tailieunhanh - Báo cáo lâm nghiệp: "Effects of drainage treatment and stand growth on changes in runoff components from a forested watershed"

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: Effects of drainage treatment and stand growth on changes in runoff components from a forested watershed. | JOURNAL OF FOREST SCIENCE 56 2010 7 307-313 Effects of drainage treatment and stand growth on changes in runoff components from a forested watershed V. Cernohous F. Sach D. Kacálek Forestry and Game Management Research Institute Opocno Research Station Opocno Czech Republic ABSTRACT Runoff generation under various natural conditions has often been studied in forested watersheds for a long time. In 1967 Hewlett designed a variable source area model. The model is based on the expansion and shrinkage ofvariable source areas and consequent changes in a drainage network during a discharge event. The runoff investigation was carried out in a forested watershed situated in the summit area of the Orlické hory Mts. The watershed has a drainage area of ha with the land-surface elevation ranging from 880 to 940 m . Runoff components their amounts and ratios were calculated using a simple graphical-mathematical method of the hydrograph recession limb analysis according to a reservoir model representing the particular components base flow subsurface flow and overland flow in other words slow accelerated and rapid flows . Comparing the amount of slow and rapid runoff constituents and respectively the greater amount of slowly moving water confirmed that overland flow was absent under conditions of forest environment. Not even the drainage treatment altered this positive ratio of the runoff constituents. During the third period under stabilized hydrology and stand conditions the accelerated and rapid runoff increased again however maximally by 10 and 4 respectively not reaching the initial size of the calibration period. Keywords drainage treatment forested watershed recession limb runoff components stormflow hydrograph Generation of runoff within forested watersheds has often been studied for many years under various natural conditions. Sach reported Horton s model Horton 1933 constructed in the 1930 s as the design used for a long time to determine .

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