Functional Assessment Potential Future Drivers
Variable / Sub-Variable Existing Condition Increasing Municipal Water Use Urbanization Warm & Wet Climate Future In-Between Climate Future Hot and Dry Climate Future New TMDs Increased Reservoir Capacity Wildfire
Streamflows
Base Flow: Dry Year A Onset and peak snowmelt shift earlier in season, exacerbating severity and duration of late season low flow spells Onset and peak snowmelt shift earlier in season, coupled with increasing air temperatures, exacerbating severity and duration of late season low flow spells Onset and peak snowmelt shift earlier in season, coupled with increasing air temperatures, exacerbating severity and duration of late season low flow spells
Base Flow: Median Year A Low flow spells increase in severity and duration Low flow spells increase in severity and duration Low flow spells increase in severity and duration
High Peakflow Frequency A Wetter and warmer climate future slightly increases peak flow magnitudes and variability Warmer climate future slightly increases peak flow magnitudes and variability, likely due to earlier melt and increased probability of rain-on-snow events Streamflow losses to warming temperatures outpace potential precipitation gaines, reducing magnitude and frequency of flood flows
Peak Flow: Dry Year C Wetter and warmer climate future slightly increases peak flow magnitudes and variability; increased peak flows may be accompaied by shorter duration of high flows. Streamflow losses from warming climate result in declines in magnitude and frequency of peak flows
Peak Flow: Median Year A Streamflow losses from warming climate result in declines in magnitude and frequency of peak flows Streamflow losses from warming climate result in declines in magnitude and frequency of peak flows
Total Volume: Dry Year B Total streamflow declines due to warming temperatures (increased vegetation ET demand, lower soil moisture, longer growing/irrigation season) drive overall streamflow declines Total streamflow declines due to warming temperatures (increased vegetation ET demand, lower soil moisture, longer growing/irrigation season) drive overall streamflow declines
Total Volume: Median Year A Total streamflow declines at higher watershed stream reaches due to warming temperatures (increased vegetation ET demand, lower soil moisture, longer growing/irrigation season) are balanced or slightly exceeded by gains from precipitation increases Total streamflow declines due to warming temperatures (increased vegetation ET demand, lower soil moisture, longer growing/irrigation season) drive overall streamflow declines Total streamflow declines due to warming temperatures (increased vegetation ET demand, lower soil moisture, longer growing/irrigation season) drive overall streamflow declines
Streambed Sediment
Continuity and Transport A Decreased total volumes and base flow magnitudes salter total annual sediment transport capacity Increased watershed responsiveness can drive increased peak floods and sediment delivery, impacting channel shaping processes like erosion/aggradation rates and seasonal sediment transport
Flushing Flows A Changes in flow regimes maintain or increase frequency of discharges at or above sediment mobilization thresholds
Water Quality
Metals A Runoff from burned areas increases dissolved metals loads to streams
Nutrients C WWTP effluent load increases with population; dilution issues during lowest winter baseflows. Stormwater fluxes from increased impervious coverage carry larger nutrient loads to streams; Runoff from burned areas increases nutrient loads to streams
Temperature B Increasing air temperatures and decreasing summer/fall baseflows creates increasing temperature risks for aquatic life Increasing air temperatures and decreasing summer/fall baseflows creates increasing temperature risks for aquatic life
Riparian Areas
Floodplain physical condition B
Riparian vegetation B
River Form
Channel Structure and Dynamics B
Aquatic Habitat
Habitat Structure A Increased sediment fluxes degrade inchannel habitat quality including spawning sites and macroinvertebrate habitat
In-channel Hydrologic Connectivity A Baseflow declines reduce stream network connectivity during late summer and fall, potential impacts to refuge seeking movements, migration, and spawning activity Baseflow declines reduce stream network connectivity during late summer and fall, potential impacts to refuge seeking movements, migration, and spawning activity Baseflow declines reduce stream network connectivity during late summer and fall, potential impacts to refuge seeking movements, migration, and spawning activity Baseflow declines reduce stream network connectivity during late summer and fall, potential impacts to refuge seeking movements, migration, and spawning activity
Aquatic Life
Aquatic Insects D Low flow spells severity and duration still increase in summer/fall still under WW future, negatively impacting abundance. Low flow spells severity and duration still increase in summer/fall still under WW future, negatively impacting abundance. Low flow spells severity and duration greatly increase in summer/fall HD future, negatively impacting abundance. Streambed Sedimentation and water chemistry impacts degrade physical habitat and water quality
Fish A Declining late summer/early fall flows place increasing pressure on instream flows, water quality (temperature, DO, nutrients, etc.), habitat connectivity Declining late summer/early fall flows and increasing air temperatures place increasing pressure on instream flows, water quality (temperature, DO, nutrients, etc.), habitat connectivity Declining late summer/early fall flows and increasing air temperatures place increasing pressure on instream flows, water quality (temperature, DO, nutrients, etc.), habitat connectivity Increased sediment fluxes degrade inchannel habitat quality and water quality, including spawning sites and macroinvertebrate habitat