Improving the SWAT forest module for enhancing water resource projections: A case study in the St. Croix River Basin

Journal Article · Sun Dec 16 04:00:00 EST 2018 · Hydrological Processes

DOI:https://doi.org/10.1002/hyp.13370· OSTI ID:1507399

Yang, Qichun ^[1]; Zhang, Xuesong ^[2]; Almendinger, James E. ^[3]; Huang, Maoyi ^[4]; Leng, Guoyong ^[4]; Zhou, Yuyu ^[5]; Zhao, Kaiguang ^[6]; Asrar, Ghassem R. ^[1]; Li, Xia ^[7]; Qiu, Jiali ^[8]

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1. Joint Global Change Research Institute, Pacific Northwest National Laboratory College Park MD 20740 USA
2. Joint Global Change Research Institute, Pacific Northwest National Laboratory College Park MD 20740 USA; Earth System Sciences Interdisciplinary CenterUniversity of Maryland College Park MD 20740 USA
3. St. Croix Watershed Research Station, Science Museum of Minnesota 16910 152nd St. N. Marine on St. Croix MN 55082 USA
4. Earth System Analysis and Modeling Group, Atmospheric Sciences &, Global Change Division, Pacific Northwest National Laboratory Richland WA 99354 USA
5. Department of Geological and Atmospheric SciencesIowa State University Ames IA 50011 USA
6. School of Environment &, Natural ResourcesThe Ohio State University Wooster OH 44691 USA
7. Department of Geographical SciencesUniversity of Maryland College Park MD 20742 USA
8. School of EnvironmentBeijing Normal University Beijing 100875 China

Insufficiently calibrated forest parameters of the Soil and Water Assessment Tool (SWAT) may introduce uncertainties to water resource projections in forested watersheds. In this study, we improved SWAT forest parameterization and phosphorus cycling representations to better simulate forest ecosystems in the St. Croix River Basin (SCRB), and further examined how those improvements affected model projections of streamflow, sediment and nitrogen export under future climate conditions. Simulations with improved forest parameters substantially reduced model estimates of water, sediment, and nitrogen fluxes relative to those based on default parameters. Differences between improved and default projections can be attributed to the enhanced representation of forest water consumption, nutrient uptake, and protection of soil from erosion. Better representation of forest ecosystems in SWAT contributes to constraining uncertainties in water resource projections. Results of this study highlight the importance of improving SWAT forest ecosystem representations in projecting delivery of water, sediment, and nutrients from land to rivers in response to climate change, particularly for watersheds with large areas of forests. Improved forest parameters and the phosphorus weathering algorithms developed in this study are expected to help enhance future applications of SWAT to investigate hydrological and biogeochemical consequences of climate change.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1507399
• Report Number(s): PNNL-SA-137109
• Journal Information: Hydrological Processes, Journal Name: Hydrological Processes Journal Issue: 5 Vol. 33; ISSN 0885-6087
• Publisher: Wiley
• Country of Publication: United States
• Language: English

Related Subjects

climate change
forest
nutrients
sediment
streamflow
SWAT
uncertainties
water resource