Bug Flows: Improving Food Web Health on the Colorado River Active
Flow Management for Hydropower Extirpates Aquatic Insects, Undermining River Food Webs
Journal article in BioScience
Water experiment to be conducted along the Colorado River while maintaining hydropower production this summer
Bureau of Reclamation news release
Native and desired nonnative fish downstream of Glen Canyon Dam are food limited—meaning that if more or larger invertebrate food items were available, there would be more and larger fish. Aquatic insects have complex life cycles that include egg, larvae, and pupal stages that are aquatic while adults have wings and are typically terrestrial. Aquatic insects are a fundamental component of river food webs and the primary prey for fish and many species of birds, lizards, fish, and even other invertebrates. Identifying the factors that limit production and diversity of the insect prey base is important when making management decisions, especially when those decision affect endangered species, like humpback chub (Gila cypha).
Making Waves podcast “River guides are science guides”
Ecologist Anya Metcalfe talks about how SBSC scientists engage with river guides on the Colorado River in this podcast.
Grand Canyon Youth StoryMap "Splashing into Science"
In the field with the next generation of scientists.
Community Science: "Not all Scientists wear Lab Coats"
Some wear life jackets and sandals. Learn about how community scientists are helping scientists in this article by PBS News Hour
In rivers, many aquatic insects lay their eggs right at the water line. In pre-dam era, water levels did not vary much on hourly or daily time scales, so this strategy ensured that eggs would stay submerged long enough to hatch. However, because of hydropower production at Glen Canyon Dam, the river now experiences a daily “tide” as more water is released during daylight hours to meet higher demand for electricity during the day. Then at night, when energy demand is lower, less water is released from the dam resulting in a drop in water levels. The magnitude of this tide during summer months is 2-3 feet, depending on location. Insect eggs laid along the high-water mark become desiccated and die, typically within a few hours, when river flows drop. USGS research has shown that these daily high and low tides created by hydropower operations are an important factor that contributes to the low abundance and diversity of aquatic insects in Grand Canyon.
Bug flows are experimental releases from Glen Canyon Dam that were designed to increase the abundance (number of individuals) and the diversity (number of types) of insects in Grand Canyon by improving egg laying conditions for insects. The Bug Flow experiment was tested at Glen Canyon Dam on weekends from May through August of 2018-2020 and in 2022. During the experiment, hydropower operations continued as normal during weekdays, resulting in daily tides. On weekends, however, a steady low-flow was released from the dam to try to improve egg laying conditions for aquatic insects. Because demand for electricity is typically low during weekends, the design of the Bug Flow experiment improves egg laying conditions for insects while minimizing negative impacts to hydropower production. The goal of the Bug Flow experiment is to support healthier wildlife populations through increases in the production and diversity of the aquatic insect prey base.
News & Multimedia
External multimedia
- PODCAST: Making Waves River guides are science guides
- PODCAST: BioScience Hydroelectric dams kill insects, wreak havoc with food webs
- PODCAST:Science Moab Aquatic insects of Grand Canyon
- FILM: Freshwaters Illustrated Citizen Science in Grand Canyon
- FILM: Freshwaters Illustrated What you take away Featured in National Geographic
- STORYMAP: Grand Canyon Youth Splashing into Science
In the news
- PBS News Hour (2022) Not all scientists wear lab coats. Volunteers are fueling research nationwide.
- Bureau of Reclamation (2020) Water experiment to be conducted along the Colorado River while maintaining hydropower production this summer
- Associated Press (2019) Changing water flow leads to more bugs in Grand Canyon
- Scientific American (2019) Re-engineering the Colorado River to Save the Grand Canyon
- Associated Press (2018) Scientists hope bug experiment fattens Colorado River fish
- Undark Magazine (2018) Essay about conducting aquatic ecology research in Grand Canyon.
- Science (2016) Scientific reinterpretation of the BioScience hydropeaking paper.
- Arizona Daily Sun (2016) Glen Canyon Dam plan aims to boost native fish, bugs
- National Public Radio KNAU (2016) Study: Hydropower decimates aquatic insects on the Colorado River
- High Country News (2016) New measures could reduce Glen Canyon Dam's impacts on the Grand Canyon - a bit..
- Columbia Basin Bulletin (2016) Study: 'Hydropeaking' of river water levels disrupting insect survival, river ecosystems
- American Fisheries Society (2016) Citizen science reveals how river food webs are affected by hydropower practices
- Conservation Magazine (2016) A hydropeak tweak could make dams less damaging
- USGS press release (2016) River foodwebs threatened by widespread hydropower practice: alternative flows might mitigate negative impacts
- Oregon State University (2016) Hydropeaking of river water levels is disrupting insect survival, river ecosystems
- SciStarter (2014) Is our thirst for energy killing the ecology of the Grand Canyon?
Below are other science projects associated with this project.
Community Science in Grand Canyon
Is timing really everything? Evaluating Resource Response to Spring Disturbance Flows
Aquatic Insects
- Overview
Native and desired nonnative fish downstream of Glen Canyon Dam are food limited—meaning that if more or larger invertebrate food items were available, there would be more and larger fish. Aquatic insects have complex life cycles that include egg, larvae, and pupal stages that are aquatic while adults have wings and are typically terrestrial. Aquatic insects are a fundamental component of river food webs and the primary prey for fish and many species of birds, lizards, fish, and even other invertebrates. Identifying the factors that limit production and diversity of the insect prey base is important when making management decisions, especially when those decision affect endangered species, like humpback chub (Gila cypha).
Making Waves podcast “River guides are science guides”
Ecologist Anya Metcalfe talks about how SBSC scientists engage with river guides on the Colorado River in this podcast.
Grand Canyon Youth StoryMap "Splashing into Science"
In the field with the next generation of scientists.
Community Science: "Not all Scientists wear Lab Coats"
Some wear life jackets and sandals. Learn about how community scientists are helping scientists in this article by PBS News Hour
Sources/Usage: Public Domain. View Media DetailsAquatic invertebrates in the Colorado River respond to hydropeaking. In rivers, many aquatic insects lay their eggs right at the water line. In pre-dam era, water levels did not vary much on hourly or daily time scales, so this strategy ensured that eggs would stay submerged long enough to hatch. However, because of hydropower production at Glen Canyon Dam, the river now experiences a daily “tide” as more water is released during daylight hours to meet higher demand for electricity during the day. Then at night, when energy demand is lower, less water is released from the dam resulting in a drop in water levels. The magnitude of this tide during summer months is 2-3 feet, depending on location. Insect eggs laid along the high-water mark become desiccated and die, typically within a few hours, when river flows drop. USGS research has shown that these daily high and low tides created by hydropower operations are an important factor that contributes to the low abundance and diversity of aquatic insects in Grand Canyon.
Sources/Usage: Public Domain. View Media DetailsDams alter river ecosystems. GCMRC scientists study how hydropeaking and other dam operations affect ecosystem function. "Bug Flows" are steady hydroflows during weekends that allow aquatic insect eggs to remain moist and viable before hatching, rather than drying and desiccating when water levels drop. The multi-year study seeks to determine whether these modified flows improve aquatic populations and thus food for fish and other animals. Bug flows are experimental releases from Glen Canyon Dam that were designed to increase the abundance (number of individuals) and the diversity (number of types) of insects in Grand Canyon by improving egg laying conditions for insects. The Bug Flow experiment was tested at Glen Canyon Dam on weekends from May through August of 2018-2020 and in 2022. During the experiment, hydropower operations continued as normal during weekdays, resulting in daily tides. On weekends, however, a steady low-flow was released from the dam to try to improve egg laying conditions for aquatic insects. Because demand for electricity is typically low during weekends, the design of the Bug Flow experiment improves egg laying conditions for insects while minimizing negative impacts to hydropower production. The goal of the Bug Flow experiment is to support healthier wildlife populations through increases in the production and diversity of the aquatic insect prey base.
News & Multimedia
External multimedia
- PODCAST: Making Waves River guides are science guides
- PODCAST: BioScience Hydroelectric dams kill insects, wreak havoc with food webs
- PODCAST:Science Moab Aquatic insects of Grand Canyon
- FILM: Freshwaters Illustrated Citizen Science in Grand Canyon
- FILM: Freshwaters Illustrated What you take away Featured in National Geographic
- STORYMAP: Grand Canyon Youth Splashing into Science
In the news
- PBS News Hour (2022) Not all scientists wear lab coats. Volunteers are fueling research nationwide.
- Bureau of Reclamation (2020) Water experiment to be conducted along the Colorado River while maintaining hydropower production this summer
- Associated Press (2019) Changing water flow leads to more bugs in Grand Canyon
- Scientific American (2019) Re-engineering the Colorado River to Save the Grand Canyon
- Associated Press (2018) Scientists hope bug experiment fattens Colorado River fish
- Undark Magazine (2018) Essay about conducting aquatic ecology research in Grand Canyon.
- Science (2016) Scientific reinterpretation of the BioScience hydropeaking paper.
- Arizona Daily Sun (2016) Glen Canyon Dam plan aims to boost native fish, bugs
- National Public Radio KNAU (2016) Study: Hydropower decimates aquatic insects on the Colorado River
- High Country News (2016) New measures could reduce Glen Canyon Dam's impacts on the Grand Canyon - a bit..
- Columbia Basin Bulletin (2016) Study: 'Hydropeaking' of river water levels disrupting insect survival, river ecosystems
- American Fisheries Society (2016) Citizen science reveals how river food webs are affected by hydropower practices
- Conservation Magazine (2016) A hydropeak tweak could make dams less damaging
- USGS press release (2016) River foodwebs threatened by widespread hydropower practice: alternative flows might mitigate negative impacts
- Oregon State University (2016) Hydropeaking of river water levels is disrupting insect survival, river ecosystems
- SciStarter (2014) Is our thirst for energy killing the ecology of the Grand Canyon?
- Science
Below are other science projects associated with this project.
Community Science in Grand Canyon
Aquatic insects are important components of riverine foodwebs as they are prey for fish, birds, bats, lizards, and spiders. The closure of Glen Canyon Dam in 1963 fundamentally altered the hydrology, water temperature, and turbidity of the Colorado River through Grand Canyon. These changes, along with competition with invasive species and limited food availability have led to the decline and...Is timing really everything? Evaluating Resource Response to Spring Disturbance Flows
Glen Canyon Dam has altered ecological processes of the Colorado River in Grand Canyon. Before the dam was built, the Colorado River experienced seasonable variable flow rates, including springtime flooding events. These spring floods scoured the river bottom and enhanced natural processes that sustained the Colorado River ecosystem. Since the dam’s construction in 1963, springtime floods have...Aquatic Insects
Aquatic insects live in the water as larvae most of their lives, then emerge onto land for a brief period as winged adults. Sampling these emerged adults on land is therefore a useful tool for understanding the condition of the aquatic insect population that is in the water, particularly in large rivers where sampling the larvae on the river bed is impractical. Our group uses a variety of methods... - Publications
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