DETECTING BASE FLOW IMPACTS IN COASTAL PLAIN STREAMS1

ABSTRACT: An established trend analysis methodology was applied to the problem of identifying and quantifying stream base flow impacts from water withdrawals and water loss through interbasin transfers. Impacts were simulated using base flow values selected from two U.S. Geological Survey (USGS) continuous record streamflow sites located within the Pinelands of southern New Jersey. Study site base flows were regressed against index site base flows with monotonic and step trend tests applied to the residuals from the regression model. The smallest, significantly detectable (α= 0.10) percentage reduction within a given simulation was used as an estimate of the sensitivity of a trend test. Evaluation of the trend analysis methodology led to the following practical considerations regarding trend test sensitivity. The proportion of study site base flow variability explained by index site base flows should be maximized, while at the same time minimizing positive, first-order autocorrelation in the regression residuals. Given the importance of detecting autocorrelation, missing values should be avoided or minimized. The quarterly (three-month) interval reduced the magnitude of autocorrelation relative to a shorter two-month sampling interval. Sensitivity appeared to improve when equalizing the number of values before and after a base flow impact(s) while seasonally biased sampling appeared to reduce sensitivity. Based primarily on past trend detection studies, nonparametric tests were deemed a better choice over their parametric counterparts, due to the lack of stringent data distributional requirements coupled with little or no loss of power even when applied to normally distributed data.     

基于GIS的东辽河流域水环境信息管理

在充分搜集东辽河流域水环境信息的基础上,采用先进的MAPGIS平台,完成了数据库、图形库、专业属性库的编辑,完满地实现了东辽河流域水环境信息的动态化管理。      

我国旅游安全预警体系的构建研究

指出我国应建立分区域、分层次且体系深入的旅游安全预警体系,其预警结构包括突发事件预警、环境污染预警、旅游容量预警和旅游业务预警等4个模块。提出建立由外交部和国家旅游局相互协作的出境旅游预警机制,建立由国家旅游局作为信息发布主体的全国性和区域性旅游预警机制,建立由省级旅游主管部门进行信息发布的区域内旅游预警机制,并可在省级行政区域之间建立相互间的旅游安全风险预警机制。     

叠层橡胶支座串联隔震体系抗火性能研究

对叠层橡胶隔震支座在高温作用下的温度场进行数值模拟,利用小模型试件进行温度传导及温度场分布试验。在叠层橡胶隔震支座经历420℃的高温作用后,将隔震支座模型试件与钢筋混凝土柱串联,并对串联隔震体系的力学性能进行压剪往复试验。结果表明,叠层橡胶隔震支座在高温作用下的性能退化相当明显,承载状态下的橡胶隔震支座在稍高的温度作用下就开始发生畸变。这表明在实际工程中对叠层橡胶隔震支座采取防火保护措施对保证隔震结构承载力安全非常重要。     

基于植被-气候最大响应模型的草地退化评价

草地植被生长现状及变化趋势的宏观监测,对草地资源的管理及生态建设有着重要的理论指导和实践监督意义。然而,多数的草地退化程度评价都没有考虑草地植被对气候条件年际变化的敏感性,评价"基准"不一,致使对草地退化程度评价的结果也无从比较,给草地生态建设恢复工作的实施与监督带来不便。基于植被-气候最大响应模型的草地退化评价方法,认为非气候因子(如病虫害、野火、放牧和人类活动等等)如果对草地植被的生长影响过度,就会造成草地植被生产力下降等后果。因此,利用长期的遥感数据和气象观测资料的空间插值结果,查找特定气候条件下同种类型草地植被所能达到的最大生产力,即可建立一定时间空间范围内草地植被生产力与气候条件的最大响应模型,以此作为草地退化的评价"基准",可对草地植被的生长状态及其变化过程进行监测与评价。对锡林郭勒盟草地植被退化状态及其变化趋势的评价结果表明:非气候因子导致的锡林郭勒盟草地退化非常严重,但从多年变化趋势来看,全盟的草地退化面积和平均退化程度均有减小的趋势。     

中江县无公害中药材基地农业环境质量监测与评价

无公害产品的产地农业生态环境质量是影响无公害产品质量的重要因子之一。对中江县中药材产业化基地调查资料和实际监测结果表明：中江县中药材产业化基地农业环境未受到污染,适合无公害中药材的生产。     

GROUNDSURFACE WATER INTERACTION IN THE LONG ISLAND AQUIFER SYSTEM1

Steady state experimental studies with a viscous analog of the aquifer system in central Long Island, New York, have shown there to be significant interaction between surface accretion, stream base flow, well recharge, and the degree of salt water intrusion. Reductions in accretion are found to cause a proportionately larger decrease in stream base flow. The degree of intrusion is found to be related to the distribution of accretion and well recharge between stream base flow and submarine flow to the sea. This interaction poses a conflict between development of the groundwater resource and maintenance of the surface water resource. Well recharge apparently offers a potential solution to the conflict.     

建立我国污水海洋处置管理信息系统

根据“八五”国家科技攻关课题的研究成果,建立了我国污水海洋处置管理信息系统。该系统界面十分清晰、直观,便于操作,有助于海域环境管理的快速决策,可用于我国沿海城市进行污水海洋处置工程规划建设和运行时的查询检索或跟踪监测海域的环境状况,并可对海域环境质量进行评价、预测及污水海洋处置规划。可确定出污水出水点近区浓度场及初始稀释度等各类污水排放参数,对当地海域环境管理及重大战略决策起到很好的技术支持作用      

微量加碱法合成聚合氯化铝的改进及Al13形成机理

通过提高反应温度和加碱速度对做量加碱法进行了改进,从而提高了反应速度,缩短了反应时间,并提高了AlCl3、和NaOH的允许浓度及产品的总铝浓度．同时对AlCl3的形成机理进行了探讨．结果表明,_Ala形态首先与OH^-反应生成Ale形态,然后Ale形态与Ala形态反应生成了Alb形态,即AlCl3形态．第二步反应较慢,为总反应的速率控制步骤,且为吸热反应,AlCl3的生成速率随反应温度的升高而增大．     

浅谈软土地基设计的一般方法

由于软土地基的低承载力、压缩性高、透水性差、结构触变性等特殊的工程特性,因此软土地基设计的好坏成为工程安全的关键。本文在传统土地设计的基础上,强调了上部结构、基础、地基共同作用的重要性,把软土地基设计概括为“一个中心、一个目的、两个基本点、六个步骤”,同时就设计参数取值和计算理论进行了讨论,供今后软基设计参考。