1. (a) A new dam shall be designed to safely pass the event indicated below without manual operation and with the freeboard requirements indicated:

   1. (1) A non-menace structure shall pass the 50-year design event or, at the owner’s option, the site-specific inflow design flood, with at least one foot of freeboard;
   2. (2) A low hazard structure shall pass the 100-year design event or, at the owner’s option, the site-specific inflow design flood, with at least one foot of freeboard;
   3. (3) A significant hazard structure shall pass ½ of the probable maximum flood (PMF) as determined using Hydrometeorological Report No. 52 (HMR 52) from the National Oceanic and Atmospheric Administration (NOAA), 1982, available as noted in Appendix B, or the site-specific inflow design flood; and
   4. (4) A high hazard structure shall pass the PMF as determined using HMR 52, 1982, available as noted in Appendix B, or the site-specific inflow design flood.
2. (b) A reconstructed dam shall be designed to safely pass the flows identified in Env-Wr 303.10, as applicable.
3. (c) The owner shall submit the results of calculations performed for hydrologic and hydraulic analyses pursuant to (a) and (b), above, and Env-Wr 403.05 and Env-Wr 403.06 with the application.

Source. #1716, eff 2-20-81; ss by #2207, eff 12-13-82; ss by #2900, eff 11-7-84, EXPIRED 11-7-90 New. #5080, eff 2-22-91; rpld by #6462-B, eff 2-21-97 New. #8414, eff 8-20-05; ss by #10510, eff 1-22-14; ss by #13980, eff 5-24-24