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Example bugflows hydrograph
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What is the “bug flow experiment?
This would be an experimental release at Glen Canyon Dam to see if short-duration steady flow might increase the diversity and production of aquatic insects below Glen Canyon Dam. This experiment is included in the Preferred Alternative of the LTEMP DEIS. These “bug flows” would occur from May to August and would maintain releases on the weekends to a level equal to the minimum release made during the week. This would allow aquatic insects two days a week throughout the river corridor to be able to lay their eggs at a stage where they would not be at risk of being dewatered or desiccated. The experiment would include monitoring to evaluate if the flows did increase the diversity and production of aquatic insects. The experiment was designed to test the hypothesis put forward in Kennedy's 2016 BioScience Paper while minimizing impacts to the hydropower resource at Glen Canyon Dam by having the steady flows on the weekend. This results in a transfer of water from the weekend to the weekdays increasing the daily minimums and maximums and the range of fluctuation during the week. Western believes that this experiment will result in only a small decrease in the energy value, but a modest increase in the capacity value of hydropower produced at Glen Canyon Dam.
LTEMP Experimental Action: Aquatic Resource-Related Experimental Treatments (BA, pages 30-41)
Low steady weekend flows (“bug flows”) would be conducted to test whether the
flows would increase insect abundance. On an experimental basis, for example,
flows would be held low and steady for two days per week (weekends) from May
through August to attempt to improve the productivity of the aquatic food base,
and increase the diversity and abundance of mayflies (Ephemeroptera), stoneflies
(Plecoptera), and caddisflies (Trichoptera), which are collectively referred to as
EPT.
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