人工强制混合对金盆水库水体藻类群落结构时空演替的影响

为探明人工强制混合过程对水体藻类群落演替的作用影响机制,本研究利用扬水曝气系统对金盆水库主库区水体进行原位人工强制混合,对系统运行过程中水库水体理化参数及藻类进行原位定点监测.结果表明,金盆水库水体藻类共6门28属51种,扬水曝气系统的人工强制混合作用可显著抑制水体藻类的生长,并对其群落结构产生显著影响:扬水曝气系统运行前,藻类主要分布在表层水体,其中以小球藻(Chlorella vulgaris)为优势种属;扬水曝气系统运行后,表层水体藻密度大幅降低,藻密度垂向分布趋于均匀,优势种属有向小环藻属(Cyclotella sp.)演替的趋势.本研究利用冗余分析(RDA)方法,结合临界层理论(critical depth theory)和藻类生长特性,分析了人工强制混合过程中金盆水库水体藻类群落结构时空演替和主要理化参数变化之间的关系.分析结果表明,扬水曝气系统的人工强制混合作用主要通过迅速破坏水体热分层稳定性和显著增加水体混合深度(Z_(mix))来影响藻类群落结构的时空演替.     

三峡库区端坊溪小流域防护林土壤改良效应研究

该文以土壤养分、容重、孔隙度、水分、下渗等指标为基础 ,采用时段对比法 ,全面分析了三峡库区端坊溪小流域防护林的土壤改良作用。结果表明 :随着林木的生长 ,防护林土壤改良作用明显 ;采用封山育林对改良防护林土壤结构效果显著。     

ESTIMATING AVERAGE MONTHLY LAKE EVAPORATION IN THE NORTHEAST UNITED STATES1

ABSTRACT: A methodology to estimate the average monthly lake evaporation, E(τ), (month τ=1,12) for fresh water bodies located in the northeast United States is presented. The approach combines analysis of at‐site, lake‐specific vertical water temperature profile data and a previously developed regional air temperature based model approximation of the widely accepted modified Penman energy budget estimate of mean monthly potential evaporation, E_p(τ) (mm/day). The paper presents procedures to develop site‐specific estimates of E_p(τ) and to convert water temperature data to average monthly conductive heat flux, G(τ). With monthly estimates of G(τ), the average monthly potential evaporation, E_p(τ), is then convertible to estimates of the average monthly lake evaporation, E(τ). This new method permits a good estimate of site‐specific lake evaporation rates without the data and computational requirements of the Penman energy budget procedure nor the comparatively expensive, time consuming field eddy correlation approach.     

Influence of Inversion Layers on the Distribution of Air Pollutants in Urban Areas

The air quality in urban areas is on the one hand determined by the intensity of emissions. On the other hand atmospheric dispersion and chemical transformation conditions as well as topographic location have great influence on the ambient air concentrations. Within, this study the correlation between pollutant concentrations and the dynamics of atmospheric barrier and mixing layers has been experimentally investigated by tethered balloon soundings.The most important barrier layer is the surface inversion. During clear sky it develops in the late afternoon and is dissolved by warm air from the heated ground in the morning. Emitted pollutants are kept beneath this inversion. But, at the same time, the component ozone is depleted below and stored above the layer within the so called `ozone reservoir layer'. During night elevated mountain sites are decoupled from the ground conditions and stay within this reservoir without a remarkable nocturnal decrease of ozone concentration. The regularly observed ground level ozone increase in the morning hours is firstly caused by down mixing from the reservoir. The conditions and dynamics are illustratively depicted by vertical profiles of the different components and diagrams of temperature and concentration isopleths over the height and the experiment time lasting over five days.     

三峡库区的文物保护

三峡工程规模宏大，举世瞩目，具有防洪、发电、航运等综合效益，是开发治理长江的骨干工程，三峡库区位于长江上游河优的下段，受回水影响的水库淹没区和移民安置涉及的20个县市称库区，总面积约5．5万km^2，三峡库区已发现853处大型文物古迹，水库蓄水后大部分文物古迹将不受影响，但少部分将全部或部分受淹，中国政府一贯重视文物保护工作，三峡工程开工后，已拔出专门经费，组织人力物力，进一步加强文物古迹调查，考古勘探，加速古文化遗址的发掘抢救，切实保护三峡库区文物。     

深圳市利用小(2)型水库进行河流生态补水研究

深圳市水环境质量改善迫在眉睫,亟需探寻新的解决思路和途径。借鉴香港、新加坡等城市经验,提出"抓大放小"思路,通过挖潜现有供水水库库容,科学调度水资源,逐步调整小(2)型水库供水功能,充分利用水库库容在旱季为下游河流实施生态补水。补水后可一定程度改善下游河流水质状况,为深圳市河流治理提供新的思路和解决方案。同时通过完善村镇供水网络,实现集中供水,保障了区域供水水量和水质的稳定。     

高山镇赤泥尾矿库溃坝风险评价研究

为研究河南高山镇赤泥尾矿库溃坝风险评价问题,首先分析了高山镇赤泥尾矿库特征和现阶段运行情况以及可能存在的溃坝风险因素,并确认该尾矿库是重大危险源;然后对汛期溃坝事故进行了故障树分析,在此基础上,建立了高山镇赤泥尾矿库溃坝风险评价指标体系,并采用层次分析法确定了各个评价指标的权重,运用多层模糊模式识别理论综合评价了高山镇赤泥尾矿库的溃坝风险等级。研究结果表明:赤泥尾矿库属于Ⅱ等库,存在轻微病害,基本具备安全运行条件,但应加强库区和坝体的日常管理和维护;汛期应采取有效的排洪措施及时降低赤泥库水位;建立了高山镇赤泥尾矿库环境应急管理体系,对尾矿库的风险预测和预防以及突发事故的应急行动有很强的指导作用,也可以结合GIS进行更高效的风险管理。     

松华坝水源保护区新能源结构研究

分析了松华坝水源保护区新能源利用现状及存在的问题,在此基础上,对保护区新能源结构进行了规划,并进行了经济技术分析。     

库区旅游生态环境敏感性评价研究——以湖北省丹江口市为例

库区生态地位突出,旅游活动频繁,库区旅游生态环境敏感性评价对库区旅游开发、旅游环境影响评价具有重要的现实意义。文章依据库区旅游生态环境特点构建了水体、植被、坡度、高程、坡向等指标,基于RS、GIS技术提取评价因子并对丹江口市旅游生态环境敏感性进行评价。结果表明,库区周边以及武当山等山势较高的山体为旅游环境极强敏感区,占全市面积的12.81%;强敏感区与一般敏感区所占的比例分别为29.41%、34.38%;弱敏感区散布在河谷平原及距库区较远的边缘地带,占23.39%,旅游活动强度较低。生态强敏感区与旅游活动高发区具有空间耦合性,旅游活动对库区生态环境的影响不容忽视。