Simulating double-peak hydrographs from single storms over mixed-use watersheds
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Journal of Hydrologic Engineering. 20(11): 06015003. http://dx.doi.org/10.1061/(ASCE)HE.1943-5584.0001225.
Two-peak hydrographs after a single rain event are observed in watersheds and storms with distinct volumes contributing as fast and slow runoff. The authors developed a hydrograph model able to quantify these separate runoff volumes to help in estimation of runoff processes and residence times used by watershed managers. The model uses parallel application of two advection-diffusion equations and calibrates the model’s fast and slow time parameters as well as a coefficient representing the relative size of the smaller hydrograph peak. The model provides an accurate representation of hydrograph timing, volume, peak, points of inflection, and recession rate, and its parameters represent physical processes of advection and diffusion and relate to watershed scale. The authors calibrated the model to match observed two-peak hydrographs with high efficiency on a watershed with distinct urban and rural land cover, and another watershed with distinct fast runoff from saturated areas. The Nash–Sutcliffe efficiency (NSE) of the simulated discharge was 0.93 for the urban watershed and 0.92 for the rural watershed. For the urban watershed, the simulated slow runoff volume was 89.6% of total runoff, and the fast runoff volume was 10.4% of total runoff; and for the rural watershed, the simulated slow runoff volume was 93.1% of total runoff, and the fast runoff volume was 6.9% of total runoff. This parsimonious two-peak hydrograph model can help researchers investigate how different storms and land cover types partition fast and slow flow and impact rainfall-runoff dynamics.
KeywordsHydrograph model, Fast flow, Slow flow, Advection-diffusion equation
Yang, Yang; Endreny, Theodore A.; Nowak, David J. 2015. Simulating double-peak hydrographs from single storms over mixed-use watersheds. Journal of Hydrologic Engineering. 20(11): 06015003. http://dx.doi.org/10.1061/(ASCE)HE.1943-5584.0001225.