改善鄱阳湖湿地生态系统管理的对策刍议

简要分析了鄱阳湖湿地生态系统管理的现状和存在的问题，提出了改善鄱阳湖湿地生态系统管理的对策与措施。     

南水北调东线东平湖水库工程地质条件综述

东平湖是黄河下游重要的防洪工程，同时也是南水北调东线重要的调蓄水库。随着南水北调东线的开工建设，它肩负着向济南及山东半岛供水的调节任务，同时还承担向河北省、天津市供水的任务，因此其战略地位非常重要。本文从工程地质这一基础性工作角度论述东平湖现状情况下的工程地质条件和所存在的工程地质问题，提出工程处理措施。     

鄱阳湖的风情及风浪特性浅析

文中叙述了鄱阳湖的风情,风浪特性及危害.分析了风在时空上的分布变化,湖陆风的基本特征.由于鄱阳湖地处中纬度,季风明显,每年6-8月为南风或偏南风,其他月均为北风或偏北风.影响湖面风浪的因素,主要是风,还有吹程和水深.风浪会直接影响湖区航运、农业、渔业生产和圩堤安全,给国民经济带来危害.大水面风还会引起增减水现象.     

Simulation Modeling as a Means of Studying Large Aquatic Ecosystems

The concept of simulation modeling of large aquatic ecosystems is discussed with special reference to a conceptual framework incorporating a series of sub-models. Practical applications of this technique are made to the Sea of Azov and Lake Baikal. One such application was the use of simulation techniques to predict the stock of omul populations in Lake Baikal. The results of this effort suggested that recommendations to increase omul harvest could be made.     

准噶尔盆地白家海凸起湖相原油与烃源岩芳烃地球化学特征

位于准尔盆地蒜部白家海凸起上的彩南油田，其原油芳烃地球化学特征与阜康凹陷原油具有同源性，与该区中、下侏罗统湖相烃源岩有密切关第。原油及烃源岩中芴含量相对较高，氧芴次之（２５％－４５％），硫芴低（６％－３５％），反映为淡水湖相环境沉积生烃。     

1996年长江中游大洪水及调度

１９９６年７月，长江中游尤其洞庭湖区出现了超历史记录的高洪水位，按“蓄泄兼筹，以泄为主”及“江湖两利”的治江方针及有关文件，提出计划分洪的方案，但终以抢大险，超工程设计标准运用而取得了防汛的胜利。就分洪区运用而言失得兼有。从防汛实践中表明了今后实行计划分洪，并由此提出了加强分洪区建设的建议。     

堤防险情严重程度划分与识别方法探讨

根据险情对堤防稳定安全威胁性大小将险情划分为早、中、晚期 .在对不同险情破坏机理定性分析的基础上 ,制定了定性与定量相结合的划分险情严重程度参照表 ,进而采用模糊模式识别方法对险期进行定量评判 ,从而为选用和制定抢护防案提供依据 .     

加筋粉细砂筑坝技术在辽河防洪工程中可行性论证

本文通过渗流稳定分析和坝体稳定分析对加筋粉细砂筑坝这一新技术在辽河防洪应急工程上的应用．进行了可行性的论证。     

Lake Powell Management Alternatives and Values: CVM Estimates of Recreation Benefits

Abstract

This paper presents data analyses based on information gathered from a recreation survey distributed during the spring of 1997 at Lake Powell. Recreation-linked management issues are the foci of the survey and this discussion. Survey responses to contingent valuation method (CVM) queries included in the questionnaire quantify visitor recreation values. The CVM estimates of the benefits provided by potential resource improvements are compared with the costs of the improvements in a benefit-cost analysis. The CVM questions covered three resources management issues including water quality improvement, sport fish harvest enhancement, and archeological site protection and restoration. The estimated benefits are remarkably high relative to the costs and range from $6 to $60 million per year. The dichotomous choice format was used in each of three resource CVM question scenarios. There were two levels of enhancement for each resource. There are, therefore, several consistency requirements—some of them unique to the dichotomous choice format—that the data and benefit estimates must satisfy. These consistency tests are presented in detail in the ensuing analysis.     

Delayed egg hatching accounts for replacement of burrowing mayflies Hexagenia rigida by Hexagenia limbata after recolonization in western Lake Erie

Egg banking may have played a role in the recolonization of two burrowing mayfly species (Hexagenia limbata and Hexagenia rigida), which recolonized western Lake Erie after over 30 years of near extirpation. H. rigida was the first of the two to colonize successfully, but was overtaken by H. limbata (the historically dominant species). To understand mechanisms of species replacement, we compared egg hatching between the two species at 20 °C in the lab under typical hatching temperatures (no incubation) and after cold storage (8 °C) for 2, 6 and 12 months. Prolonged storage at cold temperatures simulates temperature conditions to which embryos are exposed when deposited by late-emerging female imagos. Without incubation, H. rigida (95.4 ± 2.02) exhibited significantly higher egg hatching survivorship than H. limbata (85 ± 3.2) (P = 0.01). First hatch date for H. rigida was one day earlier than H. limbata, but time for 50% to hatch (5 d) and hatching duration (5 d) was the same for both species. After 2 and 6 months of incubation, H. limbata exhibited an earlier hatch date, but there was no significant difference in mean percentage of egg survival (ca 63%) between species. After 12 months of cold storage, hatching success for H. limbata was 44.6 ± 4.17%, but H. rigida eggs did not hatch. Banking of eggs at low temperature increases the chance of successful recolonization, once stressful conditions pass. The viability H. limbata eggs after long quiescence may help to explain the shift in dominance from H. rigida to H. limbata.