%0 Journal Article
%T Impact of Monthly Curve Number on Daily Runoff Estimation for Ozat Catchment in India
%A Manoj Gundalia
%A Mrugen Dholakia
%J Open Journal of Modern Hydrology
%P 144-155
%@ 2163-0496
%D 2014
%I Scientific Research Publishing
%R 10.4236/ojmh.2014.44014
%X The Soil Conservation Service Curve Number (SCS-CN) is a well-established loss-rate model to estimate runoff. It combines watershed parameters and climatic factors in one entity curve number (<em>CN</em>). The <em>CN</em> exhibits an inherent seasonality beyond its spatial variability, which cannot be accounted for by the conventional methods. In the present study, an attempt has been made to determine the <em>CN</em> for different months of monsoon season with an objective to evaluate the impact of monthly <em>CN</em> on runoff estimation for Ozat catchment (Gujarat State, India). The standard <em>CN</em> and month wise <em>CN</em> were determined by three procedures, viz, the median, geometric mean and standard asymptotic fit using gauged rainfall and runoff. This study shows that the predictive capability of <em>CN</em> determination methods can be improved by using monthly <em>CN</em>. Refined WillmottĄ¯s index (d<sub>r</sub>) and mean absolute error (MAE) were used to assess and validate the performance of each method. The asymptotic fit <em>CN </em>method with monthly <em>CN</em> resulting d<sub>r</sub> from 0.46 to 0.49 and MAE from 1.13 mm to 1.18 mm was judged to be more consistent with the existing commonly used <em>CN</em> methods in terms of runoff estimation for the study area.
%K Soil Conservation Service Curve Number (SCS-CN) Method
%K CN Variation
%K Seasonal Effect
%K Ozat Catchment
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=50446