Study On Hydrological Effect Of Water Conservation Forest In Lianhua Lake Reservoir Area

Based on located research method, as compared with waste grassland, studies on the hydrological benefits of Pinus koraiensis, Lurix gmelinii and weed trees were conducted in the permanent sample plots in Lianhua Lake watershed area in Heilongjiang Province. The canopy precipitation interception, litter layer water-holding capacity, soil physical property, water holding capacity, surface runoff, silt and sand were quantitatively measured in three types of artificial forests, their function of water conservation was compared. The results indicated that the canopy interception was 34.83%, 13.05%, 19.61%, the stem-flow was 6.79%, 0.58%, 4.01%, the throughfall was 58.37%, 86.18%, 77.66% of Pinus koraiensis, Larix gmelinii and weed trees, respectively. The canopy interception, stemflow and throughfall were positively correlated with precipitation amount; the experiential models between canopy interception, stemflow, throughfall and rainfall were given. The standing mass of litter in this area ranged from 5.7 to 23.6t.hm^-2 being larger for conifers than that for weed trees and the waste grassland. The general water-taking rate went down sharply in 3 hours after soaked in water, reaching saturated state in about 24 hours. The maximum water-holding capacity of the whole litter layer ranged from 12.0 to 24.0t.hm^-2, being in the declined order of Pinus koraiensis, Larix gmelinii, weed trees, waste grassland. The modified interception varied from 2.94 to 45.97 t.hm^-2, in the declined order of Pinus koraiensis, Larix gmelinii, weed trees, waste grassland. The modified interception rate varied from 53.45% to 65.95%, in the declined order of Pinus koraiensis, weed trees, Larix gmelinii, and waste grassland. The maximum water storage in different types of forests varied from 1838.6-2186.3 t.hm^-2, and the order was Larix gmelinii > weed trees> Pinus koraiensis >waste grassland; the water holding capacity of non-capillary porosity varied from 16.26-25.28mm, being in the declined order of Larix gmelinii, Pinus koraiensis plantations, weed trees, waste grassland. Transformation feature and availability of water moisture content for main vegetation types were studied and evaluated. The correlations between the cycle levels of soil water, stored soil water at the end of growing season were significant. The results showed as follow: the soil infiltration rate in forest land was obviously higher than that in waste grassland. Permeability function of soil was controlled by quality and quantity of soil hole. The quality and quantity of soil hole under Larix gmelinii plantation were the best, and its permeability was also the best. Soil infiltration rate decreased gradually when soil layer thickness increased. In other words, the spatial characteristics of soil infiltration rate along the soil layer was upper Iayer>middle layer>down layer. By comparison of four main types of vegetations, soil water dynamics was revealed. The change law presented the trend of high-low-high-low. The flow production and sediment production were studied in the paper, based on the data from observation in runoff plots. The results showed that, as compared with waste grassland, the runoff depth and sediment yield were closely correlatedwith slope, rainfall and maximum rate of rainfall in 15 minute, respectively. This experiment will provide the basic data and scientific evidence for further studies on water and soil conservation functions of the forests and comprehensive evaluation of ecological function of forests.