Examination of compensatory model application in site selection

Nowadays, usage of compensatory models in land evaluation process and site selection is broadly observed. Meanwhile, methods such as analytical hierarchy process are used more than the others. Whether the usage of compensatory model methods in site selection studies is essentially correct or not is an issue that should be hesitated. In this model, inefficiency of a factor, to be offset by strength of others, means that in urban development site selection, if somewhere has unsuitable aspect but suitable slope, the aspect deficiency will be compensated by the slope. But quodlibet reflection is that in this model, sometimes, deficiency of proximity to fault can be compensated by other parameters strength. And finally, a place is diagnosed as a suitable area for urban development that is close to the fault. This research aims at examination of compensatory models application in urban development site selection of Taleghan Basin using analytical hierarchy process as one of the compensatory model methods. Among this the weaknesses and strengths of compensatory model were analyzed carefully. Results indicate that despite usefulness of this model in being fast, easy, and low expense, it has some weaknesses like very high sensitivity to decision maker’s idea.     

A comparison of standard k–ε and realizable k–ε turbulence models in curved and confluent channels

Environmental Fluid Mechanics - Bends and confluences are often observed in rivers, and one of the phenomena that characterize flows in open channel bends and confluences is secondary current....     

Cumulative effects of developed road network on woodland—a landscape approach

Population growth, during the twentieth century, has increased demand for new farmlands. Accordingly, road networks have rapidly been developed to facilitate and accelerate human access to the essential resources resulted in extensive land use changes. The present study aims at assessing cumulative effects of developed road network on tree cover of Golestan Province in northern Iran. In order to detect changes over the study period of 1987–2002, the LULC map of the study area was initially prepared from the satellite images of Landsat TM (1987) and ETM+ (2002) using maximum likelihood supervised classification method. Afterwards, a total number of seven landscape matrices were selected to detect cumulative effects of the developed road network on woodland cover. The obtained results indicated that the fragile patches are mainly located at a distance of 171–342 m from the roadside. Furthermore, the majority of the patches affected by cumulative effects of development activities are situated at a distance of 342–684 m from the roadside, over an approximate area of 55 ha. The analysis of landscape metrics revealed that the developed road network has increased the landscape metrics of “the number of patches” and “patches perimeter-area ratio”. It has also followed by a decrease in metrics such as “patches area”, “Euclidean nearest neighbor distance”, “patches proximity”, “shape index”, “contiguity”, and “mean patches fractal dimension”. The road network has also increased the “number of patches” and decreased the “mean patches area” representing further fragmentation of the landscape. With identification of highly affected wooldland cover patches, it would be possible to apply adaptive environmental management strategies to preserve and rehabilitate high-priority patches.