201• 529 • 5151www.hydroqual.com
SJR DWSC DO Modeling
HydroQual, Inc.Andy Thuman, P.E.
Laurie De Rosa
SJR Technical Working GroupMay 16, 2006
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SJR Models – Study AreaSJR Models – Study Area
Downstream DSM2-delta ECOMSED/RCA Tidal portion from
Vernalis to Jersey Island
Upstream DSM2-sjr Free-flowing portion
from Stevinson to Vernalis
Source: Kratzer, et al. (2004)
USGS WRI-03-4127
33
Model GridModel Grid
R2
R5
TBRSAN058
R4R3R1
44
Modeling EffortModeling Effort
Models calibrated/validated from 2000-2001 on a continuous basis
Hydrodynamic model includes tidal transport and calculation of temperature
Water quality model uses tidal transport and includes the following parameters: EC, BOD, DO, eutrophication (nutrients &
phytoplankton), TSS
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Model Calibration Period FlowsModel Calibration Period Flows
USGS Vernalis Gage
Model Period
Annual Average
Summer Average (J-S)
2001
1923-2002
66
77
88
DWSC Hydrodynamic ModelingDWSC Hydrodynamic Modeling
Hydrodynamic model calibration: Model output compared to observed stage,
flow & temperature Compares well with data and DSM2 output Reproduces daily temperature stratification Further work may be needed in the Turning
Basin & near Old River/Mossdale
99
Temperature CalibrationTemperature Calibration
1010Temperature CalibrationTemperature Calibration
2002 Data near R5 2001 Model near R5
1111
Flow CalibrationFlow Calibration
Increased Old River flow between Jun-Aug by 530 cfs
1212
DWSC Water Quality ModelingDWSC Water Quality Modeling
Water quality model calibration: Model output compared to observed DO,
BOD, nutrients, chl-a, TSS & EC Focus on reproducing low DO events,
stratification & algal dynamics Includes a sediment flux submodel Post-processor to view output (HIMS)
Including web-based viewer
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Light Extinction(Lehman, 2005)
Light Extinction(Lehman, 2005)
Ideally – light data with depth
Determine Ke using: I = Io e -KeH
Actuality – secchi depth data
Determine Ke using: Ke = 1.8/secchi
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Light Extinction RelationshipLight Extinction Relationship
Used coupled secchi, TSS & chla data to develop relationship (Di Toro, 1978)
Ke = 0.052NVSS + 0.174VSS + 0.031Chla VSS = 0.2TSS (based on Vernalis data) Ke = 0.0764TSS + 0.031Chla
Model calculates Ke as a function of modeled TSS and Chla
1515
Spatial VariationSpatial
Variation
Secchi depth increases in DWC (lower chla & TSS)
Decreased Ke in DWSC vs upstream SJR
1616
Algal StoichiometryAlgal Stoichiometry
Data from Vernalis Limited POC data in DWSC
Redfield ratios C/N = 5.7 (Data – 3.1) C/P = 41 (Data - 32)
C/Chl Range = 20-100 Data – 37, Lehman – 40
Used Redfield & C/Chl=40
1717
Other Model InputsOther Model Inputs
Solar radiation – CIMIS Lodi West 100-700 ly/d, variations due to weather events
Boundary Conditions: Upstream based on Vernalis Downstream based on Jersey & Potato Pt Internal sloughs based on river data
Atmospheric Reaeration Based on wind speed formula (Banks, 1975 &
Banks & Herrera, 1977)
1818
Hourly Wind Speed and KL at R&R IslandSource: DWR
2000
2001
1919
Model Settling/DepositionModel Settling/Deposition
Water column settling – 2.5 m/d Deposition to sediment – variable
DWSC: 0.25-0.5 m/d (higher in TB) SJR: 0-0.05 m/d w/ adjustments to assist in
TSS & chla calibration Settling rates set based on calibration
2020
Model ParametersModel Parameters
2121
Stockton RWCF EffluentStockton RWCF Effluent
2222
DWSC SOD Data & Model Output(Litton, 2003)
DWSC SOD Data & Model Output(Litton, 2003)
2323
DO & Chla CalibrationDO & Chla CalibrationVernalis (BC)
Mossdale
2424
R1
R2
2525
R3
R4
2626
R5
R6
2727
R7
R8
2828
Spatial DO & Chla Transects(June-October Average)
Spatial DO & Chla Transects(June-October Average)
2000 2001
2929
Spatial Nutrient TransectsSpatial Nutrient Transects
2000 2001
3030
DO Deficit Components (R5)DO Deficit Components (R5)
Source
Sink
Sink
Sink
Ka – SourceSOD - Sink
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SummarySummary
DWSC WQ Model calibration completed & final report issued (Task 4 – May 2006)
Provides finer temporal & vertical resolution than previous modeling studies
Stratification, diurnal variation, DO components Can be used to assess DO aeration device
impacts (e.g., location, spreading, benefit) Links upstream & downstream water quality
for assessing management alternatives
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RecommendationsRecommendations
Further testing of models to more recent DWSC data (hydro & WQ) Different flow regimes, DO levels, etc.
More detailed data/modeling of the Mossdale/Old River area of the SJR Algal growth between Vernalis & Mossdale
More information on carbon dynamics POC/DOC data, internal loads, DO effects
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RecommendationsRecommendations
Investigate algal dynamics (2 species) Studies have shown different algal species Include more than 1 species in model with different
algal growth dynamics May help Vernalis-Mossdale algal growth
Use models in adaptive management approach Use models (as currently calibrated) to investigate
potential controls while still collecting data & completing modeling to improve the effective use of the DWSC model as a management tool
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Questions & AnswersQuestions & Answers
Contact info:Andy Thuman
Laurie De RosaHydroQual, Inc.
Mahwah, NJ(201) 529-5151 x7184
[email protected]@hydroqual.com
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Light Extinction ComparisonLight Extinction Comparison