Study On Response Of River Runoff To Climate Change And LUCC In Longchuan River Watershed

Using M-K, R/S analysis, Cumulative anomaly mathematical statistics methodsto analysis the variation of meteorological hydrological of basin, and using ENVIinterpret combined with Arcgis technology monitoring and analysis the land use andvegetation cover of more times. Through single factor and multi-factor correlationanalysis, reveals the inherent relationship between vegetation cover, climate changeand land use within the watershed. Identify the controlling factors of runoff changesin Longchuan river basin. To provide a scientific basis for the sustainable use of waterresources and sustainable development of ecological environment in Longchuan riverbasin. The results showed that:1, Context of global change, the annual average temperature in Longchuanjiangbasin is overall upward trend, and a significant upward trend (2.1438>1.96). But thedry-hot Valley region of Jinsha River in yuanmou, showed the opposite phenomenon.Through the calculation of R/S analysis method shows that watershed’s temperatureswill continue the past temperature changes in the future.2, Since1970, basin’s precipitation was changes fluctuation stronger, increasingyear by year, but the increase tendency was not significant, and the most abundantrainfall in summer, Smallest in winter, autumn than spring. R/S analysis showed that:Hurst values of basin precipitation are more than0.5except in winter, that is inaddition to winter the Precipitation in the future will continue the past increase trends.3, For25years, showed a sustained reduction trend in arable land of the basin,closing2013arable land reduction360.341Km2, the reducing rate is18.03%. Urbanconstruction land has continued to rise, to2013increase139.266Km2. The basin’s forestarea is Increase, as of2013forest area increased by843.1253Km2.4,in the basin Mainly low or Moderate vegetation cover，In the east-westdirection on both sides of the central region of the basin, the vegetation coverage isbetter,and with high vegetation cover or higher vegetation coverage; Northernwatershed areas mainly low vegetation cover, in the southern region is lowervegetation cover or moderate vegetation cover. In1989to2013, the low vegetationcover of basin area increased233.34Km2, increased4.26%; Low vegetation cover to reduce66.72Km2, decrease of1.22%; Moderate vegetation cover to reduce195.14Km2,reduction rate of3.56%; Medium or higher vegetation cover vegetation to reduce84.24Km2, reducing by1.54%; Higher vegetation cover increased112.77Km2, anincrease of2.06%.5, Longchuan river runoff variation is large inter annual variability, wavy upsand downs, and there is no obvious regularity. Using Longchuan river averageannual runoff data to calculate annual runoff coefficient of variation, basin runoffcoefficient of variation is0.71, indicating uneven distribution of river basin runoff.Watershed runoff through the95%confidence test, M-K value of its average annualrunoff of <0.01(-0.36), indicating that runoff is reduced but not significantlydecreasing trend, and the annual average of watershed runoff appears four timesmutation, respectively in1954,1957,1995,2004. Watershed average annual runoffHurst value0.63is greater than0.5, indicating that future basin runoff downwardtrend will continue, but not strong continuity. Watershed four Seasons runoff changestate is the biggest change in autumn, followed by spring, winter, and summer’schange more gentle. From the annual runoff coefficient of variation of view, thebiggest change in the autumn, followed by spring, the smallest change is winter,summer variation margin gently. All years runoff are concentrated from June toNovember. November to next year’s May is less than normal runoff. August is allyears highest runoff month, the average runoff is2.24×108m3. seasons Runoffcoefficient varies with age is first ascending then descending trend, the maximumvariation coefficient of1.06, appeared in the1970s autumn.6, The runoff was main significantly correlated with and precipitation, unusedland changes， with other factors the correlation was not significant. Runoff andprecipitation, unused land correlation coefficients were0.892,0.322. Basin has threeprincipal components factor (PC1/PC2/PC3), and analysis the load capacity of Impactfactor’s principal component. PC1principal component represents the humanactivities, the vegetation coverage is PCI largest load factor of0.994;PC2representsthe human activities and meteorological factors working together, grassland,precipitation is PC2the largest two load factors were-0.699,0.686; PC3mainrepresentative of the meteorological factors, temperature is the maximum loadcapacity in PC3factor of0.629.