Stormwater runoff emanating from panel drip edges shall be assumed to remain in a sheet flow condition provided the following conditions in (a) or (b) are met:

1. (a) All of the following are met:

   1. (1) The panel drip edges are no more than 75 degrees from parallel to the post-construction land contour lines;
   2. (2) The drip edges of the panels are more than 1.5 feet and less than 10 feet above the land surface;
   3. (3) The stormwater runoff emanating from the panel drip edges flows over at least 25 feet of vegetated area before discharging to a wetland as defined by RSA 482-A; and
   4. (4) The land cover under the panels and in rows separating panels will consist of vegetation with at least 85% vegetative cover, uniformly distributed; or

2. (b) A level spreader that collects the runoff from the panel drip edges which meets the following:

   1. (1) Runoff is directed to the level spreader through a channel that follows the contour of the slope such that the runoff entering the level spreader does not disturb the integrity of the level spreader;
   2. (2) No more than 6,000 square feet of panel area is directed to the level spreader, unless supporting calculations show that depth of runoff during a 2-year 24 hour storm does not exceed 0.1 feet;
   3. (3) The level spreader lip is no less than 20 feet and no greater than 50 feet in length; and

   4. (4) The runoff from the level spreader is immediately distributed to a vegetated buffer that:

      1. a. Does not have additional runoff directed to the vegetated buffer from upstream developed areas, other than the flow discharged from the level spreader;
      2. b. Is at least 50 feet long;
      3. c. Has a uniform slope that does not exceed 15%; and
      4. d. Is not an area of RSA 482-A jurisdiction.

Source. #13758, eff 9-28-23; ss by #14472, eff 1-19-26, EXPIRES: 1-19-36 (formerly Env-Wq 1511.05)