the phenomenon of
evaporation is essential.
Keywords: Evaporation, water body, meteorological elements, Algeria.

Résumé – L'érosion et le transport solide sont des problèmes sérieux à l'échelle mondiale mais ils sont bien
plus préoccupants dans certaines régions du monde, comme c'est le cas au Maghreb et plus particulièrement
en Algérie. Les phénomènes de précipitation et d'écoulement sont des phénomènes complexes et sont
impliqués directement dans les processus d'érosion hydrique et du transport solide. La présente étude a pour
objectif de contrôler, critiquer et analyser les données de concentrations des sédiments en suspension
mesurées au niveau de la station hydrométrique da La Traille. L'étude s'efforce de trouver et de mettre en
évidence des relations régressives, entre les débits de la matière solide en suspension et les débits liquides,
applicables dans le bassin versant de l'Oued Isser et susceptibles d'être appliquées à des régions (ou des
bassins versants) situés en milieux telliens et semi-aride Nord Africains et soumises à des phénomènes
similaires. L'optimisation des courbes de transport solide intra annuelles retenues, expliquant la plus grande
partie de la variance, a été validée par la comparaison des valeurs estimées aux valeurs observées et par
l'ajustement des résidus de la régression à la loi Normale. Les courbes corrigées ont été utilisées pour
rectifier le biais dans les données logarithmiques transformées, notamment autour de la partie supérieure des
débits élevés qui contribuent très fortement à la charge solide annuelle, et estimer la variation des bilans des
apports solides (fins et grossiers) véhiculés par l'Oued Isser au niveau de la station hydrométrique de La
Traille, durant la période (1970/71–1984/85), et déposés dans la retenue du barrage de Koudiat Acerdoune
depuis sa mise en service en 2013. Elles ont permis également d'estimer la dégradation surfacique annuelle
du bassin durant la période d'étude, qui est de l'ordre de 2142 t.km
2.an
1, au droit du barrage de Koudiat
Acerdoune. Enfin, l'extrapolation des apports solides a permis de prédire l'envasement du barrage, le classer
parmi ceux de moyen taux de comblement, de mesurer l'ampleur du phénomène d'érosion sol–transport
solide–envasement du barrage et de proposer des actions pour y remédier.
Mots clés : concentration / sédiments en suspension / courbes de transport solide / débit liquide / débit solide /
dégradation spécifique / envasement / érosion / La Traille / méditerranée

A real calamity for the design engineer of hydraulic structures when calculating annual daily maximum
frequency precipitations, the north-central region of Algeria includes urban areas of great strategic importance such
as Algiers (the capital). The estimation annual daily maximum frequency precipitations in this area from series of
observations with little or no data, becomes unreliable. A regional frequency analysis emerged as one of the methods
to resolve this problem. The L-moments method was applied to the annual daily maximum precipitations from fifty four
rainfall stations in northern Algeria. This study permitted dividing this area into three statistically homogeneous
regions. The Generalized Extreme Value (GEV) distribution and the Generalized Logistics (GLO) distribution were
identified as the most appropriate regional distributions for modeling precipitation. In this study, they were used to
calculate the regional quantiles for each region. For the above mentioned three regions, the values of roots mean
square error between quantiles were below 8% for all return periods, an indication that the method used was
appropriate.
Keywords: annual maximum daily precipitations, regional frequency analysis, L-moments, Algeria.