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

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. The PPR contains roughly 25 million ponds, wetlands, and lakes. Due to their important roles in water retention, flood-peak reduction, groundwater recharge and discharge, and water-quality regulation, these depressions have received increasing attention. However, hydrologic functions and behaviors of these depressions are poorly understood, which has raised a series of regional hydrologic issues concerning water supply, water pollution, and agriculture and natural resources management. In addition, little work has been conducted to physically quantify the effects of those depressions on overland flow generation and the dynamic surface runoff processes. Depressions are rarely explicitly incorporated into hydrologic modeling due to the complexity of simulating these 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:

     Yang, Jun, Xuefeng Chu, Yaping Chi, and Leif Sande. 2010. Effects of Rough Surface Slopes on Surface Depression Storage. World Environmental and Water Resources Congress, Providence, RI, May, 16-20, 2010.

     Yang, Jun and Xuefeng Chu. 2011. Surface Delineation and Hydrologic Connectivity Analysis. ND-SD 2011 Joint EPSCoR Conference, Fargo, ND, October 4, 2011.

     Yang, Jun and Xuefeng Chu. 2011. Surface Microtopography and Hydrologic Connectivity Analysis. AGU 2012 Fall Meeting, San Francisco, December 5-9, 2011.

     Yang, J., Bogart, D., and Chu, X., 2012. Quantification of the Spatio-temporal Variability in Threshold-controlled Overland Flow Generation Processes – A Combined Experimental and Modeling Study. AGU Fall Conference, December 3-7, 2012, San Francisco, CA.

     Yang, J., and Chu, X., 2012. Effects of Surface Microtopography on Hydrologic Connectivity. ASCE 2012 World Environmental and Water Resources Congress, May 20-24, 2012, Albuquerque, NM.

     Yang, J., and Chu, X., 2012. Modeling of Microtopography-Controlled Hydrologic Connectivity and Overland Flow Dynamics. The 2nd Annual Engineering Research Summit, April 23, 2012, Grand Forks, ND.

     Yang, J., and Chu, X. 2013. Surface Topography-dominated Overland Flow Modeling and Preliminary Applications. Joint ND Water Resources Research Institute Fellowship Research and North Dakota Water Quality Monitoring Conference, February 7, 2013, Fargo, ND.

     Chu, Xuefeng, Jun Yang, and D. Bogart. 2013. Modeling of Infiltration and Discontinuous Overland Flow Dynamics under Various Topography, Soil, and Rainfall Conditions. ASCE 2013 World Environmental and Water Resources Congress, May 19-23, 2013, Cincinnati, OH.

Publications:

     Yang, Jun, Xuefeng Chu, Yaping Chi, and Leif Sande. 2010. Effects of Rough Surface Slopes on Surface Depression Storage, p4427-4436. In: Proceedings of the 2010 ASCE World Environmental and Water Resources Congress.

     Xuefeng Chu, Jun Yang, and Yaping Chi. 2011. Quantification of Soil Random Roughness and Surface Depression Storage: Methods, Applicability, and Limitations. Transactions of the ASABE. In review.

     Yang, J., and Chu, X., 2012. Effects of DEM resolution on Surface Depression Properties and Hydrologic Connectivity. Journal of Hydrologic Engineering. Accepted (online preview manuscript: doi:10.1061/(ASCE)HE.1943-5584.0000731).

     Chi, Y., Jun Yang, D. Bogart, and X. Chu. 2012. Fractal analysis of surface microtopography and its application in understanding hydrologic processes. Transactions of the ASABE. 55(5):1781-1792.

    Chu, X., Jun Yang, and Y. Chi. 2012. Quantification of soil random roughness and surface depression storage: Methods, applicability, and limitations. Transactions of the ASABE. 55(5):1699-1710.

     Yang, J., and Chu, X., 2012. Effects of surface microtopography on hydrologic connectivity. p339-348. In: Crossing Boundaries, Proceedings of the 2012 ASCE World Environmental and Water Resources Congress, Edited by E. D. Loucks. American Society of Civil Engineers.

     Chu, X., Jun Yang, Y. Chi, and J. Zhang. 2013. Dynamic puddle delineation and modeling of puddle-to-puddle filling-spilling-merging-splitting overland flow processes. Water Resources Research. In press, doi: 10.1002/wrcr.20286.

     Yang, J., and Chu, X., 2013. Quantification of the spatio-temporal variations in hydrologic connectivity of small-scale topographic surfaces under various rainfall conditions. Journal of hydrology. In revision.