Tom 8 (2020): Zeszyt 4 (December 2020)

Swelling potential characterization of clay-silt soil is an essential issue in stabilization, settlement, consolidation, and land suitability studies. This article attempts to explain the swelling characteristics of soils around the area of West Lampung, Lampung Province, Sumatra, Indonesia, in relation to environmental issues. An investigation in relation to the soil swelling potential was carried out using 15 disturbed soil samples collectd in the study area. The methods used were analyses of clay mineral geochemistry, physical characteristics, and the free swell ratio. These results showed that the soil in the study area was Quaternary tropical volcanic residual soil. These soils were formed in a proximal volcanic hydrothermal alteration environment. The soils of the study area have characteristics of high plasticity, a reddish-brown colour, and are clayey silt grained (MH) (USCS). The soils had loose physical characteristics in dry conditions; however, these soils tends to be plastic and sticky in wet conditions. Evidence of groove erosion was found at the soil surface. Based on XRD analysis, kaolinite, halloysite, and montmorillonite were types of clay minerals found in the soil. The soil had a clay content of 11.05–78.9%, a liquid limit value > 50%, a plasticity index value of 16.7–36.9%, a shrinkage value of 14.24–36.89%, a soil activity of 0.38–2.47; and an FSR value of 0.69–0.95. These characteristics have implications for swelling soil potential. The results showed that the soils in the study area had medium to very high swelling potential. These results suggest a risk of erosion in the area, which could cause soil degradation and a change in water quality. These soils are likely to affect land productivity and aquifer replenishment and will cause negative environmental and economic impacts. Thus, soil improvement techniques are needed. It is important to maintaining vegetative cover these soils and revegetation may be required.

Groundwater quality in the alluvial aquifer of Wadi Hachem, Tipaza, was assessed for drinking and irrigation purposes. This alluvial plain covers an area of 13 km² and lies in a semiarid climate. Groundwater is the major source for domestic and agricultural water activities in this region, and it is facing natural conditions and anthropogenic activities. The groundwater quality was evaluated on the basis of its physicochemical parameters for the dry period of 2015. The results of these parameters were compared with WHO and Algerian standards recommended for drinking water. The water quality was found to be slightly alkaline, with moderate water quality for drinking based on Total Hardness (TH), Electrical Conductivity (EC) and Total Dissolved Solids (TDS), and all water samples were within the permissible limit for drinking and irrigation purposes. The samples also showed two water types, Ca- HCO3 for the majority of samples, that characterize natural water quality controlled generally by the recharge area and by geological influences and Ca-Cl water type for one sample that is likely influenced mainly by anthropogenic activities, which was affirmed by the higher values of EC, TDS and of some ion concentrations. The analytical data plotted on Riverside and Wilcox diagrams illustrated high and very high salinity, and low sodium hazard rendering groundwater usable only on soils with good permeability.

Residential suburbanization is one of the most spontaneous processes occurring in the surroundings of large cities in Central and Eastern Europe. In the case of Wrocław, the first phase of suburbanization began as early as the second half of the 19th century. Its spatial scope changed with the expansion of the administrative borders of the city between 1924-28 and 1950-73, when dozens of suburban villages were incorporated into the city. In addition, during the socialism period, the intensity of suburbanization decreased significantly, which was related to the development of the city within the conditions of planned urbanization and industrialization of the country. The second phase of suburbanization began with the system transformation in the 1990s, and its scale and intensity increased in the 21st century. New construction in the hinterlands of the city has contributed to significant changes in the morphology of suburban villages, especially as the growing share of new buildings is multi-family housing. The aim of this article was to identify the most common trends in the morphological changes that affect villages located in the suburban area of Wrocław under the influence of residential suburbanization. Using the analysis of cartographic materials, field research and graph methods, a typology of morphological transformations of villages located in the suburban area was proposed.

Like many other Central and Eastern European countries Lithuania has been experiencing significant socio-spatial transformations since the 1990s. One of the most prominent of these transformations is associated with the residential suburbanization of its major cities. The suburbs are the only areas in Lithuania where the population has been growing in recent decades, while the country has lost almost one quarter of its population. Although, extensive urban growth is a common feature for all large Lithuanian cities, it is more noticeable in Vilnius. Due to its historical and geographical context, Vilnius, and the region surrounding it, is in an area where rural-urban transformation also means transformation of the social, ethnic, and political landscape. The aim of this article is to obtain more insight into the recent process of the fast, but weakly controlled, residential suburbanization of Vilnius. The focus is on understanding the scale of suburbanization and its impact on the social and physical environment. In this study, we use quantitative data on population and residential constructions as well as presenting some visual material. Our results show that the new suburban-style settlements are spatially dispersed. New residential areas have emerged within the city limits, along its administrative boundary as well as in the most peripheral parts of the Vilnius metropolitan region. In terms of the morphology and physiognomy, a great suburban diversity exists in and around Vilnius, and different building styles are mixed creating a rather chaotic landscape, with little interference from urban planners and no clear vision for the future.

This research concerns the complex problem of morphological transformations of villages in the intra-urban area (i.e. settlements incorporated into acity), as well as the suburban area, using the example of the metropolitan area of Łódź, Poland. The main aim of the research was to analyse the diversity of selected rural settlements and their spatial changes after World War II.. The study was based on preserved historical maps and today’s plans. An analysis of morphological changes of selected villages was conducted using graph theory methods. It was noticed that the graph development index should depend on the relative number of edges in relation to the number of nodes and the number of graph cycles, which express the degree of complexity of a settlement unit. Three main groups of villages, characterised by different scales of morphological transformations, were distinguished as a result of the study. Settlement units with orthomorphic transformations, where all spatial modifications were mainly additive and the initial layouts have been preserved almost completely, represent the first group of villages. The second group is composed of units with semi-metamorphic transformations, where the spatial reorganization was significant, but not total. The third group includes villages with metamorphic changes, where the initial layouts have been totallytransformed.

In a country like Ethiopia where the vast majority of the populations are employed in agriculture, land is an important economic resource for the development of rural livelihoods. Agricultural land in peri-urban areas is, however, transformed into built-up regions through horizontal urban expansion that has an effect on land use value. In recent years Ethiopia has been experiencing rapid urbanization, which has led to an ever-increasing demand for land in peri-urban areas for housing and other nonagricultural activities that pervades agricultural land. There is a high demand for informal and illegal peri-urban land which has been held by peri-urban farmers, and this plays a vital role in the unauthorized and sub-standard house construction on agricultural land. This urbanization has not been extensively reviewed and documented. In this review an attempt has been made to assess the impacts of rapid urbanization on agricultural activities. Urban expansion has reduced the areas available for agriculture, which has seriously impacted upon peri-urban farmers that are often left with little or no land to cultivate and which has increased their vulnerability. Housing encroachments have been observed to be uncontrolled due to a weak government response to the trend of unplanned city expansion. This has left peri-urban farmers exposed to the negative shocks of urbanization because significant urbanization-related agricultural land loss has a positive correlation with grain production decrease. Appropriate governing bodies should control urban development in order to control the illegal and informal spread of urbanization on agricultural land that threatens food production.

The purpose of this study was to determine the state of dispersion and concentration of buildings in the Warsaw urban agglomeration. In particular, a goal was defined to develop a typology of basic administrative units due to the level and characteristics of the spatial concentration of buildings. The study was conducted based on the municipalities (urban, urban-rural and rural) of the Warsaw Metropolitan Area (delimitation of the Warsaw urban agglomeration used for the strategic and planning purposes) and districts of the capital city of Poland. Data on buildings was obtained from the topographic objects database. The share of buildings in total, as well as single-family and multi-family housing objects, was taken into account (these two categories were assumed to be the main determinants of suburbanization). Two methods were used to analyze their distribution: the density quotient factor, and the average nearest neighbour method. The spatial arrangement of buildings covers a wide spectrum of types, determined by combinations of both extreme and intermediate values of two dimensions of spatial concentration – the density of objects and the degree of their spatial dispersion (level of regularity, randomization, or clustering in their distribution). The typology allows us to indicate units for which similarly oriented spatial policy should be applied. The method of construction of the developed typology may be useful for application to research in other areas.