Changes in forest and agricultural practices, clearcutting in bottomland hardwood forests, and conversions from forests to agricultural lands are largely responsible for poor hydrological conditions, flood control loss and water quality degradation in the Lower Mississippi River Alluvial Valley (LMRAV) and its adjacent Gulf of Mexico in USA. Although several efforts, including pilot scale and paired-watershed studies, have been devoted to investigating the ecological, hydrological, and environmental benefits of forest managements, the functions and values of afforestation in the LMRAV on hydrology restoration, flood attenuation, and water quality improvement are still poorly documented. Since the dynamics of forest conditions, hydrological cycles, contaminant loads, and surficial processes are complex processes, it is very difficult (if not impossible) to quantify them by experimentation alone for a variety of forest species, for different contaminants and hydrological conditions, and for all possible combinations of surficial processes. The goal of this study is to assess the functions and values of afforestation upon hydrology restoration and water quality improvement in the LMRAV using computational methods in conjunction with field experiments. The specific objectives and approaches are to: (1) to assess how afforestation affects hydrological process, flood attenuation, sediment erosion, and contaminant load in selected watersheds within the LMRAV using BASINS-HSPF model; (2) develop an approach to select low stream flow in LMRAV using duration curve frequency analysis with HYDSTRA model; and (3) identify temporal patterns of peak flow using Wavelet analysis and ascertain relationships among water quality constituents using Copula method. This study demonstrates that the HSPF model, duration curve/frequency distribution analysis, and wavelet and copula tools are useful approaches for estimating the functions and values of afforestation upon hydrology restoration and water quality improvement in watersheds. Although the approaches are used for the LMRAV, they can be transferred to other regions in the world.
Dr. Ying Ouyang is a Research Hydrologist at the Center for Bottomland Hardwoods Research, Southern Research Station, United States Department of Agricultural Forest Service with duty office located on the campus of Mississippi State University. He received B.S. from South China Agricultural University and both M.S. and Ph.D. in soil physicist from Oregon State University, USA. He is currently adjunct faculty of Mississippi State University and South China Agricultural University. Dr. Ouyang has comprehensive editorial experience and has served as associate editor for Journal of Environmental Quality (USA, 10 years) and other journals. He has published over 100 SCI journal articles in prestigious journals such as Journal of Hydrology and Water Research. These SCI journal articles have been cited over 1,000 times by SCI and over 2,000 times by Google Scholar. In the past 25 years, Dr. Ouyang’s working experiences have spanned the spectrum from academic researches to real-world applications in the fields of hydrology, ecological and environmental sciences, and soil physics. He has actively participated in many dynamic and multidisciplinary programs, including (1) applied complex mathematical and GIS models (e.g., BASINS-HSPF, MODFLOW/MT3D, HYDSTRA, and STELLA) to analyze groundwater discharge, surface water runoff, wetland attenuation, and stream routing of contaminants, excess nutrients, and organic carbon under different land use conditions in St. Johns River Basin, Florida and under the impacts of reforestation in Lower Mississippi River Basin (LMRB); (2) applied 3D Kriging technique to characterize spatial distributions of pollutants and sediments, Principal Component Analysis technique to identify indicator water quality parameters, and Wavelet analysis technique to detect temporal patterns of long-term hydrological and water quality signals and climate change impacts in LMRB; (3) installed basin-scale monitoring network to measure surface and ground water quality; (4) employed Dynamic Data Driven Application System for real-time estimation of river water quality and tree sap flow using sensor technology and computation algorithms; and (5) developed STELLA models for simulating couple transport of water and contaminants in plant xylem system and vadose zone soil, biomass production and CO2 emission in short-rotation woody crop plantation; and constructed wetland treatment of wastewaters. For his current research interests, please visit: http://www.srs.fs.usda.gov/cbhr/contact-us/staffdetails.php?alias=youyang