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Effects of Forest Clear‐Felling on the Storm Hydrograph
Author(s) -
Hewlett John D.,
Helvey J. D.
Publication year - 1970
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr006i003p00768
Subject(s) - hydrograph , hydrology (agriculture) , baseflow , interflow , environmental science , surface runoff , felling , evapotranspiration , flash flood , storm , flood myth , streamflow , drainage basin , geology , geography , meteorology , agroforestry , ecology , geotechnical engineering , cartography , archaeology , biology
Earlier speculation that evapotranspiration from forests and the consequent soil water deficits under forests are factors in the production of floodwaters was verified by a paired watershed experiment. Mature hardwood forest on a 108‐acre catchment in the southern Appalachians was clear‐felled after an 18‐year calibration period. No forest material was removed, and no overland flow (surface runoff) occurred. A statistical analysis of all major storm hydrographs before (77) and after (30) clearing revealed that after felling stormflow volume (quick flow) was significantly (0.001 level) increased 11% overall, or 0.23 inch at the mean quick flow volume of 2.1 inches. Peak discharge increased slightly after felling (about 6 cfsm or 7% at the mean peak flow of 92 cfsm), but the test was not as conclusive as in the case of quick flow volumes. Time to peak (time of rise), recession time, and quick flow duration were tested to an accuracy within 10% of their respective mean values (0.05 level), but no treatment effect was detected. Quick flow increases due to felling ranged from 0 in small floods to 1.9 inches during a record 7‐day flood sequence. The latter value represented a 22% increase over the total quick flow (8.7 inches) expected during that regional record flood. The effect of forest evapotranspiration on floodwater released by deep‐soil slopes persists throughout the year, a result explainable by the variable source area concept of runoff.