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Estimating time parameters of overland flow on impervious surfaces by the particle tracking method

KC, Manoj, Fang, Xing
Hydrological sciences journal 2015 v.60 no.2 pp. 294-310
hydrograph, models, monitoring, overland flow, rain intensity, roughness, runoff, watersheds
Travel time and time of concentration T c are important time parameters in hydrological designs. Although T c is the time for the runoff to travel to the outlet from the most remote part of the catchment, most researchers have used an indirect method such as hydrograph analysis to estimate T c. A quasi two-dimensional diffusion wave model with particle tracking for overland flow was developed to determine the travel time, and validated for runoff discharges, velocities, and depths. Travel times for 85%, 95% and 100% of particles arrival at the outlet of impervious surfaces (i.e. Tt₈₅, Tt₉₅, and Tt₁₀₀) were determined for 530 model runs. The correlations between these travel times and T c estimated from hydrograph analysis showed a significant agreement between T c and Tt₈₅. All the travel times showed nonlinear relationships with the input variables (plot length, slope, roughness coefficient, and effective rainfall intensity) but showed linear relationships with each other.