Natural Resources Conservation Service Conservation Practice Standard Aquatic Organism Passage (Mi.) Code 396 DEFINITION Avoid locating fishway entrances and exits in areas that will obstruct function, increase Modification or removal of barriers that restrict harassment or predation, or result in excessive or impede movement of aquatic organisms. operation and maintenance requirements. PURPOSE Design Requirements Improve or provide passage for aquatic Design passage to accommodate present and organisms. reasonably anticipated changes in watershed conditions. CONDITIONS WHERE PRACTICE APPLIES Design passage structures according to known All aquatic habitats where barriers impede swimming and leaping capabilities of target passage of aquatic organisms. species or a similar species with comparable swimming abilities. Utilize hydraulic CRITERIA computations to document how designs satisfy Planning and Evaluation the physiological requirements of target organisms. Evaluate sites for variations in stage and discharge, tidal influence, hydraulics, Design passage structures to mimic channel geomorphic impacts, sediment transport and geometry and morphology referenced from an continuity, and organic debris movement. adjacent reach or analog stream when the Design passage features to account for the swimming and leaping abilities of target species known range of variation resulting from this are unknown, or when a project will benefit evaluation. multiple aquatic organisms. Mitigate undesirable channel plan or profile At a minimum, design and evaluate passage shifts resulting from the modification or structures for hydraulic performance and removal of a passage barrier. structural integrity at the bankfull and 25-year peak flow events. Plan and locate passage for compatibility with local site conditions and stream geomorphology, to the extent possible.
Natural Resources Conservation Service Conservation Practice Standard Aquatic Organism Passage (Mi.) Code 396 DEFINITION Modification or removal of barriers that restrict or impede movement of aquatic organisms. PURPOSE Improve or provide passage for aquatic organisms. CONDITIONS WHERE PRACTICE APPLIES All aquatic habitats where barriers impede passage of aquatic organisms. CRITERIA Planning and Evaluation Evaluate sites for variations in stage and discharge, tidal influence, hydraulics, geomorphic impacts, sediment transport and continuity, and organic debris movement. Design passage features to account for the known range of variation resulting from this evaluation. Mitigate undesirable channel plan or profile shifts resulting from the modification or removal of a passage barrier. Plan and locate passage for compatibility with local site conditions and stream geomorphology, to the extent possible. Avoid locating fishway entrances and exits in areas that will obstruct function, increase harassment or predation, or result in excessive operation and maintenance requirements. Design Requirements Design passage to accommodate present and reasonably anticipated changes in watershed conditions. Design passage structures according to known swimming and leaping capabilities of target species or a similar species with comparable swimming abilities. Utilize hydraulic computations to document how designs satisfy the physiological requirements of target organisms. Design passage structures to mimic channel geometry and morphology referenced from an adjacent reach or analog stream when the swimming and leaping abilities of target species are unknown, or when a project will benefit multiple aquatic organisms. At a minimum, design and evaluate passage structures for hydraulic performance and structural integrity at the bankfull and 25-year peak flow events.
396mn_Aquatic_Organism_Passage.docx