Water requirements of a Southern Alberta riparian cottonwood ecosystem

Abstract

The eddy covariance (EC) method was used to determine the amount of water used for evapotranspiration (ET) over the 2014 growing season by a Southern Alberta riparian cottonwood ecosystem in Lethbridge, AB, Canada. Isotopic measurements of deuterium content in water were used to determine what portion of the water supplying evapotranspiration came from the each of the two cottonwood woodland water sources: the Oldman River and seasonal precipitation. Isotopic analysis of the woodland water sources identified the Oldman River as the sole source of water for the resident cottonwood trees. Based on EC measurements, 465 mm of water was used during the 2014 growing season by the cottonwood woodland. An estimated woodland area of 1.7 x 10^5 m2 was used to determine the approximate volume of water used by the woodland over the 2014 growing season to be 7.9 x 10^4 m3.