Description: Southern California Coastal Water Research Project (SCCWRP) applied the Ecological Limits of Hydrologic Alteration (ELOHA) framework to develop regional (Soutern California) flow-ecology relationships and targets based on responses in the benthic macroinvertebrate community. SCCWRP developed a statewide classification system using a two-step approach: 1 - cluster streams into 7 classes based on differences in winter precipitation, geology, soil characteristics, and mean watershed elevation; 2 - used flow data from a subset of streams with gauge information to test and refine stream classes determine which hydrologic variables best separate streams into respective classes. SCCWRP then collaborated with UC Davis to come up with 9 stream classes.
Copyright Text: State Water Resources Control Board, Southern California Coastal Water Research Project, Surface Water Ambient Monitoring Program, California Department of Fish and Wildlife, Aquatic Bioassessment Laboratory, University of California Davis, Stormwater Monitoring Coalition, Perennial Streams Assessment
Unique Value Renderer: Field 1: CLASS Field 2: null Field 3: null Field Delimiter: , Default Symbol:
N/A
Default Label: null UniqueValueInfos:
Value: 1 Label: (SM) Snowmelt Description: Large spring snowmelt pulse (~May 24)
Very high seasonality index
Extreme low flows (<10th percentile) Sep - Feb
High elevation catchments (> 2,293 m), major snow influence
Symbol:
Value: 2 Label: (HSR) High-volume snowmelt and rain Description: Spring snowmelt pulse (~May 4)
High seasonality but larger winter storm contributions
Retain high baseflow throughout summer Bimodal snow - rain hydrograph
• Mid-elevation catchments (1,126 - 2,293 m), large contributing area (>2,144 km2 ) not underlain by volcanic geology [high stream density (>0.65 km/km2 ), mild winter temperatures (Jan temp >-5Co)] OR
• Low elevation (<1,125 m) with very large contributing area (>15,420 km2) and high clay content soils (>17% clay)
Symbol:
Value: 3 Label: (LSR) Low-volume snowmelt and rain Description: Transition between SM and HSR
Bimodal snow - rain hydrograph driven by spring snowmelt pulse and winter rain
• Mid-elevation catchments with limited area (<2,144 km2) [low winter temperatures (Jan temp <-5Co), high stream density (>0.65 km/km2 )] Symbol:
Value: 8 Label: (RGW) Rain and seasonal groundwater Description: Bimodal hydrograph driven by winter rain pulse and percolating winter rain appearing as baseflow pulse later in year; can be ephemeral
low elevation with limited winter precipitation and low slopes (< 24%) AND
Coastal catchments with small aquifers driving short residence times Symbol:
Value: 4 Label: (WS) Winter storms Description: predictable large fall and winter storms
earlies peak flows (in January)
• Low elevation catchments with substantial winter precipitation OR
• Low elevation, mid-slope (31 - 24%) catchments with low winter precipitation but high riparian soils clay content (>23%) AND
• Underlain by unconsolidated aquifers covered by thick alluvium
Symbol:
Value: 5 Label: (GW) Groundwater Description: highest mean annual flows and highest minimum flows
low seasonality and high predictability
• Mid-elevation catchments with large area (>2,144 km2 ) underlain by volcanic (basaltic and andesitic) geology [low stream density (<0.65 )] OR
• Low elevation, limited winter precipitation, very large contributing area (>15,420 km2) with low riparian soils clay content (<17%) AND
• Underlain by igneous and metamorphic rock aquifers
Symbol:
Value: 6 Label: (PGR) Perennial groundwater and rain Description: low seasonality and mean annual streamflow
transition between WS and GW, with winter rain contributions but generally stable flows
• Low elevation catchments with low clay content riparian soils (<23%) [low stream density (<1.1 km/km2)] AND
• Underlain by sedimentary rock materials in Central Coast region
Symbol:
Value: 9 Label: (HLP) High elevation, low precipitation Description: low mean annual flows
highest flows in winter
high elevation but low slope
low precipitation and limited snow influence Symbol:
Name: Flow-Ecology Stream Classes with Predicted CSCI Scores
Display Field: GNIS_NAME
Type: Feature Layer
Geometry Type: esriGeometryPolyline
Description: Southern California Coastal Water Research Project (SCCWRP) applied the Ecological Limits of Hydrologic Alteration (ELOHA) framework to develop regional (Soutern California) flow-ecology relationships and targets based on responses in the benthic macroinvertebrate community. SCCWRP developed a statewide classification system using a two-step approach: 1 - cluster streams into 7 classes based on differences in winter precipitation, geology, soil characteristics, and mean watershed elevation; 2 - used flow data from a subset of streams with gauge information to test and refine stream classes determine which hydrologic variables best separate streams into respective classes. SCCWRP then collaborated with UC Davis to come up with 9 stream classes.
Copyright Text: State Water Resources Control Board, Southern California Coastal Water Research Project, Surface Water Ambient Monitoring Program, California Department of Fish and Wildlife, Aquatic Bioassessment Laboratory, University of California Davis, Stormwater Monitoring Coalition, Perennial Streams Assessment