ENSO事件对渭河流域气象干旱和水文干旱的影响

利用渭河流域1960~2012年13个气象站的逐日降雨资料和三个水文站的径流资料,分析ENSO事件对该区域的降雨、径流、气象干旱和水文干旱的影响。结果表明,ENSO事件对渭河流域的降雨量和径流的影响较为明显,尤其是在7、8、9、10月;EI Ni1o事件对降雨量/径流有减少作用,而La Ni1a事件对降雨量/径流有增加效应;ENSO事件对径流的影响具有空间和时间的差异性,且由下游到上游逐渐变大;渭河流域共发生142次气象干旱和76次水文干旱,发生气象干旱和水文干旱平均持续时间分别为2.56、3.40个月,气象干旱和水文干旱发生次数呈增加趋势;ENSO事件对气象干旱和水文干旱的影响较大,经过卡方检验,在10月EI Ni1o事件和La Ni1a事件与气象干旱的发生有显著(α=0.05)关系,同时10月EI Ni1o事件和水文干旱的发生也有显著关系。     

基于相似过程衍生的月径流概率预报模型研究

针对传统月径流预报模型存在的缺陷,建立了相似过程衍生法与概率预报相结合的月径流概率预报模型。运用相似过程衍生法发布确定的预报结果,在定点预报的基础上利用概率预报提供一定置信水平下的预报区间作为模型预报结果。模型结构简单、易于构建且建模过程中无需考虑预报因子的选择问题。将该模型与BP神经网络模型进行对比仿真试验,结果表明该预报模型具有较好的预报精度,且合格率高于BP神经网络模型,可在水库月径流预报中推广应用。     

基于新安江模型的考虑超渗产流及塘坝调蓄的洪水过程模拟

针对山丘区众多小型水库、塘坝的兴利库容大小不一致,先蓄满的水库塘坝率先溢流,全部水库塘坝蓄满后全部溢流的现象,提出了一种改进模型,即在新安江模型中嵌入超渗产流和塘坝调蓄模块,建立了同时考虑超渗产流和塘坝调蓄影响的流域水文模型,选用大汶河黄前水库流域大水年份实测水文资料进行率定和验证,并与未考虑超渗产流影响和塘坝调蓄影响的计算结果进行了对比分析。结果表明,当不考虑超渗产流影响时,模拟的洪峰偏低;当不考虑塘坝调蓄影响时,模拟的洪峰偏高、峰现时间提前。可见在新安江模型中同时考虑超渗产流和塘坝调蓄的作用能有效提高半湿润区流域洪水过程模拟的精度。     

基于GIS的LL-Ⅱ分布式降雨径流模型的结构

主要讨论了LILAN—Ⅱ分布水文模型的结构。该模型结构是为水文过程模拟和预报而设计的，它提出了变动生态产流模式，耦舍了一维坡面流、一维壤中流、一维地下水流、一维河川径流和二维土壤含水量方程组。通过实际检验，该模型能够明显改善模拟预报精度、增强数值计算稳定性、提高参数优选的运行速度和减少存储空间，能够适合不同水文特征地区的产汇流计算，可以提供流域内任意空间网格的水文计算过程。     

2000年以来黄河流域干支流水沙变化趋势及其成因分析

鉴于2000年以来黄河流域的水沙特征发生了较大变化,采用M-K检验法对黄河干支流主要水文站2000~2014年的水沙资料进行分析,探究了干支流水沙的变化趋势及成因,并结合Yamamoto突变检验法进一步判断出更可靠的突变点。结果表明,与1950~2000年相比,干流各水文站径流量的减小比例沿程增大,支流水沙的减幅均大于干流;头道拐至潼关间的支流是影响该河段输沙量变化的主要因素,而龙门至潼关站间,渭河对该段干流的径流量影响较大;经Yamamoto突变检验法诊断后,排除20个虚假点,发现黄河干流径流量和输沙量在2000~2014年间分别出现5、6次强突变,而支流突变点分布散乱,与干流间无明显关系;干流径流量自2004年后为增加趋势,其M-K值于2010年后突破临界值上限1.96;中游年输沙量在2003年前均为增加趋势,2005年后呈减小趋势且在2008年后均突破临界值下限。     

Nitrogen export by runoff from agricultural plots in two basins in China

Runoff and sediment yields from agricultural fields are major sources of nitrogen (N) entering lakes in China. Export of sediment and N can be impacted by soil and cropping management practices, but there is relatively little information on N leaving agricultural fields in lake basins in China. Sediment and surface runoff N from a series of field plots in two experimental lake basins were evaluated in situ under simulated rainfall conditions. Objectives of the study were to evaluate the effects of crop cover, slope, and fertilizer application on N in surface runoff and eroded soils. Sediment yields varied from 4.3 to 299.0 g m^-2, depending on management practice. Mean dissolved nitrogen (DN) and total nitrogen (TN) concentrations are 1.35 and 5.4 mg L^-1, respectively, in Lake Taihu basin, while mean DN and TN concentrations are 2.66 and 4.3 mg L^-1, respectively, in Lake Baiyangdian basin. For all experimental plots in two basins, weighted average concentrations of N for total-N, dissolved N and sediment N are 1.0-5.0 mg L^-1, much higher than 0.2 mg L^-1, indicating a problem in lake eutrophication due to high N concentration from agricultural surface runoff. The estimated mean annual export of total N was 6.0 and 14.7 kg ha^-1 yr^-1 for Baiyangdian and Taihu lake basins, respectively. The study showed that significantly more N (approximately ranging from 10 to 90 of total N) exported was associated with sediment, constituting a long-term source of potentially bioavailable N in lakes.     

Stormwater runoff quality and quantity from asphalt, paver, and crushed stone driveways in Connecticut

This study compared the quality and quantity of stormwater runoff from replicated asphalt, permeable paver, and crushed-stone driveways. Rainfall was measured on-site and runoff was recorded using tipping buckets. Flow-weighted composite runoff samples were analyzed weekly for total suspended solids, total Kjeldahl nitrogen, nitrate-nitrogen, ammonia-nitrogen, total phosphorus (TP), zinc, lead, and copper. Infiltration rate was determined on each driveway annually. Repeated measures analysis of variance indicated that stormwater runoff was significantly different among each driveway type; the order of decreasing runoff was asphalt> paver> stone. Average infiltration rates were 0, 11.2 and 9.0 cm/h for asphalt, paver, and crushed stone driveways, respectively. Both paver and crushed stone driveways reduced stormwater runoff as compared to asphalt driveways. Runoff from paver driveways contained significantly lower concentrations of all pollutants measured than runoff from asphalt driveways. However, runoff from crushed stone driveways was similar in concentrations to runoff from asphalt driveways, except for TP concentrations, which were lower in runoff from crushed stone driveways than runoff from asphalt driveways. The mass export of measured pollutants followed the relative differences in stormwater runoff, rather than differences in concentrations.     

山地城市道路规划与景观探析--以重庆市云阳新县城中心城区道路规划设计为例

城市道路既是城市的骨架,又是展现城市景观的舞台。通过道路来塑造独特的城市景观不失为一种有效手段。本文通过对云阳县城道路现状与规划的分析,提出在规划设计过程中将道路网络、道路线形和道路横断面与景观相结合,探讨如何通过道路交通规划来重塑山地城市独特的景观形象。     

Modelling the impacts of climate change on surface runoff in small Mediterranean catchments: empirical evidence from Greece

During the last decades, a major factor that analysts and policy makers take into account in the assessment of the environment is climate change. This global physical process is expected to cause problems in natural and human environment. Thus, modelling climate change impacts may lead to prevention policies to minimize the degradation of life quality because of lack of water resources in the future. This study implicates Geographical Information System (GIS) and hydrological modelling tools to various scenarios of climate change such as the increase of temperature the decrease of rainfall, or even both of them, to estimate the potential impact of climate change on surface runoff in a typical catchment in Andros Island, Greece. Primary results indicate a proportional runoff decrease in the next 50 years because of global climate changes.     

西部山地小城镇核心区城市设计探究——以四川大英县隆盛镇为例

西部山地小城镇的建设是推进国家新型城镇化战略的重要组成部分,对其核心区的规划设计是改善小城镇人居环境的重要途径;该文以大英县隆盛镇核心区城市设计为例,从城镇核心区空间拓展和空间重塑两个层面入手,用城市设计手段解决西部山地小城镇面临的空间品质低下、土地利用不足、人地矛盾突出等问题,为西部山地小城镇核心区发展建设提供参考。