A distributed runoff model for inland mountainous river basin of Northwest China

In order to predict the futuristic runoff under global warming, and to approach to the effects of vegetation on the ecological environment of the inland river mountainous watershed of Northwest China, the authors use the routine hydrometric data to create a distributed monthly model with some conceptual parameters, coupled with GIS and RS tools and data. The model takes sub-basin as the minimal confluent unit, divides the main soils of the basin into 3 layers, and identifies the vegetation types as forest and pasture. The data used in the model are precipitation, air temperature, runoff, soil weight water content, soil depth, soil bulk density, soil porosity, land cover, etc. The model holds that if the water amount is greater than the water content capacity, there will be surface runoff. The actual evaporation is proportional to the product of the potential evaporation and soil volume water content. The studied basin is Heihe mainstream mountainous basin, with a drainage area of 10,009 km2. The data used in this simulation are from Jan. 1980 to Dec. 1995, and the first 10 years' data are used to simulate, while the last 5 years' data are used to calibrate. For the simulation process, the Nash-Sutcliffe Equation, Balance Error and Explained Variance is 0.8681, 5.4008 and 0.8718 respectively, while for the calibration process, 0.8799, -0.5974 and 0.8800 respectively. The model results show that the futuristic runoff of Heihe river basin will increase a little. The snowmelt, glacier meltwater and the evaportranspiration will increase. The air temperature increment will make the permanent snow and glacier area diminish, and the snowline will rise. The vegetation, especially the forest in Heihe mountainous watershed, could lead to the evapotranspiration decrease of the watershed, adjust the runoff process, and increase the soil water content.     

郁江南宁17场洪水之合成面雨量特征分析

对郁江南宁 17场洪水的合成面雨量分布特征作了较系统的分析 ,发现引发南宁洪水的主要天气系统及其配置、合成面雨量的流域值及“6 8.8”大洪水和“0 1.7”特大洪水的合成面雨量表征 ,对今后进一步做好重大洪水的气象服务具有十分积极的意义     

东亚夏季风强弱年物理量的逐候变化及其对松嫩流域降水的影响

用施能定义的东亚夏季风指数,分别找出典型夏季风强弱年1961和1980年,分析水平风速、假相当位温、高度等的逐候变化特征与盛夏季节松嫩流域逐候降水量的关系。分析表明:东亚夏季风强弱对松嫩流域盛夏降水量有显著影响。在强夏季风年,较大的南风、较高的假相当位温、较深的东亚大槽使降水持续偏多。同时还发现,无论夏季风强弱,假相当位温高值总是与多降水相联系。     

DESIGN OF SEDIMENT FLUSHING OUTLETS

1 INTRODUCTION Considerable amount of sediment discharge enters in a canal at the head works. This sediment discharge is carried safely as the slopes of the canal in the head reaches are large. Subsequently, for economy, the slopes of canal are reduced in the downstream reaches. This makes the sediment concentration far excess of its carrying capacity. This excess sediment has to be removed by suitable design of a sedimentation basin. Also, one of the requirements for successful function…     

网状河流研究进展述评

网状河流作为一种新的冲积河流类型已经引起地貌学家、水利学家和沉积学家的关注 ,成为河流地貌领域、河流沉积领域以及河流水动力领域的研究热点之一。本文在介绍网状河流基本概念的基础上 ,综合国内外的研究成果 ,从河流的平面形态、边界条件、沉积特征、水动力条件以及在河型演化序列中的位置等方面 ,对网状河流的研究进展作一较全面的述评 ,并指出目前研究的薄弱环节 ,以利于研究者把握网状河流的研究现状 ,并推动对网状河流的进一步探讨。     

三江平原沼泽性河流径流演变的驱动力分析

在分析三江平原典型沼泽性河流挠力河径流演变特征及趋势的基础上，应用灰色关联分析和径向基函数网络等方法，探讨了引起径流量减少和发生突变的原因，分析结果表明：当地河川径流演化与沼泽化流的地理特征以及近50年来沼泽及沼泽化土地的大规模开垦和水资源的开发利用有密切的关系，人类活动是本区河川径流演变的主要驱动力，气候变化在径流演变中所起的作用相应减少，沼泽湿地对区域水系统的水量平衡产生着重要的影响，在流域下垫面已明显变化，水文循环出现变异的情况下，必须加强沼泽湿地保护的水的调控和管理。     

河岸带及其生态重建研究

河岸带具有重要的生态、社会、经济和旅游价值。河岸带研究以生态学、水文学和地貌学为基础涉及多种学科和技术。我国河岸带及其退化生态系统重建理论与实践研究均较为薄弱。本文基于 6年河岸带退化生态系统重建的科学研究实践 ,阐述了河岸带研究的意义、内容及其生态、经济和社会效能 ;分析了河岸带生态重建的理论与技术方法 ,探讨了河岸带滩地生态重建的措施及河岸带今后管理的目标、原则和方向 ,并以皖天柱山麓潜水河岸带滩地生态重建为例进行了验证     

西藏帕隆藏布河谷崩塌滑坡、泥石流的分布规律

西藏帕隆藏布河谷崩塌滑坡、泥石流灾害严重。崩塌滑坡、泥石流的分布 ,因谷坡坡向的水热条件差异而导致坡向差异 ,因地貌发育和形态的沿程分异显现沿程差异 ,因其促发条件的差异又显现灾种差异。采用有序样品最优分割和方差分析等定量方法 ,揭示了崩塌滑坡、泥石流的差异性分布规律 :全河段可分为上游峡谷泥石流密集段 ,中游宽谷泥石流及崩塌滑坡较密集段 ,和下游、拉月曲峡谷崩塌滑坡、泥石流极密集段 ;北岸崩塌滑坡和泥石流比南岸数量多、规模大 ;崩塌滑坡有向下游增大增多之趋势。进而对道路平面选线原则提出了建议。     

Simulation of braided river flow using a new cellular routing scheme

Results are presented from a numerical simulation of two-dimensional flow patterns in a braided river using a simple cellular routing scheme. The results of the routing scheme are compared with field measurements of discharge per unit width obtained within the study reach at low flow and, for higher flows, with the predictions of a more sophisticated hydraulic model that solves the two-dimensional shallow water form of the Navier–Stokes equations. An assessment is made of the sensitivity of the routing scheme to variations in the values of its main parameters, and appropriate values are determined based on the physical characteristics of the study site and available flow measurements. It is shown that despite the simple approach adopted by the cellular routing scheme to simulate processes of water redistribution, it is able to replicate accurately both the field data and the results of the more sophisticated hydraulic model. These results indicate that the routing scheme outlined here is able to overcome some of the limitations of previous simple cellular automata models and may be suitable for use in modelling bedload transport and channel change in complex fluvial environments. As such this research represents a small and ongoing contribution to the field of numerical simulation of braided river processes.     

Urban Environmental Justice Indices

Environmental justice is the principle that environmental costs and amenities ought to be equitably distributed within society. Due to the ethical, political, and public–health implications, and because many choices confront those researching environmental justice, standardized measures are needed to inform public dialogue and policy. We develop and test seven indices on three Colorado cities to measure the relationship between the distribution of environmental hazards and minority and poverty–stricken populations, and recommend the Comparative Environmental Risk Index as a preliminary, standardized measure for comparing urban areas. This index is particularly relevant to disadvantaged communities, regional planning organizations, environmental–justice networks and scholars, and state and federal agencies.