SJR DWSC DO Modeling HydroQual, Inc. Andy Thuman, P.E. Laurie De Rosa SJR Technical Working Group May 16, 2006

2 2 SJR 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

3 3 Model Grid R2 R5 TB RSAN058 R4 R3 R1

4 4 Modeling Effort Models calibrated/validated from 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

5 5 Model Calibration Period Flows USGS Vernalis Gage Model Period Annual Average Summer Average (J-S)

6 6

7 7

8 8 DWSC 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

9 9 Temperature Calibration

10 Temperature Calibration 2002 Data near R Model near R5

11 Flow Calibration Increased Old River flow between Jun-Aug by 530 cfs

12 DWSC 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) u Including web-based viewer

13 Light Extinction (Lehman, 2005) Ideally – light data with depth Determine Ke using:  I = I o e -KeH Actuality – secchi depth data Determine Ke using:  Ke = 1.8/secchi

14 Light Extinction Relationship Used coupled secchi, TSS & chla data to develop relationship (Di Toro, 1978)  Ke = 0.052NVSS VSS Chla  VSS = 0.2TSS (based on Vernalis data)  Ke = TSS Chla Model calculates Ke as a function of modeled TSS and Chla

15 Spatial Variation Secchi depth increases in DWC (lower chla & TSS) Decreased Ke in DWSC vs upstream SJR

16 Algal 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 =  Data – 37, Lehman – 40 Used Redfield & C/Chl=40

17 Other Model Inputs Solar radiation – CIMIS Lodi West  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)

18 Hourly Wind Speed and KL at R&R Island Source: DWR

19 Model Settling/Deposition Water column settling – 2.5 m/d Deposition to sediment – variable  DWSC: m/d (higher in TB)  SJR: m/d w/ adjustments to assist in TSS & chla calibration Settling rates set based on calibration

20 Model Parameters

21 Stockton RWCF Effluent

22 DWSC SOD Data & Model Output (Litton, 2003)

23 DO & Chla Calibration Vernalis (BC) Mossdale

24 R1 R2

25 R3 R4

26 R5 R6

27 R7 R8

28 Spatial DO & Chla Transects (June-October Average)

29 Spatial Nutrient Transects

30 DO Deficit Components (R5) Source Sink Ka – Source SOD - Sink

31 Summary 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

32 Recommendations 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

33 Recommendations 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

34 Questions & Answers Contact info: Andy Thuman Laurie De Rosa HydroQual, Inc. Mahwah, NJ (201) x7184

35 Light Extinction Comparison