Effects of Water Diversion on Stream Health


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3rd point - which has serious implications to stream health

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RCC describes changes in channel morphology (width, flow, depth), chemical composition, channel substrate and functional feeding groups of organisms as you move downstream EPT is a widely used diversity index, which is a ratio of sensitive insect orders to all other orders

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Hypothesis: Stream Diversion affects stream health, From the Fish Observatory, we sampled from the first 5 runs up-stream of the water diversion and 5 runs down-stream.

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Invertebrates: Achieved by using the kick-net method to collect invertebrates, which were then tallied up back at camp Rock Fractionation: Calculated by using the point intercept method to get a percentage of sediment, small, medium, and large rock cover Algal Count: Using quadrat percent cover method along a belt transect across the stream We also took the temperature and velocity of stream flow at each site

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River Continuum Explains changes in functional feeding groups going downstream upstream ^# feeding groups ephemeroptera encompasses all groups, chironomidae = 1 If diversion impacted health, trends in graph would be flat bc interrupts feeding group diversity gradient Clear linear trendsm follows RCC of healthy river Collectors Predators Grazers Shredders

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Effects of Water Diversion on Stream Health CEC Summer 2018 Nagaraj, M.; Singh, N.; Abels-Sullivan, H.; Arzuyan, K.; Castro, M.

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California Waterways Perennial waterways are very valuable in CA’s mediterranean climate Important parts of large watersheds Most are heavily regulated and frequently used by humans Truckee River Watershed

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Concepts & Theory Healthy rivers adhere to the River Continuum Concept Sensitive taxa are commonly used as bioindicators to assess stream health In a healthy stream, we would expect to see little to no changes in sensitive taxa across this continuum gradient. Sensitive Taxa

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Are there differences in diversity upstream vs. downstream? Are tolerance taxa less common downstream? Do algal cover and rock size affect invertebrate diversity? Where did we study stream health? Sagehen Creek Field Station

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How did we measure stream health? Invertebrates capture: kick-net method Rock Fractionation: point intercept method Algal Count: quadrat percent cover method

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Differences in Invertebrate Abundance

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Effect of Diversion Distance on Diversity Invertebrate diversity decreases downstream of diversion

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Effect of Distance on Sensitive Taxa No difference in upstream/downstream, supports RCC

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Change in Taxa Representing Feeding Groups Chironomidae Nonbiting flies High tolerance Collectors Ephemeroptera Mayflies Sensitive High number of feeding habits

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Overall Results Are there differences in diversity upstream vs. downstream? Yes! H’ decreased downstream. Are sensitive taxa less common downstream? No! EPT is similar upstream and downstream  the stream is healthy! High-tolerance Chironomidae are more concentrated downstream. Do algal cover and rock size affect invertebrate diversity? No… they are similar upstream vs. downstream.

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Further Study Improve techniques for determining rock and sediment cover Effects of algal removal Were community composition and diversity different before algal introduction? Differences in oxygen concentration? Would we see these results with a large dam?

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Thank You, Questions?

Summary: Summer, 2018

Tags: student project