PRACTICE PASSAGE (Mi.) CODE 396 DEFINITION take steps to minimize adverse effects, or avoid removing the barrier or providing Modification or removal of barriers that restrict passage. or impede movement of aquatic organisms. Barrier removal, especially dams and road crossings, can significantly affect wetlands, PURPOSE flooding potential, existing infrastructure, and social and cultural practices and resources. Improve or provide passage for aquatic Evaluate and address the full range of impacts organisms. when planning or designing barrier removal projects. CONDITIONS WHERE APPLIES Barrier removal not be performed without All aquatic habitats where barriers impede a prior determination of the stage of channel passage of aquatic organisms. evolution, longitudinal profiles, or performing other accepted methodologies above and CRITERIA below the barrier to analyze the potential Planning and Evaluation impact to vertical channel stability (bed degradation). Evaluate sites for variations in stage and discharge, hydraulics, geomorphic impacts, Design Requirements sediment transport and continuity, and organic Design passage to accommodate present and debris movement. Design passage features to reasonably anticipated changes in watershed account for the known range of variation conditions. resulting from this evaluation. Design passage structures according to known Mitigate undesirable channel plan or profile swimming and leaping capabilities of target shifts resulting from the modification or species or a similar species with comparable removal of a passage barrier. swimming abilities. Utilize hydraulic Plan and locate passage for compatibility with computations to document how designs satisfy local site conditions and stream the physiological requirements of target geomorphology, to the extent possible. organisms. Avoid locating fishway entrances and exits in Design passage structures to mimic channel areas that will obstruct function, increase geometry and morphology referenced from an harassment or predation, or result in excessive adjacent reach or analog stream when the operation and maintenance requirements. swimming and leaping abilities of target species are unknown, or when a project will Analyze any potentially negative interactions, benefit multiple aquatic organisms. including hybridization, disease, competition, or predation, between target and aquatic At a minimum, design and evaluate passage nuisance species when passage is provided structures for hydraulic performance and a barrier or the barrier is planned for removal. If serious consequences are likely,
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, 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. Analyze any potentially negative interactions, including hybridization, disease, competition, or predation, between target and aquatic nuisance species when passage is provided a barrier or the barrier is planned for removal. If serious consequences are likely, take steps to minimize adverse effects, or avoid removing the barrier or providing passage. Barrier removal, especially dams and road crossings, can significantly affect wetlands, flooding potential, existing infrastructure, and social and cultural practices and resources. Evaluate and address the full range of impacts when planning or designing barrier removal projects. Barrier removal not be performed without a prior determination of the stage of channel evolution, longitudinal profiles, or performing other accepted methodologies above and below the barrier to analyze the potential impact to vertical channel stability (bed degradation). 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
Archived_396_tennessee_aquatic_organism_passage_july_2012_131122.docx