JOURNAL OF WATER SCIENCES AND ENGINEERING
Year:2012 | Volume:1 | Issue:3|Papers Count:8

Water deficit is one of the most important difficulties, in which happes in dry zone and half dry zones.Water deficit, as the determinative factor, determinates the growing and extension of the plant cover in these areas. Using the supper attractive, may reduce the production in the crops and control the plant cover in face of dry stress and water deficit. In this paper, the effect of supper attractive stockosorb on the irrigation interval, number of irrigation time, content of utilizable water for the one growing interval, efficiency of water use and seed practice in the surface unit and practice elements were studied.In this paper four cares were studied, including: instance care, full irrigation (in other word 4 to 5 days) (T1), under irrigation in which is after the 75% outlet of moisture field capacity (T2), under irrigation by using the supper attractive (T3), and the last care is under irrigation with supper attractive and solution propagation (T4). In irrigation level practises, irrigation for the instance was done when 50% of field capacity was outlet. For irrigation deficit practices, 75% discharge of FC moisture was the base of irrigation deficit. More over this study showed that grain practise, number of grain range in corn, biological efficiency, stem diameter, and weight of thousand again in 5% surface were meaningful. Moreover, biggest use of water is belongs to care of T4 and the lowest use belongs to care of T1. And this paper showed that in order to use this supper attractive polymer not only increase function of product efficiency but also increase the function of water using.

In this study, leaching experiments were carried out by both continuous and alternate ponding methods in the south of Khouzestan province. In equal applied water leaching, alternate ponding leaching model had a better performance than continuous ponding method in desalinization and dealkalization.In term of alternate method, there was not ayn difference between 5 and 8 day periods in one-meter depth. Even though the trends of desalinization and dealkalization showed a slight difference, particularly in early stays, the figure of two alternative methods were the same, finally. Obtained results were compared with the results of other researchers experiential models. Comparison of desalinization field experiment results and models result’s showed that Dieleman model a relationship based on experimental and theoretical opinion had a better performance than the other experiential models. The performance of this model in alternate ponding method was better than continuous ponding method. More ever, based of soil analysis results, due to enough amount of calcium in soil after leaching, there did no need reclamation materials.

Analysis of seepage and stability is considered as an important case in designing which today, with advanced numeric software acceptable results will be obtained before and after Construction. In the present study, the behavior of earth dam against effective factors was investigated by software Ansys12. The studied dam is Maroun soil dam, which is located in 19Km north of Behbehan and constructed on Maroun River. This dam is soil- gravely dam. It was tried in this research that stability of dam be evaluated by finite element method and Ansys software, and then compare by software results like Geo-studio. At first Following, the stability of dam slope was considered and the behavior of dam was stimulated by several methods and there were relatively same results for the amount of safety factor and unstable surface. Safety factor was 4.21 for upstream by bishop method in Ansys and 4.71 in Geo-studio and for downstream 1.5, 1.8, respectively. Finally, the maximum and minimum amount of tension was determined by analyzing tension, strain and movement and the areas with different sediments and possible cracking and subside regions were determined. In this part, both softwares provided relatively same results and the maximum amount of movement in dam estimated 5-6 meters. However, both softwares are best ones in analyzing and finite method and completely correct introducing of current conditions could have acceptable analyses.

Soil and water resources management of rivers has an important role because of direct relation with different systems such as earth, life, social and people. Although the use of vegetation cover in bioengineering and biological stabilization and also soil and water resources management projects has many advantages, but improper methods of design and implementation cause hydraulic specifications of river alter. The vegetation cover in river reach decreases flow mean velocity, river's width and increases sedimentation in river bed and therefore discharge capacity be reduced. In this paper, we will investigated different projects of retrieval vegetation cover and bioengineering in Shiraz Khoshk River as an influential element in Shiraz city and their effects on hydraulic specifications of river. Also, advantages and disadvantages of bioengineering and biological stabilization projects of the river are discussed. Also problematic river reach caused by improper biological stabilization was identified and the inappropriate implementation effects of vegetation cover on increase of hydraulic roughness coefficient and reduction of discharge capacity were investigated. Based on results, although erosion rate of Khoshk River’s banks in sections without vegetation cover was more than sections with vegetation cover, sometimes vegetation cover caused a significant increase of hydraulic roughness coefficient and significant reduction of section area and discharge capacity. The Khoshk River’s sections such as upstream and downstream of Chamran Boulevard Bridge, upstream of Ghadir Bridge and downstream of Fazilat Bridge were analyzed by HEC-RAS. In these sections for stream flow values of 100 to 250 m3/sec, reduction of 10 to 28.5% was obtained.

Drought is one of the most serious problems arising for human societies and ecosystems from climate variability. This phenomenon causes billions of dollars in global damages annually and affects more people than any other form of natural disasters.In this study, the trends of rainfall and meteorological drought time series were investigated at ten stations located in the east of Iran for the period of 1966–2005. Amounts of drought severity were computed using standard precipitation index (SPI) for a 12-month time scale. The trend analyses of the data were also performed using the Mann–Kendall test and the Sen’s slope estimator. The results of this study showed that the rainfall and drought data had high variations to average values in the study period, and these variations increased with increasing aridity towards the east of the study area. The results of the trend tests revealed statistically significant decreasing trends in the rainfall time series of Sar-Pol-Zohab, Bijar, Sanandaj and Saghez stations at the rates of 7.99, 6.68, 5.51 and 5.03 mm/year, respectively. Furthermore, drought severity significantly increased at Kermanshah, Saghez, Sanandaj and Khorram-Abad stations during the last four decades. The results indicated that all of the stations experienced at least one extreme drought during the study period.

Building of Dam from thousands of years BC was known, and the humans with use of them always try to preserve and utilize surface water resources, but sedimentation problem always is the most important factor in shortening the useful life of dams, and a lot of reservoirs were filled by sediments due to this process and therefore most of dams have been abandoned. One of the most important phenomena that affect sedimentation is density current. Research must be continued to recognize the role of this phenomena in sediment process. In this research the effect of changes in parameters such discharges, concentration and slope gradient in density currents were investigated in the converging channels. Experiments were carried out in a flume with changeable bed slope, width 72.5 cm, depth 60 cm, Length 6 meter, three convergence angle, three discharge, three concentrations and three bed slope in laboratory models of hydraulic of Shahid Chamran University. The results showed that increase of discharges and slope gradient will increase water entrainment and increasing of concentration will decrease it. Finally an equation is presented for water entrainment in each convergent angle.

Characteristics and behavior of the flow in hydraulic structures, a complex phenomenon that is imperative to use software that will beto be study. Gabiony stepped spillway is a simple hydraulic structures to control erosion downstream of dams, and, depreciation of structures is used. Rough stairway consisting of overflow from the stairs near the crest of the weir is started and continues to have a lower heel. Research shows that the rate of depreciation of energy in Spillways stairs of the flat (no stairs) has the same size. In this study, the ratio of width to length roughness (b / h) was equal to 0.25, 0.5, 1, and three-positions height roughness and three-state roughness height to flow 220, 4 (lit/s). In the nine-step model with a height of stair 0.1 m and 21-degree slope was investigated and the roughness effect on the distribution of power and the creation of the vortex on the stairs of a stepped spillway Gabyvny was down by Flow-3D software. This research showed rough results in the flow range 0.004, 0.009, 0.01 (m^3/s) by the nappe regime to collapse and from flow 0.016 meters per second to the higher flow is a skmming flow regime. Most energy-related depreciation in the flow 0.016 with 79.5 Percent Energy depreciate and Depreciation less energy to flow 0.22 (m^3/s) with 20.4 Percent of energy is depreciate.

Information on chlorine concentration in groundwater for drinking and agriculture is important. If the concentration of this element is in too much water can cause problems for humans and is toxic to plants. Measurement of chloride in groundwater is extensive, costly and time consuming. Find easy and inexpensive method has a special importance. the Statistical methods are based on spatial variables. Changes of these variables point to the other have a certain continuity. This study for evaluation the ability of geostatistical methods for estimating chlorine using auxiliary variables Electrical Conductivity in groundwater of Mashhad and the surrounding was conducted. For this purpose, 276 wells were sampled and Parameters were measured electrical conductivity and chlorine.The data with software GS+ were analyzed. To determine the spatial correlation of data, Variograms were calculated and plotted. The results showed good continuity exists between the measured parameters. The correlation between two variables based on the variogram, 0.91 Was calculated.Spherical model for Electrical Conductivity and Gaussian model for chlorine based on the minimum amount of RSS as the most suitable model was fitted to the data. For Comparison of methods estimation of the root mean square error (RMSE) and plot of observational and estimated values were used. Geostatistical methods, the chlorine more accurately than IDW and NDW methods were estimated.