JOURNAL OF WATER SCIENCES AND ENGINEERING
Year:2011 | Volume:1 | Issue:1|Papers Count:8

Determination of maximum rivers flow resulted from surface runoff in watersheds without adequate hydrometric records is based on rainfall-runoff models. The short duration rainfalls are one of the basic elements to apply these models. The access to quantitative and intrinsic worth storm data is restricted around the word and in Iran too. There are several empirical and statistical methods to estimate short duration rainfalls based on more common rainfall records such as daily and monthly precipitations. In this study the recorded rainfall hyetographs on Shahrekord station within Chaharmahal va Bakhtiari province were used to evaluate the suggested regional equations and SCS recommended curves containing ratios of short duration rainfall and 24 hours of maximum rainfall.The results showed that short rainfalls should be over estimated by both SCS curves and regional empirical equations. Although as the ratios method is easier to use, the SCS curves can be modified for each region by available storm data and used as an acceptable method. Results also showed that in order to apply Ghahraman-Abkhazar relationship for Shahrekord region, this relationship should be multipled by a correction coefficient of 0.7136. Finally a new logarithmic relationship was developed for estimating of the IDF for Shahrekord station.

Estimating maximum scour depth is normally required in order to determine the depth of bridge piles.The present paper uses the SSIIM Software which considers flow and sediment equations in a three dimensional manner. The software models flow field around circular bridge pile by resolving Navier-Stokes three-dimensional equations and k-e method, and by temporary solution of flow field and continuity equations variations of bottom levels around bridge pile was determined. In order to verify the results of the simulated model, they were compared with those of laboratory experiments. The results indicate that the model can be used with high accuracy to simulate scour and estimating scour depth around bridge piles.

This research was carried out to study the effect of deficit irrigation and saline water on yield and yield components of maize (KSC-500) during different growth stages for Ahwaz climatic condition in the farming years 2010-2011. This research performed in three independent experiments according to a randomized complete block design with split plot layout in three levels of irrigation water and three levels of saline water during three growth stages: vegetative (Experiment 1), flowering (Experiment 2) and after flowering (Experiment 3). Irrigation water treatments were I1=100, I2=75 and I3=50 % of crop water requirement and saline water treatments were S1=Karoon river water, S2=S1+1 and S3=S1+2dS m-1. The results of this study showed that the interaction of deficit and salinity irrigation water did not have any significant effect on factors (number of seeds per ear, 100-grains weight, grain yield, biological yield and harvest index) during all experiments but those factors decreased with increasing water and salinity stress. A maximum grain yield obtained from I2 in experiment 1 with 5.2 ton ha-1. A maximum GY obtained from I1 in other experiments with 5.8 and 6.2 ton ha-1 in experiment 1 and 2, respectively. Also, a maximum GY obtained from S1 in all experiments with 5.3, 5.5 and 6.7 ton ha-1 for experiments 1, 2 and 3, respectively. After the flowering stage was the most sensitive growth stage to water deficit and salinity stress.

Rivers are important as the main source of supply for drinking, agriculture and industry. However, drinking water quality in terms of qualitative parameters, is the most important variable. Studies and predicting changes in quality parameters along a river, are one of the goals of water resources planners and managers. In this regard, many water quality models in order to maintain better water quality management are developed. The artificial neural network models that are inspired by the structure of the human brain, as the best option will be investigated and evaluated. In this research was done on the Karoon River, the largest river in the country and using the parameters in the stations along the river (Shahid Abbaspur-Arab Asad reach). To this end, discharge, month, along river and electrical conductive in the measured in Shahid Abbaspur, Pole Shalu, Gotvand and Arab Asad station were considered as the input model and using neural network model, sodium adsorption ratio (SAR) and total dissolve salts (TDS) were measured in the same stations. Including those in this study as a new method has been used to determine water quality parameters are simultaneously at several stations. In order to optimize each of evolutionary artificial neural network models was used genetic algorithm. The results showed that chosen artificial neural network model to station non-linear regression model of skills, flexibility and more accurate in productivity water quality in rivers is capable.

Evaporation process, the main component of the water cycle in nature, is essential in agricultural studies, hydrology and meteorology, the operation of reservoirs, irrigation and drainage systems, irrigation scheduling and management of water resources. Various methods have been presented for estimating evaporation from free surface including water budget method, evaporation from pan and experimental equations that each of these methods is coupled with the restriction and measurement error. Early the new technique using Artificial Neural Networks (ANNs) based on artificial intelligence has been widely used in various scientific fields, particularly water engineering. In this study, the amount of monthly evaporation from the Siah Bisheh dam reservoir was forecasted up 3 next month using Multi-Layer Perceptron (MLP), Radial Basis Function (RBF) and Feed Forward (FF), of ANNs. The genetic algorithm was used for efficient input variables selection and number of neurons in hidden layer of ANNs. The results showed that the correlation coefficient between measured and computed outputs using RBF, MLP and FF models were 0.92%, 0.90% and 0.88% respectively in the estimation and forecasting of evaporation from the dam reservoir. Therefore the RBF model had more precision rather than MLP and FF models in the estimation and forecasting of monthly evaporation. The results of sensitivity analysis showed that the monthly evaporation from the dam reservoir up 3 next month had most sensitivity to the time of evaporation per month, air pressure on ground surface in 2, 3 and 1 months ago, wind speed on 1000mb pressure in 3 and 2 months ago and air temperature on 300mb pressure in current time respectively.

Bottom intake is an intake structure which can be considered as an alternative for regular intakes in mountain streams Water in in taking from river are very vast and complicated issues, each project has special characteristics which should be considered. Water intake from river is generally based on Pump and gravity method. The gravity method is more useful and common because of continuity and no need spare energy rather than pump method. The different methods are possible at gravity methods these methods are divided in to three categorize: side in take, front structure and bottom structure.According to the recent experiences at countries for maintain region, when longitude slope is more than 1% and 75% of bed load is particles with size more than of mm (D50>6mm) bottom in take are recommended generally. Hydraulic analyses of this type of structure are not studied numerically. In other side of Cain, building and studying physical model of this type of structure are very difficult tasks. In this research, flow simulations of bottom in take are done using the flow 3D software. As a result, it's conducted that best Slope for intake net is degree and when opening area. Increased directed discharge increase directly. Finally it's driven that when Froude number increased opening percentage, it May caused reduction of flow coefficient.

Water resource limits, missing a developed irrigation program and undesirable water quality are the basic parameters that affect agricultural development of Iran. This research focus on irrigation amount water and its duration in other to increase crop yield of potato on Hamadan-Bahar plain. To this regard, there potato farm located on different area of the plain were selected during agronomic year 2011. Consumption water amount (W) and crop yield (Y) were measured in order to calculate the water use efficiency (WUE) of the farms. Based on the measurements, the minimum and maximum used water amount in the plots farms were 4481, 7500 m3/ha. The related values in the control farms also were 5092 and 8279 m3/ha. The results showed that potato yield significantly was increased (13%) by training of proper planning program of irrigation. This increasing yield resulted decreasing (13.1%) on using water content and increasing of water use efficiency (29%) in all farms of the experiment. The farmers training also showed that tensiometer is a simple and favorite instrument for water measurement compared with gypsum blocks.

Soil correction is one of the ways in agriculture lands development. The sodic ion alongside salin vocalizes the salin-sodic soil and cause divulge in plants growth. So necessary coure of action for the Soil correction by physical and chemical ways such as usage of calsium on the leaching is inevitable.In this study, area soils are digged from deep profiles of 0-20, 20-40, 40-60, 60-80 and 80-100 cm and samples were prepared for proceeds and analysis in the laboratory and calculated values of ECe, SAR, ESP, CEC and etc and chemical and physical properties was discussed. The test experiment method were conducted by randomized complete block design with two treatments (control, gypsum) and 3 replicate plots metal 1*1 m. Amount of water needed for leaching rate of 100 cm and 5 levels (each level was 20cm) were determined. After each step, the samples were taken in the four set of determined depth and experiment was conducted. The study results and their statistical analysis show that gypsum material has not effect on the reduction of amendment SAR, ECe and ESP of soil. This can be due to the solving gypsum of soli as a result of water infilteration in the soil. It is recommended to improve saline and alkaline soils region to neutralize the effect of high sodium lands at least two preliminary rounds will be conducted with salt water (agricultural Drainage).