Sensitivity analysis of rainfall–runoff parameters models to estimate flows

Abstract Determinate the runoff of a watershed is challenge due to complexity representing all “inlets” and “outlets” involved in rainfall–runoff model. Therefore, methodologies applied for this purpose should have good representation variables that most influence process. One models used calculate design flow (USDA Urban Hydrology Small. Technical release, no 55 (TR-55). Soil Conservation Service. Washigton, DC, http://scholar.google.com/scholar?hl=en&btnG=Search&q=intitle:Urban+Hydrology+for+Small+watersheds#1 , 1986), which considers analysis changes soil coverage, time concentration (tc), recurrence period (T). In way, study sought evaluate hydrological behavior with an increase waterproofing. These modifications were correlated variation coefficients (CN), periods indicated by literature, different equations concentration. Its application was carried out Ribeirão do Suru watershed, Santana de Parnaíba, SP, Brazil. The CN {75; 80; 85; 90} increased 3.14, 5.61, 10.90 15.85%, respectively. critical situation, 15.85% higher estimated CN. precipitation as function T (2, 5, 10, 25, 50, 100 500) 11 methods designed 132 hydrographs values statistically treated Student Analysis Variance (ANOVA). Except Bransby Willians associated Cinematic Method, Dooge Johnstone CTH Tsuchyia, pairs showed degrees correlation below 59%. greatest observed Jonhstone (90%), followed Kinematic Method Service (83%) Dodge (74%). As result, it possible demonstrate SCS parameters minimize subjectivities revealing how each parameter impacts watershed. Finally, sensitivity attributed highest among three analyzed.