Effects of shrub-grass patterns on soil detachment and hydraulic parameters of slope in the Pisha sandstone area of Inner Mongolia,China

The characteristics of soil holding capacity for different shrub-grass patterns are important to research the mechanisms regulating vegetation on slopes.The objective of this study was to describe the characteristics and mecha-nisms of soil erosion and hydraulic parameters under differ-ent vegetation patterns in the Pisha sandstone area of Inner Mongolia on lands of 8°slope gradient.We carried out field scouring experiments on five different shrub-grass patterns as treatments,viz no shrubs(GL),shrubs on the upper part of the slope(SU),middle part of the slope(SM)and lower part of the slope(SL).We designated bare slope(BL)as the control.We employed three different water flow rates(15,20,30 L·min^(−1)).Our results showed that the contribution of plant root systems to slope sediment reduction ranged from 64 to 84%.The root systems proved to be the main contributing factor to reduction of erosion by vegetation.The relationship between soil detachment rate,stream flow power,and flow unit stream power under different scouring discharge rates showed that soil detachment declined in rank order as:BL>GL>SU>SM>SL.The SL pat-tern had the lowest soil detachment rate(0.098 g·m^(−2)·s^(−1)),flow stream power(2.371 W·m^(−2)),flow unit stream power(0.165 m·s^(−1))and flow shear stress(16.986 Pa),and proved to be the best erosion combating pattern.The results of decision coefficient and path analysis showed that stream power was the most important hydraulic parameter for describing soil detachment rate.The combination of stream power and shear stress,namely Dr=0.1ω−0.03τ−0.56(R^(2)=0.924),most accurately simulated the soil detachment characteristics on slopes.Our study suggests that the risk of soil ero-sion can be reduced by planting shrub-grass mixes on these slopes.Under the conditions of limited water resources and economy,the benefit of sediment reduction can be maxi-mized by planting shrubbery on the lower parts of slopes.

Models for Initial Allocation of Emission Permits in a River Basin During Industrial Development:A Case Study of Huaihe River Basin,China

At present,water pollutant emission trading plays an increasingly important role in pollution control in many foreign countries,and its pilot studies and demonstration have also been started in China.In order to solve the problem of initial allocation of emission permits:premise and basis of emission trading in a river basin,basic principles on initial allocation of actual emission permits in China are put forward.And it is thought that local development stage of industry should be taken into full account for initial allocation model of emission permits.There are five different allocation models in different development stages of industry,including models like distribution according to needs,improved same-rate reduction,performance,integration and environmental capacity,etc.The initial allocation of emission permits in various basins should choose a suitable model in accordance with their respective development stages.It is suggested in this article that integrated allocation model should be a main choice for current development stage of industry in China.

Reconstruction of the adenosine system by bone marrow-derived mesenchymal stem cell transplantation

In the present study, we transplanted bone marrow-derived mesenchymal stem cells into the CA3 area of the hippocampus of chronic epilepsy rats kindled by lithium chloride-pilocarpine, Immunofluorescence and western blotting revealed an increase in adenosine A1 receptor expression and a decrease in adenosine A2a receptor expression in the brain tissues of epileptic rats 3 months after transplantation. Moreover, the imbalance in the A1 adenosine receptor/A2a adenosine receptor ratio was improved. Electroencephalograms showed that frequency and amplitude of spikes in the hippocampus and frontal lobe were reduced. These results suggested that mesenchymal stem cell transplantation can reconstruct the normal function of the adenosine system in the brain and greatly improve epileptiform discharges.

Discussion on wind factor influencing the distribution of biological soil crusts on surface of sand dunes

Biological soil crusts are widely distributed in arid and semi-arid regions, whose formation and development have an important impact on the restoration process of the desert ecosystem. In order to explore the relationship between surface airflow and development characteristics of biological soil crusts, we studied surface airflow pattern and development characteristics of biological soil crusts on the fixed dune profile through field observation. Results indicate that the speed of near-surface airflow is the lowest at the foot of windward slope and the highest at the crest, showing an increasing trend from the foot to the crest. At the leeward side, although near-surface airflow increases slightly at the lower part of the slope after an initial sudden decrease at upper part of the slope, its overall trend decreases from the crest. Wind velocity variation coefficient varied at different heights over each observation site. The thickness, shear strength of biological soil crusts and percentage of fine particles at crusts layer decreased from the slope foot to the upper part, showing that biological soil crusts are less developed in high wind speed areas and well developed in low wind speed areas. It can be seen that there is a close relationship between the distribution of biological soil crusts in different parts of the dunes and changes in airflow due to geomorphologic variation.

Technical analysis on the emergency handling of Tangjiashan barrier lake

This paper gives a brief introduction to the emergency handling of Tangjiashan barrier lake.Some technologies for the application of geological and topographical data are summarized and the mechanism of formation of a barrier lake is analyzed.Based on the safety status evaluation,the dam breach flood point is calculated.The paper concludes with discussion of the practical effects of emergency handling scenarios and different drainage channel designs.

Study on the Suitable Water-Saving Irrigation Technology for Mining Areas in the Northwestern Arid Desert Regions in China

Water is the key factor to ensure plant survival in the process of ecological restoration in the coal base of China northwest deserts. On the premise of meeting the mine production and living water demands, we should take measures such as dirt wastewater treatment and water-saving irrigation to increase income and reduce expenditure and allocate limited water re-sources rationally, to provide mining area ecological restoration maximum usable water resources. The mining dump has large slope and thin soil layer and it is easy to produce surface runoff. So it is particularly important to study the irrigation technology needed to satisfy vegetation restoration, on the premise of guaranteeing not to produce surface runoff and the slope stability. In this paper, through field plot test, the suitable irrigation method for mine slope, slope surface soil moisture migration characteristics and slope stability analysis were studied. Results show that three slope ir-rigation technologies have their own advantages and disadvantages. On the whole, the effect of drip irrigation is the best, micro spray irrigation is the second, infiltrating irrigation is not ideal. The permeability of mine soil slope is very strong, the infiltration rate of the slope direction is the high-est, inverse slope infiltration rate is lowest. In the process of irrigation, with the increase of soil moisture content, slope safety factor is the decreased obviously, the whole slope surface soil moisture content is 14% for the slope stability safety threshold.

中国西北水资源的脆弱性(英文)

The vulnerability of water resources in Northwest China were described in terms of the sensitivity and adaptability of water resource systems effected by climate change and human activities. Most measures that reduce the vulnerability are closely linked with decreasing the sensitivity of climate change or human activity. In other words, the interaction of climate factors and human activity may either exacerbate or mitigate the vulnerability of water resources. Studying both positive and negative events in terms of sustainable utilization of water resources in the past, may establish the sound strategic base in regulating further human activity. The knowledge and correct awareness of recent and future tendencies of hydro-climatic condition may serve as an imperative scientific base for taking such actions as: 1) undertaking structural and non-structural (e.g., policy, law, and forecasting) measures in a reasonable way; 2) coordinating and allocating both differences of time and space between inflow water and water use and between water yield area and water assumption area as

Characteristics of surface runoff in a sandy area in southern Mu Us sandy land

To better understand the key role of biological soil crusts(BSCs) in redistribution processes of limited water resources in semi-arid sandy ecosystems,surface runoff over BSCs in a sandy area in the southern Mu Us sandy area was observed in this study.The results indicated that runoff occurred twice among six rainfall events during the experimental period.Runoff yields varied among types of BSCs,and that they increased in the following order:light algae crusts,dark algae crusts and moss crusts.These findings showed that runoff yields were increasing with the development of BSCs.The percentage of runoff in individual rainfall events increased from light algae crusts to moss crusts,which indicated that the redistribution ratios of different types of BSCs differed.Surface runoff of BSCs may be influenced by rainfall,rain intensity,degree of water saturation of the BSCs before the rain and degree of development of BSCs.Formation of BSCs on the surface of sand dunes changed the spatial distribution pattern of water in this semi-arid sandy ecosystem,which increased the heterogeneity of resources such as water and nutrients.Therefore,making appropriate disturbances of BSCs during storm season is beneficial to maintaining the balance of natural resources in the semi-arid sandy ecosystem.

Changes in forest biomass carbon stock in the Pearl River Delta between 1989 and 2003

Forest ecosystems play a significant role in maintaining climate stability at the regional and global scales as an important carbon sink.Regional forest carbon storage and its dynamic changes in the Pearl River Delta have been estimated using the continuous biomass expansion factor(BEF)method based on field measurements of forests plots in different age classes and forest inventory data of three periods(1989–1993,1994–1998,1999–2003).The results show that regional carbon storage increased by 16.76%,from 48....

ASSESSMENT ON DISASTER RISK REDUCTION OF TROPICAL STORM WA SHI

In December,2011,the world’s second most deadly disaster of the year,Tropical Storm Washi(known as Sendong in the Philippines)landed along the east coast of Mindanao,Philippines,causing 1,292 deaths,1,049 missing,2,002 injured,and total 695,195 people(110,806 families)affected.This paper introduced briefly the hydro-meteorological characteristics of Washi,and assessed its devastating impacts on society and economy,and the response and recovery taken by the Philippines government during the whole period of Washi.Based on the assessment of impact of disaster,the paper indicated the gaps and needs on aspects of DRR actions and identified the future challenges on typhoon related disaster preparedness and reduction in the Philippines.Finally,the report provided the recommendations within the framework of the activities of Typhoon Committee to improve and enhance the capacity building on typhoon related disaster reduction in the Philippines.

Adistributedeco-hydrologicalmodelanditsapplication

Eco-hydrological processes in arid areas are the focus of many hydrological and water resources studies. However, the hydrological cycle and the ecological system have usually been considered separately in most previous studies, and the correlation between the two has not been fully understood. Interdisciplinary research on eco-hydrological processes using multidisciplinary knowledge has been insufficient. In order to quantitatively analyze and evaluate the interaction between the ecosystem and the hydrological cycle, a new kind of eco-hydrological model, the ecology module for a grid-based integrated surface and groundwater model(Eco-GISMOD), is proposed with a two-way coupling approach,which combines the ecological model(EPIC) and hydrological model(GISMOD) by considering water exchange in the soil layer. Water interaction between different soil layers is simply described through a generalized physical process in various situations. A special method was used to simulate the water exchange between plants and the soil layer, taking into account precipitation, evapotranspiration, infiltration, soil water replenishment, and root water uptake. In order to evaluate the system performance, the Heihe River Basin in northwestern China was selected for a case study. The results show that forests and crops were generally growing well with sufficient water supply, but water shortages,especially in the summer, inhibited the growth of grass and caused grass degradation. This demonstrates that water requirements and water consumption for different kinds of vegetation can be estimated by considering the water-supply rules of Eco-GISMOD, which will be helpful for the planning and management of water resources in the future.

A two-dimensional Richards equation solver based on CVODE for variably saturated soil water movement

A numerical model of two-dimensional soil water movement under surface drip irrigation condition was developed. The physical process of soil water movement is described by 2D Richards equation,and the upper boundary condition is depicted by the improved moving ponded area boundary. The partial differential equation(PDE) is transformed into ordinary differential equations(ODEs) through spatial semi-discretization and numerically solved by an ordinary differential equation solver(CVODE) . The numerical and field experiments indicate the good performance of the model in terms of accuracy and efficiency. The model provides a useful tool for long-term simulation of soil water movement under surface drip irrigation. Also,the model can serve as a general 2D Richards equation solver for variably saturated soil water movement,which is named as TIVS model(Tsinghua Integrated Variably Saturated soil water movement model).

BRIEF INTRODUCTION TO SYNERGIZED STANDARD OPERATING PROCEDURES FOR COASTAL MULTI-HAZARDS EARLY WARNING SYSTEM

The most countries surrounding the Indian Ocean as well as Southeast Asian countries do not have operational experience in handling a combination of tsunami and other coastal hazard early warning systems.The challenge faced by warning providers,media,disaster managers,and coastal communities is in understanding the similarities and differences among different coastal hazards and the characteristics of the early warnings that are issued.There is a strong need to create synergies among different types of coastal hazard early warnings by reviewing the relevant existing standard operating procedures.These synergies can be achieved through identifying specific gaps and needs for making the existing early warning systems fully operational for the use in multi-hazards context.The project of Synergized Standard Operating Procedures for Coastal Multi-Hazards Early Warning System(SSOP) was proposed by Typhoon Committee Secretariat with the objectives of developing the SSOP Manual/Handbook and establishing the cooperation mechanism on coastal multi-hazard early warning among the target countries.The project will mainly focus on the meteorological and hydrological services for affected areas which become more vulnerable to natural disasters after tsunami and other costal disasters.The synergized standard operating procedure should be easier understandable and interpretable for decision makers,forecasters and dwellers.

Theories and calculation methods for regional objective ET(evapotranspiration):Applications

The regional objective ET(evapotranspiration) is defined as the quantity of water that could be con-sumed in a particular region.It varies with the water conditions and economic development stages in the region.It is also constrained by the requirement of benign environment cycle.At the same time,it must meet the demands of sustainable economic growth and the construction of harmony society.Objective ET based water resources distribution will replace the conventional method,which empha-sizes the balance between the water demand and the water supply.It puts focus on the reasonable water consumption instead of the forecasted water demand,which is usually greater than the actual one.In this paper,we calculated the objective ET of 2010 year level in Tianjin by an analysis-integra-tion-assessment method.Objective ET can be classified into two parts:controllable ET and uncontrol-lable ET.Controllable ET includes the ET from irrigation land and the ET from resident land,among which the former can be calculated with soil moisture model and evapotranspiration model,while the latter can be calculated by water use ration and water consumption rate.The uncontrollable ET can be calculated with the distributed hydrological model and the remote sensing monitoring model.The two models can be mutually calibrated.In this paper,eight schemes are put forward based on different portfolios of water resources.The objective ET of each scheme was calculated and the results were assessed and analyzed.Finally,an optimal scheme was recommended.

RECENT PROGRESS IN URBAN FLOOD RISK MANAGEMENT IN THE TYPHOON COMMITTEE AREA

The typhoon region is urbanizing rapidly with the increasing trend of population and economy. Fast urban development has also brought many potential troubles, and urban flooding is one of the most serious. Many aspects of urban areas are vulnerable to flood disasters and climate change. How to minimize losses caused by urban floods and harmonize relationship between floods and socio-economic development has been a significant problem that governments and international organizations work on. In recent years, risk management ideas have been introduced into flood management in the Typhoon Committee Area(TCA). This paper presents a brief review of urban flood issues and flood management in the TCA, and identifies good practices and research progress of urban flood risk management from the model cities study. In addition, some ideas about the improvement of urban flood risk management are also discussed in the paper.

PROGRESSES AND CHALLENGES ON QPE/QPF UTILIZATION IN HYDROLOGY

With the development of space technology, the accuracy of weather forecasts has steadily improved over the years. Accordingly the QPE/QPF products have been improving so that it is possible to be gradually applied for hydrological purposes. However, it has been challenging to integrate QPE/QPF into real-time operational flood forecasting and disaster monitoring and warning because of the crucial gaps on temporal-spatial resolution, systematic uncertainty and methodology of application. Aiming to the challenges, meteorologists and hydrologists have made great efforts jointly and achieved evident progresses on improving QPE/QPF products to get closer to the hydrological requirements. This paper presents an overview of hydrological prospective on QPE/QPF products, challenges and gaps in QPE/QPF application in real-time operation, and some of the recent studies on improving QPE/QPF products for hydrological purposes.