Advanced Materials Research Vols. 518-523

Abstract: Based on the principles of fairness, efficiency and sustainability, the assessment indicator system of the initial allocation of the river basin water resources is constructed in Analytic Hierarchy Process (AHP) method. By using the AHP model built, Standardization Law and Matlab software, an empirical study of the initial allocation of water resources in Yellow River Basin is got and the allocation scheme is put forward. Research shows that the AHP method is more scientific and rational in the river basin water resources allocation. The fairness and efficiency of fetching water can be reflected by readjustment on original Water resources allocation in nine provinces of Yellow River Basin. It is reasonable of the initial allocation of the Yellow River Basin Water Resources.

Abstract: We analyzed the relationship of groundwater level of wetlands at the Yellow River mouth to the ocean tide responses, as well as its impact on the spatial distribution of wetland types by field positioning observations of coastal wetland groundwater levels. The results showed that, the groundwater level is significantly affected by the tides. Its fluctuation has a negative polynomial relationship with its distance to the coast. Their correlation reached maximum during spring tide (R2=0.79); the closer to the coast, the greater the groundwater level fluctuation is, the greater the interaction between the seawater and the groundwater, the smaller the groundwater depth; In contrast, the further from the coast, the smaller the level fluctuation is, the greater the groundwater depth level. The spatial distribution of coastal wetlands is greatly affected by groundwater level and ocean tide. Thus reasonable protection of the region is of importance for protection of both the seawater and groundwater qualities.

Abstract: Due to long-term coal mining, causing ground collapse and water system damage. Therefore, it is necessary to restore the water system in coalmine subsided area with higher level of underground water and put forward the unified mode of restoration. On the basis of investigation and study, through inquiring a large number of references, the study area is divided into two functional areas: Fertile farm belt and Ecological control area. Ecological control area is further divided into deep water ecological lake area, ecological island area and shallow water planting areas. This classification not only make the water resource allot scientifically, but also realize the stereoscopic development. Meanwhile, based on the division of functional areas, it strengthens surface water, groundwater and soil water restoration to realize the restoration of water system. By building an embankment and repairing irrigation and drainage facilities to remove water logging, realizing the restoration of surface water. Establish drainage system with deep and dense ditches, to reduce the groundwater level and prevent crops staying in water for long time. Finally, put forward a filling mode, which the clay-coal gangue, coal ash and sludge are mixed in appropriate proportion when filling soil, to improve the soil reclamation filling. This mode can realize the migration of soil moisture to promote crop growth and improve the output of the land.

Abstract: The riparian vegetation is highly dependent on the groundwater which is recharged by the river in arid regions. Water is the most important limiting factor for riparian vegetation in arid regions. From 1970s to 2000, the lower Tarim River almost dried up and the groundwater table fell down obviously. The riparian vegetation degraded seriously due to the low groundwater table. From 2000 to 2006, water transfers were implemented in the lower Tarim River to restore the ecological environment. Although the observation of groundwater and vegetation was carried out along lower Tarim River, the dynamics of the groundwater and vegetation along the cross section of the river were unknown. Ecohydrological evolution model on Riparian Vegetation in hyper-arid regions (ERV model) is a distributed ecohydrological model and has been validated at Yingsu in lower Tarim River. In this paper, the ERV model is applied to analyze the ecohydrological effect of water transfers at Alagan in lower Tarim River. At the same time, the ERV model is further validated. The simulation result is validated by observed groundwater table and vegetation coverage computed from remote sensing data. The result shows that the average groundwater table at Alagan increased by 4.74m from 2000 to 2006 and the average groundwater depth reached 6.36m. The average vegetation coverage increased from 0.130 to 0.194. In order to recover the green corridor, the further water transfers are required. The results are helpful for the ecohydrological research and water resources management in lower Tarim River.

Abstract: After 1970s, Japan has established relative laws and regulations to constraint industrial water, building water usage and forbidden unreasonable ground water exploitation which is caused by large amount of groundwater exploitation in 1960s. Such measures solved ground collapse problem on one hand indeed; on the other hand, along with the prevention of ground water exploitation, the groundwater level recovered to the normal level, and the floating power brought by groundwater rising threatened the architecture underground. The claim for groundwater utilization is rising. Also, groundwater has high value and good quality to supply water resource. Therefore, this research aims to construct a comprehensive groundwater exploitation model to clarify the sustainable groundwater utilization and economic, environmental impacts brought by groundwater usage. This new comprehensive model combined optimal groundwater exploitation model, water cycle model and socio-economic model together to practice optimal simulation. Through computer scenarios, we can clearly ensure groundwater utilization amount and method considering the sustainable development. Furthermore, the simulation model can be applied in other regions adjusting by specific characteristics.

Abstract: The main environmental factors of the influence of soil temperature are air temperature, total solar radiation, effective photosynthetic radiation, wind speed and relative humidity, while the farmland water and submerging duration are the main factors affecting the change of soil temperature, and it exist complex non linear relationship between them. The aim of this study was constructed the soil temperature prediction model on farmland water level and environmental factors and obtained paddy soil temperature predictive value by using the data of existing water level and environmental factors. For the flooding treatment, the minimum and maximum soil temperature appeared at 7:00 and 18:00, for the drought treatment the minimum and maximum soil temperature respectively appeared at 6:00 and 14:00. This study trained artificial neural network based on back propagation algorithm (BP-ANN) through the existing data to predict the four characteristics the soil temperature of different water level control so as to obtain the soil temperature amplitude. Results showed that there was certain deviation between the predictive value and the actual value at the four characteristic moments, relative error were 1.19%, 1.34%, 2.09% and 1.07%, the predicted outcome was satisfactory. It is significant for guiding the rice irrigation and the production of practice facilitated.

Abstract: Nine cross sections of three typical rivers in the river-network plain to the east of Tai Lake were selected to measure water quality and water flow parameters monthly from September 2007 to August 2008. The spatial and temporal features of water quality were analyzed and the water pollution loads at river sections were estimated using statistic analysis. Combining land use in the riparian buffer zone interpreted form Remote Sensing images, the relationship between river water pollution load and land use were analyzed. It was clear that river water in the study area was polluted so seriously that water quality was ranked Grade V or worse. Pollutant input process in most river sections prevailed river self-purifying process. River qualities varied seasonally as that pollutant were denser in spring and winter than that in summer and autumn. Residential land in the 100 m buffer zone and industrial land in the 500 m buffer zone had the greatest influence on water quality. Forested and grassed riparian land appeared important in mitigating water quality degradation.

Abstract: Years’ precipitation data of Chongqing from 101 metrological stations has been adopted in the paper and the regression equations between annual precipitation and altitude, longitude, and height have been obtained by the use of SPSS, then elaborate simulation of Chongqing’s precipitation resources based on regression analysis was completed through the 1km×1km grid system and fitted equation. Elaborated simulation of precipitation resources was realized by best spatial interpolation method with the support of GIS; then the results of two different simulation methods were coupled in the form of linear combination to obtain the coupling simulation of spatial distribution of Chongqing’s precipitation resources, finally the precipitation resources were summed up and distributed according to different administration areas at county level and thus obtain precise simulation data of precipitation resources in each county of Chongqing. The results showed that there is a remarkable regional difference in the spatial distribution of precipitation resources of Chongqing, and it decreases from the southeast to the northwest in general, with the annual precipitation higher than 1270mm in southeast and lower than 1080mm in northwest.

Abstract: Following the varieties among soil texture, vegetation and precipitation events, the soil hydrologic process in the Source Regions of the Yangtze River varies obviously. By selecting typical segments in the headwater of Yangtze River and utilizing related data about man-made simulating rainfall and natural rainfall, the study shows that the soil moisture appeared clear change process on the vertical sections in the different physiognomy units, different vegetation types and different degradation degrees. In the dept of 0~10cm and 10~25 cm, the soil moisture change process is most evident. The hydrology process is more complex because of the most violent restriction of all kinds of external factors. In addition, the status of soil underlying surfaces is an important factor that affects soil hydrology process. The study indicates that the change of the soil moisture process in the Source Regions of the Yangtze River is one of the important factors that result in plateau vegetation degeneration, soil desertification and leanness, this change is due to the influence of natural environment and human activities.

Abstract: In order to achieve the accurate calculation of “rainfall-runoff” process combined with snowmelt and to provide a useful numerical method for estimating surface water resources in a basin, a runoff numerical calculation model of “rainfall-runoff” process combined with snowmelt was developed for a distributive hydrological model. Numerical method on “Rainfall-runoff” process was set up by applying kinematic wave theory, and calculations on snowmelt were made using energy budget method. Validity of the model was verified through numerical simulation of the observed surface flow. Results of the error analysis indicated that a large error existed between the numerical results and the observed ones without considering snowmelt whereas the error was at the permissible range of criterion (< 3 %) by considering snowmelt. The results showed that the snowmelt calculation should be considered at snow melt area when performing the runoff calculation.