Numerical Model of Total Sediment Transport in the Yangtze Estuary   总被引：2，自引：2，他引：0  

DOU Xiping LI Tilai  DOU Guoren Senior Engineer  River  Harbour Engineering Department  Nanjing Hydraulic Research Institute  Nanjing  P. R. China Senior Engineer  Nanjing Institute of Hydrology  Water Resourses  Nanjing  P. R. China Academician  Nanjing Hydraulic Research Institute  Nanjing  P. R. China 《中国海洋工程》1999,(3)

Based on the non-equilibrium suspended load transport equation,bed load transport equationand sediment transport capacity formulas derived by Dou et al.,a 2-D numerical model of total sedimenttransport in the Yangtze Estuary is presented.In the model,the actions of tidal currents and wind waves andthe effect of salinity on sediment transport are considered.An automatically generated boundary-fitted grid isused to fit the boundaries of the estuary and the boundaries of engineering projects.The verification of calcu-lations shows that the sediment concentration,the deformation of riverbed and siltation in the channels causedby typhoons can be successfully simulated.  相似文献   

Reflection of Short Waves     

Miguel A. LOSADA 《中国海洋工程》1999,(1)

—According to the energy equation,the relation between reflection and energy losses for shortwaves from mild beaches is established and analysed.A reflection coefficient varying with position and en-ergy losses is proposed.Different reflection tests are conducted to check the theoretical analysis.A modi-fied method to estimate the reflection coefficient at varied water depths is suggested based on the linearwave theory.The study indicates that the reflection coefficient from mild beaches has a changing trend forshort waves approaching shoreline.  相似文献   

黑河流域水资源合理开发利用的研究   总被引：4，自引：0，他引：4  

黑河流域水资源粽合考察队 《中国沙漠》1987,7(4):12-21

黑河流域是我国干旱区一个较大的内陆河流域,集水面积约13万平方公里,主流长821公里,发源于祁连山,穿越河西走廊,流泄于内蒙古西部高原。本文对黑河流域水资源、土地资源、草场资源的数显和质量进行评价。同时分析了流域水资源潜力及开发利用引起的环境变化。指出目前水资源开发已影响到中游绿洲建设规模和下游绿的安全。研究认为现阶段水资源开发利用应使经济发展和保护环境两者之间的关系相协调。实行以流域为整体的开发,采取有效的工程措施,加强中、下游水资源利用的宏观控制与管理,实行分区定量分配和综合治理,从而提高流域水资源利用的经济、环境和社会效益。  相似文献   

Experimental study on low temperature performance of polymer drilling mud agents     

ZHAN Jiajia  XU Huiwen  CAI Hongliang .College of Construction Engineering  Jilin University  Changchun  China .China Water Northeastern Investigation Design  Research Co.Ltd  Changchun  China 《东北亚地学研究》2009,12(1):32-35

Drilling fluid additives has a major impact on rheology behavior and other performances of the drilling fluid. The key to low temperature drilling fluids is choosing antifreeze and polymer agent which have a strong ability in resisting low temperature. On the basis of determining glycol as antifreeze agent, the low-temperatureperformance and capacities of anti-collapse of regular validity mud agents have been studied, the mechanism of anti-caving of the partially hydrolyzed polyacrylamide （PHPA）, polypropylene potassium （KPA） and PAC-141 polymer additives have been also analyzed. A pilot study of compatibility between ethylene glycol and the polymers has educed that the polymers, ethylene glycol and inorganic salt are compatible, and they can significantly reduce the freezing point of drilling fluid. Anti-collapse ability of the drilling mud is the results of synergistic action among the agents.  相似文献   

Impact of Urbanization and Industrialization upon Surface Water Quality:A Pilot Study of Panzhihua Mining Town     

滕彦国  杨洁  左锐  王金生 《中国地质大学学报(英文版)》2011,(5)

In order to investigate the impact of urbanization and industrialization on surface water quality,a pilot study of Panzhihua mining town was carried out.The urbanization of Panzhihua region was dominated by industry development and population growth.The level of urbanization showed that it was 18.44% in 1965,and reached 45.99% in 1983.Then,it reached 53.71% in 2005,so the urbanization process was very rapid in Panzhihua region.In the process of industrialization,the level of industrialization was fluctuated...  相似文献   

中亚热带红壤丘陵区松林生态系统表层土壤活性有机碳空间分异规律   总被引：6，自引：1，他引：5  

陈晓琳  李忠武  王晓燕  申卫平  张雪  郭旺  张越男 《地理研究》2011,30(10):1825-1834

土壤活性有机碳在指示土壤碳库平衡、表征土壤肥力与质量、衡量土壤微生物生长等方面具有重要意义。本文对中亚热带红壤丘陵区松林生态系统93个表层（0～20cm）土壤样品的活性有机碳空间分布特征及其与地形、植被和土壤特性的关系进行了深入分析。结果表明：表层土壤活性有机碳的平均值为1.92g/kg,占土壤有机碳的29.18%,变...  相似文献   

海河流域水资源短缺风险研究     

张士锋  孟秀敬  华东  陈俊旭  李九一  张永勇  夏军 《资源与生态学报(英文版)》2011,(4):362-369

本文对海河流域水平衡和水资源短缺风险进行评价。文章采用研究时段为1994-2007年,作者首先研究了海河流域的水量平衡问题,并提出了流域非用水消耗量的概念和计算方法,经过分析,计算得出海河流域多年平均非用水消耗量为5.91×109m3。通过建立水资源短缺风险的评价方法,得出海河流域1994-2007年处于缺水量较多、缺水风险较高的时期,计算出缺水风险率、恢复性指标、稳定性指标和脆弱性指标分别为0.786、0、0.154和0.173。在考虑社会系统应对措施的条件下,水资源短缺风险将会显著下降。考虑南水北调工程对于该地区的影响,分别考虑在50%和75%两种来水水平年下,如果南水北调工程一期（2014年）的来水量为5×109m3,未来该地区的水资源短缺风险会从0.229-0.297下降到0.152-0.234。  相似文献   

水电项目对越南硒圣河地区社会经济发展及环境保护的影响     

乐庭青  武四兰 《资源与生态学报(英文版)》2011,(4):375-379

硒圣河是湄公河的主要分支之一,其集水区地形条件和水资源量均对水电开发十分有利。此外,无论从物种多样性还是生物量来看,硒圣河水生生物资源非常丰富。鱼类是当地人们的重要食物来源,粗略估计鱼类物种数量可能在200-300种之间,目前具有详细记录的鱼类大约为120种。截至目前,从越南境内硒圣河上游至越-柬边界总共开发了6个水电项目,兴建了一座4A级硒圣调蓄水库。流经柬埔寨的硒圣河部分,依据发展规划将兴建3座水电站,即硒圣5号电站（硒圣1号电站以下）、硒圣3号电站、硒圣2号电站。硒圣河水电项目对区域（越南和柬埔寨）社会经济的影响体现在：为地处偏远和困难的集水区创造了新的能源资源,改善了交通系统和农村地区的生活条件。与此同时,这些水电项目也对该区域自然环境产生了重大影响。例如,改变了下游流动机理变化,导致下游河道淤积,对沿河生态系统也产生了一定影响。  相似文献   

Simulated multi-scale watershed runoff and sediment production based on GeoWEPP model   总被引：5，自引：2，他引：3  

YU Xinxiao  ZHANG Xiaoming  NIU Lili Prof. Dr.  Key Laboratory of Soil  Water Conservation  Desertification Combating  Ministry of Education  School of Soil  Water Conservation  Beijing Forestry University  Beijing  China  Dr. China Institute of Water Resource  Hydropower Research  Beijing  China Dr.  ... 《国际泥沙研究》2009,24(4):465-478

The runoff and sediment yield data from the Qiaozidonggou, Qiaozixigou, and Lu＇ergou watersheds, in the Loess Plateau of China are used to calibrate and validate the runoff and sediment yield simulated by GeoWEPP model of the WEPP Model at watershed scale. The indices of relative error, R, correlation coefficient, Re, and Nash-Suttcliffe efficiency coefficient Ens are used to evaluate the model fit. The eco-hydrological responses in the Luoyugou and Lu＇ergou watersheds are also forecast based on the WEPP Model. Meanwhile, the relation between vegetation pattern changes and sediment yield in the watershed is discussed, and the responses of runoff and sediment yield in the watersheds concerning forest growth stages are studied. The results show that the relative errors of simulated values of runoff and sediment yield are below 30%, the correlation coefficients axe above 0.90, and the Nash-Suttcliffe efficiency coefficients axe above 0.80. The simulation results present satisfactory performance, thus, the model could be used to simulate the runoff and sediment yield in these small watersheds. It is also observed that soil erosion tended to become severe as precipitation increased in the watershed, while soil erosion has a decreasing trend as forest cover increases and vegetation pattern is optimized. When the watershed is fully covered by forest, erosion and sediment yield are minimized. When the forest cover is about 30% and evenly distributed in the watershed, the erosion intensity is lower than if the forest cover is collectively distributed in the watershed. Erosion varies with different forest growth stages in the watershed; it is more serious at the young and near planting stage and is the smallest at the mature forest stage.  相似文献   

A case study of spatial heterogeneity of soil moisture in the Loess Plateau, western China： A geostatistical approach   总被引：9，自引：2，他引：7  

BI Huaxing    LI Xiaoyin  LIU Xin  GUO Mengxia    LI Jun Prof.  College of Soil  Water Conservation  Beijing Forestry University  Beijing  China  Key Laboratory of Soil  Water Conservation  Desertification Combating  Ministry of Education  China Researcher  Ji-xian National Ecological Station of China  China Graduate student 《国际泥沙研究》2009,24(1):63-73

Soil moisture distribution shows highly variation both spatially and temporally. This study assesses the spatial heterogeneity of soil moisture on a hill-slope scale in the Loess Plateau in West China by using a geostatistical approach. Soil moisture was measured by time-domain reflectometry （TDR） in 313 samples. Two kinds of sampling scales were used （2 × 2 m and 20 ×20 m） at two soil layers （0-30 cm and 30-60 cm）. The general characteristics of soil moisture were analyzed by a classical statistics method, and the spatial heterogeneity of soil moisture was analyzed using a geostatistical approach. The results showed that the spherical model is the best-fit model to simulate soil moisture on the experimental hill-slope. The parameters of this model indicated that the spatial dependence of soil moisture in the selected hill-slope was moderate. Even the 2 × 2 m sampling scale was too coarse to show the detailed spatial variances of soil moisture in this area. The dependent distance increased from 27.4 m to 494.16 m as the sampling scale became coarse （from 2× 2 m to 20 ×20 m）. A map of soil moisture was generated by using original soil moisture data and interpolated values determined by the Kriging method. The average soil moisture （area weighted） in the different layers of soil was calculated on the basis of this map （10.94% for the 0-30 cm soil layer, 11.88% for the 30-60 cm soil layer）. This average soil moisture is lower than the corresponding average effective soil moisture, which suggests that the soil moisture is not sufficient to support vegetation in this area.  相似文献