“National Flood Frequency program (NFF)” means a regression equation program developed by US Geological Survey that estimates flood-peak discharges for every state, which can be downloaded for free at http://water.usgs.gov/software/nff.html.

Source. #9343, eff 1-1-09; ss by #12342, eff 8-15-17 (formerly Env-Wq 1502.37); ss by #14472, eff 1-19-26, EXPIRES: 1-19-36 (formerly Env-Wq 1502.41)