Section Env-Wt 904.03 - Tier 1 Stream Crossings(a) A tier 1 stream crossing shall be a crossing located on a watercourse where the contributing watershed is less than or equal to 200 acres.(b) Tier 1 stream crossings shall: (1) Meet the general design considerations specified in Env-Wt 904.01;(2) Be sized so as to accommodate the greater of: a. The 50-year design storm; orb. Applicable federal, state, or local requirements; and(3) Be a span structure, pipe arch, open-bottom culvert, or closed-bottom culvert, with or without being embedded with stream simulation.(c) An applicant may propose a design that does not meet the criteria of (b)(1) or (b)(2)a., above, by submitting a request for approval of an alternate design as specified in Env-Wt 904.10. In accordance with Env-Wt 903.01(f)(1)a., a project that includes a request to approve an alternative design for a tier 1 stream crossing shall be a minor impact project.(d) An existing legal crossing that would be classified as tier 1 under (a), above, may be repaired or replaced in-kind as specified in Env-Wt 904.08 pursuant to: (1) A routine roadway maintenance SPN as specified in Env-Wt 308.04 or registration as specified in Env-Wt 309.03; or(2) If the crossing is part of a trail, a trail SPN as described in Env-Wt 308.04.(e) Compensatory mitigation shall not be required for any tier 1 minimum impact project.N.H. Admin. Code § Env-Wt 904.03
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.