Liu X.-Y.,Yellow River Conservancy Commission |
Yang S.-T.,Beijing Normal University |
Jin S.-Y.,Hydrology Bureau |
Luo Y.,Beijing Normal University |
And 2 more authors.
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2014
According to the satellite images, hydrological and meteorological data in the past six decades and the achievements in the runoff/sediment variation study, the concepts of sediment yielding coefficient and vegetation coverage ratio based on remote sensing images are introduced to set up a method, which can evaluate the effects of sediment reduction from forest and grass land over large area in the loess hilly area. The effect of sediment reduction is obvious in improving the coverage of vegetation when the coverage ratio is less than 35%-40%. The effect of sediment reduction tends to be stable and the weight of rainfall intensity is little when vegetation coverage is about 60%.
Chen X.,Hohai University |
Chen X.,Changjiang River Scientific Research Institute |
Chen X.,Columbia University |
Naresh D.,City University of New York |
And 6 more authors.
Hydrology and Earth System Sciences | Year: 2014
China is facing a water resources crisis with growing concerns as to the reliable supply of water for agricultural, industrial and domestic needs. High inter-annual rainfall variability and increasing consumptive use across the country exacerbates the situation further and is a constraint on future development. For water sustainability, it is necessary to examine the differences in water demand and supply and their spatio-temporal distribution in order to quantify the dimensions of the water risk. Here, a detailed quantitative assessment of water risk as measured by the spatial distribution of cumulated deficits for China is presented. Considering daily precipitation and temperature variability over fifty years and the current water demands, risk measures are developed to inform county level water deficits that account for both within-year and across-year variations in climate. We choose political rather than watershed boundaries since economic activity and water use are organized by county and the political process is best informed through that unit. As expected, the risk measures highlight North China Plain counties as highly water stressed. Regions with high water stress have high inter-annual variability in rainfall and now have depleted groundwater aquifers. The stress components due to agricultural, industrial and domestic water demands are illustrated separately to assess the vulnerability of particular sectors within the country to provide a basis for targeted policy analysis for reducing water stress. © Author(s) 2014.
Wang L.,Nanjing Hydraulic Research Institute |
Hu Q.,Nanjing Hydraulic Research Institute |
Hu Y.,Hydrology Bureau |
Wang Y.,Nanjing Hydraulic Research Institute |
Lin H.,Hydrology Bureau
Journal of Hohai University | Year: 2016
Based on daily water level observations of Taihu Lake during the period from 1954 to 2013, changes of three water level characteristic factors, including the highest annual water level, lowest annual water level, and mean annual water level, were analyzed and compared. In combination with rainfall and water diversion data from the Taihu Lake Basin, the dominant factors driving the three water level characteristic factors are illustrated. Results showed that changes of the highest annual water level were not significant during the period from 1954 to 2013 and its inter-annual variation was mainly controlled by the inter-annual periodic fluctuation of flood season precipitation in the Taihu Lake Basin. However, the lowest annual water level and mean annual water level of Taihu Lake were increasing significantly, with their inter-annual variations mainly controlled by the precipitation fluctuation in the Taihu Lake Basin before 2000.After 2000, their inter-annual variations were mainly controlled by the massive water diversions, such as the water diversion from the Yangtze River to Taihu Lake, maintaining high levels of the lowest annual water level and mean annual water level in spite of less precipitation. In addition, water diversion from the Yangtze River to Taihu Lake causes significant changes of the seasonal distribution characteristics of the occurrence time of the lowest annual water level of Taihu Lake. © 2016, Editorial Office of Journal of Hohai University (Nature Sciences). All right reserved.
He X.,Zhengzhou University |
Wu F.,Zhengzhou University |
Guo H.,Zhengzhou University |
Gao Y.,Hydrology Bureau
ISWREP 2011 - Proceedings of 2011 International Symposium on Water Resource and Environmental Protection | Year: 2011
Using ERDAS IMAGINE as the main tool, processed CBERS image of Zhengzhou in 2000 and 2009 years, to get images of wetland nature reserves in Zhengzhou of the two years. Extracting the NDVI information from the image of wetland nature reserves of the two years by a NDVI model, and then get a two-year NDVI change image of wetland nature reserves. While, based on the 2000 and 2009's vector data of the Yellow river, get the two-year changes image of the channel. By analyzing both the channel change and the NDVI change information, get the information that how the channel change works on the NDVI: the NDVI will has a substantial increasion after the channel changes into bottomland, while there will be a substantial decrease when the bottomland develops into a channel. But either the increase or the decrease is different in different location. Compared to 2000 year, the NDVI of nature reserves of Zhengzhou wetland in 2009 has little increasing. © 2011 IEEE.