Zoology 315: Limnology Rivers & Streams, part II Abby Popp July 30th, 2006 1. Major Concepts in River Ecology a. TLAs “All models are wrong. Some models are useful.” b. River Continuum Concept (Vannote et al., 1980) Headwaters (up to 3rd order) Mid-reaches (4th to 6th order) Lower reaches (higher than 6th order)c. Nutrient Spiraling (Newbold et al., 1982) d. Serial Discontinuity Concepte. Flood-Pulse Concept f. Thought Question(s)  “Species richness” is measured as the number of different species in a given area. Explain why fish species richness might increase from low to high order streams.  What are some potential biological impacts of having impoundments along a river?2. Reservoir Limnology Introductory Facts Reservoir Distribution Dam construction in the US Size & Operation Reservoir FeaturesFlow patterns Plunge Point Epilimnetic vs. Hypolimnetic release Reservoir Zones Sediment Loads StratificationPrimary Production Effects of reservoir’s age Oxygen dynamicsDownstream effects of dams  Flow regime  Channel form  Temperature regime  Water chemistry  BiotaCumulative Effects of many reservoirs Trends in reservoir management Dam removal3. Conservation of streams & rivers The Clean Water Act Process: Water bodies must… Tools: TMDLs NPDES