Aquatic Organism Passage (AOP): Importance of ecological connectivity at road/stream crossings. Mark Hudy Transportation Ecologist USDA Forest Service Mark Hudy Transportation Ecologist USDA Forest Service
Aquatic organism passage: it’s not just dams & salmon anymore!
Road crossings of all types are prevalent everywhere and number in the 100,000’s.
Roads Historically road/stream crossing design & installation typically do not address the needs & abilities of aquatic organisms to freely move along stream corridors.
Roads Road crossings can negatively impact aquatic organisms by prohibiting re- colonization of upstream habitats and restricting movements to locate food, habitat or spawning areas.
Fragmented Habitats
Aquatic organism passage is complex ! 1. Aquatic species 2. Life stage of species 3. Barrier type 4. Stream flow 1. Aquatic species 2. Life stage of species 3. Barrier type 4. Stream flow
Aquatic organism passage is complex ! Aquatic species: thousands of species complex life cycles variety of movement needs many rare and threatened Aquatic species: thousands of species complex life cycles variety of movement needs many rare and threatened
© Greg A. Syverson Kenneth Catania Radu Guiasu Scott Jackson Barry Wicklow © 1999 Joyce Gross Robert Jenkins & Noel Burkhead Micrographia
Aquatic organism passage is complex ! Life stage movement needs: can be local-daily, weekly, seasonally or yearly to meet a variety of needs for reproduction, colonization of available habitat, chemical or thermal refuges or to seek out available food. Life stage movement needs: can be local-daily, weekly, seasonally or yearly to meet a variety of needs for reproduction, colonization of available habitat, chemical or thermal refuges or to seek out available food.
Aquatic organism passage is complex ! n Stream flow conditions for passage Always met Frequently met Infrequently met Never met n Stream flow conditions for passage Always met Frequently met Infrequently met Never met
Aquatic organism passage is complex ! Barrier types: jump velocity exhaustion depth behavioral Barrier types: jump velocity exhaustion depth behavioral
Today a road that crosses a stream or river with minimal ecological impact is often the goal for new construction and maintenance or mitigation of existing road/stream crossings.
These low ecological impact designs simulate natural streams and rivers. Stream simulation designs often don’t require extensive studies on target species at target times and flows because the design mimics the stream.
Why is AOP, Ecological Connectivity and Stream Simulation important at road/stream crossings? 1. $$ Less maintenance 2. $$ Reduced overall long-term costs 3. Regulatory- Clean Water Act 4. Regulatory – Endangered Species Act 5. Regulatory – National Forest Management Act 6. Ecological – long-term ecological integrity “Right thing to do” 1. $$ Less maintenance 2. $$ Reduced overall long-term costs 3. Regulatory- Clean Water Act 4. Regulatory – Endangered Species Act 5. Regulatory – National Forest Management Act 6. Ecological – long-term ecological integrity “Right thing to do”
Think AOP! Think Ecological Connectivity! Think Stream Simulation! Think AOP! Think Ecological Connectivity! Think Stream Simulation!
Clean Water Act: Nationwide Roads Exemption BMP 40CFR c(6) 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.