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131.
长江流域的鱼类资源及其保护对策   总被引:40,自引:7,他引:33  
长江水系的鱼类约有300种,其中鲤科鱼类占半数以上,主要的经济鱼类多数属于鲤科。对不同江段的鱼类资源作了简介,并提出了相应的保护措施。上游江段以维护生物多样性,保护特有种为主,需要建立鱼类自然保护区;中游应保证主要经济鱼类的自然繁殖条件,加强珍稀鱼类的人工繁殖放流工作,同时对湖泊幼鱼资源进行保护;下游应注意保持江水质量,严格遵守工业废水排放标准;河口江段应规定幼鲟保护期,建议每年6月15日至7月31日停止一切损害幼鲟资源的渔捞作业。  相似文献   
132.
探讨了连接上海,崇明和江苏海门的长江河口桥隧工程在连接河口岛屿间交通,发挥崇明的区位优势,促进地区经济发展以及在上海港建设中的作用。详细论述了越江工程完成后上海新港的扩建,根据河口河水岸线的分布,提出了在横沙岛东滩修建人工岛的设想,最后对几种越江方案进行了分析比较,提出了作者的看法。  相似文献   
133.
侯平  孙卫  李霞 《新疆环境保护》2004,26(Z1):125-131
在宏观生态系统的恢复中,通常关注的层面至多达到个体水平,即只计测个体的存在和测定所关注的可视特征,而忽略了个体的生理反应,特别是在实施恢复生态工程时,大规模地重新构造生物生活资源结构,常常难以估测这种变化对生物的有效性,加之可视生态效果表达的滞后性和可测试的复杂性,常常造成效果遗漏.因此,增加微观(细胞)层面的反应指示指标,可捕捉细微的个体反应,更准确的指征生态效果在个体上实现反应的可能性,这对于丰富恢复生态学理论是具有重大意义的.本文以塔里木河下游生态恢复工程为载体,探索了以内源保护酶系活力变化为指征的个体对生态输水的响应,结果表明超氧歧化酶(SOD)、过氧化物酶(POD)和膜脂过氧化产物丙二醛(MDA)不仅对累积输水效果具有指示性,而且对短期水干扰具有敏感的指示性,相关关系也因受水而强化.  相似文献   
134.
河北省共有31个河口港址,广泛分布于河北省沿海地区。在实地调研和广泛收集数据的基础上,采用层次分析法和模糊综合评价法,对河北省河口港址的自然条件和社会经济状况进行了定性、定量分析。根据分析结果将河口港址资源划分为4个质量等级,提出了不同质量等级河口港址资源开发利用的具体措施。  相似文献   
135.
河口拦门沙的存在可导致径流流出不畅,并能引起一系列的河口生态及环境问题。特别是弯曲型河口,在波浪流、河川径流及弯道副流的共同作用下,拦门沙的形成及演变将更为复杂。通过对日本渚滑川河口多次实地调查资料的分析,揭示了渚滑川河口拦门沙的演变特性。结果表明:渚滑川河口修筑防波堤后,在东北方向的海洋入射波作用下,拦门沙由河口右岸发育并向左岸逐渐延伸扩展,其河水流动也相应由右岸偏向左岸一侧;不论河口有无拦门沙,3次洪水在右岸的最大冲深均稳定在-6m高程,且河床横剖面的形状基本不变,即汛期时该河口河床形状已达平衡状态。  相似文献   
136.
Abstract: Small streams have been shown to be efficient in retaining nutrients and regulating downstream nutrient fluxes, but less is known about nutrient retention in larger rivers. We quantified nutrient uptake length and uptake velocity in a regulated urban river to determine the river’s ability to retain nutrients associated with wastewater treatment plant (WWTP) effluent. We measured net uptake of soluble reactive phosphorus (SRP), dissolved organic phosphorus, ammonium (NH4), nitrate, and dissolved organic nitrogen in the Chattahoochee River, Atlanta, GA by following the downstream decline of nutrients and fluoride from WWTP effluent on 10 dates under low flow conditions. Uptake of all nutrients was sporadic. On many dates, there was no evidence of measurable nutrient uptake lengths within the reach; indeed, on several dates release of inorganic N and P within the sample reach led to increased nutrient export downstream. When uptake occurred, SRP uptake length was negatively correlated with total suspended solids and temperature. Uptake velocities of SRP and NH4 in the Chattahoochee River were lower than velocities in less‐modified systems, but they were similar to those measured in other WWTP impacted systems. Lower uptake velocities indicate a diminished capacity for nutrient uptake.  相似文献   
137.
ABSTRACT: During the past 15 years a number of methods have been developed that purport to evaluate the amenity values of rivers. Most methods are designed to identify the physical, biological, cultural, and esthetic features of a river or river corridor that are conducive to recreation, preservation, and other amenity values. This paper reviews and comments on 13 methods that evaluate amenity values. The methods are reviewed and discussed under three general headings: River Recreation Potential Evaluation, River Esthetic Evaluation, and River Preservation Evaluation. A final section of the paper identifies areas where improvements and further research are needed.  相似文献   
138.
: In general, the choice among reservoirs for water supply or flow augmentation is a multiobjective problem. Choices are based in part on the yield available from water supply reservoirs or, in the case of flow augmentation reservoirs, on the increase in low flows at downstream locations. Detailed estimates of these effects may be too costly for basin planning purposes. Thus this paper presents methods for rapid estimation of those quantities for New Hampshire. For water supply reservoirs, a composite empirical relation between Y95 (the draft available 95 percent of the time) and storage ratio, S*, is developed from previous studies in the region. For flow augmentation reservoirs, empirical relations between S* and degree of regulation, R*, are applied to each upstream regulating reservoir. Values of regulation arc then summed and divided by the mean flow at the downstream reach of interest. This parameter, (ΓR)*, is then related to increase in flow available 95 percent of the time by an empirical relation.  相似文献   
139.
ABSTRACT: During the last 27 years of independence, a large number of inter-state water disputes cropped up over the use of rivers. Surprisingly enough, more disputes developed in this short period than in the earlier 200 years of the development of irrigation and so far none of the disputes has been permanently solved. The major rivers of India are all inter-state rivers and this is one of the more important reasons why some of them are not yet fully developed for irrigation or power production. The Union Government has set up, so far, only three tribunals to adjudicate inter-state disputes. But the problems do not end simply by setting up the tribunals. In practice, it has also proved a dilatory process. None of the tribunals has been successful in settling any dispute in the long years of their existence. There is no codified law prescribing rights and the notion of “equity” has come to prevail restraining the upper states from drawing such quantities of water as would injure the interests of the lower states. Though the general principle of equitable apportionment had been advocated many times, in practice each contending state had given this principle an interpretation that suited it. The basic principle would be to harness the rivers not for the benefit of a particular state but for the maximization of agricultural, industrial, and navigational potential in the areas served by the rivers.  相似文献   
140.
Ji, Yuhe, Liding Chen, and Ranhao Sun, 2012. Temporal and Spatial Variability of Water Supply Stress in the Haihe River Basin, Northern China. Journal of the American Water Resources Association (JAWRA) 48(5): 999‐1007. DOI: 10.1111/j.1752‐1688.2012.00671.x Abstract: Water resources are becoming increasingly stressed under the influence of climate change and population growth in the Haihe River Basin, Northern China. Assessing the temporal and spatial variability of water supply stress is urgently needed to mitigate water crisis caused by water resource reallocation. Water supply and use data were compiled for the time period of 1998‐2003 in this synthesis study. The Water Supply Stress Index (WSSI) as defined as Water Demand/Water Supply was used to quantitate whether water supply could meet the demand of human activities across the study region. We found a large spatial gradient of water supply stress in the study region, being much higher in the eastern subbasins (ranging from 2.56 to 4.31) than the west subbasins (ranging from 0.56 to 1.92). The eastern plain region not only suffered more serious water supply stress but also had a much higher interannual variability than the western hilly region. The uneven spatial distribution of water supply stress might result from the distribution of land use, population, and climate. Future climate change and rapid economic development are likely to aggravate the existing water crisis in the study region.  相似文献   
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