Tongass National Forest

Currently applied fish passage guidelines based on best available information are different than those contained in the Forest Plan. Inconsistencies currently exist between applied fish passage guidelines, direction found in Forest Plan Chapter 4 FISH 12, iV, G (pages 4-10), and Section 404(f) of the Clean Water Act.

Section 33, Code of Federal Regulations 323.3(b), Clean Water Act states that “the design, construction and maintenance of the road crossing shall not disrupt the migration or other movement of those species of aquatic life inhabiting the water body”. Current Forest Plan S&Gs distinguish between Class I and Class II streams while Section 33, CFR 323.3(b) does not. 2) The design flow standard referred to in the Forest Plan S&G for Class I streams is based on the Q2 flow with a 4 day delay. The design flow standard currently endorsed by the State of Alaska and routinely practiced for hydraulic design is Q2 flow with a 2 day delay (Q2-D2). The Q2-D2 design flow may be more defensible. 3) There is not a design flow stipulated for Class II streams in Forest Plan S&G. 4) Forest Plan S&G uses juvenile coho salmon for the design species life stage in Class I streams and a stream process group dependent life stage in Class II streams. The process group dependent life stage stipulation for Class II streams is currently not practiced and it may not be defensible.

Chapter 4 FISH112, IV, G regarding fish passage should be rewritten. The S&G should not distinguish so overtly between Class I and II streams. More universal statements common to Class I and II streams should be provided (e.g., prevention of velocity, height, and debris barriers and selection of structure design that matches channel conditions). Greater emphasis could be placed on attempting to meet passage objectives by applying stream simulation design criteria. Stream simulation is a design method in which the diversity and complexity of the natural streambed are created inside a culvert in such a way that the streambed maintains itself across a wide range of flows. The premise is that if streambed morphology is similar to that in the natural channel the crossing will be invisible to aquatic species.

Following stream simulation design methods reduces the risk of not meeting Clean Water Act passage requirements. Occasionally stream simulation criteria are not applicable and hydraulic design criteria must be used. In these situations fish passage design flows and design fish species and life stage must be defined. In these circumstances it is recommended that Forest Plan S&G specify that a Q2-D2 design flow be used for both Class I and II streams. In addition, to account for expected changes in State of Alaska design flow criteria from the current Q2-D2 to one based on percent exceedence flows, it is recommended that standards state that design flows will meet or exceed current State of Alaska criteria. In lieu of currently defined design species and life stage for hydraulic designs it is recommended that the weakest swimming species and life stage present which requires upstream passage be identified and used in the analysis. It is recommended that the following statement be retained but made applicable to both Class I and II streams “the overall intent is to provide fish passage in all fish streams but occasionally it may not be feasible to protect short sections of habitat and passage will be restricted. In addition, it is recommended that S&G contain the stipulation that a 404 permit be obtained in all situations where passage will be restricted and therefore Section 33, Code of Federal Regulations 323.3(b), Clean Water Act BMPs are not met. The current reference to the Aquatic Habitat Management should be retained but the handbook has been updated and its reference has changed to FSH 2090.21 Chapter 30.

Determine the need to update the standards and guidelines for Class II stream fisheries to be consistent with Section 33, CFR 323.3(b) or to develop an exemption process that is consistent with Section 33, CFR 323.3(b) as well as State of Alaska requirements.

• Forest Fisheries Biologist
• Forest Hydrologist
• Transportation Planner
• Alaska Department of Fish and Game
• National Marine Fisheries Service (Essential Fish Habitat)

• Consistent approach for evaluating fish passage related stream crossings to meet Section 33, CFR 323.3(b) and Best Management Practices