جستجوی مقالات مرتبط با کلیدواژه « bojnourd » در نشریات گروه « کشاورزی »

Groundwater is the most important water resources in Iran that provides majority of agricultural and urban demands. In recent years, recharge from natural and extended urban areas caused the water table in alluvial Bojnord aquifer to be increased. Transffering water from Karstic aquifers and Shirin Dareh dam intensified this problem specially in fine grain areas of the city. Supplying water from f alluvial aquifer from natural and urban areas, low thickness and discharge potential of alluvial and development of Bojnourd were caused enhancement in the absolute height of water table in the alluvial aquifer. Also in the plains such as Bojnourd plain that are urban uses, According to the mentioned problems, water supply is very important. Therefore, it is essential as much as possible, the current situation and future of Bojnourd alluvial aquifer are identified and management solutions are pursued to eliminate probable problem. The numerical model of groundwater flow can be used as a tool to test the effect of management decisions but usually lack or incomplete information of the hydraulic characteristics of the aquifer causes limitation of use of these models. Nowadays, in the all of the world many studies are ongoing about stratigraphy of aquifers in order to more understanding about the complicated condition in the water flow hydraulics. So it seems that understand of Bojnourd plain aquifer stratigraphy and a better estimation of the hydrodynamic coefficients can help to make decision appropriately to deal with the problems. The aim of this research was to make model of Bojnourd aquifer with emphasis on hydro-stratigraphy. Discuses: According to the variety of Bojnourd aquifer sediments, it cannot be assumed one-layer aquifer; so in order to reduce uncertainties, as well as developing, the conceptual model has been tried to identify natural effects that impact on groundwater system, especially stratigraphy of sediments are introduced to models. The effective factors include geological studies, geophysical sections, boundary of modeling, using of observational wells and determination of the recharge and discharge. In this study, to verify and judge models with different fifteen lithology cross section during aquifer using Rockworks software to obtain the appropriate layer of aquifer that eventually lead to more accurate estimation of three-dimensional lithology model. Rockworks software uses lateral Bending Horizontal method to interpolate lithology of wells log data. Then using three-dimensional model techniques in Rockworks16 software, the three-dimensional model of the aquifer lithology with all available data and information, i.e., logs and geophysical studies has been obtained. Three-dimensional models of geology are as subsurface three-dimensional representative that those can show spatial relations of logs lithology and lenses. Interpolation between the existing logs is not defined as the distance fillers and increase of boreholes in aquifer adds accuracy of these models. The results of three-dimensional models represent three-dimensional groundwater flow model of the aquifer system. The result of lithology modeling of aquifer is composed of four soil textures including of coarse grain, medium-grain, fine grain and very fine grain with four layers and with a thickness of 30m that was imported to version 1.7.10 of GMS software. Conclusion The model was run in steady state for October 1380. In the first step, the initial model coefficients were calculated. After running the model in steady state, the mean square error was 2.77 m. In the next step, the results were better with changes in the soil hydraulic conductivity values and the mean square error was 0.794m after calibration. Heterogeneity and lenses in the aquifer system caused changes in hydraulic conductivities of coarse to very fine-grained sediment, so the identification of aggregation and different genders, lithology of the aquifer with higher accuracy is achieved and consequently, the hydrodynamic coefficients (k,s) will be estimated more precisely. So considering that the aquifer materials are heterogeneity, the hydraulic conductivity values were obtained as 8.1, 6.7, 1.9 and 0.4 for soil textures of Coarse grain, medium grain, fine grain and very fine grain, respectively. Totally Changes of water level were between 1020 to 1080 meter and in the first layer; the northern and eastern parts of aquifer were dry. According to flow budget of the aquifer in one layer model was obtained with acceptable accuracy in multi-layer models, to establish flow budget in accordance with the single-layer model. The calculated flow budget by the model showed that the aquifer layer was in balance with the amount of input and output approximately.

Population growth, agricultural and industrial development, degradation of surface water resources, groundwater levels drop are among the major factor causing water scarcity. The integrated management of groundwater and surface waters could serves as a solution to solve these challenges. In other words, sustainable water resources can be achieved through Integrated Water Resources Management, which is the comprehensive approach to all the components that affect and influences the status of water resources. With this approach, the importance of management tools such as integrated water resource simulation models to help planners and managers of this sector is increasingly evident. Connecting the WEAP model to MODFLOW allows the values calculated by WEAP to be sent to the MODFLOW for input on groundwater influxes, river levels, groundwater withdrawals (pumping) and surface runoffs. After it, the groundwater level, sub-streams between the aquifers and the flow between surface and underground water are sent to the WEAP as input of the next step of the calculation. The purpose of this research was to investigate the effects of scenarios related to demand and available water resources, integrated water management in the urban sector and sewage system application in Bojnourd region. In this study, with using a water resources simulation model (WEAP) and its connection to groundwater simulation model (MODFLOW), water consumptions for Bojnourd basin was evaluated. Calibration and validation of both models has done under taken data based on 6 (from 2005-06 to 2010-11) and 2 years (from 2011-12 to 2012-13) respectively. Then different management scenarios, including current state water resources scenario, dam's drinking water supply for Bojnord city via transferring water from Shirin Dareh dam, developing sewage systems and finally combination of 2 last scenarios were considered. Under these scenarios, projections for a period of 28 years (from 2013-14 to 2040-41) and its effects on water resources of Bojnord basin were studied.The hydrometric station data of Babaaman at the outlet of the Bojnourd basin, which is the only hydrometric station representing this basin, was used to calibrate the WEAP model. Also, data from four rain-sensing stations, one evaporation station and one synoptic station were obtained from the year 1380 to 1390.Demographic data and Urban water demand and rural demand, population and consumption per person was assessed. Industry sector Water demand is estimated monthly. According to geological studies, the Bojnourd basin has two types of alluvial and limestone aquifers, both of which are defined in the model. Then, sensitive and effective parameters were determined by calculating the sensitivity percentage of the mode. Finally, the results of calibration and validation of the model were done from three indicators of Nash-Sutcliff (Ef), Coefficient of determination (R2) and Root Mean Square Error (RMSE), respectively, and the reliability index were used to evaluate the scenarios. The results showed that Simultaneous applying multiple water management strategies seems to be better than any of its individual states, reducing water withdrawing on various resources. Reliability of water supply in the whole complex scenario, for urban drinking water, rural and industry purposes were estimated around 100, 100 and 65.3 percent respectively. As a result of this scenario, the annual recharge of the aquifer with 5.39 million cubic meters per year can be relative balance between harvesting and recharge. it can be concluded that reliable results will be obtained from simultaneous simulation of drinking and industry water management. Keywords: aquifer, Bojnourd, simulation, water resources management

The climate of the land has always been changing over time but the current trend in climate change has become important due to the role of humans which has been unprecedented over the past years.in this study, The LARS WG and SDSM models are used to evaluate the climate change at Bojnourd station for downscaling climate. The result of the status of the station showed the temperature of the station is higher than its long-term average. The results of the LARS WG model show that precipitation will increase at the station at 2050 year. In scenario B1, the amount of precipitation increase almost 16 mm more than base precipitation to 2050.In totally the SDSM model downloading to increase precipitation that this the increase showed A1 and B2 scenarios more than rcp scenarios, therefore In the scenarios, A2 value is 289mm, B2 is 294 mm, rcp 2.6 is 264 mm, rcp4.5 is 273 mm and in rcp8.5 is 264 mm. In the LARS WG model, the minimum temperature increases in both cases. The maximum winter temperature rise is 0.8 c in the A2 scenario. In both scenarios, the maximum temperature in March, April and May is the highest increase to compare to other months. The SDSM model showed that the maximum and minimum annual temperatures of model is lower than the base period. But the temperature in March, April and May increase the minimum and maximum, which indicates the matching of the results of both models.

Studying the forage quality of range species is among the important factors required for range management. In the present study, the forage quality of range species including Onobrychis transcaspica, Onobrychis radiate, Astragalus brevidens, Melica ciliate, Agropyron pectiniforme, and Sangisorba minor were investigated at three phenological stages. The study was conducted in the rangelands of Bojnourd. At each phenological stage, sampling was performed randomly with five replicates. Forage quality indices including CP, ADF, DMD, and ME were measured in the laboratory. The results showed that the forage quality of the study species was higher as compared with flowering and seeding stages, so that with the advancing age of the plant, crude protein, dry matter digestibility, and metabolizable energy reduced and ADF increased. In comparison with grasses, Legumes had the highest CP content (14.53% and the lowest ADF content (43.91%) in all three phenological stages. Among the study species, the maximum and minimum crude protein content was recorded for Astragalus brevidens and Agropyron pectiniforme, respectively.
Analysis of variance showed that the effects of species and phenological stages were significant (P

The capability of a soil to resist erosion depends on soil-particle size and distribution, soil structure and structural stability, soil permeability, water content, organic matter content, and mineral and chemical constituents. Among many affecting factors on aforesaid characteristics, the freezing-thawing processes may considerably affects. Freeze–thaw fluctuation is a natural phenomenon that is frequently encountered by soils in the higher latitude and altitude regions in late autumn and early spring. Effects of freezing and freezing-thawing phenomena on soil erosion and sediment yield are important. Nevertheless, soil conservation under these phenomena by using different methods as well as soil amendments has not been yet considered. Surface application of anionic polyacrylamide (PAM) in solution has been found to be very effective in decreasing seal formation, runoff, and erosion.PAM stabilizes soil structure due to the ability of the polymer chains to adsorb onto clay particles and bridge them together forming stable domains. This adsorption can be a result of interactions between the negatively-charged functional groups of the PAM molecules and the positively-charged edges of clay minerals, orexchangeable polycations (mainly Ca2) acting as ‘bridges’ between the negative charges of the PAM's functional groups and the negatively- charged planar surfaces of the clay. The PAM is adsorbed on the external surfaces of the aggregates and binds soil particles far apart together, thereby were shorter and evidently less effective in enhancing increasing their resistance to splash by raindrop impact and detachment by runoff. A lot of research work focused on freezing effects in soils on aggregation or increase aggregate stability and emphasis corresponding effects. But the effects of application of soil amendments on soil induced freeze and thaw cycle have not been studied yet.
The present study evaluated the performance of PAM in controlling freeze-thaw cycle effects on splash erosion from a silty loam soil. A freeze-thaw cycle was simulated in Soil Erosion and Rainfall Simulation Laboratory of TarbiatModares University. The present study was conducted under controlled laboratory conditions with a simulated rainfall. The maximum efforts were made to mimic natural conditions to get access to results with high level of fidelity. Towards this attempt, air and different soil depth temperatures were analyzed in natural condition and 10 cm soil depth was targeted for the soil laboratory experiments. The rainfall storm with 72 mm h-1 and 30 min duration was simulated and conducted for the study treatments. The soil was poured in small erosion box with 0.25 m2 surface area in three replicates. A thick filter, draining the lower 20 cm of the soil profile was generated using mineral pumices.The prepared soil sample was evenly packed into the soil plots at a bulk density of 1.3 Mg m−3 similar to that measured under natural conditions. The plots were then placed in saturated pool for 24 h and then left to be drained to achieve an average moisture content of 35% similar to that recorded for the realities in the study area. So, splash erosion rates were measured using splash cups in two control treatments without PAM subjected to freezing and freezing-thawing processes, and two other plots treated by freezing and freezing-thawing processesplus application of 20 kg ha-1 of PAM. After securing thenormality ofdata, the average net splash erosionand the average upward and downward rates of splash erosion in allexperimental treatmentswere comparedby paired sampled T-test.
According to the results of statistical analyses, the PAM application had a significant effect (p

One of the factors that play a significant role in the contamination of ground water resources, solid waste and urban waste. 200 tons of waste is generated daily in the city Bojnourd and the amount of waste causes the release of 33 million liters of leachate per year. That the lack of proper waste disposal systems and landfills poor design caused concern about the influence of hydrocarbons and heavy metals into groundwater is has been. In this study, 2 wells upstream and 2 wells downstream in the side of landfill were sampled. The average concentration of variables NH3¡ NO3-¡ PO43-¡ SO42-¡ Cl¡ Mg2¡ K æ Na in the upstream wells Is measured respectively, 0.02, 20.27, 0.17, 141.2, 89.8, 38.52, 2.8, 27.6 mg/l and wells downstream, 08.8, 51.25, 0.5, 200.1, 182.2, 71.32, 7.1, 218.8 mg/l. Due to the high concentration of ppllutants of NO3-¡ PO43-¡ Mg2¡ K¡ Na æ TDS to a standard amount can be found that Influence of waste landfill leachate to the of groundwater in the area causes contamination wells surrounding the landfill. In this paper, in addition to examining groundwater pollution in the city of Bojnourd, is recommend that to design and locate the new standard burial place by using fuzzy logic and to found fourth place with ranking criteria for burial or should be used anaerobic digestion instead of waste disposal.