洞庭湖区平垸行洪,退田还湖,移民建镇工程效益分析

1998年湖南省洞庭湖区出现了历史罕见的大洪水 ,湖区人民遭受了严重的洪涝灾害。灾后 ,党中央、国务院作出平垸行洪、退田还湖、移民建镇 (以下简称平垸行洪 )的英明决策。 1 998年度湖南省洞庭湖区实施的平垸行洪工程涉及到 2 3个县 (市、区、场 ) ,共 1 53个堤垸 ,51 333户、1 892 65人。平垸行洪工程在各级政府的重视下 ,进展顺利 ,大部分堤垸已按计划完成任务。本文在进行调查研究的基础上 ,对平垸行洪工程的效益进行了分析。1　经济效益分析1 1　费用计算工程费用包括建设期和运行期内各年实际投入工程的固定资产投资、年运行费和流动…     

洞庭湖区平退堤垸后续发展管理问题探析

在洞庭湖平垸行洪堤垸功能定位分析的基础上,对当前的行洪垸土地利用和淹没补偿现状与不足之处进行了分析。对洞庭湖“单退”堤垸的合理土地利用管理与补偿机制进行了探析。探讨了洞庭湖区平退堤垸后的发展管理问题。在分析研究的基础上尝试提出了行洪垸土地利用综合管理政策、行洪垸承载人口控制政策和核算淹没损失的补偿办法,并对促进“单退”堤垸经济发展的政策进行了探析。     

平垸行洪减轻洞庭湖区洪涝灾害

20世纪90年代以来，洞庭湖区洪涝灾害频繁，洪水位不断抬高，高洪水位持续时间延长，这与泥沙淤积、阻碍行洪有直接的关系，党中央提出平垸行洪是减轻洪涝灾害的有力措施。文章阐述了平垸行洪的重要性以及实施方案并提出建议。     

鄱阳湖地区平垸行洪、退田还湖、移民建镇后防洪减灾态势

'98大洪水之后，针对我国大江大河的实际情况，国务院提出了平垸行洪、退田还湖、移民建镇的治理方针。本在对鄱阳湖地区平垸行洪、退田还湖、移民建镇实地调研基础上，指出鄱阳湖地区平垸行洪、退田还湖、移民建镇的综合效果及出现的问题，分析了采取这一措施后鄱阳湖地区防沤减灾态势，明确了未来鄱阳湖地区防洪减灾工作的重点。     

长江流域 "平垸行洪、退田还湖"的防洪作用

1998年长江发生了自1954年以来的又一次全流域性大洪水.洪水过后,国务院适时提出了"封山植树,退耕还林;平垸行洪,退田还湖;以工代赈,移民建镇;加固干堤,疏浚河湖"的灾后重建政策措施.其中"平垸行洪,退田还湖"旨在通过扩大长江的江湖槽蓄,提高长江调蓄洪水的能力.通过槽蓄对洪水的调蓄作用机理分析,结合1998年冬至1999年春长江中下游"平垸行洪,退田还湖"的计划实施情况,初步分析计算了"平退"前后长江再遇1954、1996年及1998年型洪水,中下游水位及分洪量的变化,从而阐明"平垸行洪,退田还湖"对长江中下游防洪的作用.     

"平垸行洪、退田还湖"对血吸虫病扩散的影响及对策研究

血吸虫病是一种严重危害人民健康、影响社会经济发展的传染性疾病,钉螺是血吸虫的唯一中间宿主.1998年洪水后实施的"平垸行洪、退田还湖"措施对于钉螺和血吸虫病的扩散有着重要的影响.总结影响钉螺和血吸虫病扩散的因素,并对典型"平垸行洪、退田还湖"后钉螺和血吸虫病变化情况进行调查研究,结果表明,认识某一区域钉螺和血吸虫病扩散...     

洞庭湖区堤垸经济发展模式探讨

洞庭湖区“平垸行洪、退田还湖、移民建镇”工程实施后缓解了湖区的防洪压力,降低了洪涝灾害,改善了湖区人民生活条件。合理利用平退堤垸,以农业产业化、工业规模化和社会城镇化为主要途径,合理进行经济结构调整,走可持续发展之路,促进区域经济发展,提高湖区人民的生活质量,有助于解决移民生存的实际问题,同时可为提高类似项目决策水平提供依据。     

长江平垸行洪、退田还湖的建设情况与效果浅析

平垸行洪，退田还湖是长江防洪保安的一项重要措施，是长江中下游防洪工程建设的重要组成部分，该工程的实施改善了工程区的社会，生态环境，促进了地方经济发展，具有显著的社会效益和经济效益。     

"平垸行洪,退田还湖"在我县存在的问题及对策初探

“平垸行洪，退田还湖”是根治水患的重大举措，但存在的情况和问题不容忽视。对存在的问题及对策，结合当地实际进行初步探索。     

结合长江防洪实际 做好流域治理专项规划

针对长江流域及其它大江，大河在１９９８年大洪水中暴露的问题，根据水利部的统一安排，长江委充分考虑了长江洪水及防洪特点，防洪工程现状，长江中下游地区的自然条件以及社会经济情况，编制了做好“平垸行洪，退田还湖，加固干堤，疏浚河湖”的流域治理专项规划，确定了“平垸行洪，退田还湖”的范围和原则。今后２－３年内长江干堤的设防水位仍宜按照防御１９５４年型洪水标志确定，并应根据堤防保护对象的重要性及堤防失事后的     

"引江济太"工程对浙江的影响分析

通过位于长江口的常熟水利枢纽和连接太湖的望亭立交水利枢纽引长江水入太湖的“引江济太”工程，旨在增加太湖流域水资源量，加快流域水体流动，缩短换水周期，提高水体自净能力，缓解流域水恶化的趋势。针对“引江济太”的调水原则、分期控制水位、引水路线和2002—2007年调水实况，客观分析了“引江济太”调水对太湖水质，杭嘉湖平原的防洪排涝、农作物生长、供水和水环境的影响。     

Nitrogen dry deposition to Lake Superior and Lake Michigan

Nitrate (NO₃^?) levels in Lake Superior have increased from historic levels of about 5?μM to its current concentration of about 25?μM. The atmosphere makes a substantial contribution to the nitrogen budgets for Lake Superior and Lake Michigan. This study provides a more well-defined estimate of nitrogen dry deposition rates derived from the measurement of over-water concentrations, and in situ meteorological measurements, which were input into the Resistance Model. We obtained a nitrogen dry deposition rate of [(3.41?±?2.26)?×?10⁷?kg?N/yr; (5.90?±?3.91)?kg?N/ha/yr] over Lake Michigan, and [(1.54?±?1.06)?×?10⁷?kg?N/yr; (1.87?±?1.27)?kg?N/ha/yr] over Lake Superior. Nitric acid (HNO₃), which originates from the combustion of fossil fuels, contributes 84% of the total nitrogen dry deposition to Lake Michigan; and 66% to Lake Superior. Ammonia (NH₃), which originates from agricultural activities and gasoline combustion, is the second highest contributor of nitrogen dry deposition to both lakes: contributing 13% to Lake Michigan and 32% to Lake Superior. The nitrogen dry deposition is approximately 68% of the nitrogen wet deposition over Lake Superior, and approximately 80% of wet deposition over Lake Michigan. The over-water dry deposition velocity of HNO₃ and NH₃ were also evaluated. We obtained morning deposition velocities of 0.099?cm/s for NH₃ and 0.095?cm/s for HNO₃; and afternoon values of 0.137?cm/s for NH₃ and 0.132?cm/s for HNO₃. Another key finding is that the atmospheric concentrations of nitrogen compounds near Lake Michigan and Lake Superior have decreased since 2003.     

Using Microfossil Remains in Lake Sediments to Examine the Invasion of Eubosmina coregoni (Cladocera,Bosminidae) in Lake of the Woods,Ontario, Canada

Many nonindigenous species (NIS) present in the Laurentian Great Lakes are expanding their ranges to inland lakes and streams. This study used cladoceran microfossils to examine the invasion history of Eubosmina coregoni, the first known nonindigenous zooplankter to invade Lake of the Woods (LOW), Ontario, Canada. Sediment cores from 16 sites in LOW were used to analyze broad-scale presence/absence of E. coregoni prior to human development (bottom sediment samples) in comparison with present-day distribution (top sediment samples). E. coregoni had the highest relative abundance in the northern and eastern regions of LOW and the abundance of all cladoceran remains was low in the southern region of the lake. A long core (time core) from Clearwater Bay provided a more detailed historical account of E. coregoni's abundance in the northern region of LOW, indicating that E. coregoni was first detected in the lake in the early 1990s, approximately 25 years after it was discovered in the Laurentian Great Lakes. Results obtained in this study have illuminated temporal and spatial patterns of colonization of this inland water body. Study of the early invasion dynamics of NIS in these inland lakes may aid in the prevention of future invasions of taxa that have already altered the food web dynamics in the Laurentian Great Lakes.     

引江济太工程与太湖流域水资源可持续利用刍议

太湖流域突出的水环境问题引起国家和社会各界的高度关注,两年的引江济太试验对缓解太湖水质恶化、使死水流动产生了明显的作用和效益.但是太湖流域的水环境修复和保护在本质上仍然还是要先治污.因此,引江济太工程需要与太湖流域水资源可持续利用和水环境综合治理规划有机结合,分阶段实施.     

Foreword to the second Lake Winnipeg special issue

Lake Winnipeg is the 10th largest freshwater lake in the world and, like many of the world’s great lakes, it is increasingly being affected by anthropogenic pressures, such as high nutrient loads and invasive species. The consequences of these on the hydrology and ecology of the lake are the focus of continuing research, funded by the renewed investment of Federal and Provincial agencies. Complicating this, Lake Winnipeg is still very much a wilderness lake and despite two decades of research there is much we don’t know. This second special issue on Lake Winnipeg is a collection of 21 research articles that describe some of the most recent and emerging research on the lake.     

南四湖应急生态补水唱响生命之歌

会计委派制度是在目前我国现代企业制度尚不够规范的形势下产生的一种具有过渡性质的做法。会计委派制度可以有效地遏制会计信息失真，治理社会腐败现象，防止国有资产流失。随着我国经济体制改革目标的实现和法律法规体系的完善，会计委派制度将会退出历史舞台。     

On food security and access to fish in the Saugeen Ojibway Nation,Lake Huron,Canada

This exploratory study offers insights to the complex relationships between accessing local fisheries and food security in the traditional territory of the Saugeen Ojibway Nation (SON), Lake Huron, Canada. Based in qualitative research, including focus groups and key informant interviews conducted in the SON community in summer 2016, we identify the inter-related structural and relational mechanisms influencing the ability of SON community members to derive food security benefits, including culturally appropriate and nutritious diets and sustainable livelihoods, from local fisheries. There is, however, a need for ongoing efforts to better link the fisheries management, economic and cultural development, and traditional food access objectives of the community, ideally through better connecting and managing existing social networks.     

Challenges to Deep-water Reproduction by Lake Trout: Pertinence to Restoration in Lake Michigan

Restoration efforts for lake trout Salvelinus namaycush in Lake Michigan are increasingly being focused on re-establishment of the species in deep water. This focus is based in part on examination of historical records of indigenous lake trout, which suggest that offshore reefs, especially deep reefs, sustained the greatest numbers of lake trout. This focus is also based on the increasing impact of non-indigenous species, such as alewife and round goby, on lake trout survival on shallow reefs. Development of a successful strategy for re-establishing deep-water lake trout in Lake Michigan will require a better understanding of the challenges to a species that evolved in shallow water and whose nearest relatives are shallow-water fishes. The challenges include an annual temperature cycle with fall warming rather than cooling, which may impact reproductive timing and embryo incubation. Deep water presents challenges to fry in that there is no apparent physiological mechanism for producing swim bladder gas and initial filling of the swim bladder at the surface has little impact on buoyancy once a fry returns to depth and the swim bladder is compressed. First feeding is a challenge because there is no local primary production to support a rich prey supply and the phenology of zooplankton prey abundance differs from that in small lakes. We propose that plans for restoration of lake trout into deepwater habitats in Lake Michigan must proceed in concert with research leading to a better understanding of extant deepwater strains in Lake Superior.     

Diets of Siscowet Lake Trout from the Apostle Islands Region of Lake Superior, 1993

Stomach contents of 384 siscowet lake trout (Salvelinus namaycush siscowet) from the Apostle Islands region of Lake Superior were examined to determine if diets exhibited seasonal trends or shifted with predator size. The information was also used to qualitatively compare siscowet and lean lake trout (S. namaycush) diets. Stomachs from siscowet less than 500-mm total length (TL) contained primarily macroinvertebrates (clams, Mysis relicta, and insects), sculpins (Cottidae; mean TL = 45 mm), and coregonines (Coregonus spp.; mean TL = 120 mm). Stomachs from siscowet between 500- and 699-mm TL contained items similar to smaller siscowet, but burbot (Lota lota; mean TL = 162 mm and a 254-mm siscowet were also present. Stomachs from siscowet longer than 699-mm TL contained fishes such as burbot (mean TL = 246 mm) and coregonines (mean TL = 240 mm). Dietary proportions of coregonines increased significantly with increasing siscowet length groups. The proportion of the total number of identified taxa and frequency of occurrence of terrestrial insects and sculpins declined significantly across all length groups between June and December. Siscowet and lean lake trout diets were not found to be substantially different and a potential for competition exists.