مجله مهندسی آبیاری و آب ایران
پیاپی 7 (بهار 1391)

Water as a symbol of life، the most important gift that nature has، Considering the importance of this matter is in arid and semi-arid climate than other regions، Therefore، measures should be used for the management of this liquid of life، can be taken to bring the critical conditions in these areas will prevented، Desertification after two challenges of climate change and lack of fresh water as the third most important global challenges in the 21st century will be considered، Desertification is a process that includes both natural factors of luck and human performance are inappropriate. Thus the process of desertification is growing that this phenomenon affected by many factors including the loss of underground water and its salinity، The crisis in many areas of our country can be seen in many areas of natural resources and agricultural use of inappropriate and lack proper management of underground water have been turned into desert، This study examines the role of underground water and the intensity maps by desertification indexes ground water level depth، CL index، EC، and SAR index، shortage of water resource، falling underground water table level (cm / year) to review and determine the class severity of desertification in each of the units were paid for work، The final score of each work unit of the geometric mean of each indicator was determined and each of these units in terms of severity of desertification from the perspective of class criteria groundwater classes low، medium، severe and very severe has been، In this study 41/37 and 59/62 and the percentage of land surface area، respectively، in the classroom and very severe desertification are severe.

During the last decades، because of incorrect using of natural resources، the degradation rate of watersheds soil and water resources has been increasingly grown. Furthermore، while this issue intensifies floods occurring، increases sediment production rate and decreases useful life time of dam reservoirs، it has provided the causes of decreasing the country national investments and products. This research which has been done in Heydarie watershed with 112 kilometers area in Charmahal province، deals with evaluating of mechanical operations impact on the watershed behavior in decreasing flood and flooding potential. The work method is on the basis of field investigations results and also on recording the physical and spatial characteristics of built buildings. In the next stage، using SCS model and simulating the watershed flood، the effect of buildings on the watershed flood and runoff control has studied. The results show that the built buildings with volume about 13067 m3 in addition to store runoff and to impact on percolation of runoff flow is also capable of controlling the flood with time period of 50 years. The analysis of output data resulted from SCS model in normal conditions and statistical comparison with simulated flood data along with watershed operations indicates that in percent level there is a meaningful difference among data. Also، using the research results، an equation has been proposed to estimate the required numbers of small dams.

Drought is one of the most important phenomena in environmental and climatic changes is an integral part. Reversible phenomenon and an inevitable reality in the arid and semiarid climates lack of rainfall that occurred in a period and can affect large parts. Influential variables in determining the hydrological drought and relationship variables as the most important coping strategy are consumption losses due to drought. Analysis of the applicable principal components factor analysis and multivariate statistical methods to analyze data. Due to the large variety of variables affect the hydrological drought، this study introduces an important variable that had the main role، and determine the effectiveness of each of the research necessary to find them. For this purpose the data for 25 hydrometeric stations located in Lorestan province in terms of geographic distribution and diversity of an area within a thirty-year period (59-1358 to 89-1388) were considered. Physiographic area using data from topographic maps and then factor analyzed 15 variables measured in the selected areas was performed with SPSS software. The study also uses the main component analysis and linear structural relations by LISREL software، and how the relationships of the variables were analyzed. The final model، reflecting the positive impact of each component of the study variables، which، respectively: average rainfall، drainage area and has the highest density levels influence the incidence of hydrological drought in the region are studied.

Shahr-e Babak’sDasht-e Robat is one of the important areas prone to cultivate pistachio in Kerman province. In the past three decades، the excessive use of groundwater resources، high evaporation، and recurrent droughts have caused the poor quality of irrigation water. Irrigation of pistachio gardens with saline waters has adverse effects on soil properties and yield of pistachio. This research has been done to examine the effect of the use of irrigation water with different quality on the characteristics of the cultivated lands and yield of pistachio. First، 16 water source with different quality were sampled by evaluating the results of the analysis of irrigation waters and soil maps; and some profiles were also digged، described and sampled in the gardens. In addition، managerial questionnaires were provided for the gardens studied. The results show that the chemical properties of soil are more influenced by the quality of irrigation water، compared to physical parameters and fertility Studies showed that with increasing salinity، more than 10 dS/m is much reduced performance. West Plains، so the performance is very low and some orchards have been abandoned. Soil salinity in the West region of the higher 30 dS/m. Greatest accumulation of salts in the second and third layers were observed. The yield per unit area from East to West Plains، but much lower salinity، sodium absorption ratio، anions and cations is increased and exceeded. So in pistachio orchards and leaching of soil salinity management isessential

The effect of internal and external forces on the transmission and distribution networks of potable municipal water makes more problems in the Iran water and waste water Corporation. Therefore، analyzing loaded forces is very important. Pipe insertion in the trenches، the channel filler material tend to have subsidence because of its reload and the channel subsidence on its bed causes trenches and the soil column above the channel move downward compared to adjacent undisturbed soils. The mentioned phenomena and its modeling are not considered along with many water pipeline designs. Thereafter، the current case study is presented. In order to evaluating this research، the data of flexible steel pipeline with large diameter is gathered from Mashhad Abfay company and its modeling is done with 5 atmospheres internal pressure in Ansys finite element software. The more credibility is satisfied with selecting the current elements of Ansy’s Plane 42 and Plane 82. The output results showed 8/5 mm mean subsidence in the pipe and also 5 cm in the asphalt surface. Amount of subsidence in the element Plane 42 was about 0/6 mm less than average. Subsidence process was similar in both elements and was in accordance with the assumptions. In one hand، Plane 82 element was found that due to damping by considering the characteristics and volume of soil، more efficient than other element in determining the substrate deformation behavior and around the tube and on the other hand، the flexible pipes are tolerant to deformation and its preventive force against to stress concentration is higher than rigid channels.

This study investigated the determination of sediment thickness and depth of bed rock below the plain of Kerman، by existent available data. The research methodology is collecting of rough information and plot of section and plans ana analyzing the results for determining of bed rock depth and thickness of deposits. The used information are as follows: The result of some of 5000 electrical sounding line with AB equal to 1000 and 2000 m in 35 profiles (General Geophysics company 1343 and 1344). Excavation of 8 discovery well in different areas in Kerman plain (Hydra company 1343). Using the groundwater model has been developed for kerman plain (Ahmadi Afzady، 1381)، The geological sections that plotted on geological map of Kerman sedimentary model (Consulting Engineers of Water Resources، 1385). Results of studies show that the thickness of the sediments according the Excavation of discovery well is about 230 meters. In general the depth of the bed rock، except for the South East region and the central part of the plain that is about 250 meters، in other regions is between 130 to 150 meters. But the seismic studies indicate the existence of a deep basin in the West of Kerman and in the Taherabad region. The bed rock thickness in these areas has also been reported to 350 m. therefore the variety of sediments thickness in Kerman plain is between 30 to 350meters.

In the recent years، using GIS is considered in different field، including ground water researches. At present، this technique is wildly applied in modeling and zonation of ground water resources due to high efficiency، economic reason and saving time. In this research، GIS method has been used for the assessment of ground water resources in Quchan - Shirvan plain by using two quantity models which developed by Kamaraju et al. (1996) and Krishnamurthy et al. (1996). For this purpose different maps such as slope، topography، drainage density، geology، soil type and geomorphology maps are provided. The assessment of the mentioned methods was done by calibration the models based on the discharge rates of the available data from drilled wells in the study area. The result shows there is a good agreement between the well discharge data and the Krishanamurthy method. It seems that the main reason for this agreement is that the data using in this model is more than the data using by the Kamaraju method. In this paper quantity map of ground water resource is provided by using the Krishanamurthy method. This map shows that the best potential of ground water sources can be found around Farouj city.

Due to the low number of hydrometry stations in Iran and the lack of continuity of sediment smapling and measuring in many existing stations، on one hand the exact amount of sediment load in many rivers in the country is not available and because of differences in climatic، hydrological and topographical conditions in the country، on the other hand، the preparation and calibration of sediment rating curves for different regions، is unavoidable. The current study was therefore carried out for preparing and improving the accuracy of the suspended sediment rating curve in hydrometry stations located on Telvar and Cham Shor Rivers in a part of the Sefidrood Watershed in Kurdistan Province. To achive the study purpose، sediment rating equation was used as a base equation and then the data were separated using effective factors on sediment transport including hydrological and climatic factors. The models were then extracted from the data series and finally 12 statistic indicators were applied to select the optimal models. The results showed that the M6-9 model (based on separated data considering high/low flows and hydroclimatic seasons) in Hasan Khan and Shadi Abad Stations and the M9-4 model (based on separated data considering hydroclimatic seasons and classified flows) in Dehgolan Station were selected as the best models. The suspend sediment loads based on total and optimal models were estimated by an average 73. 32 and 34. 20% lower than observed values in three studied stations. Referring to the results، the data set separation for different conditions of precipitation and flow leads to data homogeneity to the extent required to preparing sediment rating curve with a higher accuracy. Results also confirmed that the natural delays in rainfall and flow conditions with the complexity of temperature and vegetation، causes the data separated into hydroclimatic seasons may be more effective than those separated into the main seasons on increasing the accuracy of sediment rating curves.

The hydrological variables estimation is very important for safety of hydraulic structures and facilities، surface water resources management and planning. The streamflow measurement as one of the important hydrological variables has various limitations. For this reason، application of the hydrological models with available and easily measured variables is the important and necessary approach. The aim of this research is the possibility of available climatic variables e. g. precipitation and temperature for seasonal and annual discharge estimation. Data of precipitation، temperature and discharge related to upstream watersheds of Boukan reservoir dam were used for 16 years period during 1993-2007 in this study. Multiple and stepwise regression models were determined in annual and seasonal scales for each watersheds using SPSS 17 software، then calibration and validation of each models were examined. Root mean squared error (RMSE)، relative error (RE) and efficiency coefficient (CE) were used for models evaluation. The results showed that the most models performance was very good and stepwise regression has more accurate results than multiple regression. Also، the RE، RMSE and CE range criteria were changed between 20. 96 to 44. 69 and 22. 80 to 81. 11 percent، 0. 37 to 7. 37 and 0. 05 to 7. 53 m3 s-1 and 0. 7 to 0. 94 and 0. 31 to 0. 92 for annual and seasonal scale، respectively. Ratio of precipitation influence on discharge was very low in summer in comparison to other seasons because annual model will not be accurate for estimating discharge in summer.