element is within the channel, but the clear span is greater than the active channel width, then the structure would still be considered to meet Stream Simulation requirements. This allows for channel migration and assumes at least one naturally- functioning bank is present. See Figure 6.
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element of a new, replacement, or existing bridge, or any part of an existing crossing being replaced by a bridge, is within or below the channel (see Figure 5). FISH PASSAGE REQUIREMENTS FOR BRIDGESExisting criteria in rule for road-stream crossings only describe a Stream Simulation option and an Alternative option (OAR 635-412-0035(3)). Bridges and other crossings do not qualify under the Stream Simulation option if a) there is any bridge element within the channel (including on, or replacing, the bed and banks) and b) they do not have a clear span greater than or equal to the active channel widthx (see Figure 6). In these cases it is also difficult or time-consuming to show that an Alternative design will meet certain hydraulic conditions in the channel that allow for fish passage, based on known or assumed fish swimming abilities (i.e., the "Hydraulic Design" method). Therefore, other Alternative options for fish passage approval of bridges are presented here. So, if a) native migratory fish are or were present in a location, b) a new, replacement, or existing bridge has any element within or below the channel, c) there will be a trigger event, and d) fish passage will be provided, the following design options may be used to obtain fish passage approval for bridges from ODFW. If none of these options can be met for a new, replacement, or existing bridge, the owner/operator of a crossing should have more detailed discussions with ODFW about how best to meet legal fish passage requirements. Other possible approval options include providing passage under some other Alternative design (which may entail exceptions to criteria or guidelines, some combination of the options noted above, or the use of another entity's criteria or guidelinesxix), waivers, exemptions, or deferrals for structural emergencies that may affect human safety. As with all temporary construction activities, passage requirements for temporary bridges or construction isolation measures shall be approved by ODFW staff on a site-specific basis and do not necessarily have to meet ODFW's full passage criteria or guidelines. Temporary construction activities are those which take place only within an approved in-water work window. An approved in-water work window may include extensions to published dates that are approved by ODFW. Any structure in place outside of an approved in-water work window will require more formal fish passage approval from ODFW. Work bridges that are not permanent, but do not m...