| The Puzhehei peak forest-lake basin of southeastern of Yunnan located at the southern of Yunnan Guizhou Plateau, is a relatively closed fault basin, a typical karst watershed. Nearly half a century of climate and land use patterns have changed significantly, and has a certain influence on the local hydrology and water resources. This paper analyzed variation characteristics of climate and land use, and the establishment of semi distributed hydrological model of lake catchment runoff based on simulation, effects of land use changes in the study area of hydrology and water resources, especially the influence of the structure and function of the karst water conservation water storage storage function. 1 Analysis of climate changeBy using linear regression, Mann-kendall rank correlation test were used for statistical analysis of meteorological data in the study area, research area in recent 56 years the average temperature of the overall upward trend, the annual precipitation showed a decreasing trend, the annual evaporation decreased. 2 Analysis of land use changeStatistical analysis of the transfer matrix and the transition probability matrix of land use types in study area, to understand the main landscape elements in Puzhehei lake basin area of Southeast Yunnan in 1990 peaks for bare land, accounting for 34.25% of the total area;In 2000 and 2010 the main landscape elements are still bare, followed by dry land and forest land; the main landscape elements in 2014 into the forest, secondary landscape elements as the bare rock and dry land.From 1990 to 2014, the study area of construction land, forest land showed an increasing trend, dry land, paddy field, the water was in a fluctuating tendency, bare land showed a decreasing trend. 3 The semi distributed hydrological modelThe semi distributed hydrological model of this article is based on Puzhehei peak forest-lake basin, according to calculating the runoff of waters, paddy field, forest land, dry land, bare land construction land, and the flow concentration calculating is based on subcatchment, The surface river and underground pipelines. The semi distributed hydrological model has good simulation results in both calibration period and validation period: the Nash-Sutcliffe efficiency coefficient is 0.80 and the relative error of annual runoff is-5.80% in calibration period; the Nash-Sutcliffe efficiency coefficient is 0.80 and the relative error of annual runoff is-5.80% in validation period. 4 land use change on hydrological response(1)The North Lake area of Southeast Yunnan peak runoff increased gradually from April, July or August began to gradually reduce;The runoff in June increased significantly, up to peak in July or August, from the beginning of October runoff decreased significantly, up to the minimum value in March or April.In the rainy season runoff was bigger, the dry season runoff.(2)Associated study area runoff to a great extent, and the rainfall runoff peak, but does not necessarily appear in the peak month rainfall, runoff minimum value does not necessarily appear in the smallest monthly rainfall.Increasing trend of runoff lag in rainfall runoff increased, decreased and decreased rainfall trend of basic synchronization.(3)After vegetation restoration, the study area runoff decrease, and the peak value lags behind the rainfall; rainy season due to heavy rain, the water conservation function of forest vegetation is weakened; Drought, vegetation restoration can reduce runoff decrease. Vegetation restoration in general can increase the runoff in the study area, characterized by "peak clipping fill dead".(4)In the same rainfall, runoff extreme naked than extreme woodland; two kinds of different land use scenarios in the rainy season, dry season runoff, runoff rate is higher than the rate of change, the hydrological response in the rainy season than in dry season. |
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