长江中下游河道冲淤演变的防洪效应          下载免费PDF全文

徐照明  徐兴亚  李安强  张黎明  胡春燕 《水科学进展》2020,31(3):366-376

近年来长江中下游来沙量持续减少,河道面临长距离、长历时的冲淤调整,河道蓄泄关系发生变化,对防洪造成影响。在长江中下游河道冲淤及其蓄泄能力变化预测成果的基础上,对比计算了现状和未来河道蓄泄能力条件下,遇1954年洪水,长江上游水库防洪调度和中下游地区超额洪量的变化情况。结果表明,未来随着长江中下游河道进一步冲刷,河道槽蓄容积增加,相同防洪控制水位下的河道安全泄量增大,三峡水库在进行防洪调度时可下泄流量增大,总拦蓄洪量减小,长江中下游地区总超额洪量减小,但超额洪量在地区分布上存在从上游向下游转移的情况。  相似文献   

多点入流汇流计算法在北京城市洪水计算中的应用与研究   总被引：1，自引：0，他引：1  

文立道  范本贤 《水文》1998,(1):22-28

根据北京城市化水平,城市汇流特点,通过用多点入流汇流计算法模拟实测洪水过程线,分析了北京城市河道的汇流特点与规律,初步提出了一种适合于北京城市洪水计算的方法,为城市防洪排水工程规划,设计提供依据。  相似文献   

基于土壤侵蚀遥感调查的河流输沙量的计算     

陈曦川  钟邵南 《水文》1998,(6):14-18

河流泥沙来量的计算是工程水文计算的一个重要组成部分。有水文站观测资料的地方,输潲星的计算比较容易。而对于没有水文站分布或观测资料不足的边远地区,用常规无法计算出输沙星。  相似文献   

图们江地区水环境容量及其对区域开发的影响研究   总被引：10，自引：1，他引：9  

田卫  俞穆清 《地理科学》1998,18(2):169-175

以ＣＯＤ为控制指标,计算了图们江地区５条河流逐月环境容量以及污水达标排放时的允许污水排放量。结果表明,各月环境容量分配极不均匀,丰水期２个月约占５０％,而长达５个月的枯水期环境容量很小,不足全年的１０％;即使以１９９５年污水排放量衡量,污水达标排放时,枯水期图们江干流等５条河流控制断面水质也达不到指定功能水质标准,已无环境容量可利用。因此,河流水环境容量已成为制约图们江地区开发的主要因素,为了确保  相似文献   

乌鲁木齐河“960719”洪水分析   总被引：3，自引：0，他引：3  

张谆  龚建新 《干旱区地理》1998,21(1):49-56

本文依据大量实测洪水数据对乌鲁齐河“９６０７１９”洪水的来源,特点及时空分布变化进行了讨论,分析了这场洪水的重现期,并提出了有关建议。  相似文献   

Drainage density changes during rainfall     

D. G. Day 《地球表面变化过程与地形》1978,3(3):319-326

Observations of stream behaviour during rainfall indicate that previous notions of a simple expanding and contracting network need review and refinement. In a small rural catchment near Armidale, N.S.W. changes in flowing stream length during rainfall have been depicted on flow length graphs which indicate a varied network response to similar rainfall amounts. Channel flow phenomena include discontinuous flow, the generation of flow points within the channel and movement of water downslope from saturated depression sources. Localized physical controls have a significant effect on stream growth which is a sensitive indicator of the catchment response to rainfall. During rapid changes in stream length total flowing length and discharge are highly correlated. A model of the pattern of network expansion and contraction involves several phases of flow contraction.  相似文献   

The characteristics of rain electricity in Nigeria. I — Magnitudes and variations     

A. I. I. Ette  E. O. Oladiran 《Pure and Applied Geophysics》1980,118(2):753-764

The characteristics of rain and point charges based on routine measurements extending over four rainy seasons are presented. An average rain current density of (1.0±0.1)×10^–10 A m^–2 and charge per unit volume of rain water of (0.43±0.02)×10^–4 C m^–3 for the locality are obtained, which are compared with data obtained elsewhere by other workers. The point-discharge current measurements lead to a revised estimate of (0.86±0.08)×10^–9 A m^–2 for the average point discharge current below storm clouds.  相似文献   

Quantifying groundwater discharge to a small perennial stream in southern Ontario, Canada   总被引：3，自引：0，他引：3  

Edwin E. Cey  David L. Rudolph  Gary W. Parkin  Ramon Aravena 《Journal of Hydrology》1998,210(1-4):21-37

A study of the interaction between groundwater and surface water was undertaken within a small agricultural watershed in southern Ontario, Canada. Groundwater contributions to streamflow were measured along a section of stream during baseflow conditions and during rainfall events. Four techniques were used to estimate the contribution of groundwater to the stream along a 450 m reach (three during baseflow and one during stormflow conditions). Under baseflow conditions, streamflow measurements using the velocity–area technique indicated that the net groundwater flux to the stream during the summer months was 10 ml s⁻¹ m⁻¹. Hydrometric measurements (i.e. hydraulic gradient and hydraulic conductivity) taken using mini-piezometers installed in the sediments beneath the stream resulted in net groundwater flux estimates that were four to five times lower. Seepage meters failed to provide any measurements of water flux into or out of the stream. Therefore, based on these results, the velocity–area technique gives the best estimate of groundwater discharge. Hydrograph separations were conducted using isotopic ratios and electrical conductivity on two large rainfall events with different antecedent moisture conditions in the catchment. Both events showed that pre-event water (generally considered groundwater) dominated streamflow and tile drain flow with 64%–80% of the total discharge contributed by pre-event water. High water table conditions within the catchment resulted in greater stream discharge and a greater contribution of event water in the streamflow than that observed under low water table conditions for similar intensity storm events. The results also showed that differences in riparian zone width, vegetation and surface saturation conditions between the upper and lower catchment can influence the relative magnitude of streamflow response from the two catchment areas.  相似文献   

Lichens and the determination of river channel capacity     

Ken J. Gregory 《地球表面变化过程与地形》1976,1(3):273-285

The identification of channel capacity associated with a particular frequency of peak discharges is necessary for discharge estimation for planning purposes at ungauged sites. Although lichen limits have been suggested to be useful for this purpose, previous studies have not elaborated their hydrological significance. Lichen limits are clearly defined on the sides of rock channels in New England. Australia and they are analyzed in relation to discharge at 6 gauging stations with up to 52 years of continuous record. It is demonstrated that the lowest lichen limit is maintained by peak discharges which occur on average at least once or twice each year. Recurrence intervals based on Annual Series and on Annual Exceedance Series are calculated and for the annual series are fairly consistent for the lowest lichen limit and range from 1·14 to 1·37 years. Lichenometry can be applied to the analysis of river channels in relation to the frequency of peak discharges. By reference to growth curves based upon lichens on Armidale tombstones it is shown that lichenometry may be employed to indicate dates for channel modification due to the removal of blocks and to dam construction and also to date the rock surface between lichen limits. Detailed analysis of the record from gauging stations indicates that where several lichen limits occur in a channel cross section each limit is related to periods when peak discharges exceeded the limits on at least 5 occasions. The lichen-free surfaces were then recolonized by Parmelia spp. and the size of the lichen thalli indicates the time elapsing since these frequent high discharges.  相似文献   

POLLUTION TREND IN THE TUMEN RIVER AND ITS INFLUENCE ON REGIONAL DEVELOPMENT     

田卫  俞穆清  王国平  郭传新 《中国地理科学(英文版)》1999,9(2):146-150

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