Ma T.,Wuhan University |
Zeng W.,Wuhan University |
Zeng W.,University of Bonn |
Li Q.,Wuhan University |
And 3 more authors.
Journal of Soil Science and Plant Nutrition | Year: 2016
Experiments in soil columns were conducted to evaluate the single and interactive effects of water, salt and nitrogen stress at different sunflower (Helianthus annuus L.) growth stages in Hetao Irrigation District, China. The study factors included soil salinity (S0: ECe=2.5-3.6 dS m-1; S1: ECe=9.6-10.7 dS m-1), soil moisture (W0: 35 ％-55％ of field water capacity; W1: 75％-100％ of field water capacity), and nitrogen application rates (N0: 0 kg N ha-1; N1: 135 kg N ha-1). The results indicated that the S1 treatments increased the duration of the seedling stages by 23.91% but decreased the duration of maturity by 33.09% on average compared with the S0 treatments. Similarly, water deficit significantly retarded anthesis and prolonged the total growth period. The comprehensive stress assessment index (CSAI) was obtained using principal component analysis (PCA) and membership function analysis (MFA). The CSAIs in different treatments showed that soil salinity was the main limiting factor for sunflower vegetative growth from seeding to bud (SS1), whereas water stress dominated the development from bud to flowering (SS2) and flowering to maturity (SS3). Although statistically non-significant, nitrogen stress was intensified after bud initiation and the CSAI in W1S0N0 treatment was 40.68% lower than W1S1N1 treatment in SS3. Moreover, the interactive effects of the three factors were complicated. Our experiments suggested that adequate water supply after bud initiation and the reasonable nitrogen application rate (135 kg N ha-1) can alleviate adverse effects on sunflower reproductive growth under different saline conditions. © 2016, Sociedad Chilena de la Ciencia del Suelo. All rights reserved.
Yang Y.,Tianjin Research Institute for Water Transport Engineering |
Zhang M.,Tianjin Research Institute for Water Transport Engineering |
Li Y.,Wuhan University |
Zhang W.,Wuhan University |
And 4 more authors.
Dili Xuebao/Acta Geographica Sinica | Year: 2016
Construction of basin reservoir projects can change the water and sediment transport processes in the lower reaches. The effects of the Three Gorges Project (TGP) on water and sediment transport in lower reaches are emerging. Specifically: (1) The duration and volume of floods in the lower reaches of TGP declined sharply. The sediment value was of such a low concentration that the water was nearly clear. The suspended sediment discharge gradually recovered downwards but its total amount still could not outcompete the annual average of that before the impoundment of TGP. (2) The sediment with d > 0.125 mm recovered to some extent in 2003-2014 (more in 2003-2007 than in 2008-2014) and basically recovered to the average value before the impoundment at the Jianli Station. After recovery, its transport trend in the lower reaches was in line with that before the impoundment. (3) After the impoundment, sediment with d < 0.125 mm recovered to some extent but its total amount was still less than the average of before the impoundment. (4) The recovery of sediment with d > 0.125 mm was mainly from river-bed erosion but with an amount not exceeding 44 million t/y which was primarily limited by duration and average flow of floods and secondarily by the upper mainstream, tributaries between river sections and the sub-sink effects of lakes. Recovery of the suspended sediment with d < 0.125 mm was controlled by the upper mainstream, tributaries between river sections, the sub-sinks of lakes and river-bed compensation. The suspended sediment compensation from river-bed decreased due to the coarsening of bedsands. (4) In 2003-2007 and 2008-2014, both coarse and fine sands were eroded in the Yichang-Zhicheng section in the upper Jingjiang River while coarse sands deposited and fine sands eroded in the lower Jingjiang River. In the Hankou-Datong section, coarse sands deposited and fine sands eroded. From 2003 to 2007, coarse sands deposited while fine sands eroded in the Chenglingji- Hankou section. In 2008-2014, both coarse and fine sands eroded in the Chenglingji-Hankou section. The differences were caused by the duration and volume of the floods in the Luoshan Station. © 2016, Science Press. All right reserved.
Wang T.,Huazhong University of Science and Technology |
Zhou J.,Huazhong University of Science and Technology |
Jiang Y.,Flood Control and Drought Relief Office of Hubei Province |
Weng Z.,Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute |
And 2 more authors.
Journal of Natural Disasters | Year: 2016
Refuge migration in the flood attack makes up an important part of the emergency refuge system. A reasonable refuge migration can effectively reduce the social, economic losses and casualties induced by flood disaster. In view of seeking the optimal evacuation path in the flood disaster, a new network-flow-based migration strategy model which considers road classification, capacity of shelters, evacuation unit, and the traffic jam in the evacuation process was proposed in this paper, and the Jingjiang flood diversion area was taken as the research object to validate its effectiveness. Also, the result from the network flow-based model was compared with the existing evacuation scheme. The comparison showed that, the new evacuation strategy reduced time-consumption and route length, and relieved the congestion in the evacuation process. The proposed new network flow model has good applicability. It can be also applied to other flood impact areas. © 2016, Science Press. All rights reserved.
Shu C.W.,Wuhan University |
Han S.S.,Wuhan University |
Kong W.N.,Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute |
Dong B.L.,Wuhan University
IOP Conference Series: Earth and Environmental Science | Year: 2016
Extreme urban flood events occur frequently in China, often leading to heavy casualties. Thus, it is of great importance to study the mechanism of the instability of the human body in floodwaters. The results of such research can provide scientific reference for city flood control standards. In this paper, a formula for the incipient velocity of the human body, during toppling instability in floodwaters, was derived based on mechanical characteristics, instability mechanism, and critical conditions during instability. A series of flume experiments were conducted to investigate the incipient velocity of two 3D printed human body models of different sizes; the resultant experimental data was used to determine parameters in the derived formula. Additionally, grip strength was taken as a standard of a person's ability to withstand floodwaters. Finally, crowd factors were introduced, and based on this study, a criterion for the toppling instability of different subjects in floodwaters was proposed. Compared to the results of previous studies, the proposed formula can better predict the instability of the human body in floodwaters. © Published under licence by IOP Publishing Ltd.
Zhou Y.,Wuhan University |
Zhou Y.,Changjiang River Scientific Research Institute |
Guo S.,Wuhan University |
Xu J.,Changjiang River Scientific Research Institute |
And 2 more authors.
Journal of Hydro-Environment Research | Year: 2015
For floodwater utilization, seasonal flood-limited water level (FLWL) plays a more and more role in compromising between flood control and beneficial use in reservoir operation during flood season. The prerequisite of determining a seasonal FLWL is that flood control risks should not be increased in reservoir operation as compared with the original operating rule using a fixed FLWL. In this paper, a risk analysis model for deriving seasonal FLWL that considers uncertainties of hydrology, hydraulic condition and reservoir volume is proposed and developed. The risk analysis model consists of three modules: the first is a hydrological uncertainty analysis module, the second is a hydraulic uncertainty analysis module, as well as the third is a reservoir volume uncertainty analysis module. The acceptable risk constraints are given, and the upper limitation of seasonal FLWL is estimated by using Monte Carlo simulation. The China' Wanjiazhai reservoir (WR) is selected as a case study. The application results show that (1) the hydrological uncertainty and the reservoir volume uncertainty are major contribution factors to seasonal FLWL while the discharge capacity uncertainty is inapparent influence of seasonal FLWL, (2) the most reasonable upper limitations of seasonal FLWL in WR during main-flood and post-flood seasons are 972.3 and 974.1m, respectively, which considers hydrological uncertainty, minimum hydraulic capability and minimum reservoir volume. The relative magnitudes of seasonal FLWL and the flood water utilization rates during main-flood and post-flood seasons are 0.65% and 61.05%, as well as 0.84% and 81.60%, respectively. Seasonal FLWL can effectively enhance flood water utilization rate without lowering the annual flood control standard compared with annual FLWL. © 2015 International Association for Hydro-environment Engineering and Research, Asia Pacific Division.
Cai J.,China Three Gorges University |
Cai J.,Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute |
Liu J.,China Three Gorges University
Yantu Lixue/Rock and Soil Mechanics | Year: 2013
A large three-dimensional model of double hole four dimensional Danba hydropower station diversion tunnel excavation is established, and rock mechanics are calculated by using the Mohr-Coulomb model finite element analysis method and unloading rock mass theory and method, and the effect of stress on tunnel is considered to excavate in different depths of tunnel face, from the hole to a certain depth. The displacement changes of tunnel faces at different key points at each excavation are counted. In comparison, the depth of the best tunnel face propulsion should be selected. Under the propulsion depth, the amount of reserved displacements at different segments and locations of holes is counted to provide data support of necessity of advanced support so as to ensure the construction process successfully. It provides references for other similar engineering design.
Liu Y.Y.,Changjiang Water Resources Commission Changjiang Institute of Survey |
Liu B.J.,Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute
Applied Mechanics and Materials | Year: 2014
Hydrologic responses to climate change have become a great challenge and attracted widespread attention of the researchers. The mountainous Qingyi River watershed in the southwest, China, had experienced significant climate change in the past three decades. It is necessary to investigate the hydrologic responses to these changes. Therefore, the effect of climate change on evapotranspiration (ET), surface runoff, baseflow and streamflow were assessed using Variable Infiltration Capacity (VIC) hydrologic model. The Mann-Kendall test analysis was first used to identify the long-term change in precipitation and temperature over the period of 1980-2010. It revealed that there is a significant change in annual temperature particularly in February, March, July and September, whereas an insignificant change in annual precipitation was founded. Hydrologic simulations show that hydrologic responses to climate change were varied from region to region. Surface runoff was more sensitive than ET and baseflow. Monthly variation of the hydrologic processes, especially the change in surface runoff, was mainly attributed to seasonal variation in precipitation. The results of this research can be a useful source of information for the decision making in water resources management and protection. © (2014) Trans Tech Publications, Switzerland.
Lei J.,Huazhong University of Science and Technology |
Nian F.,Huazhong University of Science and Technology |
Nian F.,Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute |
Feng G.,Huazhong University of Science and Technology |
And 3 more authors.
Chinese Journal of Environmental Engineering | Year: 2016
Eutrophication is the major main negative consequence of dredging in landscape water. To study the combined effects coation of dredging and microbial remediation, three different groupstreatments, which were classified as dredging, microbial remediation, and remediation after dredging, were studied based using on a simulated laboratory model. The results showed that the release of ammonia was reduced in dredged water and that microbial activities stimulated the releasing of ammonia, which increased the risk for eutrophication. However, nNitrification was increased while and denitrification was weakened after dredging, thus retarding total nitrogen removal. Therefore, supplementationed with nitrogen cycle relatedbeneficial microorganisms could stimulate denitrification, to remove dissolved nitrogen, and mediate the precipitation and deposition of nitrogen in to the sediments, which as has been observed provided for during the bioremediation of eutrophic lakes. This study confirmed that combining dredging with microbial remediation reduces the accumulation of nitrogen and eliminates the risk of blue algae blooms. Thus, the combined technique is dredging was an effective way strategy to for stabilizinge water quality by reaccumulation nitrogen and of blue algae bloom. © 2016, Science Press. All right reserved.