塔里木河流域综合治理的环境影响趋势分析

塔里木河流域综合治理已被列入国家和自治区的重点工程,本文分析了目前塔河流域的环境现状和的问题,着重讨论了综合治理规划实施对塔河流域环境的影响趋势。     

AFTER THE 1993 FLOOD: A WATER AND SURFICIAL BED SEDIMENT QUALITY SCENARIO ON THE ILLINOIS AND UPPER MISSISSIPPI RWERS1

ABSTRACT: Effects of the 1993 flood on river water and sediment quality were investigated using historical data and data collected from the Illinois River and Upper Mississippi River in a post‐flood period. Overall the post‐flood results showed systematic reductions and individual changes in the water and sediment constituents. The reductions in sediment metals and nutrients were most obvious at the Keokuk and Lock and Dam 26 stations. By analyzing and comparing the physical changes to the changes in water and sediment constituents at each station, it was found that physical processes such as sediment entrainment and, more importantly, the removal of fine sediment to be the main causes for the reduced concentrations in sediment constituents. On the other hand, sediment redistribution and associated secondary contamination could have caused the emergence of several water and sediment constituents that were undetected before the flood.     

The Coachella Valley Multiple Species Habitat Conservation Plan: A Decade of Delays

This article describes the history of the Coachella Valley Multiple Species Habitat Conservation Plan (CVMSHCP), in the Riverside County region of Southern California. When this collaborative biodiversity conservation planning process began, in 1994, local participants and supporters had numerous factors working in their favor. Yet, as of April 2007, nearly 13 years had passed without an approved plan. This is a common problem. Many multiple species habitat conservation plans now take more than a decade to complete, and the long duration of these processes often results in negative consequences. The CVMSHCP process became bogged down—despite strong scientific input and many political advantages—due to problematic relationships between the Plan’s local supporters, its municipal signatory parties, and officials from the state and federal wildlife agencies, particularly the regional office of the US Fish and Wildlife Service. This case study demonstrates the crucial importance of institutional structures and relationships, process management, and timeliness in habitat conservation planning. We conclude by offering several related recommendations for future HCP processes.     

闽江流域畜禽粪便的污染负荷及其环境风险评价

从闽江流域畜禽养殖业现状分析入手,根据作物所需畜禽粪尿肥的最大量,估算流域各县市的畜禽污染物产生量和农田畜禽粪便负荷量,对各县市畜禽养殖粪便污染进行潜在的环境风险评价.结果表明:闽江流域大多数集约化养殖场集中分布于中上游,并有向下游扩散的趋势;流域农田畜禽粪便负荷量平均达22.95 t·hm-2·a-1;整个流域的畜禽污染已对环境产生风险,尤其是富屯溪、沙溪流域更为突出.     

伊犁河谷北坡野果林群落结构及其与环境的关系

结合野外植被调查,在获取较为详细的生境数据基础上,探讨伊犁河谷北坡野果林群落与环境因子之间的定量关系.TWINSPAN和去趋势典范对应分析(DCCA)的结果表明:1)在伊犁河谷北坡野果林群落分布地段,地形因子、养分和水分条件是群落生境的基本因子;2)海拔因子指示出研究区野果林群落最基本的分化,说明海拔条件是制约研究区植物群落分布的最重要的因子;3)土壤表层水分状况与海拔关系较密切,反映了草本层群落所受到的水分条件影响;4)养分状况的差异,除了说明生境条件本身的差异外,也在一定程度上指示了群落现在生境的养分状况,受人为的影响较大.总之,在山地复杂的地形条件下,群落生境条件的差异非常显著,海拔、土壤含水率、全氮、坡向和pH值的组合,影响并控制着研究区各群落分布格局的形成.     

新疆玛纳斯河流域灌溉水资源保证程度及提升策略

从供需两方面,构建了区域灌溉水资源保证程度分析模型,利用该模型对玛纳斯河流域灌溉水资源保证程度进行了分析。结果表明,现状年玛纳斯河流域灌溉水资源保证程度为79.21%,各灌区存在较大的差异,下野地、莫索湾、金安、玛纳斯等灌区灌溉水资源保证程度较低,分别为69.09%、78.76%、78.25%、71.24%,明显处于亏缺状态,而石河子灌区达115.06%,处于相对盈余状态。在各灌区灌溉总面积维持现有数量以及保证灌区水资源安全的前提下,随着加大部分灌区(金安、玛纳斯和石河子灌区)地下水资源开发力度,大力发展高新节水技术以及调整种植结构,近期流域灌溉水资源保证程度总体可接近100%,但流域内除石河子灌区外,下野地、莫索湾、金安、玛纳斯等灌区灌溉水资源仍处于亏缺状态。2020年随着各种综合措施的进一步实施,全流域灌溉保证程度将增加至113.19%,各灌区将实现灌溉水资源供需平衡。最后,针对3类不同灌溉水资源保证程度地区的水资源利用状况,提出了差别化的提升策略。     

“94.6”湘江流域特大洪水分析和防洪对策

对１９９４年６月湘江流域特大洪水的灾情和成因进行了系统分析，通过对这次洪水的反思，总结经验教训，并提出了防洪对策。     

长江源头区孟宗小流域泥石流危害成因与防治对策浅析

通过对长江源头孟宗流域泥石流成因的调查，列举泥石流危害典型事例，分析了泥石流发生的条件和影响因素及其不同侵蚀类型在泥石流成因中所起的作用，并进一步提出了泥石流危害的防治对策。     

Structural and photocatalytic properties of TiO2 films fabricated on silicon substrates by MOCVD method

Silicon(111) and Silicon(100) were employed for fabrication of TiO2 films by metal organic chemical vapor deposition( MOCVD).Titanium(Ⅳ) isopropoxide(Ti[O(C3H7)4]) was used as a precursor. The as-deposited TiO2 films were characterized with FE-SEM, XRD and AFM. The photocatalytic properties were investigated by decomposition of aqueous Orange Ⅱ. And UV-VlS photospectrometer was used for checking the absorption characteristics and photocatalytic degradation activity. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, the photoactivities varied following a shape of “M”: at Iower(350℃ ), middle(500℃ ) and higher(800℃ ) temperature of deposition, relative lower photodegradation activities were observed. At 400% and 700% of deposition, relative higher efficiencies of degradation were obtained, because one predominant crystallite orientation could be obtained as deposition at the temperature of two levels, especially a single anatase crystalline TiO2 film could be obtained at 700℃.