مجله سامانه های سطوح آبگیر باران
سال چهارم شماره 4 (پیاپی 13، زمستان 1395)

In recent years, rainfall reduction and the occurrence of drought phenomenon has exacerbated the quality changes of Zeydon plain groundwater. Therefore, this study was carried out to evaluate the rainfall fluctuations on the quality of groundwater and to improve the utilization management and optimal utilization of groundwater resources. In this study, sampling of the water resources of Zeydon plain was performed in two stages in order to study the quality of Zeydon plain groundwater and assess the role of rainfall in the qualitative results of these resources. First, 10 samples of water wells in April 2012 as the rainy season and then 10 samples were selected in September 2012 as the dry season. Finally, it was concluded that in terms of quality along with the rainfall, the concentration of groundwater ions and salts in this plain is increased, which means that during rainy years along with the rainfall, the quality of the aquifer groundwater is getting worse. Based on the obtained reviews, the increase in the concentration of ions during rainfall in Zeydon aquifer is due to the presence of Gachsaran, Mishan and Aghajari formations in the north of the plain and the high groundwater level in some areas, especially in the center of the plain.

The most intractable climate parameters are precipitation Change and variability in precipitation studies are really significant, and they have an important role in climate prediction In order to review low and high rainfall patterns, a data base of rainfall has been formed initially in the northwest of Iran. Then a 30-year period, monthly, were selected for the present study from 1984 to 2014, and cells dimension of 10 × 10 km were created in study area. The modern methods of spatial statistics such as spatial autocorrelation global Moran and hot spots were used in order to achieve changes of seasonal precipitation in the northwest by GIS software. The results of this study showed that the spatial distribution of rainfall in northwest of Iran has a high cluster pattern. In the meantime, according to global Moran index and hot spots, precipitation patterns has a positive spatial autocorrelation pattern (high rainfall pattern) in the northwest and northwest, west and southwest region, and parts of the northeast, northwest and southwest region has a negative spatial autocorrelation (low rainfall pattern). In most cases during the study period, a large part of the region, almost half of the total studied area had no significant pattern of spatial autocorrelation.

Initial soil moisture content has an important role in soil water infiltration, therefore the values of infiltration and the coefficients of infiltration models are not similar in different initial soil moisture content. Single and double ring methods can be used for infiltration measurement. In this study, 24 infiltration experiments were used based on single and double ring methods in different initial soil moisture content to evaluate the values of cumulative infiltration and infiltration rate. The experiment was done on a soil sample with silty clay loam texture, and the model of Kostiakov was used for fitting the measured infiltration data. Also, the coefficients of the Kostiakov model were determined for all single and double ring experiments, and then the relationships were derived between the coefficients of the Kostiakov model and initial soil moisture content. Furthermore, the relationships were derived between infiltration rate in 180 minute and initial soil moisture content, and between cumulative infiltration with double ring method based on single ring method. For these purposes, 17 experiments were used for calibrating the relationships and the other remained 7 experiments were used for validating the results. The results showed that the values of cumulative infiltration and infiltration rate were higher in all 24 experiments with single ring method than double ring method. Also, the results demonstrated that the obtained relationships for estimating the cumulative infiltration with double ring method based on single ring method are appropriate

Water shortage in arid and semi-arid regions has caused development of specific measures for utilization of floodwater by farmers of these regions, which Bandsar is one of these measures widly used in Razavi Khorasan and South Khorasan provinces of Iran. In this research, the effects of flood harvesting on Bandsar’s soil organic mater as well as texture has been evaluated. For this purpose, 5 sites were selected in the research area in south Sabzevar. In eatch site, three soil profiles inside the Bandsars and also three soil profiles outside the Bandsars (as observation plots) were excavated with 60 cm depth, and soil samples were collected from depths of 0-20 cm, 20-40 cm and 40-60cm. totally 90 soil samples were transported to the laboratory for analysis and measurement of organic mater content, and also sand, silt and clay percentage. The results were analysed using SPSS software. Results show that the percentage of organic mater inside the Bandsars is greater than the related outside plots, and the difference is statistically mraningful. The highest values of organic mater is 1. 75% and belongs to inside Bandsars in site 4, and the lowest values of this parameter is 0. 48% measured outside of Bandsars in sites 2 ansdd 5. The highest value of sand is 82. 32% measured outside the Bandsars in site 2, but the highest value of silt (52. 86%) belongs to inside the Bandsarsin site 4 and also the highest percentage of clay (52. 93%) was measured inside the Bandsars in site 5. Overally, Bandsars have increased the organic mater content of the soil and also caused finer soil texture.

Artificial recharge of aquifers using flood spreading method is a way to increase the groundwater volume and decrease the trend of water table depletion. The most important step in the implementation of flood spreading is the identification of suitable zones. Hence, geographic information system (GIS) and integration methods consist of Boolean logic, fuzzy logic, and overlay index were used to identify the most suitable zones for flood spreading with the aim of artificial recharge of the Sarkhoon plain of Bandar - Abbas. Firstly, five effective factors including surface permeability, slope, alluvium thickness, the ability to water convey in the alluvium and the salinity of water were prepared in ArcGIS software environment. Then, the weights of the layers were determined using the mentioned methods. The comparison of the weighting methods was accomplished using the Kappa statistic, based on the comparison of projected layers with ground control points. According to results, Boolean logic, overlay index, and fuzzy logic respectively projected 34.4%, 35.8%, and 71.4% of the study area as suitable for flood spreading without the constraint of land us. By the use of land use constraint these areas decrease to 21.9%, 26.7%, and 45.66%, respectively. Totally, fuzzy logic with the highest similarity and the highest Kappa statistic was identified as the best method.

Due to the importance of analyzing the hydrological behavior of basin, especially basins with no hydrometric station, applying new methods for predicting water balance is necessary. Therefore, in this research daily runoff stream of Gamasiab basin in the south of Hamadan and Kermanshah provinces was simulated based on cellular network using hydrological spatially distributed WetSpa model in GIS. Digital maps of DEM, land use and soil texture and continuous time series of temperature, precipitation, evapotranspiration and discharge are main model inputs. Model in any cellular network by using rainfall, temperature and evaporation data, simulates all water balance components. Calibration of model parameters for the last 20 years of the studied period (1991 to 2010) and validation of model for the first 5 years (1986 to 1990) was done. The results of the model application showed good agreement between observed and simulated data based on statistical criteria of Nash- Sutcliffe efficiency criterion with accuracy above 0.6 .This model based on the coefficient of performance showed that ability to simulate rainfall-runoff in major sub basins is satisfactory.

Atmospheric precipitation management and efficient use of these resources are extremely helpful to the management of water resources and it has the basic role in the management of the water resources of hydrological parameter estimate as well. In this research, rainfall estimate of three synoptic station situated in Astara, Lahijan and Jirandeh in Gilan province has been done using artificial neural network (ANN) and support vector machines (SVM). The principal component analysis method (PCA) was applied to determine the data pre-processing and input data. According to the results, the main component analysis method for synoptic stations as well as for the five main components of Astara and jirandeh, and for the four main components of Lahijan station is selected. The results of model-making indicate that the artificial neural network model based on principal component analysis (PCA-ANN) in Astara and Jirandeh stations in order with average 2.74 mm squares of 2.62and mm backup-based support vector machine model analysis of the main components (PCA-SVM) mean squares of squares in Lahijan station with error 2.53 mm can be selected as selected models for the aforementioned stations. Finally, with respect to the results can be fitted such that the methods used for data pre-processing in this research to predicate the rainfall as well as the SVM in Lahijan station and model Ann model in Astara and Jirandeh stations have been acceptable.