Ensemble modeling of watershed‐scale hydrologic effects of short‐rotation woody crop production

Abstract

Short‐rotation woody crop (SRWC) production involves a set of silvicultural practices that aim to produce large volumes of biomass over relatively short time frames. The area over which these practices are employed is likely to increase in the coming decades as the demand for bioenergy increases, but the potential effects of this change in land management, including the hydrologic effects, are largely unknown. Here we outline the results from an ensemble modeling study that was developed to forecast the range of potential hydrological responses to the implementation of SRWC production over areas that are large (>1000 ha) relative to the size of individual clearcuts. The three models, SWAT, MIKE‐SHE, and Envision‐SRS, a physically based model designed to represent watersheds with dynamic land cover, represent a range of simulation tools that include hydrological response to landcover change. Results suggest that SRWC production will affect the hydrologic balance, primarily through changes in the volume of transpired water associated with the rapidly growing young stands. In particular, average annual actual evapotranspiration (ET) rates tend to decline under SRWC production in response to the less mature vegetation. These reductions in ET are balanced in the hydrological cycle through elevated groundwater recharge, expressed in the model results as elevated annual stream discharge. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Watersheds and stream networks viewed longitudinally: Example insights from novel spatial portrayals of watershed characteristics

“…Below the stream elevation occurs a dense clay hydrostratigraphic layer, known locally as the Tan Clay, which acts as the base of the surficial aquifer. This site has been previously instrumented with wells, interflow interception trenches, soil moisture sensors, and flumes (Du et al, 2016;Ferreira, Rau, & Aubrey, 2021;Griffiths et al, 2016Griffiths et al, , 2017Griffiths et al, , 2019Jackson et al, 2016;Jackson, Bitew, & Du, 2014;Klaus et al, 2015;Vache, Meles, Griffiths, & Jackson, 2021). Here we plot the distribution of monthly water levels measured in the wells located in the focal watershed.…”