Advanced Materials Research Vols. 550-553

Abstract: Soil Salinization poses a potential threat to human health, socio-economic development, national food security, local ecological environment, and also leads to substantial risks. Therefore, non-engineering and engineering control measures are required to reduce the risks and hazard levels. To achieve the goal, the nature of factors, which affect the salinity formation whether it can be regulated or not, had been first made a thorough analysis. Then the combined control mode which was water and salt regulation management simulation model of soil salinization based on change of land utilization had been put into pratice in Songyuan irrigated district. The specific process is as follows: under the premise of land utilization re-adjustment, three-dimensional hydrogeological numerical model was used as a tool to evaluate the distribution ratio of surface water and groundwater, taking the water table changes as clues to achieve the goal that verifies the mode of soil salinization in Songyuan irrigated district, and can forecast the water and salt movement tendency. On the other hand, from the perspective of critical groundwater depth of soil salinization to analyze its variation trend, different management measures were suggested. The research results showed that the mode of regulation can effectively head off the deterioration of salinization, and taking environmental and economic benefits into account, it can also provide basis for scientific amelioration and field management for saline soil.

Abstract: It is important to build the accurate internal relationship between the utilization degree of water resources and parameters of local economy in the evaluation of regional water resources utilization. Water poverty index (WPI) can solve this question properly. The WPI of every three years during 2000-2009 of Harbin is calculated by using weighted average method. The results show that WPI appears in an increasing trend during past 10 years in Harbin. If the following aspects can be improved in the future including controlling the pesticide and fertilizer, reducing water loss and soil erosion, increasing forest coverage, irrigation efficiency and investment in hydraulic construction, the utilization rate of water resources will be further improved.

Abstract: The improved model for double layer snowpack melting was put forward to overcome the disadvantages of the DG (Degree-Day) model which had simple principle and neglected the relevant factors which could be important to the simulation of snowmelt runoff. The surface snowpack model, improved top layer snowpack model and model parameters calculation were studied. The structure and calculation method were put forward to improve double layer snowpack runoff model. Finally, taking the Lancangjiang River as an example, the snowmelt runoff was calculated by the improved SWAT model. Through comparison, it revealed that between two models that the simulation results of the improved double layer snow melting model was obviously better than that of the DG model in evapo-transpiration loss, the distinguish among cover layer, snowfall, rainfall and snowpack water equivalent calculation, and melting snowpack refrozen as well as adaption condition.

Abstract: Frozen soil in cold regions can be divided into 2 types --- seasonal frozen soil and permafrost. Because of the frozen soil layer, there are obvious differences between the characteristics of groundwater seepage in cold regions and normal regions. The paper analyses the disappearance regulation of frozen soil layer and the mechanism of groundwater seepage in the unsaturated zone and saturated zone under the seasonal frozen soil and permafrost. The results show that the frozen soil layer has obvious influence towards soil water seepage in the unsaturated zone during the freezing and thawing process. When the warm period comes, it makes influence of soil moisture conservation in the unsaturated zone. At this time, the freezing porosity is completely filled with the ice of volume expansion. It is equivalent to the impermeable layer that is difficult to receive the vertical recharge. In the permafrost area, the atmospheric precipitation and surface water are major recharge sources to the aquifer, and the aquifer can also receive recharge from groundwater. During the cold season, the surface is frozen and the rainfall recharge source is cut off. It will be unconfined seepage with free surface, and form a saturated zone above the permafrost layer. During the freezing period, with the increase of frozen depth, the aquifer will freeze from top to bottom, and it will convert to a confined aquifer.

Abstract: Through the double mass curves analysis, it concluded that the relationship between the areal and the runoff depth within upper reaches of the Naoli River, the Naoli River basin had experienced a great change since 1963, especially the runoff coefficient which appeared in a decreasing trend. By adopting the runoff coefficient difference Rank and T test (α=0.05,n1=7,n2=43,T=255,T1α=108.52,T2α=248.47, T＞T2α＞T1α), it also concluded that there was no consistency between the runoff coefficient series from 1956 to 1962 and the ones from 1963 to 2005. By analyzing the frequency curves of precipitation-runoff depth, it indicated that, under the same precipitation frequency, the runoff coefficient in 1963-2005 was much smaller than that in 1956-1962. The research results revealed that: (1) The precipitation was the key driving force to runoff variation; (2) The land use/cover changes posed by human activities was one of important causes contributing to runoff coefficient mutation in the catchment area; (3)The runoff depth variation was mainly controlled by the Longtouqiao reservoir and the water consumption was influenced by irrigation of paddy field since 2001.

Abstract: To deal with specific groundwater inundation problems such as large-scale study area, complicated recharge and discharge terms and special aquifer structures, there may be some inappropriateness or limitation in accuracy, range or flexibility when using traditional methods, including the experience analysis method, water balance method and the principle of Hydrodynamics. However, the numerical modeling method, which can break the constraints of space, time and accuracy, can conquer the problems above, even though there have been very few utilizations of the numerical simulation method on inundation prediction. With the real case of the inundation-affected areas located in the upstream of the Dadingzishan Reservoir, firstly, it analyzed and listed out the major controlling elements, including fundamental controlling elements (location and range, topography, land utilization, hydrology and meteorology, reservoir operation, and human activities, etc.) and key controlling elements (structures, boundaries, functions, input features of the aquifer) in this paper. Secondly, a hydrogeological conceptual model and numerical simulation model had been established to serve for the prediction of inundation range and degree. After the identification and verification of the model and calculating the future recharge and discharge, the fully qualified model had made a forecasting of the inundation situations in 2015 and 2020. This paper is expected to provide practical example and method application for the relative reservoir inundation research.

Abstract: Evaporation is the most significant process that affects the isotopic transport of surface water. The study of mechanisms and modeling of the evaporation process has a very important practical significance in improving the isotopic analysis method. This paper reviews the international development of the mechanism of hydrogen and oxygen stable isotopic fractionation and model. It indicates that as the most ideal tracers of hydrologic cycle, stable hydrogen and oxygen isotopes have their unique and irreplaceable functions. However, field experiments of evaporation and further research are limited by the complexities of kinetic flow in the atmosphere and observation technique. Modeling and experiments are commonly based on the assumption that evaporating water is well-mixed, and isotopic stratification in liquid is not considered by most laboratories. While it dose affect. Flow disturbance in the atmosphere is the most uncertain factor for isotopic fractionation in the process of evaporation. The modeling example shows isotopic evaporation line of natural water can be simulated properly while detailed simulations are limited by the lake of observational data of isotopic diffusion processes in both air phase and liquid phase.

Abstract: In cold area of China, freezing process usually takes place in diversion open channels in winter, which may cause damage to these channels, the property and even the lives of people along these channels. In order to safely transport water using these channels in winter, it is necessary to study water temperature distribution and icing position in the channels. The water temperature distribution in a typical water diversion open channel in Ningxia of China is simulated by using three water temperature models, i.e. cross-section averaged one dimensional model, depth averaged two dimensional model, and width averaged two dimensional model. The numerical results are compared and analyzed among these models. The simulated results indicate that air temperature, wind speed and flow velocity are three key factors that affect the water temperature distribution and icing positions.

Abstract: Considering that the limits with determined water quality classification using maximum degree criteria in traditional fuzzy comprehensive evaluation method, a improved fuzzy comprehensive evaluation method for water quality assessment is established based on confidence criteria. The method can effectively avoid the problems that include the water quality unclear classification and the unreasonable result, etc. Finally, the water quality of Chaping River is taken as a case study and the assessment results show that the sections in Chaping River water area can be described into 3 “category Ⅰ”, 5 “category Ⅱ” and 2 “category Ⅲ” states in 2008.

Abstract: Seven systems of one-step synthesis of aniline were designed, and it was determined which one could occur spontaneously through the calculation of Gibbs free energy of it. Among the seven systems, the Gibbs free energy of the one with ammonia as the aminating agent and hydrogen peroxide as the oxidant was the lowest, thus its process driving force was the largest, that is, .For this system just mentioned above, the standard Gibbs free energies, the equilibrium constant and the equilibrium conversions of benzene under different conditions were discussed ,which was expected to provide a theoretical basis for further development and application of the system.