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371.
海平面上升对海岸带环境的影响与危害及其防治对策 总被引:5,自引:1,他引:5
本文阐述了过去近百年来和未来特定年份海平面上升的趋势,分析了海平面上升的原因及其对海岸带环境的影响与危害,最后提出了防治对策与措施。 相似文献
372.
山东沿海的9216号台风暴潮灾害 总被引:5,自引:1,他引:5
在1992年第16号强热带风暴和天文大潮的作用下,山东沿海发生了特大风暴潮灾害,直接经济损失43.5亿元,死亡76人;砂质海岸遭受强烈侵蚀,损失土地约145.3ha。 相似文献
373.
洪水的等级划分及其减灾意义 总被引:11,自引:3,他引:11
根据地震,风力等级的数学结构,提出一种洪水等级划分公式;对用等级表示洪水大小的减灾意义作了初步分析。 相似文献
374.
Jill M. Noel Robert H. Chamberlain Alan D. Steinman 《Journal of the American Water Resources Association》1995,31(1):21-32
ABSTRACT: A study was initiated to examine the effects of wind speed, wind direction, freshwater inflow, and tide height on suspended solid concentration and distribution in the Loxahatchee estuary, Florida. Recent efforts to increase freshwater flows in this system raised concerns that suspended solid concentrations would increase as well, which might result in negative impacts for the estuary. The data indicated that total suspended solids (TSS) in the estuary are derived primarily from the inlet and not from freshwater tributaries. In addition, total suspended solids and volatile suspended solids were correlated strongly with salinity, suggesting that suspended sediments act conservatively throughout this system. No one environmental factor had an overwhelming influence on suspended solid concentration throughout the estuary; different regions of the estuary were influenced by different factors. Freshwater inflow was negatively related to TSS in the upper reaches of the estuary but was positively related to TSS in the central embayment region of the estuary. We attribute this latter finding to the fact that extremely high inflows both prevented the normal transport upstream of tidal borne suspended sediments and promoted mixing when the freshwater front moving downstream confronted the tidal front moving upstream. Wind speed, wind direction, and tide height had relatively small effects on TSS concentration but were most influential in reaches upstream of the central embayment, where tidal velocity begins to diminish. 相似文献
375.
376.
报告了哈密地区居民饮用水总α、总β放射性比活度平均值分别为11.6(1.4~79.4)×10~(-2)Bq·L~(-1)(另有一突出值287.0×10~(-2)Bq·L~(-1)未计入平均值);0.40(0.05~1.76)Bq·L~(-1).估算结果表明,本地区95%以上居民的饮用水源是安全的。 相似文献
377.
珠江三角洲腹地洪水位异常变化及成因分析 总被引:2,自引:0,他引:2
珠江三角洲是我国东南沿海的经济发达地区.三角洲地区的防洪安全保障对区域的社会、经济发展具有举足轻重的作用.由于三角洲地区复杂的网河及口门构成,以及径流和潮汐共同影响的水动力条件,使三角洲的洪水水势表现出随时间和空间复杂变化的动态特征.20世纪80年代以来,三角洲地区受水土资源无序开发的人类活动的影响,90年代的洪水表现出了网河腹地河段洪水位异常壅高的现象,使区域的防洪安全受到严重威胁.结合"94.6","98.6"洪水期间三角洲腹地洪水水位异常壅高现象,综合分析了区域洪水位异常壅高的外部及内在成因,为科学制订三角洲地区防洪对策提供技术依据. 相似文献
378.
松花江干流洪水预测和影响评估及对策建议 总被引:4,自引:0,他引:4
根据历史数据,分析了松花江干流(哈尔滨段)水位变化的历史规律和典型洪水年洪水的成因,计算和分析了其与松花江、嫩江、二松流域面雨量的相关性,统计和分析了其与拉尼娜、厄尔尼诺、太阳黑子等的关系.利用方差周期和均生函数方法,建立了2004-2013年拉尼娜、厄尔尼诺、太阳黑子及松花江、嫩江、二松流域面雨量的预测方法,并进行了预测,建立了松花江干流(哈尔滨段)最高水位趋势的综合预测方法,得出了2004-2013年的预测值.提出了相应治理的对策建议. 相似文献
379.
Ramsis B. Salama Richard Silberstein Daniel Pollock 《Water, Air, & Soil Pollution: Focus》2005,5(1-2):3-26
The flow pathways of water in the soils of the Gnangara Mound are highly irregular and depend upon the moisture content, the
repellency and preferential wettability potential of the soils. The occurrence of preferential flow is more evident in dry
soils. As the soil wets during the rainy season, the water repellence and differential wettability decreases, the fingering
and the preferential flow paths disappear. Most of the agricultural sites in the Spearwood Sands which showed more irregular
flow than the Bassendean Sands are under continuous irrigation during cultivation season. As the repellency problems are chemically
treated, it is therefore expected that the flow will be more uniform all the year round. Landuse is mainly responsible for
variation in recharge rates; however, the hydraulic properties control aquifer response and water level pattern to a greater
degree. Water levels in the mid 1970s were in a semi steady state. Since that time, a combination of increasing water use
by pine plantations, heavy pumping from private boreholes in market gardens and private homes and intensive pumping from the
Gnangara Mound for the metropolitan water supply have caused water levels to continually decline in the Superficial aquifer.
Nitrate and phosphate concentrations in the regional Superficial aquifer are generally very low. None of the tested pesticides
(atrazine, diazinon, dimethoate, endosulfan, fenamiphos, iprodione, malathion and chlorpyrifos) were detected in the groundwater
samples collected from the monitoring bores. 相似文献
380.