The daily runoff in 29 years of Pingle Station in Guangxi province was predicted by ANN after non-linear smoothing transferring. The results showed that days in 10% relatively error averagely increase 47.8%,and days in 20%,relatively error averagely increase 35.6%.
As a result,the average annual areal precipitation is 80.6×108m3,the average ratio of runoff and areal precipitation(R/P) is 0.38,its maximum and minimum is 0.53 and 0.32 respectively.
Using the material of hydrology in the upper Yangtze River and the runoff, the temperature, and the precipitation observed in meteorological stations from1956 to 2004, the intermonthly and interdecadal evolution characteristics of the runoff and the sudden change characteristic in the area are analyzed by the climatic diagnosis method.
Change trends slope of calculated areal precipitation and the observed runoff of Aksu river on were 5.79×108m3/10a and 4.29×108m3/10a respectively, and both of them have increased trend. The annual change trend and extent of the areal precipitation are higher then the runoff. Both of their coefficients of variation (Cv) are 0.17 and 0.13, respectively.
Conversion from forests to cropland, wooded grassland or grassland covers tends to reduce evapotranspiration by 3.1-22.2 % and increase runoff volume by 2.0-15.0 %. This invariably could make flood peaks increase and appear in advance.
Soil runoff volume and rainfall volume had linear relationship in all communities. Soil runoff volume of four secondary forest communities were 135.58 mm-160.48 mm.
With the support of GIS technology, the SCS (soil conservation service) model was selected to model runoff of the upper watershed of the Luohe River(a tributary of the Yellow River) using a 1 : 250 000 DEM and a 1 : 1 000 000 DEM. By comparison of the simulated annual average runoff yield from 1992 through to 2000, it was found that a higher runoff volume was obtained using the 1 : 250 000 DEM.
Three meteorological fields of Northern Hemisphere H500, H100 and temperature of West Pacific Ocean (SST) are taken as forecasting elements to do one-year-prediction in Datong station of Yangtse River for monthly runoff and gross runoff volume from July to October.
The paper introduces the method calculating the design peak flow and the design runoff amount in the river without data by utilization of precipitation through an example.
The results showed that on the slope of 5°,there was a power regression between sedimend yield and runoff amount for flow discharge of 15 L/min,20 L/min and 25 L/min,and a linear regression for 10 L/min.
With the support of GIS technology, the SCS (soil conservation service) model was selected to model runoff of the upper watershed of the Luohe River(a tributary of the Yellow River) using a 1 : 250 000 DEM and a 1 : 1 000 000 DEM. By comparison of the simulated annual average runoff yield from 1992 through to 2000, it was found that a higher runoff volume was obtained using the 1 : 250 000 DEM.
At the same time, better correlative relationship between runoff and sediment production and rainfall and rainfall intensity were testified by multiple regression, but the correlation decreased gradually with the increase of canopy density of forest.
Thirdly, based on gray cognate analyses of factors affecting runoff and sediment production in sloping land, the factors of stand canopy density and herb and litter biomass were the most significant ones, whose gray incidence degree exceeded 0.6.
When the soil is covered only by litter, both the maximal rainfall amount and intensity in different forest stands are different if there is no water infiltration and runoff from the ground surface.
The quantity of organic substance inflow with each river depends both on the water runoff volume and on the value of mean weighted concentrations of organic substances in water of these rivers.
Based on the water resources of the Shiyang, Heihe and Shule river basins in the Hexi Corridor and their original runoff volume, the actual annual water resources in the oasis of every county and town of the Hexi Corridor are calculated in detail.
The relationship between the runoff and suspended sediment rates was explained exponentially as S = 1.99 QA1.62 (P >amp;gt; 0.01 and R2 = 0.846) (S is the suspended sediment rate in t d-1, and QA is the average daily runoff rate in m3 s-1).
Depending on changes in the lysimeter runoff rate during the infiltration stages, the pore space continua with uniform, stable functioning and those with varying functioning (increasing or decreasing runoff) can be distinguished in a soil body.
Results of this analysis demonstrate that the annual stream runoff rate changes from 6.3, towards 3.95, and then to 2.09?l?s-1?km-2 (the difference is significant based on Student's criteria).
A moving control volume approach was used to model the advance phase of a furrow irrigation system whereas a fixed control volume was used to model the nearly stationary phase and the runoff rate.
径流量
runoff 
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