Peak Discharge Estimation for Rural Areas Using APSWM and OTTHYMO Models

Abstract

<p>Traditional methods for flood estimation can be categorized as (1) simplified methods, e.g., regression analysis, (2) frequency analysis of streamflow data, (3) design storm-based precipitation-runoff modeling, and ( 4) continuous precipitation-runoff simulation modeling. The new approach - the Analytical Probabilistic Stormwater Model - was developed as an alternative to provide an efficient way of getting realistic estimation of peak discharges of desired frequencies for use in stormwater management of urban areas. To extend APSWM's application to rural areas, a series of comparisons were made between the calibrated design storm-based OTTHYMO model results, frequency analysis results and APSWM results for the Ganaraska River watershed. Special considerations were given to the transformation of the input parameter values of OTTHYMO model to those of APSWM. Comparable results were obtained for large floods, while APSWM may underestimate peak discharges of low return periods. Upon further testing and development, APSWM may be used for large rural areas.</p>