Culvert AOP Definitions
| Term | Definition |
|---|---|
| Anadromous |
Anadromous describes fish born in freshwater who spend most of their lives in saltwater and return to freshwater to spawn, such as salmon and some species of sturgeon. [Source: NMFS https://www.fisheries.noaa.gov/node/8071] |
| Bridge [for projects with a transportation nexus] |
A structure including supports erected over a depression or an obstruction, such as water, highway, or railway, and having a track or passageway for carrying traffic or other moving loads, and having an opening measured along the center of the roadway of more than 20 feet between under copings of abutments or spring lines of arches, or extreme ends of openings for multiple boxes; it may also include multiple pipes, where the clear distance between openings is less than half of the smaller contiguous opening. [See 23 CFR 650 subpart C, at 23 CFR 650.305.] Structures under this definition are subject to the National Bridge Inspection Standards (NBIS) [See 23 CFR 650.303]. A bridge may have a span of 20 feet or less, but those structures are not subject to the NBIS. However, bridges with a span of 20 feet or less are subject to applicable design standards to ensure the safety of the traveling public [See 23 CFR Part 625]. |
| Climate Resilient Stocks | Fish stocks capable of resisting, recovering, and adapting to changes in environmental conditions such as increases in stream temperature or changes in flow. |
| Culvert [for projects with a nexus to a highway] |
A structure comprising one or more barrels, beneath a (transportation) embankment and designed structurally to account for soil-structure interaction. These structures are hydraulically and structurally designed to convey water, sediment, debris, and, in many cases, aquatic and terrestrial organisms through roadway embankments. Culvert barrels have many sizes and shapes and have inverts that are either integral or open, i.e., supported by spread or pile-supported footings. A culvert structure less than 20 feet in centerline span width between extreme ends of openings for multiple boxes is called a roadway culvert. If this width is more than 20 feet, the structure is called a bridge culvert (see Bridge). [Source: AASHTO Drainage Manual, 1st edition, Volume 1 (Policy), Chapter 11 “Culverts,” Section 11.1 (Introduction), page 11-1, 2014]. |
| Endangered Species | For the purpose of the program, endangered species are those listed as endangered species under Section 4 of the Endangered Species Act, 16 U.S.C. 1533. [See 50 CFR § 17.11]. |
| Could reasonably become listed | Species proposed for listing under Section 4 of the Endangered Species Act or are a Candidate for listing under Section 4 of the Endangered Species Act. |
| Protected Species | A protected species under Federal statute or regulation. |
| Threatened Species | For the purpose of the program, threatened species are those listed as threatened species under Section 4 of the Endangered Species Act, 16 U.S.C. 1533 [50 CFR § 17.11]. |
| Transportation Nexus | A project involves, is related to, or is situated in close proximity to a road/rail crossing, pipeline, highway, or other transportation infrastructure (see NOFO Section B.4). Generally, the transportation nexus should be a part of a public or Tribal transportation network. |
| Weir | A constructed barrier on a stream channel designed to provide hydraulic control without completely stopping flow or creating a large storage impoundment. A dam is not a weir for the purposes of this program. |