Morteza Shahnori; Maryam Azarakhshi; Mehdi Bashiri; Hasan Rezaee Moghadam
Abstract
Evapotranspiration as an important component of the hydrological cycle plays a major role in the study of water balance in watersheds. The purpose of present research was to investigate the response of Atriplex canescens to different levels of water salinity and the effect of irrigation water salinity ...
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Evapotranspiration as an important component of the hydrological cycle plays a major role in the study of water balance in watersheds. The purpose of present research was to investigate the response of Atriplex canescens to different levels of water salinity and the effect of irrigation water salinity levels on actual evapotranspiration under lysimetric conditions. For this purpose, four treatments inclusive 0, 25%, 50%, and 75% of maximum salinity tolerance of Atriplex canescens with 3 replications were considered which equal as zero, 19.6, 39.2, and 58.8 ds/m of Sodium Chloride. The lysimeters were placed in greenhouse and two Atriplex canescen shrubs were cultivated in per lysimeter. 5 liters of water with mentioned salinities were added to each lysimeter every two weeks. During the vegetative period of the plant, from 6th March to 15th of August of 2019, the measurement of evapotranspiration was done by weighing the lysimeters at intervals of one week. After the end of the experiments, the weights of shoots and roots of each treatment were measured in wet and dry situation. The results showed that evapotranspiration decreased from 3.94 to 2.84 liters with increasing salinity of irrigation water from zero to 58.8 ds/m, and there was a significant difference between control and 58.8 ds/m salinity treatments at 5% level. By increasing salinity from 0 to 19.6, 39.2 and 58.8 ds/m, the dry weight of shoots increased compared to control treatment 20.13%, 41.87% and 11.55% respectively. Therefore, with the conditions of the present researchو Atriplex Canescens was produced the highest amount of dry shoot in 39.2 ds/m salinity.
Zakieh Safarpour; Jalil Farzadmehr; Ali Golkarian; Mahdi Bashiri
Abstract
Landslide is one of significant mass movement which causes normous annual human and sesmic region. Therefore, finding hazardous areas for planning and management of them is necessary. So, in this reasearch, occurred landslide in watershed region of bidvaz dam which has area of 161 square kilometers and ...
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Landslide is one of significant mass movement which causes normous annual human and sesmic region. Therefore, finding hazardous areas for planning and management of them is necessary. So, in this reasearch, occurred landslide in watershed region of bidvaz dam which has area of 161 square kilometers and 125 landsliding points are surveyed in different hydrological conditions by index model of slope stability. For specified slopes, graiding test was done and geotechnical parameters were attained. Then, by using Arc view and Arc GIS packages and calibrating parameters in SINMAP and incorporating the geotechnical and hydrological parameters with digital elevation model, SINMAP was conducted. After that, validation was done in two common and high hydrological conditions including rainfalls with a return period of 2-10 years and 20-50 years Respectively. Results showed that the performance of model in simulation of landslides is not appropriate at common hydrological cases. However, increase in hudrological humidity condition, performance of model improves. In calibration and validation, prediction of model increase 21 % and 26 %, respectively. Therefore, utilizing SINMAP model in high hydrological humidity conditions can be useful for choosing dangerous ways according to the landslide map.
mehdi bashiri; Seyede Maedeh Kavousi Davoudi
Abstract
The soil erosion affects watershed health and lead to different negative consequences.Marl is an erosion sensitive rock that due to its special physicochemical characteristics,establishment of vegetation on it is difficult,so,it needs to management.One of the soil improvement methods is dynamic compaction,which ...
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The soil erosion affects watershed health and lead to different negative consequences.Marl is an erosion sensitive rock that due to its special physicochemical characteristics,establishment of vegetation on it is difficult,so,it needs to management.One of the soil improvement methods is dynamic compaction,which applies using devices such as rollers.Also,adding pozzolan is another method for soil improvement to modify its physical and mechanical properties.Because the pozzolan in the presence of water,show adhesive properties in a stable and non-solvent form.Therefore,this study tried to evaluate the roles of soil compaction(using rollers having weights of 0,20,25,30and35Kgs)and adding natural pozzolan(in values of 0,50,100,150and200g/m2)in the taftan-pumice type on marl stabilization in Islam-Qaleh region of Razavi-Khorasan.A factorial experimental design done with3replications and totally75field plots with an area equal to30*30centimeters exposed to a rainfall with a10minutes duration and0/8Mm per minute intensity with a slope of15/5°.The results of statistical analysis in the95%confidence level showed that considering runoff,sediment load and sediment concentration variables together,the main effects of soil compaction and pozzolan treatments are significant(sig.=0/000)but their interaction effect isn’t significant(sig.=0/780).Soil compaction treatment has an increasing and significant effect(sig.=0/000)on runoff and sediment production. But the pozzolan treatment showed decreasing and significant effect (sig.=0/000) on sediment and no significant effect (sig.=0/709) on runoff. Also, the interaction effect of 2 treatments on runoff and sediment was not significant. Therefore, the soil compaction due to degradation of surface sealing and marls structure is not suitable, but according to low price and availability of natural pozzolan, for marls stabilization operations, is suggested as an economic and appropriate option.
parisa farzi; maryam azarakhshi; ali rasoulzadeh; mehdi bashiri
Abstract
Characteristics of stones forming the earth's surface contribute significantly to environmental changes such as soil erosion and movements of soil particles. This study seeks to investigate the main and reciprocal effects of geological units and slope gradient on runoff and sediment production in Senobar ...
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Characteristics of stones forming the earth's surface contribute significantly to environmental changes such as soil erosion and movements of soil particles. This study seeks to investigate the main and reciprocal effects of geological units and slope gradient on runoff and sediment production in Senobar watershed using rainfall simulator. To this aim, the geological map was created in Arc GIS 10 software and three dominant units i.e. green tuff, sandstone, marl (Et), Orbitolina Limestone (Kl) and Conglomerate, Sand stone (Ngcs) were identified. Besides, to study the effect of slope gradient, the slope map was provided in three classes: 0-10, 10-30 and more than 30%. Then, the rainfall intensity equal to 0.9 mm min-1 (10- years return period) was created by rainfall simulator. Analysis of variance showed significant differences between geological units for runoff, sediment yield and sediment concentration at 5% significant level. It was found out that there is significant difference between different slope gradients in runoff and sediment production; however, there was no significant difference regarding sediment concentration. The results of interaction between geological units and slope gradient for runoff volume was significant at the 95% level of confidence but regarding sediment yield and sediment concentration interaction effects were not significant. Generally, it was found that the type of geological units and slope of the study area impacted on soil erosion process. Also, the impressibility of runoff variable was more than that of the sediment.