IRAN-WATER RESOURCES RESEARCH
Year:2011 | Volume:7 | Issue:3 (21)|Papers Count:9

Water resources are among basics for sustainable development. The non uniform temporal and spatial distribution of water resources is led to shortage water in arid and semi arid regions. The inter basin water transfer projects are one remedy to this problem. According to the diversity of the feasible water transfer projects, ranking of the projects with different criteria is currently one of the important issues in water resources management. Fuzzy Multiple Criteria Decision Making (FMADM) is a collection of methodologies which can be used to compare, select, or rank multiple alternatives that typically involve incommensurate attributes. The aim of this research was to use some of the fuzzy multiple attribute group decision making methods for ranking some inter-basin water transfer projects of Karoon River, western Iran. Maximizing and minimizing sets method, the Bonissone’s method for group decision making, Fuzzy TOPSIS for group decision making, and Fuzzy Decision Making software were used in this study. A set of 10 interbasin water transfer projects with 8 criteria were considered. First, the weight of each criterion was determined within a group of five water resources experts, Then the rating preference for each alternative were obtained by the same group of experts. Finally, the results of different methods were compared. The results showed that the Tunnel Koohrang 1 posses the higher rank. Also, the Spearman rank correlation coefficient was obtained between different methods. The results showed that the Fuzzy TOPSIS and Bonissone method provide the best correlation. For evaluating the criteria weightings, the sensitivity analysis was conducted and the results were compared.

Eutrophication is one of the main environmental problems in dam reservoirs which affect the availability of water with suitable quality. Effective management and control of such phenomenon in a reservoir may support by implementation of low-complexity simulation models employing the most effective water quality parameters and processes. System dynamics (SD) is one of object oriented simulation tools that is able to simulate the eutrophication process in a reservoir according to the systemic approach and with emphasis on the causal relationships and feedbacks. In this paper, a system dynamic simulation model for phosphorous concentration of the Satarkhan reservoir in Eastern Azerbayejan Province, North-western Iran, has been developed. In this model, the phosphorous has been considered as the main factor of eutrophication. Also the interaction between the phosphorous in the reservoir and the bed sediment has been considered with monthly variable coefficients of phosphorous burial in sediments. Sensitivity analysis were made on the coefficients and calibration and validation of the model have then been achieved based on a 47 month period of data. Results showed an acceptable reliability in simulation of phosphorus concentration despite the simple assumptions used. Fractions of the phosphorous in the input, output, sediments, and the reservoir showed the significance of sediments in phosphorus concentration equilibrium. Analysis of scenarios regarding the reduction and increase of input load to the reservoir also showed that the impact of phosphorous input load reduction is at a smaller extent effective which should be considered in nutrient load management in the watershed.

In this paper, an optimization model has been developed for computing the optimum sizing of a combined structural flood control system. The combination of a dam and a levee has been considered in this study without losing the generality of approach for other structural combinations. Compared to the previous studies, this study uses less simplicity assumptions. For example the geometry of the river and the levee were considered with more details and the levee were considered non-symmetric along the river axis. The optimization problem formed a large-scale nonlinear model with the objective to maximize the expected annual net benefits of the developed system, to result the optimum design return period (i.e. design flood), as well as, the optimum size of the system components, such as dam height, spillway dimensions, and levee’s height and setback. The Tang-e-sorkh River and the flood control system (under study) in Shiraz, Iran, have been selected as a case study. The model solution proposed a combined dam and levee system, with a design return period of 1000 years.

Snowfall is one important form of precipitation in hydrology cycle in mountainous basin which plays reliable role on agricultural and domestic water supply in low and high flow seasons as well as on energy production. The main objective of hydrological modeling in watersheds is the better understanding of the hydrology cycle including governing processes in water cycle. Snow covered area is a basic parameter in global hydrology cycle and climatology. In this research snow melt runoff was simulated in Karadj dam watershed, using SRM model in water year 2001-2002 and validated for water year 2002-2003. SRM, a degree-day model which simulates snow melt runoff, needs 14 parameters and variables. These include rain, temperature, discharge, daily surface of snow, recession curve, snow and rain runoff coefficients, and degree-day factor. Model also needs physical parameters such as elevation boundary. Temperature and rain were distributed using gradient equation in elevation boundaries. Also physical parameters ofthe watershed were added to the model using geographic information system. The R2 and the deviation of the runoff volume in 2001-2002 were calculated as 0.4678, 0.1292%, respectively. These values for 2002-2003 are 0.935, 6.7736%, respectively. SRM model can effectively be used to modeling of snow melt runoff.

The output of an ensemble for country-wide daily precipitation probabilistic forecasts were calibrated with two models of WRF and MM5 with respectively 5 and 3 different configurations. The cumulative precipitation of 257 synoptic stations in the country has been used from 1st of November 2008 to 30th of April 2009. These data have been divided into two three-month periods which has been used for training and evaluating. The ensemble’s rank histogram in training period, has been divided into two sets with the standard deviations of (0<s<0.45) and (s>0.45). Finally, daily precipitation forecast has been calibrated for thresholds p£0.1, 0.1£p<10, and p>10 millimeters at each day of the evaluating period. This was done by means of the rank histogram produced by training period and probabilistic precipitation standard deviation in the same day. For different verification tools it has been shown that calibration with rank histogram leads to an improvement in probabilistic forecasts of daily precipitation (especially in heavy precipitation categories).

The Muskingum-Cunge method is still frequently used for flood routing. During the last decade different modifications were proposed for this method to increase its accuracy. However, difficulties arise in the selection of an appropriate ‘‘reference’’ discharge for evaluating the routing parameters and in the small volume loss that can occur. In this research in order to study the applicability of the different schemes of the Muskingum-Cunge method in field conditions, some observed flood events of Karoon River, Western Iran, have been routed by these schemes and the results were compared with that of the observed values of the downstream end of the reach as well as outputs obtained by the dynamic wave model. The results indicated that the studied schemes generally provided reasonable output in comparison with the observed hydrographs. Also the discrepancy among the results of these schemes was not significant. In addition, the computed results reasonably concurred with that of dynamic wave model. Finally, the sensitivity analysis of computational grid size is performed. The results showed that the effect of changing the time step rather than the space step is bigger on the output of models.

In This paper a Lagrangian model is presented based on weakly compressible SPH method used for simulation of free surface flows with violated changes in free surface. Dam break in a closed tank was simulated here as one of the main test cases for validation of the free surface flow model and its results were compared with the experimental data, analytical solutions, and previous numerical results. Also, in order to study the effects of viscosity, the shear flow between two parallel plates (Couette flow) and shear cavity flow are modeled and the results were compared with the available analytical and numerical results. All comparisons showed the power of the developed model in modeling free surface and shear flows.

With respect to the critical circumstances of watering resources in Mashhad and other cities of Iran and also the importance of reasonable consumption of fresh water which is used in large amount in watering cooler in warm periods, we intended to examine the rate of water usage by watering cooler in iwo condition of sunshine and shadow. Two watering cooler were fixed in the same environmental and physical condition. The first cooler was under the shadow of light roof the second one was in free access to the sunshine. Temperature and the moisture levels measured before and after examination in both condition and the water usage was evaluated too. The result showed that water usage of the cooler in the shadow was more than 10 percent lower the other one. Although the temperature and the moisture levels was the same in both conditions but these parameters’ levels were a little more in the cooler which was in shadow.

Delineation of the wellhead protection area for drinking water wells is an effective method to manage and protect water supply resources. The current study focused on the effects of the aquifer's hydraulic features on the shape of each well's protecting area and the capture zone. A mathematical simulation is performed for YaftAbad district in Tehran metropolitan area using the data for 24 drinking water wells. Based on the results, the hydraulic gradient around each well and the hydraulic conductivity of the aquifer, among other parameters, have a direct correlation with the length of each well's upstream length. Also, both the aquifer's effective porosity and thickness, has an inverse correlation with the size of each protection area. The study showed that the convergence of groundwater flow lines around each well causes the well to receive same amounts of water from around itself that leads to a symmetric shape of wellhead protection area.