Projection of Sediment Loading from Pearl River Basin, Mississippi into Gulf of Mexico under a Future Climate with Afforestation
Citation:
Ouyang, Y., Y. Huang, P. Parajuli, Y. Wan, J. Grace, P. Caldwell, AND C. Trettin. Projection of Sediment Loading from Pearl River Basin, Mississippi into Gulf of Mexico under a Future Climate with Afforestation. Climate. MDPI, Basel, Switzerland, 11(5):108, (2023). https://doi.org/10.3390/cli11050108
Impact/Purpose:
Evaluation of sediment load under future climate conditions depends on valid watershed water quality models. The EPA's HAWQS-based model is demonstrated to be a useful tool to simulate sediment load using the Pearl River Watershed as an example. Good agreements were obtained between model predictions and field measurements during the model calibration. Simulation scenarios were created to project sediment loads for the past 40 years (from 1981 to 2020) and future 40 years (from 2025 to 2064) with and without afforestation. While the seasonal pattern of the sediment yield remain unchanged in the future, the results indicate that afforestation reduces sediment load significantly, suggesting that forest restoration will be a valid practice in the future climate to reduce sediment loading into the northern Gulf of Mexico.
Description:
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.
URLs/Downloads:
DOI: Projection of Sediment Loading from Pearl River Basin, Mississippi into Gulf of Mexico under a Future Climate with Afforestation