1 guadalupe watershed model year 2 update presentation to splwg may 27, 2009 michelle lent, john...
TRANSCRIPT
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Guadalupe Watershed ModelYear 2 update
Presentation to SPLWG May 27, 2009
Michelle Lent, John Oram, Lester McKee
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• 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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Canoas Creek
Guadalupe Creek
Los Gatos Creek
Revised calibration &
validation sites:
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Upper Guadalupe River
Ross Creek
Lower Guadalupe River
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Extended simulation
period
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Added urban irrigation
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Revised imperviousness estimates
Land Use Type % T.I.A. % E.I.A. Residential - rural/estate 5 - 20 1 - 10 Residential - low density 20 - 45 10 - 32 Residential - med. density 45 - 70 32 - 60 Residential - high density 65 - 95 54 - 92 Commercial 85 - 95 79 - 92 Industrial 70 - 95 60 - 92 Public/Quasi-public 80 - 95 72 - 92 Park 10 - 30 4 - 18 Open space 2 0 Forest 0 0 Water/Wetland 0 0
E.I.A. = 0.15*(T.I.A.)1.14
(Alley and Veenhuis, 1983)
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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 revisions
Ross Creek flow with Vasona & Alamitos precipitation
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Compare model versions - Annual flow volumes for Guadalupe River
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Water Year
Prec (in)
Obs. Flow Volume (106 cf)
Sim. Flow Volume (106 cf)
% Diff. from Obs. Flow Volume
Rating Sim. Flow Volume (106 cf)
% Diff. from Obs. Flow Volume
Rating
2003 17.6 2,148 2,042 -4.9%Very good
2,342 9.0%Very good
2004 13.2 1,874 1,442 -23.1% Fair 1,828 -2.5%Very good
2005 20.5 2,590 2,431 -6.6%Very good
3,040 17.4% Fair
2006 16.3 4,474 4,371 -2.3%Very good
5,040 12.7% Good
2007 7.2 1,260 870 -30.9% Poor 1,027 -18.5% Fair
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
• Target sediment loading rates
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Natural AgriculturalLow Density
UrbanHigh Density
UrbanIndustrial
72 2,461 450 996 1,836
Sediment production rates estimated for land use classes (tonnes/km2/yr)
D.R. = 0.418*Area-0.135 - 0.127
Apply sediment delivery ratio
“edge of stream” inputs
• Particle Size Distribution
Soil Texture map Soil Texture % clay/silt/sand
Particle size distribution map
Fractionation ratio
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Next time, calibrated SSC…
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Next Steps
• Calibrate sediment portion of model• Extend model to Hg and PCBs• Calibrate contaminant portion of model
Deliverable
Draft report by November SPLWG meeting
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