Ouyang Ying, Huang Yanbo, Parajuli Prem B, Wan Yongshan, Grace Johnny M, Caldwell Peter V, Trettin Carl
USDA Forest Service, Center for Bottomland Hardwoods Research, Southern Research Station, 775 Stone Blvd., Thompson Hall, Room 309, Mississippi State, MS 39762, USA.
Genetics and Sustainable Agriculture Research Unit, Crop Science Research Laboratory, USDA-Agricultural Research Service, 810 Highway 12 East, Mississippi State, MS 39762, USA.
Climate (Basel). 2023 May 17;11(5):1-13. doi: 10.3390/cli11050108.
Sediment load in rivers is recognized as both a carrier and a potential source of contaminants. Sediment deposition significantly changes river flow and morphology, thereby affecting stream hydrology and aquatic life. We projected sediment load from the Pearl River basin (PRB), Mississippi into the northern Gulf of Mexico under a future climate with afforestation using the SWAT (Soil and Water Assessment Tool)-based HAWQS (Hydrologic and Water Quality System) model. Three simulation scenarios were developed in this study: (1) the past scenario for estimating the 40-year sediment load from 1981 to 2020; (2) the future scenario for projecting the 40-year sediment load from 2025 to 2064, and (3) the future afforestation scenario that was the same as the future scenario, except for converting the rangeland located in the middle section of the Pearl River watershed of the PRB into the mixed forest land cover. Simulations showed a 16% decrease in sediment load for the future scenario in comparison to the past scenario due to the decrease in future surface runoff. Over both the past and future 40 years, the monthly maximum and minimum sediment loads occurred, respectively, in April and August; whereas the seasonal sediment load followed the order: spring > winter > summer > fall. Among the four seasons, winter and spring accounted for about 86% of sediment load for both scenarios. Under the future 40-year climate conditions, a 10% reduction in annual average sediment load with afforestation was observed in comparison to without afforestation. This study provides new insights into how a future climate with afforestation would affect sediment load into the northern Gulf of Mexico.
河流中的泥沙负荷被认为既是污染物的载体，也是潜在来源。泥沙淤积显著改变河流流量和形态，从而影响河流水文和水生生物。我们使用基于SWAT（土壤和水资源评估工具）的HAWQS（水文和水质系统）模型，预测了在未来造林气候条件下，珠江流域（PRB）进入墨西哥湾北部的泥沙负荷。本研究制定了三种模拟情景：（1）过去情景，用于估计1981年至2020年的40年泥沙负荷；（2）未来情景，用于预测2025年至2064年的40年泥沙负荷；（3）未来造林情景，与未来情景相同，但将PRB珠江流域中段的牧场转变为混交林地覆盖。模拟结果表明，与过去情景相比，未来情景下的泥沙负荷减少了16%，这是由于未来地表径流减少所致。在过去和未来的40年里，每月最大和最小泥沙负荷分别出现在4月和8月；而季节性泥沙负荷顺序为：春季>冬季>夏季>秋季。在这四个季节中，两种情景下冬季和春季的泥沙负荷约占86%。在未来40年气候条件下，与无造林相比，造林使年平均泥沙负荷减少了10%。本研究为未来造林气候如何影响进入墨西哥湾北部的泥沙负荷提供了新的见解。
