The Curve Number method is a long standing, widely researched method. Although the methodology dates to the 1950s or 1960s, like other widely used unit hydrographs, it is a preferred procedure for studying watersheds and the impact of development, fire, or any changes in a watershed. It is generally accepted that the CN method was originally developed for rural farmlands on relatively small slopes using a 24-hour storm. Due to its popularity, the Curve Number method has expanded to a wide range of applications from mountains, plains, and used for pre and post fire calibration and research. As presented in the Hydrology Technical Note 4 from the US Department of Agriculture, there have been many studies that use post fire comparisons and back into the Curve Number method, making it a well-researched methodology. It can be argued that the Curve Number method is not always the best method for certain regions. It can also be argued that the Curve Number method, if calibrated properly, is the best usage for post fire hydrologic analysis due to the large amount of research that backs results into a modified Curve Number based on soil burn severity. This study presents how the Curve Number method can be used and calibrated to particular regions for pre and post fire analysis within mountainous regions and also describes the advantages of frequency storm distribution for calibration to regional mountainous statistical gage estimates.
