Advanced Materials Research Vols. 518-523

Abstract: In order to find out the origin of geothermal water in Xianyang urban area and provide scientific basis for sustainable use, taking the geothermal water as study object, we systematically studied supply circulation mechanism of geothermal water in Xianyang urban area through environmental isotope hydrogeochemical methods, and come to the conclusion: geothermal water in Xianyang urban area is bounded by shore fracture of Wei River, which shows totally different hydrogeochemical features. The differences suggests that the geothermal water belongs to different tectonic geology units and sedimentary environment. The distribution characteristics of environmental isotope such as δD、δ18O and 14C confirmed that geothermal water exists contact between the study area and northwest of Wei River. The supply water source of geothermal water comes from the atmospheric precipitation of Holocene in northwest direction, its updating ability is poor except partial deep fault slightly being recharged from modern atmospheric water.

Abstract: In this paper, based on the fact of water resources shortage, environmental degradation in Chanba River basin, using multi-objective optimization theory, we established the ecology-oriented water resources optimal allocation model and achieved the coupling between water quantity and quality. According to supply and demand of water resources in two levels of years (2020, 2030) and the guaranteed rate 75%, developed model parameters (coefficients), called the optimization function to solve it. The model is applied to Chanba River basin, indicating that the model is reasonable, efficient algorithms The optimal allocation model and the results reflect the concept of sustainable development for ecological, economic efficiency and help to improve water supply reliability, the sustainable use of water resources planning and management provides a basis for decision making.

Abstract: Seasonal runoff series can be described by seasonal autoregressive model, which is extensively applied in long-term runoff forecasting. The common way of parameters estimation is moment estimation. This paper estimates parameters of seasonal autoregressive model by recursive least square method and applies the method in forecasting the monthly runoff for the Three Gorges. An effective procedure based upon the least fitting error is proposed to determine the model order. The forecasting results are satisfactory.

Abstract: The Taklimakan Desert, located in the center of the Tarim Basin, northwest China, is the arid center of the Europe-Asia Continent. Due to the scarcity of surface water resources in the Taklimakan desert, the groundwater feeding water supply system was constructed by some ecological engineering and power engineering such as Tazhong Oilfield and the Shelter-forest Project of the Tarim Desert Highway in the hinterland of the desert. In this work, the chemistry data of shallow groundwater was obtained through positional observation section along Tarim Desert Highway in the Taklimakan desert and the main chemistry indicators of groundwater were carried out system analysis. The relationship between the major ions and TDS in the desert shallow groundwater was clarified by using descriptive statistical methods and correlation coefficient methods. The results were shown that the TDS in desert shallow groundwater was relatively high, its value ranged between 30.246 ~ 3.093 g/L. The spatial distribution characteristics were high in the north and lower in the south, and the south was slightly higher than central region.

Abstract: Based on the ancient harmony idea, using the system theory, the man-water harmony index was brought up. It describes the harmonious level between man and water in cities. It quantitatively reflects the coordinating relationship between the water system and man city system of certain cities in certain periods. Improved Fuzzy Comprehensive Evaluation（ IFCE）, Improved Grey Relational Analysis（IGRA） and Analytic Network Process（ANP）are comprehensively used in calculating the man-water harmony index,building the IFCE-IGRA-ANP model. The index can be effectively used in sustainable development evaluations and water convervancy construction planning of modern cities.

Abstract: The δD-δ¹⁸O line features are very important properties of isotopic characteristics. The δD-δ18O line usually is estimated by regression analysis when samples are sufficient. In this^{Superscript text} paper, the isotopic characteristic of rain water, shallow groundwater and lake water in Golmud drainage area of Qaidam Basin were analyzed, and the isotopic evaporation line of lake water was calculated with Rayleigh fractionation function because the regression analysis method is insufficient in the condition that measured samples of lake water are short. The result shows that the groundwater is the main source of lakes; and the isotopic fractionation of hydrogen and oxygen in lake water controlled by kinetic effect in the process of evaporation. The calculated evaporation line of lake water is δD=3.26δ¹⁸O-21.00, which is matched with measured samples. The sensitivity analysis of the slop to the temperature, dissolved salt composition in lake water and relative humidity of air shows that the slop is negative related to the temperature and dissolved composition and is positive related to relative humidity. In typical environmental condition, the slop is increased by 0.0303, 0.1016 and 0.0205, respectively, when temperature decreased 1°C, dissolved NaCl decreased 1mol/L and relative humidity increased by 1%.

Abstract: Under the A2 climate change scenario, the future runoffs in the upper Hanjiang basin are predicted by coupling the general circulation models (GCMs) and hydrological models. The future precipitation and temperature are obtained by downscaling CGCM2 and HadCM3 outputs using the Smooth Support Vector Machine (SSVM) method, and then they are used as input to the two parameter monthly water balance model and the distributed VIC model, respectively, to predict the future runoffs in the upper Hanjiang basin. The results of both hydrological models show that the future runoffs projected on the basis of CGCM2 outputs will decrease in 2020s (2011~2040), increase in 2080s (2071~2100), and show no significant change in 2050s (2041~2070), when compared to the average level of runoff during the baseline period of 1961~2000. For the A2 climate change scenario simulated by HadCM3 outputs, the future runoffs simulated by both hydrological models will increase in 2050s and 2080s. While for 2020s, decrease is predicted by the two parameter monthly water balance model, but no significant change is predicted by the distributed VIC model.

Abstract: Based on the method of investigating natural vegetation and exposing groundwater table by sinking shallow wells with hand drill, the relations between total coverage of vegetation community, respective coverage of each species and species succession and groundwater depth are established in Subei Lake of Ordos plateau. The results indicate that there is significant correlation between total coverage of vegetation community and groundwater depth within 1.6m. The respective coverage of some wetland species has different peak values. It indicates that these species have certain ecological groundwater depth. The relation between species succession and groundwater depth shows that wet and saline vegetation are predominant when groundwater depth is less than 0.6m. xerophyte and sandy vegetation are predominant when groundwater depth is above 3.2m. In addition, 1.6m is the critical groundwater depth of vegetation ecotone. This region has the largest number of vegetation species.

Abstract: In order to restore ecological function of wetland, determine the exploitation plan of water resources reasonably and promote the sustainable development of ecological function in wetland, based on the exploitation and utilization situation as well as the planning objectives of Panjin Shuangtai estuary wetland, this essay focuses on discussing water demand of natural ecological system, water quality of agricultural irrigation and aquaculture, and residential water consumption in wetland. Using various areas of wetland as decision variables and aiming to restore the size of all areas back to that in 2000, this essay takes the view of system engineering as guidance, establishes multi-objective programming model for rational allocation of wetland resources, and makes it able to compare with the other three created configurations plans. Results show that only giving priority to the needs of ecological water consumption of wetland to achieve an efficient use of surrounding water resources can we make the recovery of this wetland better and faster, and therefore achieve a desired sustainable development of ecological function. This has an important significance in leading us to a sustainable development of ecological restoration and constructing a framework of coordinated use of water resources of wetland system.

Abstract: An object function of hydraulic efficiency for subsurface wastewater infiltration system (SWIS) is presented in this paper. The hydraulic behaviors of two infiltration systems with different configurations were simulated using SEEP/W. The results indicated that choosing appropriate configuration of SWIS can improve the hydraulic efficiency.