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Analysis and Mapping of Water Erosion Vulnerability Using GIS for the Mghila Watershed, Northwest of Algeria

Ratiat Abdelkader, Haddad Ali, Bouaichi Ilham, Matene Chahrazed Naziha

Archives of Hydro-Engineering and Environmental Mechanics

2023

Vol. 70, nr 1

71--87

Intensification of extreme rainfall-runoff events in arid and semi-arid regions because of climate change induce the water erosion that contributes considerably to the loss of vegetal layers of soils and reduce the storage capacity of dams by silting of transported sediments from the watershed to the impoundment. This paper aims at proposing means for protecting the Mghila dam against silting by identification and delimitation of vulnerable areas to water erosion. This dam, built in the North-West of Algeria, ensures irrigated cultivation. Topographical, geological, and land use characteristics of the watershedwere analyzed using the geographic information system (GIS). Analysis of results has allowed the identification by area percentage four-vulnerability classes with sensitivity to the water erosion: low (18.89%), medium (13.08%), high (65.05%) and very high (8.38%). The spatial distribution of the lithological substratum friability, the vegetation cover and slope degrees have led to the development of an efficient strategy for the watershed management in order to reduce the effect of water erosion on soil degradation and silting of the Mghila dam.

Evaluation of human thermal comfort and heat stress in an outdoor urban setting in summer under arid climatic conditions

Abdel-Ghany A. M., Al-Helal I. M., Shady M. R.

Environment Protection Engineering

2014

Vol. 40, nr 3

139--150

Thermal sensation and heat stress potential were evaluated in summer in an outdoor arid environment. Such evaluation had never been made in arid regions. Various scales: the temperaturehumidity index (THI), physiological effective temperature (PET), universal thermal climatic index (UTCI) and standard effective temperature (SET*) were used for the evaluation. RayMan software model was used to estimate the PET and SET* and the UTCI-calculator was used for UTCI. The required air dry and wet bulb temperatures (Td, Tw), solar radiation flux (S0) and wind speed (V) were measured in summer (April 29–July 15). The results showed that: Persons are exposed to strong heat stress and would feel very hot most of the day time; and they are safe from heat stress risk and would feel comfortable most of the night time. Heat stress levels can be determined using the PET or UTCI scales; both are valid for arid environment and their results are almost similar; however, the THI cannot be used. SET* index specifically describes the thermal sensations and discomfort conditions along with summer days at any activity under arid conditions.

Foliar stable carbon isotope discrimination and nutrients contents in two desert plant species

Zhao Liangju, Xiao Honglang, Liu Xiaohong, Li Jingxiu, Xiao Shengchun

Polish Journal of Ecology

2007

Vol. 55, nr 1

57-66

Variation of foliar stable Carbon Isotope Discrimination (CID [Delta] [per mil]) and nutrient contents of Artemisia ordosica (Krasch) (semi-shrub species) and Caragana korshinskii (Kom.) (shrub species) were studied at the south-eastern margin of the Tengger Desert, China. Foliar CID [Delta], total phosphorus content (TP) and potassium content (K) in A. ordosica were markedly higher than in C. korshinskii while foliar total nitrogen content (TN) and water-use efficiency (WUE) (calculated from foliar CID[Delta]) in C. korshinskii were significantly higher than those in A. ordosica. There were significant and positive relationships between foliar CID [Delta], TN and TP contents (P <0.001) in C. korshinskii, while in A. ordosica a strong and significant positive correlation existed between CID [Delta] and K content (P <0.001). Based on WUE, TN, TP, and K contents, as well as their relationships, we may conclude that in arid environments, the survival of C. korshinskii profits from itshigher WUE, while the survival of A. ordosica from its higher TP and K contents in leaves. In addition, the correlations of foliar CID [Delta] values with TN and TP contents in C. korshinski and with K content in A. ordosica revealed that the water was one of the main factors limiting the absorption capacity for N and P in C. korshinskii, and for K in A. ordosica. While nutrient conditions were not the factors affecting the growth of C. korshinskii and A. ordosica in the study areas.