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Anna Dłużewska and Maciej Dłużewski

Abstract

Ksours form a cultural landscape for most of the countries of North Africa. They are an important part of the cultural heritage of the desert areas in Algeria, Libya, Tunisia, Mali or Morocco. They also become an undeniable attraction for tourism. The article looks at the impact of tourism on the transformation of ksours. It is based on comparative field research in the Dadès-Drâa Valley (Southern Morocco), the region of the highest ksour concentration. The results show that despite being very close to most sustainable tourism indicators, the whole impact of tourism is rather negative. Tourism is creating social disproportions, being the first incentive to abandon the ksours by those who are not involved in the sector. This is leading to the destruction of particular houses first, and later to the destruction of the whole village. The revitalization of ksours remains a theoretical solution only; thus the author suggests paying greater attention to social equity in order to stop the transformation of ksours at the 2nd stage of development.

Open access

Elwira Żmudzka, Dariusz Woronko and Maciej Dłużewski

Abstract

Climatic and meteorological conditions may limit the aeolian transport within barchans. An explanation of that issue was the main goal of the investigation held in Western Sahara dune fields located around Tarfaya and Laâyoune. Particular attention was paid to the factors causing the moisture content rising of the sand dune surface layer, which could influence the wind threshold shear velocity in the aeolian transport. The wetted surface layer of sand, when receiving moisture from precipitation or suspensions, reduces the aeolian transport, even in case of wind velocity above 4-5 m s-1. Fog and dew condensation does not affect the moisture of deeper sand layers, what occurs after rainfall.

Open access

Irena Tsermegas, Maciej Dłużewski, Katarzyna Biejat and Adam Szynkiewicz

Function of Agricultural Terraces in Mediterranean Conditions - Selected Examples From the Island of Ikaria (The Southern Sporades, Greece)

The aim of the research was to define the influence of agricultural terraces on slope erosion. There have been selected three plots located on the Greek island Ikaria. On the plots detailed geomorphological mapping was done, spatial relief models were created based on the measurements taken using GPS RTK, georadar profiles were made using RAMAC/GPR and the extent of destruction of terrace resistance walls was evaluated.

In comparison with similar forms on other Aegean islands, Ikarian terraces are narrow and high. Their stability depends on: lihtology, slope gradient, height and spatial arrangement of particular terrace steps and the current way of their usage. It was acknowledged that the most stable are the forms created on crystalline schists and gneisses, whereas the slopes, which erode the easiest, are the terraced ones consisting of carbonate rocks.

The obtained results indicate that on Ikaria similarly to numerous other regions the most significant factor facilitating erosion on the terraced slopes is the cessation of their agricultural usage.

Open access

Maciej Dłużewski, Rafał Kozłowski and Anna Szczucińska

Abstract

In arid zones, the availability of fresh water is usually very limited because of high salinity, which greatly limits their use for irrigation purposes. High mineralization of water used for irrigation leads to increased soil salinity. The aim of the study was to examine the potential use of alluvial groundwater for irrigation in arid zones. The works were conducted in the Middle Draa Valley in southern Morocco (the Mhamid Oasis) in October 2015. Water samples of alluvial groundwater were collected for laboratory analysis from 42 wells located in the oasis. In order to determine the possibility to use the water for irrigation purposes, the Sodium Adsorption Ratio (SAR), sodium percentage (%Na), permeability index (PI), Kelly’s ratio (KR), magnesium hazards (MH) and electrical conductivity (EC) were assessed. EC values, exceeding 3000 μS·cm-1 in all the samples, classify the water as unsuitable for irrigation. MH and the KR indexes show that 30% of water samples represent levels making them unsuitable for irrigation. SAR confirms the very high degree of susceptibility of the analyzed waters to salinity hazard. The PI index of these waters is moderate, however in terms of sodium content they can be deemed suitable for irrigation purposes. It has been found that even within a small area of the oasis, a very large differentiation in the alluvial groundwater suitability for irrigation purposes occurs.