IRAN-WATER RESOURCES RESEARCH
Year:2007 | Volume:3 | Issue:2 (8)|Papers Count:10

Dealing with Water Scarcity is one of the important problems in water resources management. There is no one of financial capability to execute all the water resources projects in one lot, so it is important to rank execution projects. In this study, one of the fuzzy multiple attribute decision making methods was employed for ranking some of the inter-basin water transfer projects, by using different criteria and modifying the Raj and Kumar method for both benefit and cost criteria conditions. The approach has been applied to the Karun river basin. For ranking alternatives, first criteria and their weight were determined and then 10 inter-basin water resources projects of Karun river with 8 criteria were considered. The weight of each criterion determined by 5 water resources experts. The fuzzy weights of alternatives are computed by using standard fuzzy arithmetic. The concept of maximizing and minimizing sets is used to compute the total utility of each of alternatives. Finally, the results of maximizing and minimizing method were compared to FDM software.

The water basin transfer project is an alternative for balancing the non-uniform temporal and local distribution of water resources and water demand, especially in arid and semi arid regions. A water transfer project can be executed if it can be economically and environmentally justified. In this study, this challenge has been investigated for water transfer from Solegan in the Khuzestan vicinity to Rafsanjan in Kerman. The environmental impacts of such a project on Karoon Rivers between the Gotvand Dam to Darkhoien are considered. Monthly water quality simulation was carried out and one year of observed data was used for model calibration. A multiple regression was performed to estimate river water quality variations based on the simulation results. The regression equations were used in calculating water quality and environmental costs imposed on the river by investigating the effect of the development plans with an economic based objective function. Then a mathematical model was developed to maximize the net benefit of interbasin water transfer. Costs and benefits including agricultural production, hydropower generation, dredging, physical construction costs, pumping groundwater and environmental costs were also considered. The optimization period is 23 years (the length of historical data); and the Genetic Algorithms is used to solve the model. Model output is the optimum flow rate of water transfer in each month. For real time operation, an Artificial Neural Network (ANN) model is developed. The results show that the high benefit of agriculture production in the Rafsanjan plain and the costs of decreasing agricultural production in Khuzestan plains are the governing factors.

One of the important inputs for a water resources study is rainfall. Choosing improper interpolation methods may result in extensive errors. Geostatistical methods may also fail to be used, in case of insufficient data. However, generated data has small errors that produce unequivalency in data. Using fuzzy set theory, every data (observed, generated value and obtained from an expert or imprecise) valuated by membership function. Kriging, Weighted Moving Average (WMA), Thin Plate Smoothing Splines (TPSS) and Fuzzy Kriging Interpolation is executed for annual rainfall in eastern and southeastern Iran. Two cases were studied. The first case generated the data for some of the points and fuzzified these points. In the second case, the number of the generated points is increased. Variogram analysis demonstrated spatial correlation between the runoff and the annual rainfall in the study area. Also, fuzzy variogram showed spatial correlation with larger ranges. The results show that the fuzzy kriging method is an accurate method in estimating monthly and annual rainfall. Increasing the number of generating points would however increase the estimating error.

In recognition of the need for effective and efficient methods for protecting groundwater resources from future contamination, scientists and resource managers have sought to develop aquifer vulnerability assessment techniques for predicting which areas are more likely than others to become contaminated as a result of activities at or near the land surface. This research is focused on the evaluation of Tehran-Karj groundwater vulnerability to pollution. Among several assessment methods, DRASTIC has been selected for this study. A major portion of Tehran’s drinking water is supplied from groundwater. ArcGIS has been used to overlay and calculate different layers and obtain the vulnerability map. In addition, groundwater balance has been evaluated in order to calculate the net recharge parameter in DRASTIC index. About 50 percent of the aquifer has been classified as moderate and almost 20 percent has low pollution vulnerability. The Boolean algorithm is usually used in categorizing the index but it is proved that using the Boolean algorithm causes the discrepancy in classification. On the other hand, fuzzy algorithm can produce more accurate results. Therefore, in this research, both Boolean and Fuzzy algorithms were used and compared together. Fuzzy algorithm could recognize the areas with low and very low vulnerability potentials while the Boolean model was not able to do so, therefore, the fuzzy model showed better performance. According to the developed map, most of the areas in the moderate class and very high class had the minimum area in the region.

The most important characteristic of a stepped spillway compared to other kinds of spillways is the high energy dissipation. The understanding of head loss, evaluation and promotion of energy dissipation are the basis of more research. In this study, a new step-pool formation is designed in stepped spillway based on natural high gradient mountain stream bed formation. Residual energy downstream of both the step-pool stepped spillway and the normal stepped spillway are measured in the hydraulic laboratory of the School of Engineering of Shiraz University.For new design, the experiments were made at two slopes, under six discharges and six step-pool configurations. Therefore, a total of 72 tests were performed. Based on this laboratory results, it was concluded that the step-pool (compound) stepped spillway caused an extra 30% reduction in energy dissipation compared to the simple stepped spillway. This result confirms the optimization of natural step-pool formation for stepped spillways.

In the present study western Iran has been regionalized based on 10 factors in 170 stations using principal component analysis (PCA) and Cluster Analysis (CA). In this way, all 10 factors were reduced to 4 principal components and then rotated using Varimax rotation criterion. Applying Ward’s Algorithm, a Hierarchical Cluster Analysis, on principal component scores, the stations were grouped into 5 individual clusters. The results indicated that the study area comprises of 5 distinctive homogenous subdivisions. Topography and latitude play an important role in determining boundaries between identified subdivisions and existence of spatial differences between them as well.

Beside their aesthetic aspects, mineral springs present sight-alluring-scenes in mountainous-environments. They are also gifted with blessings of therapeutic and healing qualities. In Iran, benefiting from and exploiting the curative aspects of mineral springs, has been in vague in the past. With all the scientific verification of the therapeutic properties of these mineral springs on one hand, and the geographical distribution of hot-water-mineral springs in Iran on the other hand, the performance of these mineral springs can, quite substantially, be improved through proper planning and competent management within the framework of the tourism industry.This report introduces and elucidates the geographical distribution of mineral springs in Iran and endeavors to state the existing stumbling blocks and to explore pertinent means for making better and greater use of such resources in the tourism industry.

Thermal stratification in prevents reservoirs oxygen to reach the bottom layers. In this study, the effects of upstream reservoirs in thermal stratification of downstream reservoirs have been investigated. This paper presents the results in two different conditions; single and tandem reservoirs.In single reservoir conditions, inflow to each reservoir is the natural river stream. In tandem reservoirs condition, the effect of each reservoir on downstream reservoirs is examined. Comparing the results of these two conditions explained the induced thermal stratification phenomena. This study is performed using HEC-5Q software.

One of problems that affects the hydro-installation and reduces the useful life of dams, is sedimentation in the reservoir, which is unavoidable. In estimating reservoir sedimentation and accumulation, a number of uncertainties arise. These are related to the quantity of streamflow, sediment load, sediment particle size, and specific weight, trap efficiency, and reservoir operation. To evaluate suspended sediments and bed load in some hydrometric stations, separating the field data into wet and dry time periods and total time periods are used. Harr’s method is used to quantify the uncertainty of accumulated reservoir sedimentation through time. To examine the importance of various factors on the uncertainty of accumulated reservoir sedimentation, sensitivity analysis was conducted. In this study, the effect of each uncertain factor, on the uncertainty of accumulated reservoir sedimentation through time has been examined for Shahar Chai Dam in northwestern Iran. The results show that in Harr’s method, the uncertainty of accumulated reservoir sediment volume is 0.384 in total time periods and 0.244 for wet and dry time periods.