城市道路降雨径流中悬浮颗粒特性及其全过程削减探讨

道路表面尤其是交通活动频繁的城市道路表面,能够通过汽车尾气排放、轮胎和路面磨损以及油脂的渗漏等累积大量的悬浮颗粒等污染物质,其中悬浮固体颗粒在城市路面降水径流污染物中占很高的比重。文章分析径流中悬浮颗粒的特性,详细分析了它与其它污染物的关系和它在水中的去除特性,以及径流冲刷对其形成的规律,为径流污染全过程控制提供参考,对径流污染的工程控制和非工程管理都能提供帮助。认为悬浮颗粒全过程削减对径流污染物的全过程控制起着极为重要的作用,是径流污染物全过程削减的主要途径之一。     

基于变点识别的区域河川径流量特征值变异研究

基于变点原理,运用最大似然比和西沃兹信息标准方法,对广东省4种径流量序列进行均值变点和方差变点的识别,研究存在变点的河川径流量序列、时间位置、空间分布及变点后的特征值变化状况,以揭示广东省河川径流量时空变异特点。结果发现:广东省河川年径流量和汛期径流量序列的一致性较好,而枯期径流量和最小月径流量序列的特征值变点具有普遍性,年均值明显增加,年际离散程度增大,时间位置主要为1972-1973年和1981年两个时间段。枯期径流量序列均值变点的典型地区主要为东江流域,方差变点的典型地区主要为北江流域、韩江流域、粤西地区和珠江三角洲;最小月径流序列主要为均值变点,典型地区有东江流域、韩江流域;而北江入珠江三角洲的河川径流量变异尤其典型,4种径流序列均存在均值变点和方差变点。     

渭河生态环境问题浅析

以渭河河道径流量和河流水质的实测资料为基础,应用不均匀系数法对河道径流在年内的分配规律作了分析,采用Spearman秩次相关检验对河流年均径流量进行趋势性判识,运用Kendall非参数秩次相关检验法对流域降雨量时间序列进行趋势性检验,选取综合污染指数法对河流水质变化进行了分析。结果表明,(1)渭河河道径流量整体处于波动下降的状态,与降雨量的变化趋势相似;河道径流量的年内分配不均匀系数有上升倾向,且从中游到下游亦有上升趋势。(2)河流水质的变化在2003年之前没有大的起伏,处于波动平衡状态,2003年河流水质处于最差点,之后呈现好转态势。     

百年一遇大旱后城区降雨径流污染时空差异与可生化性

2009年入秋至2010年春,中国西南地区发生了百年一遇的特大旱灾。为探讨百年一遇大旱后城市降雨径流污染特性,对昆明市典型交通干道路面及屋面进行了三次降雨径流监测,研究了百年一遇大旱后的昆明城区降雨径流污染时空差异与可生化性并同其他城市做了比较。结果表明,径流污染物浓度基本上并未随降雨时间表现出明显的下降趋势。大旱后首场降雨形成的地表径流污染最严重,次日降雨的最轻,路面污染显著高于屋面污染。总体上径流的可生化性较差,不宜用生物法进行处理。同国内外部分城市与2007年调查的昆明比较发现,大旱后的昆明城区屋面和路面径流污染较严重。     

榆林大柳塔矿区乌兰木伦河径流量衰减的影响因素分析

矿产资源开采与水资源破坏相关性显著,因而定量分析开采的各类行为对水资源的破坏程度对干旱资源开发区具有重要意义.本研究应用有限分布滞后模型改进了多元回归模型,进而建立了煤炭开采与河流径流量相关关系的代数表达式,并利用其分析大柳塔矿区和乌兰木伦河的调查资料,进而说明煤炭开采是否是影响煤炭开采区河流径流量的主要因素.结果表明...     

Spatial and temporal variation of nitrogen exported by runo from sandy agricultural soils

The eutrophication problem has drawn attention to nutrient leaching from agricultural soils, and an understanding of spatial and temporal variability is needed to develop decision-making tools. Thus, eleven sites were selected to monitor, over a two-year period, spatial and temporal variation of runoff discharge and various forms of N in surface runoff in sandy agricultural soils. Factors influencing the variation of runoff discharge and various forms of N in surface runoff were analyzed. Variation of annual rainfall was small among 11 sites, especially between 2001 and 2002. However, variation of annual discharge was significant among the sites. The results suggest that rainfall patterns and land use had significant effect on discharge. The concentrations of total N, total kjeldahl N （TKN）, organic matter-associated N （OM-N）, NO3- -N, and NHn＋-N in the runoff ranged widely from 0.25 to 54.1, 0.15 to 20.3, 0.00 to 14.6, 0.00 to 45.3, and 0.00 to 19.7 mg/L, respectively. Spatial and temporal variations in the N concentration and runoff discharge were noted among the different sites. Annual loads of N in the runoff varied widely among monitoring sites and depend mainly on runoff discharge. High loads of total N, OM-N, NO3--N, and NHn＋-N in the runoff either in citrus groves or on vegetable farms occurred from June to October for each year, which coincided with the rainy season in the region. This study found that N in surface runoff was related to rainfall intensity, soil N level, and fertilizer use.     

Impact of fertilization on chestnut growth, N and P concentrations in runo water on degraded slope land in South China

Growing fruit trees on the slopes of rolling hills in South China was causing serious environmental problems because of heavy application of chemical fertilizers and soil erosion. Suitable sources of fertilizers and proper rates of applications were of key importance to both crop yields and environmental protection. In this article, the impact of four fertilizers, i.e., inorganic compound fertilizer, organic compound fertilizer, pig manure compost, and peanut cake （peanut oil pressing residue）, on chestnut （Castanea mollissima Blume） growth on a slope in South China, and on the total N and total P concentrations in runoff waters have been investigated during two years of study, with an orthogonal experimental design. Results show that the organic compound fertilizer and peanut cake promote the heights of young chestnut trees compared to the control. In addition, peanut cake increases single-fruit weights and organic compound fertilizer raises single-seed weights. All the fertilizers increased the concentrations of total N and total P in runoff waters, except for organic compound fertilizer, in the first year experiment. The observed mean concentrations of total N varied from 1.6 mg/L to 3.2 mg/L and P from 0.12 mg/L to 0.22 mg/L, which were increased with the amount of fertilizer applications, with no pattern of direct proportion. On the basis of these experiment results, organic compound fertilizer at 2 kg/tree and peanut cake at 1 kg/tree are recommended to maximize chestnut growth and minimize water pollution.     

长江-黄河源寒区径流量波动变化的气候因素分析

长江－黄河源区属典型寒区,降水、冰雪融水等共同成为径流的补给来源,径流量的变化同时受到区域内降水量和气温变化的影响。采用互谱分析方法研究表明,长江、黄河源区降水与径流周期波动间的关系明显好于气温与径流之间的关系,降水对径流量的主要周期波动有较明显的控制作用。气温虽然对径流量的部分周期波动变化有一定的影响,但不如降水明显。相对来说,黄河源区降水对径流量的波动变化的影响要好于长江源区。20世纪80年代后期长江－黄河源区径流量大幅下降的主要原因是区域内降水量的减少。     

乌鲁木齐河流域径流与气候变化的年内相关性分析

为了分析干旱区河流乌鲁木齐河径流在年内的分配及变化特征,定量辨析气温、降水对径流年内变化的驱动作用,根据流域水文气象台站的观测资料,对1993-2012年乌鲁木齐河山区流域降水、气温与径流变化的特征和趋势进行了分析,并对降水、径流的集中期和集中度进行分析,以期发现径流对降水的时滞效应;运用正积温来拟合温度与径流的关系.在此基础上,运用灰色关联度和相关分析法分析径流与气候变化的关联程度.结果表明,降水和气温直接或间接地对径流产生影响,三者各有其年内变化特征,又存在着很大的相关性.     

EPS外保温材料火灾蔓延速率的数值模拟与试验研究

根据火灾动力学理论,建立了热塑性外保温材料火蔓延速率模型。该模型对实际燃烧过程做了一定的假设简化,主要考虑了材料厚度和火源位置对材料燃烧发展过程的影响。并提出无量纲参数"耦合燃烧度",用来表征热塑性材料的燃烧壁面与高温熔滴形成的油池火之间相互作用的程度。基于ISO9705全尺寸热释放速率实验室,采用20×20×10 cm3正庚烷油槽火源为火源样式,设计了4种不同的燃烧工况研究EPS外保温材料的火蔓延规律和影响因素。结果表明:其火蔓延速率随时间变化呈指数增长,EPS的火蔓延速率的回归方程通式为Vp(t)=Aexp(Bt),与理论推导方程Vp(t)=φ1exp(φ2t)有较好的相关性。当EPS的厚度为50 mm时,火蔓延速率增幅最小;"耦合燃烧度"越大,火蔓延速率增长越快;"耦合燃烧度"随材料厚度的增加而增大;不同火源位置下,"耦合燃烧度"从大到小为中火、底火、顶火、边角火。理论模型与试验结果有较好的一致性,可以有效预测热塑性外保温材料的火蔓延速率。