نشریه هیدروژیومورفولوژی
پیاپی 5 (زمستان 1394)

Variations in route and morphology of the rivers are among the important characteristics of floodplains. Since these variations occur within time scale, it is appropriate to study those using remote sensing techniques. This study aims to identify and extract part of Zarineh Rud river variation from 1989 to 2014 using landsat satellite images. To gain this objective, radiometric and geometric modifications have been carried out in the first phase. Afterward, the images have been developed by linear method for enhancing the resolution. Then, by principal component analysis and band combination, the best component and band were determined. By adding these components and bands to ArcGIS, the river range within the mentioned time span was extracted and analyzed. Furthermore, for quantitative analysis of the river route variation, curvature coefficient and Fereaktaly dimension indices were used to compare the different years. It was found that there is a low potential in river to have morphologic variations in different parts. This is due to the fact that there has been a negligible change in river flow rate since 2000. The highest variation is observed in 1989. Instability of the river route during the studied time span was very low, except for one of the river’s twists from the 1989 pattern. The results of river extraction methods also confirmed that principal component analysis for identifying the border line of the river is more appropriate than the other methods.

Tabriz metropolitan is located in an area of active fault which crosses the lower part of the Gomanabchai and Varkeshchai watershed in the north of the city. This research is studying Tabriz fault tectonic activity in the range of Tabriz metropolitan using geomorphic indicators, remote sensing and GIS techniques. To achieve this goal, geomorphic indicators were used as tools including drainage density, branching ratio, the ratio of the basin, basin asymmetry, polarity reverse topographic, hypsometric integral, sinus mountain front, sinus river valley floor width to valley height, longitudinal gradient, and index assessment of active tectonic model and concept. Satellite images ASTER sensor, geological maps, digital elevation model and ENVI4.8, ArcGIS10.2 software were other physical means in this research. As a result, small amounts of drainage density indices 0.51 and 0.57, the branch 2 and 2.1, 2.2 and 1.8 of the basin, basin asymmetry 39.7 and 23.2, 0.36 and 0.59 reverse topographic symmetry, hypsometric integral 0.28 and 0.39, 1.4 sinus mountain front and 0.93, 1.1 and 1.3 sinus river, valley floor width to valley height of 1.08 and 1.2, longitudinal gradient the 1202 and 318 calculated for Gomanabchai and Varkeshchai watershed respectively. Relative Active Tectonics Index assessment showed that Gomanabchai and Varkeshchai watershed values 1.9 and 1.7 respectively have high tectonic movements. Results indices show Gomanabchai and Varkeshchai watershed morphology influence the Tabriz fault tectonic movements. With processing satellite data, as evidence of tectonic Tabriz fault deviation, Ajichai stream, cliff fault and lens-shaped phenomenon were also interpreted in the metropolitan area Tabriz. The results were confirmed by field evidence area. So, Tabriz was located as a perilous zone of tectonic movement.

There are many valleys in the city of Zanjan and Eijrood and parts of Abhar, Tarom and Mahneshan Zanjan province. The valleys are very different in terms of geology, lithology and physiographic factors and they are dispersed in different directions geographically with different forms. First the valleys were classified according to geological structure; totally 149 valleys was identified, 37 valleys had a structure of perpendicular to the fault, 9 valleys faulty and perpendicular to the syncline in parallel structures the fault, 6 valleys in a parallel structure with the fault, 5 valleys in a mixed structure of the fault with syncline or anticline (the mixed valleys) and the remained valleys 64, were classified as "the other valleys". Then tectonic-geomorphologic indexes were used, such as the longitudinal gradient of the river (SL), asymmetry of drainage,(AF), the index of Width of valley floor to its height (VF) and the index of maze in rivers (S), to determine the amount of neotectonic activities of the valleys. The results show that the Average Index (VF) is between one and two in the area of hybrid and perpendicular to the fault, they have semi-active and active tectonics in other classes. The entire region is active with tectonics in Index (AF) and due to the symmetry of the drainage basin. The low index (S) in all classes is the indication of young and active area and straight rivers. All sub-systems based on faults are active tectonic in all indexes. Valleys indicated as "other" are less effected by Neotectonic.

A valid estimation of runoff volume and maximum discharge in the dried and semiarid regions which lack data is important for flood management. One of the estimating methods of runoff volume is related to curve number (CN) of American soil conservatives services (SCS). In this study, the drainage basin of Darrehshah Sarab has been studied with regard to its runoff volume potentiality, maximum discharge and effective factors. To estimate the runoff volume and maximum discharge of the sub-catchments, the curve number method has been used. First, the layers and the needed data including the land use, soil hydrological groups and a maximum 24 hours precipitation was prepared for basin. Then the CN values, infiltration (S), runoff volume (Q) and maximum discharge (Q max) were calculated for the entire basin and each sub-basin. Finally, factor analyses based on 19 parameters were used to identify the effective factors on maximum discharge at sub-basins. The results showed that among the used parameters in sub basins, two physiographic parameters (area and drainage density) were effective parameters in flooding potential of the drainage basin of Darrehshah Sarab.

The study area is Ahrchay upstream basin. Because of the mountainous region is a sensitive area in terms of erosion. Most parts of the basin, are permanent. When Ahrchay branches arrive the flat area, the river meanders be converted. Ozomdel Varzeghan Plain, as a result of blockage by volcanic activity has occurred near the village of Sghendel. Digging trenches and sediments of the seabed by Ahrchay cause appears to have been made. In spring and late winter rainfall and melting snow caused river flooding is causing erosion and transportation of sediments found there by the river. In areas where the slope is to slow the stream sediment deposition. The material in foothill and lowland areas has formed alluvial terraces. In this study the geomorphic characteristics of the terrace deposits is investigated. For this study, 15 out of deposits terraces for grain harvested. Charts on different parameters such as (MD), (MZ), (QI), (SKG) and (SKI) is extracted and were analyzed separately. Grading of terraces and other characteristics of sediments show also features river terrace.

In this study for the purpose of simulation of runoff originated from snowmelt in Shahrchay River basin two models namely SRM and HEC-HMS were used. For this purpose, entering the snow cover data, meteorological variables and other needed parameters an input to SRM model the runoff from snowmelt was simulate. In HEC-HMS model, after derivation of watershed model using the HEC-GEOHMS software in GIS environment and derivation of meteorology model and entering the required parameters such as water losses, flow routing and snow melt was simulated. The coefficient of determination (R2) of SRM model was 0.9 and the percentage of volumetric error (DV) was equal to 1.96. On the other hand, the HEC-HMS model simulated snowmelt runoff was satisfactory (but less than SRM), so that the R2 and DV obtained for this model were as equal to 0.85 and 2.1%, respectively. Utilization of air temperature and precipitation data (neglecting the high accuracy of SRM) can be considered as advantages of HEC-HMS. In contrast, in SRM model in the snow covered area of region apart from the mentioned parameters satellite images of the region is also required. Results indicated that the total volume of runoff in the study area was 129.9×106 cubic meters for SRM, whereas it was 129.6×106 cubic meters for HEC-HMS. Comparing these values with that of the observed (i.e.134.4×106 m3) it can be concluded that SRM model performance is relatively better than the HEC-HMS.
[1]- Professor, Department of Meteorological, the University of Tabriz.

Farub Roman River with a length of about 19 km in the Northeast Neyshabur is a perennial river. To determine the sedimentary parameters in this river, 55 samples were taken from the main channel of this river and then granulumetry analysis and statistical parameters were calculated. The mean sorting of sediments is1.609phi (Poorly sorted) and skewness is 0.393 (Strongly fine skewed) and Kurtosis is 0.965 (Mesokurtic). This river is of braided type with load gravel bed. In this river, four sedimentary discontinuities and five sedimentary links are detected. Grain form of the river is in the range of very bladed, and major of deposits are in gravel range. Facies that could be identified in this river are: Gci (grain supported gravel), Gmm (matrix supported Gravel), Gmg (graded and matrix supported Gravel), Gh (grain supported gravel with horizontal bedding)) for gravelly facies, sand with horizontal bedding (Sh) for sandy facies and massive mud (Fm) for muddy facies. The facies formed in these structural elements are such as Channel (CH), Gravity flow deposits (SG), Gravel bars and Bed forms (GB) and Fine grain clastic deposits (FF). Based on the results, sedimentary model for Farub Ruman River is of braded type with loaded gravel bed.

The current study investigates the effect of ENSO atmospheric-oceanic pattern as an effective factor in hydrological conditions of Kashkan River. To do so, the related data of Southern Oscillation patterns using East Angelina university website was gathered, and the statistics period of 1984-2010 was considered. The related data of Kashkan’s annual discharge was also collected using related references. Pearson coefficient analysis was used in order to analyze the monthly and annually data, with at least (p_value=0.01) 0.99% significant level. For assessing the effect of cold and warm phases of this macro-scale weather pattern, discharge’s annual data based on the mentioned monthly phases was considered and Independent two-tail t-test was run. Applying this test, the meaningfulness of differences among discharge’s annual data in cold and warm phases was investigated. Finally, the cause and atmospheric relationship between data was analyzed using Synoptic map analysis. The results show that Kashkan River’s discharge has a meaningful significant coefficient with ENSO index in October, November and December. Also the result of synoptic map analysis shows that in years with warm phase of ENSO (El-nino), autumn raining around Kashkan River increased about 26 percent over the long term. But in the cold phase autumn raining in that area had been about 10.5 percent less than the normal amount. Running the Independent two tail t-test on the annual discharge shows that in the years with warm phase of ENSO, the average amount of Kashkan River’s annual discharge has been 35 percent more than the years with cold phase of ENSO.