جستجوی مقالات مرتبط با کلیدواژه « حوزه آبخیز جنگلی » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

The present research was conducted with the purpose of assessing the interaction between some soil properties and runoff generation time in the downstream of Educational and Research Forest Watershed of Tarbiat Modares University (Kojoor Watershed) located at Southeastern of Nowshahr. Rainfall simulation was done through applying a pumping rain simulator generating rain intensity of some 1.6 mm min-1. Accordingly, runoff generation time was determined from starting time of the simulation until runoff generation. In this research, some soil characteristics such as percentages of organic matter, clay, Silt, sand, antecedent soil moisture contents and soil bulk density were analyzed at two topography characteristics of slope steepness and aspect. For statistical analysis, a normality and variance homogeneity test was firstly carried out and variance analysis was then adopted. The significant relationships were ultimately evaluated using the Pearson correlation test. Results showed that the soil properties were strongly correlated to each others. Amongst them, there were just a positive correlation between the percentage of organic matter and topography properties with runoff generation time in the significant level of 5 %. Most of the runoff generation time were measured from plots of 44% and located at the western aspect that had the highest percentage of organic matter of 5.9%. It could be inferred from the results that the runoff generation time was significantly sensitive to environmental variables.

Sediment yield mirrors the resultants of interaction among many different watershed components. It therefore can be studied for better understanding the governing situations on a watershed system. Annual based estimation of soil erosion and sediment yield cannot be supposed as a proper basis for designing hydraulic and watershed management structures. Estimation of suspended sediment load on storm basis is therefore necessary. Studying temporal variation of suspended sediment is an important tool for soil and water resources management of a watershed. However، the development of sediment graph under real conditions is very time and money consuming task and derivation of synthetic sedimentgraph has also been rarely considered. The present study was thus conducted in Tarbiat Modares University Forest Watershed [it needs address] with an area of 13263 ha to analyze accuracy of Time-Area Method (TAM) in sedimentgraph development. The TAM was then applied to the study watershed after providing necessary input data viz. isochrone area curve، input variables of the USLE and soil erosion routing with considering areal distribution of rainfall. The applicability of the TAM was then assessed for eight storm events occurred during October to December 2008. The results of analyses of application the TAM verified inapplicability of the model in simulating study sedimentgraphs.