Modeling Event-Based Coupled Hydrologic and Mass Transport in Small Urban Watersheds
To investigate the event-based coupled hydrologic and mass transport processes of particulate matter and their eventual fate in unit operations/processes, several methodologies were developed. Discrete rainfall-runoff events data were collected at two similar urban watersheds for model calibration and verification. A mathematically and physically-based criterion was proposed to differentiate rainfall-runoff events between either mass-limited or flow-limited. Statistical techniques of Logistic Regression and Discriminant Analysis were utilized to derive classification rules for event categories based on hydrologic data only. With watersheds assumed as either lumped systems or distributed systems, physically-based semi-empirical models were developed to simulate particulate mass delivery process during rainfall-runoff events. The use of measured particle size distributions (PSDs) as compared to a single particle index such as a d50 was found to have a significant influence on model simulation. The application of fractional calculus to the advection-dispersion equation was also investigated for the distributed system model. A novel mass transport model based on a unit pollutograph (UP) concept analogous to the unit hydrograph (UH) theory was proposed and successfully illustrated. A design and analysis methodology for rainfall-runoff quantity and quality basins was proposed and the feasibility was demonstrated through design charts for a Baton Rouge, LA watershed, a 1-year, 1-hour design storm loading and a measured PSD from 1 to 10,000 ìm. Results indicated that the methodology was useful and effective for basin unit operation design.
Advisor:Robert Bengtson; Zhi Deng; Robert Downer; Lingbing Wang; John Sansalone; Dean Adrian; Marc Levitan
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:civil environmental engineering
Date of Publication:09/01/2004