The Flood Control District of Maricopa County has officially released the Card Drainage Area Calculation Tool 1.3.0 (Beta) on 5/8/2012. This program is released as a beta version.
HEC-1 HC Card Drainage Area Calculation Tool 1.3.0 is a software package designed to automatically calculate the drainage area (HEC-1 HC card's second field) at each hydrologic concentration point in an existing HEC-1 input file with the consideration of adjusted drainage area due to diversions and retrievals.
The tool is easy-to-use. The input file for the tool is an existing HEC-1 input file. The output file for the tool is a modified HEC-1 input file with an updated drainage area value in each HC card area field. The tool was developed at the Flood Control District of Maricopa County.