Recommended hydroperiod standards for wetlands (Source: State of Minnesota Storm-Water Advisory group, 1997
Link to this table

Hydroperiod standard
Highly susceptible wetlands Moderately susceptible wetlands Slightly susceptible wetlands Least susceptible wetlands
Storm bounce Existing Existing plus 0.5 feet Existing plus 1.0 feet No limit
Discharge rate from wetland Existing Existing Existing or less Existing or less
Inundation period for 1 and 2 year precipitation event Existing Existing plus 1 day Existing plus 2 days Existing plus 7 days
Inundation period for 10 year precipitation event and greater Existing Existing plus 7 days Existing plus 14 days Existing plus 21 days
Run-out control elevation (free flowing) No change No change 0 to 1.0 feet above existing run out 0 to 4.0 feet above existing run-out
Run-out control elevation Above delineated wetland Above delineated wetland Above delineated wetland Above delineated wetland

This page was last edited on 3 August 2022, at 13:35.