N.H. Admin. Code § Env-Wt 904.01

Current through Register No. 50, December 12, 2024

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; and

b. 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); and

b. 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

#9714, eff 5-12-10

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.