Applied Mechanics and Materials Vols. 212-213

Abstract: Abstract. Groundwater is to be pumping near the riverside could be induced recharge from the river surface and lateral aquifer layers, and could be reduced the negative effect on the aquifer. In this research, proposes the method of pumping groundwater from the Maoluo riverside and assesses the effect on the riverbank filtration in the middle of Taiwan. This research constructed the four analytical models using MODFLOW to identify the reliability of numerical model. Five groundwater pumping schemes based on the assessment on the effect of the Maoluo river seepage were implemented. For replace with the external water sources is 60,000 CMD, the ratio of river seepage to pumping is from 37.5% to 40.2%, and the groundwater radius of influence is from 290m to 470m. The research area is 700 m away from the residential area, none pumping schemes will thus affect the residential area.

Abstract: Sediment has the function of adsorption and desorption of the nitrogen in water body. This study provides the theoretical basis of calculating the nitrogen content discharged into the Poyang Lake. The results show the nitrogen adsorption of sediment reaches balance basically in about 4~ 6h, the adsorption capacity is increased with the increment of the initial concentration of nitrogen, and decreased with the increment of sediment conentration.The isothermal adsorption of nitrogen by sediment can be fitted preferably by Henry and Langmuir equation.The adsorption and desorption process can be fitted by Langmuir equation.The nitrogen desorption of sediment reaches balance basically in about 8~14h.The nitrogen desorption capacity of sediment is decreased with the increment of sediment concentration.

Abstract: Take observational data of March 2011 of study area to analyze changes of snow characteristics during snowmelt period (SP), such as snow grain size (SGS), snow water content (SWC) and snow density (SDS), and to analyze the influential factors. The results show that: SGS decreased during SP, and increased from snow surface layer (SL) to snow bottom layer (BL). That related to the snow depth (SD) and snow temperature (ST). SWC has a sudden increase in late SP. It decreased from snow BL to SL during early and late SP. It has a big daily variation in SL and snow middle layer (ML). It changes hours later than the atmospheric temperature (AT). That related to SD, ST and daily AT. SDS value in SL is the biggest during early SP. It has acute change in SL and a big daily variation in BL .That related to snow age (SA).

Abstract: The Taipei Basin in Taiwan is an extremely special case under the constraints of environmental conditions. Pumping of groundwater in the basin was banned in 1968 due to the land subsidence. Since then, groundwater level in the Taipei basin has risen over the years and the land subsidence has also stopped. However, due to the continuous rise of groundwater level, the soil liquefaction potential of saturated sand soil strata has increased. Thus, the groundwater in Taipei basin should be controlled based on the suitable groundwater level to reduce the possibility of land subsidence or soil liquefaction. This study proposes a novel performance of groundwater management model, which considers the three aspects of safe yield, soil liquefaction, and land subsidence. In this process, a three-dimensional groundwater numerical model is primarily established with MODFLOW, and the safe yield and groundwater level are deduced through the Hill method. The second part requires an estimation of the soil liquefaction potential by applying the Seed97 method. The third part of the process includes an estimation of the subsidence of sand by adopting the Ishihara method and the subsidence of clay blanket through the Terazaghi method. Finally, combine the limited groundwater level through the application of the said methods, the proper scope for the level of groundwater in the Taipei Basin is then estimated. Hence, the maximum amount of groundwater that can be pumped could be estimated based on the suitable lower limit of groundwater level, and the minimum amount of groundwater that can be pumped could be estimated based on the suitable upper limit of groundwater level. The study result indicates the central region in the basin has a high potential of soil liquefaction, while the periphery of the basin has a high potential for land subsidence. In consideration of three environmental limited constraints, namely, safe yield of groundwater, soil liquefaction, and land subsidence, could estimate the maximum groundwater amount that can be generated per annum is about 0.77x109m3 to 1.03x109m3, while the minimum groundwater amount per annum is about 0.53x 109m3 to 0.71x109m3.

Abstract: The simulation test on the late sediment storage period in shaping program of high floodland and deep-cut channel on the Xiaolangdi reservoir, and the evolution of high floodland and deep-cut channel, for the Xiaolangdi reservoir sediment retaining period reasonable reservoir operation mode, provide reference for reservoir extending service life.The study shows that:①Formation of High floodland and deep-cut channel evolution, which based on the beach sediment uplift and slot synchronization channel and then washed down the process, whether the erosion and scour quantity to whether can form high floodland and deep-cut channel topography is essential;②The tributary of the riverbed is equivalent to extending transversely, tributary river sedimentation process and topographic condition and tributary junction of the main river deposition pattern and process and other factors are closely related, tributary cross-sectional deposition morphology is mostly parallel to the raising tendency, department branch flow entrance there was a sandbar;③the reservoir during the flood period rainfall scouring camera, in favor of hyperconcentrated flow is generated, to a certain extent, recovery tank capacity, play long term use of reservoir.

Abstract: The study of the beginning of the density current is the first formation of density current. The relation formula for gravitational correction coefficient had been derived on Taylor series. Then the explicit changing formula between Froude number and sediment concentration had been obtained. Analysis and discussion about the formula had been carried out. With the data surveyed from Xiaolangdi Reservoir had been validated on the coefficient. The results show that the formula can support Xiaolangdi reservoir for the density current design of water and sediment regulation on Yellow River.

Abstract: This paper was based on the Ganjiang Valley ‘s 50a rainfall data (1959～2010) and the WRF numerical weather prediction model rainfall to establish a new mathematical model for water level prediction in the valley through the excellent performance technique - Muskingum model parameters optimal estimation, which realized the quantification of water level forecast. In the last of this paper the rainfall data in April 2012 of this valley was used to test the new model and the experimental results show the error between the model and the observed data is varied in -15cm to 15cm, it is very small.

Abstract: In order to discuss the water resources carrying capacity in Liaohe river basin, which is defined as the ultimate water resources carrying capacity, this paper mainly calculated the water resources threshold based on the lower and upper available water resources according to the minimum and appropriate ecological water requirement. Bring forth water resources carrying capacity threshold theoretical system, multi-objective algorithm is used to calculate the ultimate water resources carrying capacity for three different social and economic development projects, such as ‘ecological maintenance’, ‘ecological soundness’ and ‘ecological soundness with water saving’, and analyzed the calculation result with the characteristics of each city. The results showed that the water resources in Yingkou and Panjin have been overtaken, that in Shenyang and Anshan are over lifted to some extent and water resources in other cities still have some space to extract. Meanwhile, the ecological social and economic benefit of the third project is the best compared with the other two.

Abstract: In order to obtain more accurate results than the traditional method of wave statistics，the third-generation ocean wave model WAVEWATCH III (WW3) is applied to simulate the sea wave field of the Northwest Pacific. The model is driven by the QSCAT/NCEP blended winds. Then wave parameters are analyzed by statistical analysis method. The comparison of the significant wave heights between the simulation results and observation data indicates that the correlation coefficient is greater than 0.9. Furthermore, a post-processor system which integrates data analysis and graphic display is established. A comprehensive evaluation is presented after analyzing the time and spatial distribution of computational wave heights. During the winter there is a big wave area in the Japan Sea. In the East China Sea, there is a period of relatively big wave in summer. Throughout the year, the average wave height is the maximum in the South China Sea.

Abstract: In this article, the Least Square Support Vector Machine(LS-SVM) regression analysis and prediction methods were briefly introduced. Radial basis kernel function was chosen and a streamflow forecast model based on the toolbox of Matlab was constructed. Then the model was validated with a case study. After the model validation with a case study, it could be seen that the prediction model shows high accuracy and convergence speed. According to the analysis of the results, it is feasible for LS-SVM utilization in streamflow forecast.