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1.
河口切变锋引起的滩槽泥沙交换效应 总被引:3,自引:1,他引:2
朱慧芳 《长江流域资源与环境》1995,4(1):54-57
切变锋是河口湾锋系中最为常见和最易观察到的锋面类型。本文对长江口的切变锋进行现场观察和滩,槽同步水文资料分析,简述了长江口切变锋发生的部分和基本特性,提出了切变锋引起的滩,槽泥沙呈现螺旋形交换形式等论点。 相似文献
2.
本文从柑桔冻害和热害的危害因子和指标等级划分的研究和选取入手,着重探讨了长江三峡地区(湖北境内)两害显著的时空变化特征、差异与关联性及对柑桔生产的影响;揭示了80年代以来冬暖春热的重大气候变化是使两害向“两极分化”的根本原因;讨论了三峡水利工程对两害时空格局的可能调整及减灾原理;最后提出了可能的对策。 相似文献
3.
岷江上游崩塌滑坡分布规律研究 总被引:1,自引:0,他引:1
乔建平 《长江流域资源与环境》1994,3(4):365-370
岷江为长江—级支流,上游长330km,自1986年以来,发生崩塌滑坡200余处,体积约2.1亿m ̄3。作者研究了岷江上游崩塌滑坡的分布规律。采用统计指标法,将岷江上游分为三种不同的崩塌滑坡分布密度区:①UXS.高密度区;②MXS,中密度区;③LXS_3低密度区。 相似文献
4.
三峡工程与长江中游沿江产业带建设 总被引:3,自引:0,他引:3
讨论了长江中游沿江产业带发展条件、限制因素和未来发展,指出三峡工程的建设将对长江中游产业的布局和经济发展带来深刻的变化;防洪作用促进中游两岸大型工业项目的兴建,调整现有沿江城镇的布局,使之结构趋于合理化;电力供应经解能源的紧张状态,改善航运条件,发挥长江黄金水道的综合效益。当然,由于坝下河道冲刷,对现有的码头带来一定的影响,由于冬季水位抬升引起两岸低湖田地下水位上升,加剧两岸土壤潜育化和沼泽化。 相似文献
5.
Mfon T.Udo 《环境科学学报(英文版)》2002,14(4)
Aspects of the trophic attributes of the mudskipper,Periophthalmus barbarus occurring in the mangrove swamps of ImoRiver estuary, Nigeria, were investigated during a 12-month period(April, 1992-March, 1993). Feeding intensity increased with size;it was higher in the dry season (November-April) than in the wetseason (May-October); monthly changes in the indices of feedingintensity were significantly correlated. Major food objectscomprised detritus and benthic algae; crustaceans, insects,macrophyte matter and sand grains were minor food objects whilefish, molluscs, Chilopoda, nematodes and fungi were unconsciouslydevoured objects. Diet varied seasonally; algae and sesarmid crabswere generally more in the dry season than during the rains whereasFPOM and fish increased in the wet over dry season. The mudskipperdisplay a high degree of euryphagy and can be considered as ageneralist and an omnivore. The lower trophic status of P. barbarusqualifies it as a good aquaculture candidate. Food richness washigher in big-sized class (BSC) than small-sized class (SSC).Size-based and seasonal variations were not apparent in foodrichness. Diet breadth was higher in the BSC than the SSC; therewas dry season increase in diet breadth. 相似文献
6.
Evolution of environmental impact assessment as applied to watershed modification projects in Canada
Herman J. Dirschl Nicholas S. Novakowski M. Husain Sadar 《Environmental management》1993,17(4):545-555
This article reviews the application of environmental impact assessment (EIA) procedures and practices to three watershed
modification projects situaled in western Canada. These ventures were justified for accelerating regional economic development,
and cover the period during which public concerns for protecting the environment rapidly made their way into the national
political agenda. An historical account and analysis of the situation, therefore, seems desirable in order to understand the
development of EIA processes, practices, and methodologies since the start of construction of the first project in 1961. This
study concludes that there has been good progress in predicting and evaluating environmental and related social impacts of
watershed modification proposals. However, a number of obstacles need to be overcome before EIA can firmly establish itself
as an effective planning tool. These difficulties include jurisdictional confusions and conflicts, division of authority and
responsibility in designing and implementing appropriate mitigative and monitoring measures, lack of tested EIA methodologies,
and limited availability of qualified human resources. A number of conclusions and suggestions are offered so that future
watershed modification proposals may be planned and implemented in a more environmentally sustainable fashion. These include:
(1) EIA processes must be completed before irrevocable decisions are made. (2) Any major intrusion into a watershed is likely
to impact on some major components of the ecosystem(s). (3) Mitigation costs must form part of the benefit-cost analysis of
any project proposal. (4) Interjurisdictional cooperation is imperative where watersheds cross political boundaries. (5) The
EIA process is a public process, hence public concerns must be dealt with fairly. (6) The role of science in the EIA process
must be at arms length from project proponents and regulators, and allowed to function in the interest of the protection of
the environment and public health and safety.
The views expressed here are the authors’ own and do not necessarily reflect those of FEARO and/or other government agencies
and officials involved in the review of these projects. 相似文献
7.
Xiao Yali Jiang Dahe Wang Dan 《中国人口.资源与环境(英文版)》2007,5(3):51-56
Urban agglomeration of the Yangtze Delta (UAYD), one of the most developed regions of China, has witnessed an increasing prevalence in building ecological cities when the ecological cities are pursued by many modem cities, and great achievements have been made in this regard. It is inevitable, however, that certain problems exist during the construction of ecological city, which include but not limited to non-harmonious development of urban complex ecosystem, and the difficulty in quantifying eco-city construction or incomplete quantification in assessing the construction of present and future eco-city. Based on the analysis on social-economic conditions and regional conditions of the UAYD, this paper attempts to set up an index system of eco-cities combining with local characteristics, and to adopt the indices of eco-city, urban harmony, and eco-city colligate to evaluate the ecological level, urban harmonious development and eco-city construction of cities within the UAYD. Results indicate that among 15 cities in UAYD, Suzhou City ranks the highest in terms of eco-city construction, whereas Nantong ranks relatively lower; sustainable eco-city construction is possible only when cities are developed in every respect of harmony. 相似文献
8.
详细讨论了卫星遥感技术在长江流域水资源管理方面的应用问题,提出了两种实用的方法:①卫星遥感技术在灌溉水资源管理方面的应用;②长江流域地下水、地表水资源估算。进一步分析了两种方法的特点,介绍了卫星遥感技术的优点及用途,建议在长江流域水资源管理中加以利用。 相似文献
9.
长江中游平原湖区农业开发地域分工与农产品专业化生产研究 总被引:6,自引:1,他引:5
农业生产地域分工与农产品专业化生产是使农业从自然经济阶段向以市场为导向的商品农产品生产转变的一个标志。本文在分析该区农业布局现状及其存在问题的基础上,提出了农业总体布局的设想与不同类型地域农业开发的主攻方向与对策,并对市场经济体制下粮食、棉花、猪、禽、水产品等农产品生产基地的地域选择、建设规模与技术措施等进行了探讨。 相似文献
10.
黄河三角洲土地质量模糊综合评价 总被引:12,自引:0,他引:12
针对土地复杂性、模糊性的特征,本文采用模糊数学中“多级模糊综合评判”的方法进行了黄河三角洲土地质量评价,并对其科学性和可行性作了探讨。 相似文献