Guadalupe Watershed Model Year 2 update

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Guadalupe Watershed ModelYear 2 update
Item 7

• Presentation to SPLWG May 27, 2009
• Michelle Lent, John Oram, Lester McKee

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Item 7

• Basic Objective (revised)
• To understand the source, release, and transport
  of suspended sediment, Hg and PCBs from a large,
  mixed land use watershed to San Francisco Bay
• Timeline
• Year 1 (2008) Hydrologic model
• Year 2 (2009) Sediment and contaminants model
• Details
• Establish model input and calibration parameters
  to assist in developing other local watershed
  models
• Improve accuracy of mercury and PCB load
  calculations
• Addresses
• STLS Q1 (Impairment), Q2 (loads), Q3 (Trends), Q4
  (Support for management actions)
• Modeling Strategy Q3 (Small tributary loads)

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Re-cap of last time
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• Model Overview Set-up
• Software data sets used
• Delineation segmentation
• Model Calibration/Validation
• Split data into two sets (2000-05, 2006-07)
• Summary of Model Performance
• Captures general watershed hydrology storm
  events
• Needs improvement for
• Annual flow volume and base flow
• Storm event peak flow and timing

• Model Improvement Plan
• Extend calibration period
• Add urban irrigation
• Revise imperviousness estimates
• Re-evaluate meteorological and calibration
  segmentation
• Suggestion from Workgroup
• Shift to spatial calibration/validation split
• -Calibrate upstream, validate downstream

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Revised calibration validation sites
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Lower Guadalupe River
Los Gatos Creek
Canoas Creek
Ross Creek
Upper Guadalupe River
Guadalupe Creek
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Extended simulation period
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Added urban irrigation
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Revised imperviousness estimates
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Adjusted meteorological segmentation
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Re-evaluated calibration parameters model
parameterization
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7 model segments
12 model segments
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Example result of model revisionsRoss Creek
flow with Vasona Alamitos precipitation
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Compare model versions - Annual flow volumes for
Guadalupe River
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Old version (v1)
New version (v2)
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Compare model versions - Observed versus
simulated daily flow for Guadalupe River
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Old version (v1) WY 2003-2007
New version (v2) WY 1995-2007
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Compare model versions - Hourly flow for
Guadalupe River
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Sediment model development Data needs for
parameterization calibration
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• Target sediment loading rates

Sediment production rates estimated for land use
classes (tonnes/km2/yr)
Apply sediment delivery ratio
edge of stream inputs
D.R. 0.418Area-0.135 - 0.127

• Particle Size Distribution

Soil Texture map
Soil Texture clay/silt/sand
Fractionation ratio
Particle size distribution map
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Next time, calibrated SSC
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Next Steps
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• Calibrate sediment portion of model
• Extend model to Hg and PCBs
• Calibrate contaminant portion of model
• Deliverable
• Draft report by November SPLWG meeting