Predicting Runoff in Small Ephemeral Watershed.
(4949)
Authors:
C.R. Mello* - UFLA-BRAZIL J.M. Lima - UFLA-BRAZIL A.M. Silva - UFLA-BRAZIL
L.R.G. Guilherme - UFLA-BRAZIL
Abstract:
CN-SCS Method is an important model to estimate the design runoff and peak discharge in watersheds. Its application to isolated rainfall events needs to be evaluated and adjusted for application at hydrological simulation. This work objectives to analyze the CN-SCS Method’s parameters, comparing them to the values recognized by the Method, modeling semi-conceptual models based on the antecedent soil moisture and rainfall characteristics, making the CN-SCS Method able to be applied to isolated events. CN-SCS Method was applied to 30
rainfall-runoff events that were monitored from Nov/02 to April/03. Antecedent soil moisture was monitored each 2 days. Potential water storage was calculated for each event based on monitored runoff and rainfall and determined initial
abstraction. Real curve number was calculated. Hydrographs were close to a
triangular shape, with runoff, peak discharge, and ascension time monitored. Time of concentration was estimated by 2 different methods and associated to the time to peak, extracted from each hydrograph. The analyze of parameters did not show a clear trends that express the relations using only one value. This suggests that the CN-SCS Method needs adjustment in order to be applied to isolated rainfall events.
Semi-conceptual models were adjusted to ascension time, ratio between recession and ascension time, initial abstraction and the curve number, and they have
produced good results, being suitable to the monitored watershed.
Speaker Information: Carlos Mello, UFLA-BRAZIL, DCS/UFLA C. Postal 37, Lavras, MG 37200-000; Phone: 0553538291332; E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 10:00 AM-12:00 PM Presentation Start: 10:00 AM (Poster Board Number: 1571)
