Abstract
Because groundwater is Earth's largest pool of freshwater, understanding the sensitivity of deep drainage to climate, soils, and land cover is critical in managing water resources. To better understand controls on this critical flux in the context of woody encroachment, we determined the sensitivity of deep drainage to climate, soil texture, soil compaction, rooting depth, growing season duration, and plant-water stress response using Hydrus-1D to simulate deep drainage. To evaluate the simulation results, we compared these results with ground measurements at two anchor sites. At both anchor sites, Hydrus-1D predictions of deep drainage matched measured values within the errors inherent in ground measurements. Sensitivity analysis suggested greatest sensitivity of deep drainage to climate (24mm yr-1) and rooting depth (12mm yr-1), moderate sensitivity to growing season duration (5mm yr-1) and soil texture (4mm yr-1), and lowest sensitivity to topsoil compaction and plant-water stress response (3mm yr-1). The sensitivity analysis indicated the relative importance of the plant-related factors considered, which, in decreasing order, were rooting depth, growing season duration, and plant-water stress response - factors that change concomitantly as a result of forestation or woody encroachment. Further ground-truth measurements of woody encroachment effects on deep drainage are needed to confirm or refine the results of this simulation modelling study.
Original language | English |
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Pages (from-to) | 3779-3789 |
Number of pages | 11 |
Journal | Hydrological Processes |
Volume | 29 |
Issue number | 17 |
DOIs | |
State | Published - 15 Aug 2015 |
Externally published | Yes |
Keywords
- Chloride mass balance
- Deep drainage
- Groundwater recharge
- Hydrus
- Juniper
- Rangeland hydrology
ASJC Scopus subject areas
- Water Science and Technology