مجله علوم و مهندسی آبخیزداری ایران
پیاپی 25 (تابستان 1393)

Rivers have been addressed as one of main resources of water supply for different consumptions including agriculture، drinking and industry. Therefore، with regard to recent droughts، also rural and urban development، monitoring the quality of these resources is considered as an important function in the context of environmental management. With respect to the importance of Godarkhosh river، located in Ilam province، its entrance into Iraq country، its removal for different consumptions، also discharging various pollutants into this river، its qualitative assessment seems necessary. On the one hand، zoning، contamination and presenting proper image of qualitative condition of surface water by means of GIS resulted into the situation that every management decision that affects directly or indirectly on national surface waters، must be made consciously. Research method is cross- sectional descriptive. It''s various stages are including: sampling 10 stations across the river during 6 months (From September 2010 to march 2011)، measuring such qualitative parameters as temperature، measuring such qualitative parameters as temperature، dissolved oxygen (O2)، essential biochemical oxygen، fecal coliform، Nitrate، phosphate، turbidity، pH، total dissolved solids and data analysis by using national water quality index (NSFWQI). To prepare water qualitative zoning model of this river، besides above index in relation to natural factors، (geology، soil quality، vegetation and local permeability). GIS software was used to consider this model. Obtained results indicated that mean NSFWQI in the best condition with the effect of natural factors is related to stations 5 and 7 with 50/33 and 59/33، respectively. Actually this would determine intermediate condition in regard to qualitative index and average index in worst state with the effect of natural factors is related to station 4 with 49/33 that indicated the appearance of bad qualitative condition.

Flood water spreading projections have been done with many objectives. One of these objectives is increasing vegetation cover. Flood spreading leads to increasing soil moisture and forage production. The purpose of this paper is to study the effect of flood spreading on quantitative changes in native vegetation cover in Sabzevar. At the first، canopy cover and vegetation density were measured by transect of 100m and plots of 225m2 (15×15)، respectively. A region as a flood spreading area including three phases، two phases of Atriplex and one phase of Haloxylom was selected. Also، a region was considered as control area. Then، common species (endemic species) were compared in flood spreading region to control area. The results showed that water spreading has positive effects on endemic spices، especially in Haloxylon phase and these effects were significant at 1%. Flood spreading has no effect on canopy cover and vegetation density in Atriplex phase1 and the effects in Atriplex phase2 were negative. So، flood water has different effect on endemic species based on planted species in region.

The wind plays an important role in different hydrologic phenomenon such as spatial distribution of snow accumulation. In order to compare the function of the wind in different locations of the basin، a magnitude called wind shelter index is being used، which its calculation encounter special difficulties because of its need to various information. An algorithm has been presented in order to reach an efficient method to determine wind shelter index. The results showed that the presented algorithm can be used more easily by the users، and it is more qualified for calculating wind shelter index of all the optional locations placed on the surface of the basin، in comparison to the direct method of calculating wind shelter index.

The physiographical and climatological attributes of basins and maximum annual flood statistics were obtained from 38 hydrometric stations of Mazandaran province with minimum and maximum statistical periods of 13 and 56 years. The first، homogenous regions based on neighborhood approach were determined using canonical kriging method. The Canonical Correlation Analysis was used to design physiographic space using the six physiographic variables affecting the flood and two hydrological variables. The Gaussian model had the best fit to semi-variogram model in 10، 20، 50 and 100 year return periods، and regional estimates obtained using ordinary Kriging technique based on physiography space. The accuracy of results was evaluated using L-moments method for regional flood frequency analysis. In this method، Ward hierarchical clustering has been used to the determination of homogeneous regions. Homogeneity areas were adjusted by using homogenous and discordancy tests. Using goodness-of-fit Z DIST the Generalized Logistic distribution was selected for all clusters as the best regional distribution and regional estimates obtained by parameters selected distribution. Finally، performance methods evaluated using Jack Knife procedure and the five statistical indexes BIAS، BIASr، RMSE، RMSEr and NASH. Both methods give the same and desirable performance based on NASH، however results of other indexes showed that canonical kriging method provide better performance than linear moments. Increasing the return periods will improve the estimation، but the L-moments offers better performance for short return periods.

A magnetic property is one of the features inherent in the minerals that are used to identify minerals so that type and location of the mineral can be traced using them. In the present study، we used four magnetic parameters XLF، XHF، XFD XFD% for tracing sediment and differentiation of sediment sources in the Hasan Abdal watershed. Sediment samples were taken from the small dams and bed sediments of streams and from lithological units with three replications as sources of sediment. Then the samples were passed through from sieve 62. 5 microns and magnetic parameters were measured using magnetic susceptibility meter. Then the contribution of lithological units in the sediment production was determined using statistical and multivariate compositional techniques and the relative importance index was considered as representative of sediment production of the lithological units. The results showed that the Pd unit has the largest share in sediment production with 49. 76%. This unit consists of quartz sandstone، and pink to white shale and sandstone and massive dolomite. The second is the Pl-Qc unit that consists of loose conglomerate with poorly roundness and medium sorted in color light gray and its contribution in sediment production 15. 13%. Єz unit with 7. 40% is third grade; this unit consists of pink to red micaceous shale. The contribution of lithological units PMl، Єl، Ef، Ev، Ek1، Qt، Js، Єbt and Et، respectively is 5. 54%، 5. 39%، 3. 53%، 3. 44%، 2. 96&، 2. 37%، 2. 13%، 1. 94% and 0. 42%.

Water issue is one of the most critical and challenging، meanwhile the most complicated forms of resource and production management. However، water resources governance as the most valuable natural resource along with local user’s engagement for water resource co-management، is considered one of the necessities of water security program. Network analysis has a lot of capabilities to organize water co-management of watersheds. So، this method has been used to measure criteria and quantitative and mathematical indicators associated with Jajrood river in Darbandsar village in Latian watershed. All Local users of water resources in Darbandsar village have been deliberated in the research. The results revealed that degree of social cohesion based on trust and collaboration among Darbandsar residents، is very poor to poor. Also social network stability is reported as poor to average. In addition، the results indicate a high correlation of trust and collaboration among local stakeholders of water resources in this study. Based on these results it can be stated improving social cohesion and social fund among local stakeholders is considered one of the requirements of water resource co-management program in order to achieve water security and sustainable development

The study of changes of sediment beds is of the issues which has attracted river engineers. Attention to investigate the rate of scour and sedimentation is significant in studies of rivers. The change of bed topography, scour and sedimentation pattern have caught the attention of hydraulic engineering profession. This paper examines the topography changes using experimental data in a laboratory flume with a length of 8 meters and a width of 0.255 cm and changes of bed morphological will be discussed. For this purpose, interpolate methods contained in the Surfer used to convert point measurement to continuous surfaces. Accuracy assessment accomplished by validation method and MAE, RMSE also. The result showed that Minimum Curvature and Kriging methods have best accuracy to create surfaces for studying changes of bed morphology in rivers.

The objective of this study is to find empirical equation for the determination of the estuaries displacements of Gilan Province’s Rivers، Iran. For this purpose، first، the displacement of estuary of each river was determined using the Geographical Information Systems (GIS). Remote sensing data and topographical maps of four different years were used in this study and the displacement of estuary of the rivers were determined by providing the estuaries map in those periods. On the other hand، the sediment transport rate of the rivers was calculated in different periods using observed sediment data. Correlation between the sediment concentration indices and displacement of the estuaries indices in Gilan Province’s Rivers were studied. Results show that the ratio of maximum sediment concentration to average sediment concentration of each river has high correlation with the transversal average displacement of the estuaries in each period. Examination of results show that variation of transversal displacement of rivers’ estuaries with sediment index can be investigated in three intervals. In the first interval، sediment index was 0-50، in the second interval 50-100 and in the third interval 100-150. The average transversal displacement of rivers estuaries in three intervals are about 15 m، 87 m، 286 m per year، respectively. This research shows that erosion and sedimentation management of watersheds، debris flood control and limiting the up-stream dams’ flushing play crucial role in estabilization of the morphology of Gilan’s estuaries.