Huanren Section Of Hun River Runoff Model Based On The Change Of Forest Vegetation

Forests play an important role in watershed regulation,transformation and water transport.To fully understand regional hydrological effects,and to study the runoff model,Considering the factors affecting runoff,improving the accuracy of the model and the applicability of the model in the study area,deeply understand the relationship between forest and runoff.This paper takes Huanren River Hunjiang River in Liaoning Province as the study area,the Landsat series of remote sensing data from 2005 to 2015 is used as a data source for calculating vegetation coverage,combined with the meteorological data of China Meteorological Resources Network,on the basis of full production flow,considering the impact of forest vegetation coverage,to calculate and rate the parameters of the basin model.The model calculates the runoff depth,the peak flow rate,the confluence time result and the measured value to verify the accuracy,achieve better results.Using the model to calculate the average runoff value of the Huanren section of the Hunjiang River from 2005 to 2015,correlation analysis of forest vegetation cover change and runoff measured in the corresponding period was carried out to verify the model accuracy and regional applicability,the conclusion is that higher forest vegetation coverage can reduce watershed runoff.The main contents and conclusions of this study are as follows:(1)Preprocessing the 11-year remote sensing data for landsat-7 and landsat-8,The vegetation coverage of Huanren section of Hunjiang River Basin was calculated by using the binary model and decision tree.The results show that the woodland was the largest proportion of the huanen region between 2005 and 2015,it's around 70%.The average single dynamic state of the change of vegetation cover type is the degree of intensity from the largest to the following:construction land,woodland,other land,cultivated land,water;based on a five-year analysis of the regional integrated land cover type of dynamic attitude;The dynamic degree of comprehensive land cover in the 2005-2010 and 2010-2015 years of the study area is becoming larger and larger in two stages,Respectively 0.617 and 0.684;the forest coverage rate in Huanren area increased year by year,from 69.4%to 76.6%,the area of forest land in 2005,2010 and 2015 was 2462.859 km2,2506.452 km2 and 2718.705 km2,respectively,above the national average..(2)The forest cover of the liaodong area is high,the underside of the basin is closer to the wet area of the south.The forest vegetation coverage factor as a parameter to determine one of the main factors,Using the experience of synthetic model in humid area,the model parameters of full runoff generation are formulated.Effects of forest vegetation on soil water evapotranspiration in watershed by WM value of water storage capacity,Determine the amount of soil storage capacity WM is 110 mm at the beginning of the rain.The effect of forest interception on rainfall is determined by the watershed parameter,the area allocation curve,and the magnitude of runoff,Take the basin parameter value as 0.4.(3)Using the model to calculate the precision of the production flow in more than 80%and the fitting is less volatile,the correlation coefficients R2=0.9179,and the models have higher precision.The convergence calculation is higher than the measured value,and the calculated value of the peak time is generally 2?4 hours,and the precision satisfies the applicable requirement.The correlation coefficient R2=0.8991,the difference was less than 15%,the fitting volatility is not big,the relative error of calculation results show the overall model and successfully verified the accuracy to meet the requirements,storage full production has a high precision flow model,but also has certain applicability and rationality.(4)The monthly average runoff value of the Huanren section in the Hunjiang River from 2005 to 2015 is compared with that of the corresponding period.The results show that the higher vegetation cover has the hydrological effect of decreasing the runoff of the river basin.There was no difference between 2007 and 2012,and forest vegetation coverage was 68.501%and 71.402%,respectively,with an increase of 2.901%,The calculated values and measured values of monthly mean runoff models in June,July,August and September were significantly smaller than those in 2007,which indicated that the higher forest vegetation cover had the effect of reducing runoff.The difference of rainfall between 2010 and 2014 is 1450 mm and 589 mm respectively.In 2010,it is 2.5 times of that in 2014,but the calculated value of monthly mean runoff is not different from the measured value.The results show that forest vegetation The regulation of runoff under low rainfall conditions is not significant for larger rainfall conditions,and the increase of forest coverage is more obvious for larger rainfall runoff.