Jun Yang

Jun Yang is a Ph.D. student in the Department of Civil Engineering at North Dakota State University. He received a B.S. degree in Hydrology and Water Resources Engineering from Jilin University, China in 2006, and M.S. degree in Water Resources from China University of Geosciences (Beijing), China in 2009. His current research focuses on surface delineation, hydrologic connectivity analysis, and topography-controlled overland flow modeling.

Email: jun.yang.2@ndsu.edu

 

Improved Overland Flow Modeling for Hydrologic Connectivity Analysis of Potholes

Fellow:Jun Yang

Advisor: Xuefeng Chu, Ph.D., Assistant Professor, Department of Civil Engineering, North Dakota State University

Matching Support:North Dakota State University

Degree Progress:Ph.D. in Civil Engineering expected graduation in fall 2013

Research:

Surface topography is generally not smooth, and it influences overland flow generation, delays the initiation of surface runoff, and enhances the retention of runoff water. In the recent decade, research efforts have been made to quantify the hydrologic role of surface topography, analyze the dynamic behaviors of depressions, and investigate hydrologic connectivity. However, more efforts are needed to physically quantify the effects of depressions on surface runoff generation. Under the influence of surface topography, overland flow is generally characterized by a series of hierarchical puddle-to-puddle (P2P) filling, spilling, and merging processes. These processes are rarely simulated in overland flow models due to their complexity. Most of the widely used modeling software packages utilize depression-filled topographic surfaces. They are not capable of simulating the spatial and temporal dynamics of individual depressions and their interactions.

The Prairie Pothole Region (PPR) is located in northern United States and southern Canada. It covers the most part of the Red River basin in North Dakota. The potholes in the PPR have received an increasing attention due to their important roles in water retention, flood control, groundwater recharge and discharge, and water quality management. The variability and the dynamic hydrologic processes of these depressions have been identified as critical topics to improve the understanding of the hydrologic issues related to the PPR. However, hydrotopographic properties, hydrologic functions and behaviors of these potholes are poorly understood due to their spatially and temporally varied hydrologic processes.

Efforts have been made to investigate the aforementioned hydrologic issues in our research group. New methods have been developed to characterize surface topography with focus on delineating puddles in a “dynamic” fashion. In the 2012 fellowship project, a P2P overland flow model was developed to physically simulate the topography-influenced overland flow generation processes and the dynamic P2P processes.

Project objectives:

The objectives of this study is to improve the P2P overland flow model developed in 2012 and apply the model to investigate hydrologic connectivity of potholes for several sites selected in the PPR. Specific research tasks include:

  1. development of an improved P2P overland flow model by incorporating a two-dimensional diffusion wave equation as an alternative method (2nd method);
  2. development of new methods to accurately quantify the relationships between pothole storage (DS) and pothole ponded area (PA), and DS and pothole depth (h) to investigate the hydrotopographic properties of potholes; and
  3. Analyses of hydrologic connectivity and threshold behaviors of potholes under various meteorological conditions for watershed-scale testing sites in the PPR.

Expected Outcomes and Significance:

In this proposed research project, an improved, physically-based model will be developed to simulate the topography-controlled P2P dynamics and overland flow processes. This model can be used to improve the knowledge of: (1) how the water stored in depressions interacts with soil water and atmospheric water, and changes spatially and temporally, and (2) threshold behaviors and hydrologic functions of potholes. The proposed research and the developed model will potentially help address the following regional hydrologic issues: (1) understanding the hydrologic roles of potholes in the PPR, (2) predicting water levels in potholes for flood control, (3) understanding the chemical and biological characteristics of water bodies, and (4) managing natural resources.

Presentations:

Publications:

Xuefeng Chu


Xuefeng Chu Assistant Professor,

Department of Civil Engineering,

North Dakota State University

Email: xuefeng.chu@ndsu.edu

Webpage: http://www.ndsu.edu/pubweb/~xuchu/index.htm