Advanced Materials Research Vols. 1010-1012

Abstract: To elucidate the relationship between stable isotopes of precipitation (SIP) and the extreme drought in Kunming area, based on the stable isotopes data of the GNIP in Kunming site from 1986 to 2003, the precipitation line equation is brought forward and the seasonal change rule of stable isotopes are discussed. The stable isotopic compositions of precipitation exhibit great diversities in different seasons during to influences of multiple factors, such as monsoon, rainfall amount moisture source and others. The δ¹⁸O values in rainwater exhibit significant seasonal variations, the average of-10.12‰ in rainy season, the dry season is-4.5‰, having lower values in the rainy season and higher one in the dry season. The amount effect of precipitation is very distinct, that concealed the temperature effect. Got the special geographical position, d values present unique characteristics, the average of d values is 10.78‰ in rainy season, and is 4.86‰ in dry season, the mean value is generally lower than most parts of the world.

Abstract: Based on the comprehensive analysis of domestic and foreign scholars on the status on the basis of the definition, the water resources carrying capacity, we put forward a more exact definition of the water resources carrying capacity and expound its connotation, by analyzing of the research on water resources carrying capacity and its development trend of the scholars at home and abroad for many years, we put forward the effective measures to deal with the water resources.

Abstract: The seawater intrusion of the Gou River, China and the impact of Houshan Reservoir are studied using numerical simulations. The results show that the natural seawater intrusion length is 1.66km for Gou River estuary, and once the Houshan reservoir is constructed the intrusion length increases to 1.98km, which is 0.32km longer than the natural condition. At present, the highest salinity at the estuary is around 18‰, and recovers to fresh water environment in 3.0km. After the construction of the reservoir, the salinity value increase to 20‰ at the estuary. To around 2.0km from the estuary, the salinity recovers to the natural condition.

Abstract: In order to reduce the losses of drought and flood disasters, the spatiotemporal characteristics and evolution of drought and flood in Northeast China were analyzed by Z index based on the monthly precipitation data of 111 meteorological stations during 1961-2013.The Mann–Kendall test and linear regression analysis were used to analyze the change trend of drought and flood. The main conclusions are as follows: (1) Affected by the monsoon climate, flood is concentrated in summer extensively and frequently in Northeast China, while drought is concentrated in winter. (2) Drought mainly occurs in January, February, March, November and December concentrated in east and southeast of Northeast China. Flood is found in May to September. Especially The highest frequency of flood is observed in July (up to 84.9%), next is August with 69.8%, and followed by June with 48.7%. (3)7 months in a year (March-June and October-December ) show wetting trend over Northeast China , while 3 months (July-September) are observed drying trends. Significant upward trend of wet conditions occur in March and December; while significant trends towards drier conditions occur in September. (4) Drought areas dominate the Northeast China in January, February, March, November and December with a decreasing trend. Flood areas dominate the Northeast China from May to September. Extensive flood is most likely occurred in July. Flood area in May and June show an increasing trend, while a decreasing trend is from July to September.

Abstract: Cyclone and cold front are the important weather systems causing storm floods in Dahuofang reservoir. Through analyzing the precipitation daily distribution and flood processes affected by cyclone and cold front weather systems, the influence of different weather systems on reservoir flood control has been summarized. The study results show that flood processes caused by compound weather systems are the most serious threat to reservoir flood control, while flood processes caused by single cold front system have the least risk to reservoir flood safety and the flood threat caused by single cyclone is intermediate.

Abstract: According to the relationship between the sustainable development and the optimal allocation of water resources, the evaluation system based on the sustainable development of optimal allocation of water resources is established in respect of the index system water resources carrying capacity, the social economic and ecological environment. Henan is taken as an example to evaluate the sustainable degree with actual index value from the regional water resources supply and demand balance of simulation results. Its results have a guiding significance for the water resources planning, management and sustainable utilization.

Abstract: Abstract. Datong hydrological station is the last control station in the Changjiang River mainstream, and its runoffs have great significance on evolution of the tideway and the estuary of the Changjiang River. Therefore, this paper compiled long term series (1950~2010) of daily water discharges at Datong gauging station, and utilized the statistic methods to analyze the long term evolution characteristics of the Datong runoff. The results show that: (1) Inter-annual variability of runoffs was relatively stable, with average fluctuation range below 104m3/s, which may be caused by the location of the river basin and regulation of many large scale lakes; (2) The monthly runoffs have distinctly seasonal variation characteristics, wherein, the runoffs from June to September occupy 51% within a year, and the other months occupy the residual 49%, moreover, the runoff proportion of flood season within 2003~2010 has a slight decline of 2%, compared with that of 1995~2002.

Abstract: Abstract. The saltwater intrusion in the Yangtze River Estuary is very frequent and complicated with a great effect on freshwater supply in Shanghai and nearby cities. By using the hydrologic data observed in dry season, the temporal and spatial variation of the saltwater intrusion in the Yangtze River Estuary were analyzed. The results show that the saltwater intrusion of the south branch is mainly induced by the saltwater spilling over from the north branch, which causes the Chenhang reservoir being plagued by saltwater intrusion during dry season. As the saltwater group from the north branch moving downward along the south branch, the longitudinal salinity distribution present a high-low-high shape during spring tide cycle, low-high-low-high shape during medium tide cycle and low-high shape during neap tide cycle along the south branch-south channel-south passage. Moreover, the north branch is controlled by high saline water with the increase of the salinity in the upstream reach in medium and spring tides, but this phenomenon is vanished in neap tide. In addition, the vertical distribution of salinity is more homogeneous in shoals than that in deep channels, which is induced by mixing degree in water column.

Abstract: The phytoplankton blooms in the tributary bays have become the most serious environmental problem in Three Gorge Reservoir (TGR), China. In order to understand the mechanism of those phytoplankton blooms, the factors to affect the eutrophication and Phytoplankton blooms have been summarized. Generally, in lakes eutrophication is a natural evolutionary process, which is affected by light, temperature, nutrients, predation, migration and stratification. Recent decade's human activities played a role to promote this evolution but not to change the evolutionary direction. However, in the TGR, the changed hydrodynamics caused by the TGD are considered to be the most important triggers to the phytoplankton blooms, especially the longer residence time, thermal density currents and stratification.

Abstract: The effects of different land use types on soil quality was studied in cultivation areas of the mango, longan, greening plant, Ziziphus mauritiana, shelter-forest, and macadamia, as well as in the undeveloped land of the South Subtropical Crops Research Institute. Different land use types showed various effects on soil quality. Higher soil pH and bulk densities in the undeveloped land, higher content of available phosphrous (P) and available potassium (K) in macadamia cultivation areas, and higher organic matter content in shelter-forest land were observed relative to those of other land use types. The integrated fertility index of soil was ranked as follows: shelter-forest land>undeveloped land> Ziziphus mauritiana land>macadamia land and>mango land>longan land>greening plant land. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.