Section Env-Wt 904.01 - General Design Considerations(a) All stream crossings, whether over tidal or non-tidal waters, shall be designed and constructed so as to: (1) Not be a barrier to sediment transport;(2) Not restrict high flows and maintain existing low flows;(3) Not obstruct or otherwise substantially disrupt the movement of aquatic organisms indigenous to the waterbody beyond the actual duration of construction;(4) Not cause an increase in the frequency of flooding or overtopping of banks;(5) Maintain or enhance geomorphic compatibility by:a. Minimizing the potential for inlet obstruction by sediment, wood, or debris; andb. Preserving the natural alignment of the stream channel;(6) Preserve watercourse connectivity where it currently exists;(7) Restore watercourse connectivity where: a. Connectivity previously was disrupted as a result of human activity(ies); andb. Restoration of connectivity will benefit aquatic organisms upstream or downstream of the crossing, or both;(8) Not cause erosion, aggradation, or scouring upstream or downstream of the crossing; and(9) Not cause water quality degradation.(b) For stream crossings over tidal waters, the stream crossing shall be designed to: (1) Match the velocity, depth, cross-sectional area, and substrate of the natural stream; and(2) Be of sufficient size to not restrict bi-directional tidal flow over the natural tide range above, below, and through the crossing.N.H. Admin. Code § Env-Wt 904.01
Amended by Volume XXXVIII Number 32, Filed August 9, 2018, Proposed by #12578, Effective 7/21/2018, Expires 7/21/2028.Amended by Volume XXXIX Number 28, Filed July 11, 2019, Proposed by #12809, Effective 12/15/2019, Expires 12/15/2029.