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Response of mean annual evapotranspiration to vegetation changes at catchment scale
Author(s) -
Zhang L.,
Dawes W. R.,
Walker G. R.
Publication year - 2001
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 - 10.1029/2000wr900325
Subject(s) - evapotranspiration , groundwater recharge , environmental science , hydrology (agriculture) , water balance , vegetation (pathology) , interception , drainage basin , groundwater , geography , geology , ecology , aquifer , medicine , geotechnical engineering , cartography , pathology , biology
It is now well established that forested catchments have higher evapotranspiration than grassed catchments. Thus land use management and rehabilitation strategies will have an impact on catchment water balance and hence water yield and groundwater recharge. The key controls on evapotranspiration are rainfall interception, net radiation, advection, turbulent transport, leaf area, and plant‐available water capacity. The relative importance of these factors depends on climate, soil, and vegetation conditions. Results from over 250 catchments worldwide show that for a given forest cover, there is a good relationship between long‐term average evapotranspiration and rainfall. From these observations and on the basis of previous theoretical work a simple two‐parameter model was developed that relates mean annual evapotranspiration to rainfall, potential evapotranspiration, and plant‐available water capacity. The mean absolute error between modeled and measured evapotranspiration was 42 mm or 6.0%; the least squares line through the origin had as lope of 1.00 and a correlation coefficient of 0.96. The model showed potential for a variety of applications including water yield modeling and recharge estimation. The model is a practical tool that can be readily used for assessing the long‐term average effect of vegetation changes on catchment evapotranspiration and is scientifically justifiable.