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- Title
Understanding the Shift of Drivers of Soil Erosion and Sedimentation Based on Regional Process‐Based Modeling in the Mississippi River Basin During the Past Century.
- Authors
Bian, Zihao; Sun, Ge; McNulty, Steven; Pan, Shufen; Tian, Hanqin
- Abstract
Soil erosion and sedimentation problems remain a major water quality concern for making watershed management policies in the Mississippi River Basin (MRB). It is unclear whether the observed decreasing trend of stream suspended sediment loading to the mouth of the MRB over the last eight decades truly reflects a decline in upland soil erosion in this large basin. Here, we improved a distributed regional land surface model, the Dynamic Land Ecosystem Model, to evaluate how climate and land use changes have impacted soil erosion and sediment yield over the entire MRB during the past century. Model results indicate that total sediment yield significantly increased during 1980–2018, despite no significant increase in annual precipitation and runoff. The increased soil erosion and sediment yield are mainly driven by intensified extreme precipitation (EP). Spatially, we found notable intensified EP events in the cropland‐dominated Midwest region, resulting in a substantial increase in soil erosion and sediment yield. Land use change played a critical role in determining sediment yield from the 1910s to the 1930s, thereafter, climate variability increasingly became the dominant driver of soil erosion, which peaked in the 2010s. This study highlights the increasing influences of extreme climate in affecting soil erosion and sedimentation, thus, water quality. Therefore, existing forest and cropland Best Management Practices should be revisited to confront the impacts of climate change on water quality in the MRB. Plain Language Summary: Climate and human activities have the potential to aggravate soil erosion and sediment yield in rivers, causing water quality degradation in the Mississippi River Basin (MRB). This study evaluated the impacts of climate and land use changes on sediment yield across the entire MRB by using a regional computer simulation model. The simulated results show that the increased extreme precipitation (EP) has amplified soil erosion and sediment yield in cropland‐dominated regions in the 2010s. Since the 1930s, climate variability has replaced land use change and become the dominant contributor to the changes in sediment yield. This study highlights the risks of EP on soil erosion and water quality in the MRB and emphasizes the need for appropriate management strategies to address these emerging challenges. Key Points: Increased extreme precipitation (EP) events have amplified soil erosion and sedimentation in the Mississippi River Basin since the 1990sA shift in the spatial pattern of EP events substantially intensified sediment yield in the Midwest in the 2010sThe major driver of soil erosion and sediment yield shifted from land use change to climate change during the past century
- Subjects
MIDWEST (U.S.); SOIL erosion; CLIMATE change; WATERSHEDS; SEDIMENTATION &; deposition; CLIMATE extremes; RIVER sediments
- Publication
Water Resources Research, 2023, Vol 59, Issue 8, p1
- ISSN
0043-1397
- Publication type
Article
- DOI
10.1029/2023WR035377