澜沧江中游段洪水随机模拟研究

本文分析计算了澜沧江中游段洪水过程随机统计特性，阐述了采用典型解集模型和周期性一阶自回归模型模拟洪水过程情况，取得了比较满意的结果。     

黄河河口清水沟流路演变及其治理措施分析

本文利用实测资料，分析了清水沟流路自１９７６年改道以来的水沙特点，演变规律以及河口淤积延伸的特点。１９９６年清８人工出汊工程实施后，在减轻河口地区防洪压力和淤海造陆变海上石油开采为陆上开采方面取得了很好的效益。同时对入海流路规划改走北汊的海域条件和改走北汊的行水年限进行了分析和详细计算。通过分析认为：只要辅以必要的治理措施，清水沟流路还有一定的行河潜力，预计改走北汊后，可行水１５年左右。     

River wildlife databases and their value for sensitive environmental management

A survey over a 3-year period, which commenced in 1987, of the plant and bird communities along 1200 km of river in Lincolnshire and South Humberside, Eastern England, is described. Analysis of data from 247 km of river recorded a great diversity of wildlife, comprising 570 species of plant and 80 species of breeding birds. The management value of such surveys is discussed and these include the preparation of detailed maps of each 500m section of river, which illustrate the habitat structure, and plant and bird communities. A maintenance procedure for each 500 m section of river is then agreed between conservation and operations personnel, preventing areas of wildlife importance from being accidentally destroyed. An index which combines both the diversity and rarity of the plant and bird communities is proposed as a measure of conservation importance. This index allows sections of river to be graded according to their conservation value into one of five groups. The surveys also enable predictions to be made of the effects of management actions on the wildlife and provide information by which fundamental reviews of operational activities can be carried out.     

Long-term nitrate trends in the river trent and four major tributaries

Nitrate levels which have been rising in many British rivers for at least thirty years have become of particular interest since Britain adopted the EC Drinking Water Directive. The literature examining nitrate trends in the rivers of the U.K. and Eire is reviewed. Long-term nitrate concentration trends are derived for eight sites in the River Trent drainage system. These include sites on two rural tributaries, two urbanized tributaries, and the main river. Currently, mean annual concentrations for these sites range from about 4.0 mg1^?1N in the rural catchments, to 12.4 mg 1^?1 N in the urbanized tributaries, and to between 8.7 mg 1^?1N and 11.0 mg 1^?1 N along the mainstream. Moreover rates of increase of nitrate concentration of approximately 0.06 mg 1^?1 N yr ^?1 in the rural catchments, contrast with values up to 0.20 mg 1^?1 N yr ^?1 in the two urbanized tributaries and River Trent. Long term nitrate loads have been calculated for the River Trent at Nottingham using a discharge weighted mean interval method. This method probably provides the best available estimate of nitrate loads calculable from irregular data of variable sampling frequency for lowland rivers. Annual nitrate loads varied between 10700t yr ^?1 and 29 800t yr ^?1 over the period of record. A rate of increase in nitrate load of 455 t yr ^?1 was obtained. The increases in nitrate concentrations and loads within the Trent basin are matched by similar rates of increase in other European catchments.     

Dewatering Cofferdam for Construction of Olmsted Locks

Twin 110-ft×1,200-ft (SI unit conversions are provided in the Appendix) locks and a dam are being constructed in the Ohio River near Olmsted, IL. Construction of these locks required digging a 1,200-ft-wide and 2,200-ft-long excavation in the Ohio River to 100 ft below the design river stage. The size of the cofferdam required for lock construction, and the depth of excavation, made control of groundwater of paramount importance to excavation safety. The work included removing and/or controlling all ground and surface water within the cofferdam; controlling seepage through or beneath the coffercells and from the open cut along the Illinois bank; reducing the artesian head in an underlying stratum of highly jointed, indurated clayey silt and/or siltstone; and lowering the water level in the coffercells. The dewatering was accomplished by installing and pumping deep wells with submersible pumps, with vacuum, within the cofferdam area. The dewatering system was pump tested and evaluated before unwatering the excavation. Evaluation of the pump test data showed that the dewatering system as designed and installed would be adequate for the maximum design river stage with the addition of a few wells in the bottom of the excavation.     

黄浦江河口建闸工程规划

为维持上海市千年一遇高潮位设防标准 ,对继续加高加固防汛墙和黄浦江河口建闸这两个方案进行分析比较 ,认为无论从对黄浦江最高水位再次突破历史记录的适应性、安全性来看 ,还是从景观、经济、工期和综合效益来看 ,黄浦江河口建闸挡潮是长治久安的合理决择 .推荐了闸址、闸区总体布置、工程结构型式和挡潮闸运行方式 ,并提出了工程投资匡算和预计施工工期 .     

Considerations on direct stream flow measurements using video imagery: Outlook and research needs

The paper presents measurements acquired with Large-Scale Particle Image Velocimetry (LSPIV) during normal flows and floods in the Iowa River (U.S.A). For normal flows, comparison is made with measurements obtained with Acoustic Doppler Current Profilers (ADCP) in order to test LSPIV’s performance and to address concerns potentially affecting the accuracy of the measurements. The historic flood of the Iowa River during the summer of 2008 was captured for testing LSPIV capabilities during extreme flows. Lacking alternative measurements during the flood, the LSPIV measurements are compared to the rating curve extrapolated for high flows using a one-to-one discharge–stage relationship. The comparison reveals limitations of the single-values rating curve for providing discharge estimates during high flows. Finally, the paper summarizes lessons learned during these and previous LSPIV studies with the intent to chart the research needed to enhance this promising non-intrusive field measurement technique.