The result showed: 1) the effect is visible to control soil erosion,the surface runoff of the forest land was reduced from 75.25%-85.21%,and the soil erosion reduced 85.4%-95.6% comparing with the farmland every year;
(6) The comparative results of different ecological function of allocation model wasthat the amount of surface runoff and sediment in the region of river valley was from largeto small, Dodonaea viscose(B)>Flousiana(D)> Cratoxylon prunifolium(A)>Kalopanaxseptemlobus(E)>bamboo(C);
For the rainfall balance of the non-forest land,the surface runoff of the outer space is 3.10% of the rainfall,the evapotranspiration is relatively big,which is averagely 65.70% of it,and during this course,it adds up to 94.90% in May,August the least,48.90% of the rainfall,the conflux 25.00%,and the interflow only 6.20%;
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.
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.
The annual low flow runoff volume increased 28.87mm in forest coverage of 65 percent than of 32 percent, but annual flood runoff volume reduced 98.87mm.
Based on a comparison analysis of retention data from measuring weirs in the forestcathment and control unforested catchment,runoff volume in the forest catchment was decreasedbv 57.5% and peak flood was decreased by 20% to 90%in each floOd Drocess as comoared withthe control unforested catchment during the observation period.
Through measuring the indices of soil water storage and runoff volume,the functions of the conserving water and preserving soil and water of the hillclosing vegetation in the present landscape patten were analyzed.
Annual runoff amount of river basin is a significant basis for water resources evaluation and its allocation in reason,while the water reduction function of artificial afforestation is a foundation of estimating influences of soil and water conservation on annual runoff amount.
Tumenxigou watershed is selected to validate the model, which in the upper reaches of Miyun Reservior. The runoff amount and the distribution of nitrogen and phosphorus output was simulated by AnnAGNPS model.
Evapotranspiration was the main form of water transportation in different ecosystems. The amount of runoff of natural mixed forest and larch plantation was significantly less than that of other forest types.
Without litters in forests amount of runoff is increased by 1 96 times and soil scouring 2 87 times as much as their original stands for Pinus tabulaeformis, and 1 67 and 8 15 times respectively for Populus davidiana.
By contrasting the surface runoff and underground runoff in these two areas, the results showed that,with the same precipitation,the gross amount of runoff in bamboo forests was larger than that in broadleaved forests and the runoff in bamboo forests appeared before that in broadleaved forests.
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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