201• 529 • 5151www.hydroqual.com

SJR DWSC DO Modeling

HydroQual, Inc.Andy Thuman, P.E.

Laurie De Rosa

SJR Technical Working GroupMay 16, 2006

22

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

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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

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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

3333

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

athuman@hydroqual.comlderosa@hydroqual.com

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Light Extinction ComparisonLight Extinction Comparison