IRANIAN JOURNAL OF WATERSHED MANAGEMENT SCIENCE AND ENGINEERING
Year:2015 | Volume:9 | Issue:28|Papers Count:9

Structural operations in watersheds, particularly check dams cost a lot. Therefore, it is important to evaluate their performance. To evaluate the performance of any project, one needs some indicators that can evaluate the overall performance of the project by assessing them. For evaluating of check dams' efficiency, one should evaluate in detail the influencing indicators. Indicators based on behavior of the nature and the efficiency of implemented measures. The purpose of this research is providing scientific and precise criteria for assessing overall efficiency of check dams and evaluating some series of check dams in Chaharmahal and Bkhtiary streams using these criteria. In this work, 12 streams are selected with Gabions and Stone- mortar check dams that are in operation within 1986-2011 and have the most diversity in design, dimensions and catchment conditions. Then, seven Criteria defined that affect group efficiency of check dams or relate to entire network like; spacing of check dams based on compensation gradient, type of check dam, use of existing material, minimal destruction in the site, fixed elevation of channel, coordination of reservoir volume with sediment deposited, and minimal flooded areas. The score of any item in these criteria computed based on introduced formulas. Then, all criteria weighted with paired comparisons questionnaire method. Finally using an optimized model in analytical hierarchy process, all understudy check dams were assessed. Results showed that the criterion" spacing check dams based on compensation gradient" was 0.297, and "type of check dam" was 0.168, have the most effect on group efficiency of check dams. Also, between studied waterways, series of check dams in "Marghmalek" and "Sorkhkooh" despite of their simplicity and being small get the highest scores (80%) and in fact had the best performance.

Use of flood distribution as a tool to reduce flood damage associated by optimizing the exploitation of floods to restore natural resources and environmental resources has been fashionable in many parts of the world. Considering the number of parameters identifying zones or areas appropriate for flood spreading plans, particularly aimed at feeding aquifers, the use of modern methods of production and new methods of synthesis and the decision making is inevitable. In this study, the Central Plains Khorramabad was selected as the study area. Method in this study is based on a hierarchical analysis process. The purpose of this study is the use of decision support systems and geographic information systems in order to achieve the appropriate places to distribute floods, and after identifying the criteria, indicators and sub-indicators associated by targets (based on the review of internal and external sources), the mentioned criteria, indicators and subindicators were weighted using the AHP and the priority of each criteria and sub-criteria was identified.The study includes four main criteria, 11 indicators, and18 sub-criteria. In this study, the weights of the main criteria were considered identical. The results showed that for 11 indicators, the highest and the lowest weight is related to physical damage index and aquifer parameters, respectively. For 18 sub-indicators in this study, the highest and the lowest weight is related to Sub-criteria of the flood event number and Subcriteria of water needed for industrial activities. Assessment of appropriate regions to distribute flood in the topographical viewpoints showed that most of regions occur in range of 1200 meters, in east aspect and in> 10% slope class. Results of region zoning to distribute flood showed that the highest and the lowest of the study area occurs appropriate and most appropriate class for flood distribution.

Integrated water resources management considers economical, environmental, technical and social aspects and also sustainability of water resources for future generations. Integrated water management implies cooperative approach and involves all stakeholders and also introduces issues to managers, decision and policy makers. Solving these issues needs integrated and system approach. According to the recognition of actors or key persons to apply cooperative management of water resources is essential. Therefore, based on stakeholder analysis and social network analysis, it can be shown that the most effective actors are environmental decisions. In this research, social powers accordingly are specified to social network approach at water utilizers’ level of Jajrood River in Darbandsar village of Latian basin. In this paper, utilizers of water resources were recognized using field trips and then, trust and collaboration matrix produced using questionnaires. In the next step, degree centrality index were Examined. Finally, geometric position of each actor was illustrated in the network. The results of the research based on centrality index have a key role in recognition of cooperative management of water resources in Darbandsar and also will help managers and planners of natural resources in the case of recognition of social powers in order to organize and implement sustainable management of water resources and water security.

One of the major natural disasters that caused tremendous damages each year in many areas of the country is desert, especially in Yazd, Iran. Strong winds and the formation of dust storms will take place several times each year. In this study, data from meteorological stations in Yazd (thunder storms, wind magnitude (size, amount), wind duration, visibility, fastest wind speed, average wind speed, prevailing winds and dust storms) in the period 1953-2005 were used on a monthly basis. In order to determine the most appropriate combination of neural network and input parameters (inputs) that influence the phenomenon of dust storms from Variable reduction technique of factor analysis (maximum likelihood, principal component), principal component analysis, stepwise progressive and gamma test were used. Each of the methods presented, each with a different combination of these compounds neural network feed Forward back propagation with the algorithm of Levenberg-Marquardt have been used. The results showed that the stepwise progressive R2=0.87 and RMSE=0.04 provides the most suitable combination for a neural network. Comparison of simulated dust storm phenomenon in seasons and months in different years showed that the phenomenon of dust storm in summer and spring seasons and months of April, May, June, July, August and September are different. In comparing the neural network feed forward back propagation models with algorithm of Levenberg-Marquardt and decision tree with algorithm CART, Neural networks with a correlation coefficient of 0.87 and the root mean square error of 0.04, the decision tree method with a correlation coefficient of 0.86 and the root mean square error of 0.06 has more carefully in order to simulate dust storm.

Snow depth is the most common parameter used for the assessment of water resources in the mountainous areas. Therefore, knowledge about spatial distribution of snow depth is the substantial knowledge of watershed characteristics. At present research, it was tried to estimate the spatial distribution of snow depth using regression kriging based on M5 model tree. Therefore, location of 216 points was selected systematically, and then snow depth was measured with a Monte - Rose sampler in Yazd-Sakhvid region.Then, 30 terrain parameters were derived from a digital elevation model using SAGA software. Our results indicated that channel network base level, stream power and wetness index were the most important parameters in decision-tree model. The correlation coefficient of 90% confirmed the strong performance of regression kriging model. Moreover, this method is very simple, so it is recommended the regression kriging model is being used to estimate spatial distribution of snow depth in other regions.

Before modeling the estimation of erosion and sedimention in order to select suitable criteria and indices, it is necessary to analyze factors affecting erosion. Based on the quantitative geomorphology model developed by the national specialists, the Analytical Hierarchy Process (AHP) was used to conduct the quantitative measurements of parameters affecting erosion. According to geomorphology, the hierarchical tree was developed consisting of six criteria: land cover, pedology, topography, land use, climate, geology, as well as ten indices: percentage of vegetation, growth forms, soil texture, permeability, slope, aspect, land use, type of precipitation, annual average precipitation, and lithology. When the weight and importance of each criterion and indeces were determined, the factors affecting erosion in Zonouz chai watershed were prioritized and the weighted erosion rate map was developed. Finally, it was determined that as compared to other factors, pedology and land cover had the priority weight by 0.896 and 0.51, respectively, in terms of impact on erosivity of Zanoz Chai watershed.

Flood is one of the complex and destructive natural phenomena that cause heavy damages every year.The factors of river routing and spatial location of sub-catchments are effective on catchment outlet flood.Hence for performing of flood control measures in upstream parts of great catchments, their effect on catchment flood must be investigated and sub-catchments were prioritized with respect to the contribution of these factors to outlet flood. Karaj Dam catchment was selected due to flooding for this study. In this research, geographic information system (GIS) and HEC-HMS hydrologic model were jointly used to investigate the contribution of each sub-catchment to whole catchment outlet flood based on SCS method.For this purpose, flooding potential of sub-catchments was prioritized using unit flood response approach in HEC-HMS. The results show that Tekyesepahsalar sub-catchment has the most contribution to whole catchment flood and Velayatrud sub-catchment has the least contribution to flooding potential.

Ab-bandans are the local and traditional water storage structures in the north of Iran which have always been regarded as the important source by farmers. Considering this fact that during the non-growth seasons a significant percentage of water of the streams, permanent and seasonal rivers fall into the sea. However, increasing the capacity of the Ab-bandans, one can store much more water in these seasons and use it in both increasing the production and substituting the rainfall land with irrigated ones. In this study, investigating the cost of dredging and improvement of 11 Ab-bandans during the 2009-2011 in the Alborz integrated land and water project area, the water potential has been measured economically. The results showed that the increase in the potential of water per cubic meter of water costs 1, 900 Rials.

One of the most important and widely used indices for drought monitoring, especially in our country, is the Standardized Precipitation Index (SPI). This index is the basis for drought definition and monitoring in most of studies. In this study, two procedures were used for the calculation of SPI. In the first procedures, with the hypothesis that the precipitation data follow the gamma distribution and in the second, using the optimum distribution, the SPI series in three time scales of 3, 6 and 12 months were calculated. In the next step, the t-student test was applied to consider significance differences in the results of two procedures.In three time scales, on average, the frequency of significant difference in the results of two procedures was maximum in normal class and thereafter, across the wet classes, extreme wet class and mild wet class and across the drought classes, mild drought class and moderate drought class, had the most frequency of significant differences. The results of the study showed that the calculation of the SPI based on gamma distribution give rise to the wrong diagnosis of the SPI classes. Then, calculation of SPI on the basis of the optimum distributions instead of blindly using of gamma distribution is proposed, in order to more accurate drought monitoring for the suitable management of drought.