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Commonwealth of Virginia Flow-Ecology

Commonwealth of Virginia Flow-Ecology. Project Meeting VDEQ January 24, 2012. The ELOHA Framework modified from Poff et al. (2010). Data Sources. Spatial distribution of benthic community samples (i.e., excluding presence/absence samples) by data source.

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Commonwealth of Virginia Flow-Ecology

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  1. Commonwealth of VirginiaFlow-Ecology Project Meeting VDEQ January 24, 2012

  2. The ELOHA Framework modified from Poff et al. (2010)

  3. Data Sources

  4. Spatial distribution of benthic community samples (i.e., excluding presence/absence samples) by data source

  5. Spatial distribution of fish community samples (i.e., excluding presence/absence samples) by data source

  6. Distribution of hydrological pour points by stream flow classes and sizes. CP = Coastal Plain; NCP = Non-Coastal Plain; PR = Perennial Runoff; SBF = Stable Base Flow; CSIIF = Coastal Swamp Intermittent/Intermittent Flashy

  7. Numbers of sites of associated hydrologic and biological data, separated by flow class and stream size. CP = Coastal Plain; NCP = Non-Coastal Plain; PR = Perennial Runoff; SBF = Stable Base Flow; CSIIF = Coastal Swamp Intermittent/Intermittent Flashy • These 171 hydro points are associated with 846 biological samples: • 122 hydrologic sites associated with benthic samples • 212 hydrologic sites associated with fish samples

  8. Distribution of matched hydrologic and biological sampling sites among flow and size classes

  9. Distribution of hydrologic pour points around the Commonwealth of Virginia, with each point designated by flow class membership. Watersheds shown in green were included in analyses

  10. Biological Information Relating to Classification

  11. NMS on fish community data for all stations (statewide), categorized (by color coding) according to selected classifications. A) Coastal Plain (CP) and Non-Coast Plain (NCP; B) Ecoregion (45=Piedmont; 63=Middle Atlantic Coastal Plain; 64=Northern Piedmont; 65=Southeastern Plains; 66=Blue Ridge; 67=Ridge and Valley; 69=Central Appalachians); and C) the major river basins used in the Virginia water quality standards (WQS) (1=Potomac-Shenandoah; 2=James; 3=Rappahannock; 4=Roanoke; 5=Chowan and Dismal Swamp; 6=Tennessee and Big Sandy; 7=Small Coastal Basin and Chesapeake Bay; 8=York; 9=New River; 10=Yadkin).

  12. NMS on fish community data, by flow class for A) all (statewide) stations; B) Coastal Plain stations; and C) Non-Coastal Plain stations. (11 = PR1 = Perennial Runoff1; 12 = PR2 = Perennial Runoff2; 21 = SBF1 = Stable High Baseflow1; 22 = SBF2 = Stable High Baseflow2; 31 = CSI = Coastal, Swamp and Intermittent; 32 = IF = Intermittent Flashy).

  13. NMS on fish community data, all stations, for A) axes 1 and 2; B) axes 1 and 3; and C) axes 2 and 3. Color coded by classification: Group 1=Non-Coastal Plain-Ohio Drainage; 2= Non-Coastal Plain-Atlantic Drainage; 3=Coastal Plain

  14. NMS on Benthos - classes

  15. Biological Responses to Stream Size

  16. NMS on fish community data, with results highlighted by stream order for A) axes 1 and 2; and B) axes 1 and 3; and the same NMS result with stations highlighted by stream order size groups, where group 1=stream orders 1-3, and group 2=stream orders 4-6, for C) axes 1 and 2, and D) axes 1 and 3

  17. Color coding indicates class member ship (red=CP; orange=NCP-Atl; green=NCP-Ohio) lithophilic fish (J) : r = -0.344 stream size accounts for <12% of the variation in this metric

  18. NMS on Benthos – stream size

  19. Flow Classes

  20. Flow Classes

  21. Flow Classes

  22. Flow Classes

  23. Flow Class Groupings • McManamay, Orth and others show hydrologic distinctions between classes, but • Some closely related flow classes have commonalities in some characteristics • Combined across some of these if need to increase ‘n’ and the biology also supported this: • PR-1 • PR-2 • SBF 1 & 2 combined • CSI & IF combined

  24. Statewide The degree and types of changes in IHA metrics varies across classes, but the CP/NCP classification captures a lot of these

  25. In this case, SBF-2 small streams show greater hydrologic changes than the other classes. May need to focus on this under-represented class in the future.

  26. CSI and IF classes were combined for analyses – justified based on biological community similarities, but the IF class shows much larger increases in spring flows, which should be considered in the future.

  27. Biological response • Flow • Flow velocity • Shear • Thickness of laminar layer • Habitat • Water • Substrate • What changes habitat? • Stream power – ability to carry & alter sediment • Bed stability • How do IHA metrics affect these?

  28. Stream size with respect to IHA metrics • Most IHA metrics include flow, hence are controlled by overall size (flow) • IHA flow metrics (peak flows, fall rates, etc.) are distinct power functions of mean annual flow (in modeled streams)

  29. 1-day max: flow 0.97

  30. 1-day min: flow 0.89

  31. 90-day max: flow 0.99

  32. 90-day min: flow 0.96

  33. 7Q10: flow 0.80

  34. Rise rate: flow 0.94

  35. Large flood rise: flow 0.69

  36. Summary and Implications: • Benthos did not show strong variation across stream sizes • Fish showed some variation, but not necessarily at a level that warranted correction of fish metrics to account for stream size • IHA metrics do bear a relationship to stream size, but this is based on modeled hydrologic outputs • Further consideration should be given to accounting for stream size – e.g., investigate further using gaged data

  37. Potential Problem with Use of Percent Change • Percent change = (current-baseline)/baseline • Percent change removes effect of average flow • BUT, percent change has potential problem depending on shape of response to flow metrics: do biological metrics show response to IHA metrics or to % change? • Why? And is this a problem?........... Yes

  38. 10 Response to percent hydrological change Response 5 0 10 Hydrological metric 0 5 10 Baseline = 1, current = 2; change=100% Response 5 0 0 100% 200% Hydrological Change, %

  39. 10 Response to percent hydrological change Response 5 0 10 Hydrological metric 0 5 10 Baseline = 5, current = 10; change=100% Response 5 0 0 100% 200% Hydrological Change, %

  40. 10 Response to percent hydrological change Response 5 0 10 Hydrological metric 0 5 10 Baseline = 5, current = 5; change = 0% Response 5 0 0 100% 200% Hydrological Change, %

  41. 10 Response to percent hydrological change Response 5 0 10 Hydrological metric 0 5 10 Baseline = 1, current = 3; change = 200% Response 5 0 0 100% 200% Hydrological Change, %

  42. 10 Response to percent hydrological change Response 5 0 10 Hydrological metric 0 5 10 Baseline = 3, current = 9; change = 200% Response 5 0 0 100% 200% Hydrological Change, %

  43. 10 Response to percent hydrological change Response 5 0 10 Hydrological metric 0 5 10 Baseline = 3, current = 3; change = 0% Response 5 0 0 100% 200% Hydrological Change, %

  44. 10 Response 5 0 10 Hydrological metric 0 5 10 What is response to percent hydrological change? Response 5 0 0 100% 200% Hydrological Change, %

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