鄂西三峡库区森林变化对河川径流泥沙的影响

该文针对鄂西三峡库区森林变化及河川径流泥沙的特点,采用流域自身对比法,以森林覆盖率和活立木总蓄积量为主要森林指标,分析研究了森林变化与年径流、枯水期径流、洪枯比及年输沙模数的关系,并在鄂西三峡库区内进行了验证．结果表明：年径流深与森林覆盖率呈正或负相关;森林覆盖率与洪枯比及年输沙模数呈负相关;活立木蓄量与枯水期径流深呈正相关．     

Meander in valley crossing a deep-ocean fan

Seaward of most submarine canyons there are large sediment fans comparable to the fans at the base of mountain ranges. Many of the submarine fans are cut by valleys called fan-valleys which usually connect with the mouths of submarine canyons. Loop-like bends or meanders characterize the channels of rivers in their lower flood plains, but have never been found in the shallow channels that cross the alluvial fans at the base of mountain canyons. Therefore, it was surprising to find that the channel in a very deep submarine fan-valley off Monterey Bay, California, has a tight meander.     

日本山地森林小流域悬移质泥沙研究

以日本山地源头森林小流域为研究对象,利用泥沙自动取样器和自计水位计,研究了悬移质泥沙的输出过程及其与洪水过程间的关系.研究结果表明,该森林流域的泥沙来源主要是林道、沟道、沟道两边裸露地;河川径流中悬移质泥沙浓度与总泥沙浓度间有很好的相关性;降雨时悬移质泥沙浓度随流量过程的变化呈现出顺时针变化的套索;悬移质泥沙的输出过程属于波浪式变化;悬移质泥沙浓度最大值与洪峰流量几乎同时出现,属同步型;悬移质输沙量主要取决于10 min最大雨量;场降雨量对悬移质输沙量的贡献较大;单场大暴雨造成的悬移质输沙量占全年输沙量的5％左右;悬移质年输沙量的30％是由为数不多的几场降雨造成的.      

Climate-driven bedrock incision in an active mountain belt

Measurements of fluvial bedrock incision were made with submillimeter precision in the East Central Range of Taiwan, where long-term exhumation rates and precipitation-driven river discharge are independently known. They indicate that valley lowering is driven by relatively frequent flows of moderate intensity, abrasion by suspended sediment is an important fluvial wear process, and channel bed geometry and the presence of widely spaced planes of weakness in the rock mass influence erosion rate and style.     

Storage and remobilization of suspended sediment in the lower Amazon river of Brazil

In the lower Amazon River, suspended sediment is stored during rising stages of the river and resuspended during falling river stages. The storage and resuspension in the reach are related to the mean slope of the flood wave on the river surface; this slope is smaller during rising river stages than during falling stages. The pattern of storage and resuspension damps out the extreme values of high and low sediment discharge and tends to keep them near the mean value between 3.0 x 10(6) and 3.5 x 10(6) metric tons per day. Mean annual discharge of suspended sediment in the lower Amazon is between 1.1 x 10(9) and 1.3 x 10(9) metric tons per year.     

白龙江中上游土壤侵蚀及防护林配置

对白龙江流域水土流失考察表明,该流域水土流失严重,输沙模数为4000t/km~2a多,河水含沙量3.41kg/m~3。土壤侵蚀以基岩侵蚀为主,侵蚀类型主要有鳞片状面蚀,沙砾化面蚀,岩石泻溜、滑坡,泥石流及沟道侵蚀等。并提出了水土保持林配置的原则和造林措施。     

静脉河道负荷削减工程及其效果分析

在分析太湖流域入湖河流水环境现状的基础上,通过负荷削减工程的实施,使河网水质达到功能区要求,削减入湖河流的污染物排放总量,从而降低太湖污染负荷。以武进港流域的建华河、跃进河、红旗河等8条河为研究对象,开展了静脉河道负荷削减技术研究,对8个负荷削减工程的运行效果进行比较,研究出适用于流域河网地区的负荷削减技术,包括垂向移动式生态床技术、生物接触氧化技术、生态浮岛技术等。负荷削减效果表明,该技术可有效去除静脉河道低中度污染水中的N、P等污染物质,并具有良好的生态景观效果。通过进一步优化,可形成适合于太湖流域河网地区水环境质量改善和生态修复的关键技术。太湖流域的污染负荷主要来自入湖河流,开展入湖河流水环境综合治理对太湖流域水环境和湖体富营养化改善具有重要的意义。     

城市污水管道沉积负荷计算与分析

管道沉积物会影响排水管道的排水容量,在溢流排放下会造成水体污染,是目前合流制排水区域河道黑臭的重要原因之一。该文采用管道沉积物沉积负荷模型,结合南京市主城区管网分布数据,计算了主城区三大污水处理系统管网沉积负荷,并对三大污水处理系统沉积负荷差异进行了分析。结果显示,主城区管道COD沉积负荷与COD实际处理量占比为6.72%,其中江心洲污水处理系统因管网结构差、管道密度大,管道COD沉积负荷占比达7.68%。     

池塘养殖污染负荷核算方法研究及比较分析

为科学、准确和定量地分析池塘养殖水管理过程及污染负荷,实现水产养殖的控污减排,对现有污染负荷核算方法进行调研,对其进行了适应性评价和实例计算,并在此基础上对化学分析法进行了优化改进。结果表明:不同方法下污染负荷核算结果为污染负荷率法竹内俊朗法物料平衡法排污系数法化学分析法;基于物质守恒的3种方法计算结果远高于化学分析法和排污系数法,表明池塘底泥对养殖期间所产生的污染负荷贡献较大;改进化学分析法计算结果显示饵料是池塘养殖中产生污染的主要来源,在试验池塘养殖生产中底泥在TN排污中占比约60%,TP占比高达85%左右。研究表明,池塘水管理及底泥对污染负荷核算结果影响较大,且改进化学分析法可定量反映池塘养殖总产污量及水体和底泥排放分别对外界环境产生的影响。     

Transport capacity models for unsteady and non-equilibrium sediment transport in alluvial channels

This study investigates transport capacity models based on different dominant variables-shear stress, stream power, unit stream power, flow discharge, flow velocity, and energy slope – in a model of unsteady and non-equilibrium sediment transport in alluvial channels. The model simulates fully coupled system of water flow, suspended sediment, and bed load sediment transport processes in two-layer system of water flow phase and movable bed. The model employs conservation of mass equation for the water in both the layers; suspended sediment in the water flow phase; sediment in the movable bed layer; and the momentum equation for the water flow in the flow phase. The system is closed by relating the sediment flux in the movable bed layer to the sediment concentration in the same layer by employing the kinematic wave theory. Using the sediment transport capacity expression with different dominant variables, a series of numerical experiments are carried out for unsteady and non-equilibrium sediment transport. The results seem theoretically reasonable for hypothetical cases. The model is calibrated and validated using different experimental data sets. The calibrated value for the transport capacity model’s exponent (k_i) is found to be 1.50, 1.65, 0.24, 0.56, 4.80, and 0.22 for shear stress, stream power, unit stream power, discharge, velocity, and slope approaches, respectively. The numerical investigation results show that transport capacity model based on any dominant variable can be employed for modelling unsteady and non-equilibrium sediment transport.     

遏制潼关高程抬升及渭河下游淤积发展之对策

对潼关断面与渭河下游特殊地理位置及潼关断面高程抬升与渭河下游淤积发展的关系进行分析后认为,潼关断面高程的上升是导致渭河下游淤积发展及萎缩的内在根源,解决潼关高程上升问题是解决渭河下游泥沙淤积发展的前提和条件;并从历年潼关站1000m3/s流量的水位变化情况和控制运用期的汛期冲刷实测资料,以及2003年非汛期的原型试验和汛期的畅泄排沙试验实测资料,论证分析了降低潼关高程的可行性;进一步分析论述了治理和解决潼关断面抬升问题的方法和措施,其中包括加强潼关上游水保措施和泥沙拦蓄工程,降低汛期和非汛期水库运用水位,对潼关以下河段裁弯整治并辅以机械挖淤与疏浚等措施。     

和田河肖塔站水沙特性及水位流量关系的初步研究

和田河属冲积性多泥沙游荡型河流，汛期洪峰与沙峰的暴涨猛落和单一的河床边界组成条件，造成河道水位同流量关系的复杂性和不定性。本文通过对肖塔站三十三年水文系列资料统计分析表明，在时空变化上，和田河河床冲淤变形呈缓慢堆积抬升之势。在论述水位流量关系上，引用相关分析法，根据同流量不同水位出现的不同机率，确定三组相关线，从而较好地阐述了水位同流量的数值对应关系，对今后研究水文数值预报和制定防洪风险留具有一定可借鉴性。     

冲积河流河型影响因素及判别式研究

通过对河型的影响因素分析,确定出河槽边界条件、来沙条件、来水条件为河型的形成和转化的主要条件.将河型按从稳定-不稳定的原则分为6级,并对河型进行量化编码.以黄河、长江等河流12个河段的实测资料为依据,采用Cp统计量作为变量选择准则及多元线性回归分析法建立了新的河型判别式.得出对河型影响最大的因素为河槽边界条件,其次为来水条件,来沙条件对河型影响较小.     

彰武县境内柳河流域降水、流量、含沙量的变化规律

为了解彰武县境内柳河流域降水、流量、含沙量的变化规律,分析了该流域1968—2009年的降水、流量、含沙量的时间序列变化趋势及其相关性。结果表明,该段流域秋季降水呈极显著下降趋势,各季节及年际流量均呈显著或极显著下降趋势,各季节及年际含沙量均呈极显著下降趋势;春季、冬季的流量与含沙量及夏季的降水与流量呈极显著正相关,秋季降水、流量、含沙量之间及年际降水与流量、流量与含沙量均呈极显著正相关,年际降水与含沙量呈显著正相关。     

黄河6条支流域非点源污染分布现状

对黄河流域6条支流域的土壤、河床泥沙、河流水体的非点源污染物荷载量进行了测定。结果表明,在黄河6条支流域土壤中,洛河流域硝态氮含量高达45.2 m g/kg,远高于其他流域;渭河、洛河、泾河流域土壤的铵态氮、有机质、全氮和全磷含量均高于无定河、窟野河、皇甫川流域,其中洛河流域土壤铵态氮含量最高,窟野河流域最低;无定河、窟野河、皇甫川流域土壤pH值高于渭河、洛河、泾河流域。各流域泥沙中硝态氮含量以渭河中的最高,并远高于其他河流;皇甫川流域泥沙中铵态氮含量最高,其次是泾河流域,窟野河流域最低;与土壤相比较,6条支流域泥沙中的铵态氮含量明显高于土壤,硝态氮含量明显低于土壤。渭河和泾河流域泥沙中的全氮含量差异较小,但均高于其余4条支流域。流域泥沙中全磷含量总体差异不大;泥沙中的有机质含量由高到低依次为:窟野河流域>泾河流域>渭河流域>洛河流域>皇甫川流域>无定河流域;窟野河流域泥沙中的硝态氮、铵态氮、全磷和全氮含量在6条流域泥沙中都是最低的,但有机质含量在6条河流中却最高。水体中pH值以无定河流域的最大,渭河流域水体最小;渭河流域水体硝态氮含量最高;铵态氮含量以泾河水体中最高,窟野河最低;泾河水体的高锰酸盐指数远高于其他河流;6条河流水体的COD指数与高锰酸盐指数在6条河流中的差异趋势基本一致。     

北京燕山河沉积物中多环芳烃分布规律及来源分析

采用GC/MS法分析了北京燕山河沉积物中多环芳烃的含量及其来源。结果显示:在这些沉积物样中,18种多环芳烃的含量分布范围在0.3476～4.4781mg/kg之间,平均为2.6675mg/kg,主要特征是在近排污口处含量最大,远离排污口的源头含量较低。除了SA采样点沉积物中多环芳烃含量相对较低外,其余采样点多环芳烃分布均匀且含量较高,显著高于长江南京段、辽河及台湾高平等河流含量。对多环芳烃特征组分的比值(荧蒽/芘(F/Py)、苯并(a)蒽/(苯并(a)蒽 ■)(BaA/(BaA Cy))及甲基菲与菲的比值分析表明:该河流表层沉积物的多环芳烃主要来源于原油污染。     

漏斗式全沙排沙技术在陕西东雷抽黄灌区泥沙治理的成功实践

介绍了黄河第一座排沙漏斗工程的成功运行经验，并对其其原型观测结果进行了分析：对粒径大于0．1，0．05，0．025mm泥沙的平均截沙率分别达到96．58％，81．37％和78．71％，而平均排沙耗水量为7．23％。这一结果充分说明排沙漏斗的截沙率和排沙耗水量等重要指标都远优于过去黄河上普遍采用的条渠或者复合型厢形沉沙池等排沙设施。同时也说明排沙漏斗能有效地排除推移质泥沙，对悬移质泥沙的排除亦非常有效，尤其是为黄河泥沙的治理开辟了一条新途径。     

Fragmentation and flow regulation of river systems in the northern third of the world

Seventy-seven percent of the total water discharge of the 139 largest river systems in North America north of Mexico, in Europe, and in the republics of the former Soviet Union is strongly or moderately affected by fragmentation of the river channels by dams and by water regulation resulting from reservoir operation, interbasin diversion, and irrigation. The remaining free-flowing large river systems are relatively small and nearly all situated in the far north, as are the 59 medium-sized river systems of Norway, Sweden, Finland, and Denmark. These conditions indicate that many types of river ecosystems have been lost and that the populations of many riverine species have become highly fragmented. To improve the conservation of biodiversity and the sustainable use of biological resources, immediate action is called for to create an international preservation network of free-flowing river systems and to rehabilitate exploited rivers in areas that lack unaffected watercourses.     

人工线源液化起动泥沙试验研究

通过横断面渗流土工试验,人工加压线源液化土体,观察到泥沙起动的过程和液化土体横断面的基本形态,发现线源渗透破坏服从最小阻力趋向原则。利用土体产生渗透破坏而深层起动泥沙的潜力,通过河道中泓取直深埋压力渗管,达到节水冲沙、稳定主槽、降槽防洪之目的。     

SWAT模型在新蔡河流域面源污染研究中的应用

[目的]应用SWAT模型对新蔡河流域的径流、泥沙及面源污染负荷的产输出过程进行模拟计算。[方法]首先介绍了SWAT模型的原理,然后对模型径流参数和水质参数进行率定和验证,最后利用SWAT模型研究新蔡河流域的泥沙及面源污染负荷的产输出特性。[结果]SWAT模型基本合理可行,可用于新蔡河流域面源污染的模拟计算。模拟结果表明,丰水年泥沙和各种面源污染物负荷都比较大,平水年次之,枯水年最小,这说明泥沙和面源污染的产输出与当年的降雨径流量有关。[结论]该研究为流域面源污染的防治提供了科学依据。