New Hampshire Code of Administrative Rules
Env - Department of Environmental Services
Subtitle Env-Wt - Wetlands Programs
Chapter Env-Wt 900 - STREAM CROSSINGS; CERTIFIED CULVERT MAINTAINER PROGRAM
Part Env-Wt 904 - DESIGN AND CONSTRUCTION OF STREAM CROSSINGS
Section Env-Wt 904.05 - Tier 3 Stream Crossings

Universal Citation: NH Admin Rules Env-Wt 904.05

Current through Register No. 13, March 27, 2025

(a) Subject to (b), below, a tier 3 stream crossing shall be a crossing located:

(1) On a watercourse where the contributing watershed is 640 acres or greater;

(2) Within a designated river corridor, unless:
a. The crossing would be a tier 1 stream based on contributing watershed size; or

b. The structure does not create a direct surface water connection to the designated river as depicted on the national hydrography dataset as found on GRANIT;

(3) Within a 100-year flood plain;

(4) In a jurisdictional area having any protected species or habitat; or

(5) In a prime wetlands or within a duly-established 100-foot buffer, unless a waiver has been granted pursuant to RSA 482-A:11, IV(b) and Env-Wt 706.

(b) The applicant for a project in which a stream crossing is categorized as tier 3 based solely on being in a 100-year floodplain may request that the crossing be categorized as a tier 1 or tier 2 stream crossing, as applicable based on watershed size, if the impacts to the floodplain are specifically mitigated in accordance with Env-Wt 800.

(c) The applicant for a project in which a stream crossing is categorized as tier 3 based solely on being in a jurisdictional area having any protected species or habitat may request that the crossing be categorized as tier 1 or tier 2 based on watershed size, provided:

(1) The applicant consults with NHB to determine whether any protected plant species or habitat would be impacted;

(2) The applicant consults with NHF & G to determine whether any protected species or habitat is impacted; and

(3) The NHB, NHF & G, or both, as applicable, recommend(s) such a downgrade to the department in writing.

(d) A tier 3 stream crossing shall be a span structure or an open-bottomed culvert with stream simulation, not a closed-bottom culvert or pipe arch.

(e) The applicant may propose an alternative design by submitting a request as specified in Env-Wt 904.10.

(f) Compensatory mitigation shall not be required for:

(1) Any new tier 3 stream crossing that:
a. Meets the general design criteria in Env-Wt 904.01 and the tier-specific criteria of Env-Wt 904.07;

b. Is self-mitigating; and

c. Improves aquatic organism passage, connectivity, and hydraulics; or

(2) Any replacement of a crossing that met all applicable requirements when originally installed but is in a location that results in the crossing being classified as tier 3 under these rules, provided the proposed stream crossing meets the requirements of Env-Wt 904.09.

(g) Plans for a tier 3 stream crossing shall be dated and bear the signature and seal of the professional engineer who prepared or had responsibility for and approved them, as required by RSA 310-A:18.

#9714, eff 5-12-10

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