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Normative Flow Studies

Normative Flow Studies. King County Department of Natural Resources Water and Land Resources Division. Establishing links between flow regimes and aquatic ecosystem health - . Using a normative flow approach to guide river restoration in the PNW. Flow Regimes and Restoration.

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Normative Flow Studies

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  1. Normative Flow Studies King County Department of Natural Resources Water and Land Resources Division

  2. Establishing links between flow regimes and aquatic ecosystem health - Using a normative flow approach to guide river restoration in the PNW

  3. Flow Regimes and Restoration • Historical conditions • Ecological processes • Prioritization • Design

  4. Geology Climate Regional Vegetation Runoff regime Sediment supply LWD supply Land Use Pollution Roads CIP’s Floodplain Development Restoration/LWD Biotic Condition (Salmon Viability) Flow Regime Habitat Structure & Dynamics

  5. GEOLOGY, CLIMATE Ecological Condition ‘Reference Condition’ Unaltered flow regime Flow variables Geomorphological, Biotic, Biogeochemical Variables Key Flow Variables Key Ecological Indicators

  6. Why has this not been done in PNW? • Most information from: • Semi-arid/arid regions • Hydroelectric/irrigation diversions • Single-species bias • Focus on minimum flows • ‘Noise’ associated with effects of urbanization • Several efforts underway (TNC, King Co., Ecology….)

  7. Approach How have flows been altered? How has this impacted PNW rivers? Types of hydrologic alteration Ecological effects of flow alteration

  8. Predicted Ecological Effects • Literature review • Focus on 1998-present • Most common flow alterations • Most common ecological responses • Empirical relationships • What is relevant to PNW?

  9. Literature Review: Suites of Common Ecological Effects Habitat complexity Connectivity Community attributes Life-history strategies Q t

  10. Changes in Flows  Connectivity Vertical Longitudinal Exchange of matter and energy: Lateral • Flood pulse • Nutrient cycling • Productivity/food web support Access to habitats: Population Viability: • Refugia • All life-stages • Dispersal • Migration • Recruitment

  11. Changes in Flow  Habitat Complexity • Channel form • Patch complexity • Disturbance regime • Species Diversity • Life-history Diversity • Genetic Diversity • Population Structure • Population Persistence • Productivity Complex, Diverse Simple, Uniform

  12. Changes in Flow Life-history Seasonality; Predictability; Variability Life-history strategies: Recruitment/spawning Life-spans, age at first reproduction Timing first floods Stable baseflows, drought Q t

  13. Changes in Flow Communities Community attributes: Diversity Range expansions/contractions Invasibility Seasonality;Predictability; Variability Q t

  14. Evaluate Flow Changes:Indicators and Metrics • Connectivity • Habitat Complexity • Life-history Traits • Community Attributes

  15. Habitat Complexity • Spatial • Number of: • Geomorphic surfaces • Channel islands • Un-vegetated patches • Length channel segments • Temporal • Patch turnover rates • Structural diversity • Size classes trees • Rates channel migration

  16. Life-History Traits • Relative abundances/Presence-absence of life-history traits: • Timing of spawning runs • Number of runs • Length of reproductive season • Short-lived vs. long-lived species • Age at first reproduction • Generations/year • Tolerant/Intolerant

  17. Approach Can we use flow regimes to design better river restoration? Predict effects of flow alteration on river health Evaluate restoration actions under range of flow regimes

  18. Historical Feasible Priority 1 Restoration Priority 2 Stewardship, Enhancement Flow Regimes and Restoration • Historical flow regimes/existing constraints • Current flow regimes/limitations • Prioritization • Design

  19. Prioritization A-seasonal high or low flows ‘Flashiness’ Timing of peak flows Frequency overbank flows

  20. Restoration Design • Feasibility • Potential for success • Goals and targets Historical Feasible Priority 1 Restoration Priority 2 Stewardship, Enhancement

  21. Flow Regime Geomorphic Response Frequency peak flows Magnitude peak flows • Velocity • Bedload transport capacity • Depth of bedload scour (in relation • to egg pocket depths) • Grain size Biotic Response – Community Composition Biotic Response – Individual, Population • Egg/alevin survival • Population size (fall spawners) • Salmon to cutthroat • Invertebrate diversity • Species diversity • Life-history diversity

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