The EFH-2, version 1.1.2 (August 6, 2014) software implements the procedures described in the NEH 650 - Engineering Field Handbook Chapter 2 (EFH-2) for estimating runoff and peak discharge. Required information includes watershed characteristics (drainage area, runoff curve number, watershed length, watershed slope) and rainfall amount and rainfall distribution.
This program has restricted applications. May be applied when:
Watershed is accurately represented by
a single runoff curve number between 40 and 98.
Watershed area is between 1 and 2,000 acres.
Watershed length is between 200 and 26,000 feet.
Average watershed slope is between 0.5 and 64%.
No valley or reservoir routing is required.
Urban land use within the watershed does not exceed 10%.