Field scale water balance is difficult to characterize because controls exerted by soils and vegetation are mostly inferred from local scale measurements with relatively small support volumes. Eddy covariance flux and lysimeters have been used to infer and evaluate field scale water balances because they have larger footprint areas than local soil moisture measurements.. This study quantifies heterogeneity of soil deep drainage (D) in four 12.5 m2 repacked lysimeters, compares evapotranspiration from eddy covariance (ETEC) and mass balance residuals of lysimeters (ETwbLys), and models D to estimate groundwater recharge. Variation in measured D was attributed to redirection of snowmelt infiltration and differences in lysimeter hydraulic properties caused by surface soil treatment. During the growing seasons of 2010, 2011, and 2012, ETwbLys (278, 289, 269 mm) was in good agreement with ETEC (298, 301, 335 mm). Annual recharge estimated from modelled D was 486, 624, and 613 mm for three calendar years (2010, 2011, 2012). In summary, lysimeter D and ETEC can be integrated to estimate and model groundwater recharge.
Hydrological Sciences Journal, 2015, Vol 60, Issue 9, p. 1520-1537
groundwater recharge; lysimeters; eddy covariance; field water balance; soil water flow model; Hydrus 1D; hydros ID