Variability in riparian zone potential and actual evapotranspiration in a 1 st order agricultural catchment in Southern Ontario, Canada

Abstract

Micrometeorological and hydrological measurements were made over one growing season using automatic weather stations and weighing lysimeters at several locations within a multiple land-use agricultural catchment in Southern Ontario. This paper com- 5 pares modelled potential evapotranspiration (PET) and measured actual evapotranspi- ration (AET) values obtained from the soil weighing lysimeters, and determines the spatial variability in riparian zone AET in a multiple land-use agricultural watershed in Southern Ontario. Two sites were chosen in two different riparian areas of the water- shed, representing the surface conditions dominant in the upper and lower reaches of 1 the basin. 0 The results indicated that AET was higher in the northern end of the basin than in the southern portion of the basin, while the hydrological and energy balance compo- nents were similar at both sites. The causes of the different rates are attributed to the surrounding vegetation on adjacent fields and the differing wind regimes.