Résumé:
The present study focused on the analysis and then the measurement of some of the environmental impacts associated with the phenomenon of urban expansion to the detriment of semi-urban agricultural areas and mountainous areas near major Algerian cities. Because of the increasing migration of the population to the outskirts of cities and their settlement in them since the early eighties. This has further accelerated the change in the morphological shape of cities and the areas around them due to the phenomenon of urban expansion, which depends on the random (unplanned) model and affects the environmental and climatic level at the national and international levels.
Historical, descriptive, analytical and quantitative methods have been used in the temporal
and spatial monitoring of the population and land cover and land use patterns in these semiurban areas. Therefore, the wilaya of Constantine and its semi-urban area, composed of four subordinate municipalities (El Khroub, Hamma, Bouziane, Ain Smara and Didouche Mourad), were chosen as the geographical area for the application of this study, which covered the period between 1984 and 2020. A questionnaire was distributed to a sample of 50 farmers throughout the state, and field interviews were conducted with 25 representatives of local and state administrative authorities. The study has led to a series of results, the most important of which are the following: the first reason for the appearance of the negative environmental impact in the semi-urban area is temporary administrative practices that do not allow the environment to be affected by the environment. The study resulted in a series of results, the most important of which is that there is a notable change in the area of agricultural land occupation and use for semi-urban areas in mountainous areas of 29.70%. There is a significant difference in the distribution of values of the studied botanical indicators NDVI, MNDWI, NDBI and EVI from year to year, as most of them tend to change. An increase in the temperature of the earth's surface in the semi-urban area of Constantinople by 05°C in the last thirty-six years alone. Finally, the study recommends the need for a serious implementation of a policy of environmental awareness, the use of modern technologies and the activation of dissuasive
laws to reduce the phenomenon of expansion to the detriment of semi-urban land, which will
continue to intensify and affect the environment in the future (horizon 2040).
