Location: Northwest Watershed Research CenterTitle: Estimating actual evapotranspiration from stony-soils in montane ecosystems
|PARAJULI, KSHITIJ - Utah State University|
|JONES, SCOTT - Utah State University|
|TARBOTON, DAVID - Utah State University|
|HIPPS, LAWRENCE - Utah State University|
|ALLEN, L. NIEL - Utah State University|
Submitted to: Agricultural and Forest Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2018
Publication Date: 11/26/2018
Citation: Parajuli, K., Jones, S.B., Tarboton, D.G., Flerchinger, G.N., Hipps, L.E., Allen, L.N., Seyfried, M.S. 2019. Estimating actual evapotranspiration from stony-soils in montane ecosystems. Agricultural and Forest Meteorology. 265:183-194. https://doi.org/10.1016/j.agrformet.2018.11.019.
Interpretive Summary: Quantifying evapotranspiration (ET) is crucial for understanding the water balance and for planning efficient use of water resources. However, the presence of stones in the soil complicates estimates of ET. This study focused on modelling ET from stony soil in montane ecosystems where we accounted for the presence of stones in the soil and for whether the stones were porous or not. The modeled ET assuming negligibly porous stones were 10 to 30% lower than estimates made considering highly porous stones due to the substantial decrease in soil water storage. These results reveal the important role stones play in modulating water balance by affecting ET.
Technical Abstract: Quantification of evapotranspiration (ET) is crucial for understanding the water balance and efficient water resources planning. Agricultural settings have received much attention regarding ET measurements while there is less knowledge for actual ET (ETA) in natural ecosystems. This study is focused on modelling ETA from stony soil in montane ecosystems where we account for the contribution of stone water retention properties in soil. We employed a numerical model (HYDRUS-1D) to simulate ETA in natural settings in northern Utah and southern Idaho during the 2015 and 2016 growing season based on meteorological and soil moisture measurements at a range of depths. We simulate ETA under three different scenarios, considering soil with (i) no stones, (ii) highly porous stones, and (iii) negligibly porous stones. The simulation results showed significant overestimation of modeled ETA when neglecting stones, in comparison to ETA measured by eddy covariance. The modeled ETA assuming negligibly porous stone were much lower in all stations than estimates made considering highly porous stone due to the substantial decrease in soil water storage. Assumptions of highly porous or negligibly porous stones in the soil, lead to reductions in simulated ETA of up to 10% and 30%, respectively, when compared with the no stones condition. These results reveal the important role played by stones, common in many wildland soils, in modulating water balance by affecting ETA in montane ecosystems.