# DYNHYD5 HYDRODYNAMIC MODEL (VERSION 2.0) AND CHLORIDE WATER QUALITY MODEL FOR THE DELAWARE ESTUARY

DELAWARE RIVER BASIN COMMISSION WEST TRENTON, NEW JERSEY December 2003This report was prepared by the Delaware Ri v e r Basin Comm i ssion staff: Carol R. Collier, Executive Director. Dr. Nam s oo S. Suk was the principal author of the report. Dr. Suk is a Water Resources Engineer/Modeler in the Modeling and Monitoring Branch of the Comm i ssion. Significant technical recomm e ndations and support were provide d by Scott C. Hinz and Dr. Victor J. Bierm an, Jr. of LimnoTech, Inc., and Dr. Thom as J. Fikslin, head of the Modeling and Monitoring Branch of the Comm i ssion. Overall technical guidance and comm e nts were provided by the PCB Model Expert Panel established by the Comm i ssion. The current and form er m e m b ers of the PCB Model Expert Panel during the m odel developm ent process are (in alphabetical order): Robert B. Am brose, USEPA; Dr. Joel Baker, Univer sity of Mary lan d ; Dr. Steven C. Chapra, Tufts University ; Dr. Steven Eisenreich, Rutgers University ; Dr. Kevin Farley , Manhattan College; Dr. Ro l l a nd Hemm e tt, USEPA Region II; Dr. Jam es L. Martin, Missi ssippi State Universi ty ; Dale Rushneck, Interface Inc.; and Dr. Lisa Totten, Rutgers University

. The efforts of the following persons and organizations are gratefully acknowledged (in alphabetical order): Steve Bearer, intern of the Comm i ssion provided editorial effort. Gail R. Blum of the Comm i ssion com p iled and provide d water tem p erature and specific conductance data. Gregory J. Cavallo and John R. Yagecic of the Comm i ssion com p iled and provided flow data. Richard W. Greene of DNREC provided chloride data for the C &D Canal. Dr. Shih-Long Liao of the Comm i ssion provided technical support. Patricia McSparran of the Comm i ssion retr ieved and com p iled the PCS flow data. Karen Reavy of the Comm i ssion provided all the GIS works in this docum ent. Edward D. Santoro of the Comm i ssion provided chloride m onitoring data. Robert D. Schopp of USGS provided tidal he ights data of Burlington, NJ station. Dr. Christopher K. Somm e rfield of University of Delaware provided current velocity data. Dr. David Velinsky of the Academy of Natural Scie nces provided chloride data in Schuy lkill River. Dr. Kuo-Chuin Wong of University of Delaware and Dr . William C. Boicourt of the University of Mary land shared their knowledge on C & D Canal hy drody nam i cs through personal comm unications.EX ECUTIVE SUMMARY A new hy drody nam i c m odel was needed as a part of the developm ent of Stage 1 TMDLs for poly c hlorinated bipheny ls (PCBs) for the Delaware River Estu ary . The downstream boundary of the existing DYNHYD5 hy drody nam i c m odel (Version 1.0) was updated to establish a hy drody nam i c and m ass transport link to the ocean boundary

. High resolution of Zone 6 would require a m o re com p rehensive data collection effort and result in unacceptable increases in sim u lation ti m e . Alternatively , introducing nine junctions to represent Zone 6 allowed for im proved sim u lations, r esulting from this linkage to the ocean boundary , while m i nim i zing im pacts to sim u lation tim e and m odel stability

. Furtherm ore, since PCBs TMDLs to be derived using this hy drody nam i c m odel applies only to Zones 2 through 5, a m o re coarse represent a t i o n in Zone 6 was acceptable. The newer version of the hy drody nam i c m odel (Version 2.0) exte n d s t h e d o w nstream boundary to the m outh of the Delaware Bay (Zone 6) , and consists of 105 j unctions and 111 channels. The concept o f a r o l l i ng calibration was used. In rolli ng calibration, as m o re data becom es available, the sim u lation period of the m odel is se quentially extended, and the m odel is re-calibrated to the expanded data set for each extension. The final calibration cove rs the period from Septem ber 1, 2001 to March 31, 2003, which is19 m onths or 577 day s . The tidal datum for the C&D Canal, Chesapeake City , MD , was m odified to correctly sim u late the m a gnitude and the am ount of net flow through the C&D Can a l

. Version 2.0 DYNHYD5 hy drody nam i c m odel was calibrated again s ttidal heights to ensure that th e m odel correctly sim u lated the advective water m ass m ovem e nts within the Estuary

. The sim u lated tidal heights were com p ared with the hourly observed tidal heights at six locations along the Estuary

. Linear regression y i elded slopes ranging from 0.945 to 1.027, and intercepts ranging from -0.087 to 0.035 with R-square d values of 0

. 9 3 0 to 0.994, respectively

. The cum u lative frequency distribution com p ariso n s sh o w ed good agreem ent between the sim u lated and the observed tidal heights throughout the ranges of the tidal heig h t s. Lastly , tem por al com p arisons confirm e d that the m odel reasonably sim u lated both the am plitudes and the phases of the tidal heights throughout the calibration period. The predicted current velocities we re also co mp ared wi th the lim ited observed data to further confirm the Model. Based upon these resu lts, the DYNHYD5 hy drody nam i c m odel for the Delaware Ri v e r E s tu ary (Version 2.0) correctly generates the advective m ovem e nt of the water m ass throughout the Delaware Estuary for the entire calibration period. A T OXI5 (water quality ) m odel consisting of 87 water columnsegm e nts was then linked with the outputs from the calibrated DYNHYD5 hy drody nam i c m odel and calibrated against the chloride concentrations. The m a in objective in this calibration process was the determ ina tion of an advection factor and a set of dispersion coefficients for the water quality m odel to co rrect l y sim u late the dispersive m i xing within the Estuary

. Review of com p arison plots and the results o f r e g r e s s i o n analy ses indicated that the m odel was able to reproduce the tem poral and spatial trends, and the ma gnitude of the chloride concentrations, within a reasonable range throughout the tidal portion of the Delawa re River. It was therefore concluded that the calibrated m odel properly sim u lates the advective and di spersive m ovem e nt of the chloride for the entire Estuary
. Even though Version 2.0 of the DYNHYD5 hy drody nam i c m odel for the Delaware River Estuary could be further enhanced with additional data collection and refinem e nts, the calibrated m odel d e mo n s trates the capability to accurately sim u late the advective and disp ersive m ovem e nt of a conservative substance in the Delaware River Estuary over a wide range of hy drologic conditions.TABLE OF CONTENTS
1. INTRODUCTION

................................................................. 1 1.1 Background

............................................................... 1 1

. 2 S tu dy O b j e c t i v e s ........................................................... 2 2

. C O N C E P T U A L A P P R O A C H F O R T H E M O D E L C A L I B R A T I O N
......................... 2 2

. 1 C o n s tr a i n t s f o r th e E x t e n s i o n o f th e M o d e l S e g m e n t s .............................. 3 2

. 2 C o n c e p t o f th e R o l l i n g C a l i b r a t i o n an d th e C a l i b r a t i o n P e r i o d

....................... 3 3

. O V E RV I E W O F T H E M O D E L S

..................................................... 3 3.1 Overview of DYNHYD5 Hy drody nam i c Model

.................................. 3 3

. 1

. 1 G o v e rn i n g E qu at i o n s ............................................... 3 3

. 1

. 2 M o d e l N e tw o rk

.................................................... 5 3

. 2 O v e rv i e w o f T O X I W A S P 5
................................................... 5 4. CALIBRATION OF THE HYDRODYNAMIC MODEL

.................................. 6 4

. 1 M o d e l B ath y m e try an d G e o m e try .............................................. 6 4

. 1

. 1 B ath y m e try ....................................................... 6 4

. 1

. 2 M o d e l G e o m e try an d th e S e g m e n t a t i o n ................................. 6 4

. 2 D at a C o m p i l at i o n ......................................................... 1 7 4

. 2

. 1 T i d a l H e i g h t
..................................................... 1 7 4

. 2

. 2 I n f l o w s ......................................................... 1 8 4

. 2

. 3 C urr e n t V e l o c i ty .................................................. 1 9 4.3 Calibration of the DYNHYD5 Hy drody nam i c Model

............................. 2 0 4

. 3

. 1 C o d e M o d i f i c at i o n ................................................ 2 0 4.3.2 Assignm ent of Open Boundaries With Forcing Tides and the Com putational Tim e Step

............................................................. 2 0 4

. 3

. 3 D e t e rm i n at i o n o f M an n i n g ’ s C o e f f i c i e n t s .............................. 2 0 4

. 3

. 4 I n f l u e n c e o f th e C & D C an a l

......................................... 2 2 4

. 4 C a l i b r a t i o n R e s u l t s ........................................................ 2 6 4

. 4

. 1 C o m p ar i s o n s w i th C urr e n t V e l o c i ty ................................... 2 6 4

. 4

. 2 C a l i b r a t i o n R e s u l t s o f th e T i d a l H e i g h t s ................................ 2 7 5 CALIBRATION OF WATER QUALITY (CHLORIDE) MODEL

........................... 3 0 5.1 Water Quality Model Segm entation

........................................... 3 0 5.2 Data Com p ilation and Processes

.............................................. 3 2 5.2.1 DRBC (BoatRun) Monitoring Data

................................... 3 2 5.2.2 USGS Continuous Monitoring Stations

................................ 3 2 5.2.3 Other Sources of Data

.............................................. 3 2 5.2.4 Data Process

..................................................... 3 3 5.3 Calibration of the Chloride Water Quality Model

................................ 3 6 5.3.1 Assignm ent of the Boundary Conditions

............................... 3 6 5.3.2 Determ ination of the Advection Factor (ADF) and Dispersion Coefficients

............................................................. 3 6 5
. 4 C a l i b r a t i o n R e s u l t s o f C h l o r i d e C o n c e n tr a t i o n s .................................. 3 8 5.4.1 Com p arison with the DRBC Data

..................................... 3 8 5
. 4

. 2 C o m p ar i s o n w i th U S G S D a t a ........................................ 4 0 6

. F U T U R E R E F I N E M E N T S

......................................................... 4 57 REFERENCES

................................................................... 4 6 A P P E N D I X
....................................................................... 4 8 A. Input File of the Calibrated DYNHYD5 Hy drody nam i c Model (Version 2.0)

.......... A 1 B. Input File of the Calibrated Water Quality (chloride) Model

......................... B 1 C. Calibration Results of the DYNHYD5 Hy drody nam i c Model for the Delaware River Estuary

.................................................................... C 1 D. Calibration Results of the Water Quality (chl oride) Model for the Delaware River Estuary

.................................................................... D 1LIST OF TABLES

T a b l e 4

- 1 : S u mm ary o f th e j un c t i o n d a t a . ........................................... 1 3 T a b l e 4

- 2 : S u mm ary o f th e c h an n e l g e o m e tr y . ....................................... 1 5 Table 4-3: Summ ary of available water surface elevation data from NOAA and USGS for the Delaware R i v e r E s tu ary . ........................................................ 1 8 Table 4-4: The d i rectio n an dmag n itu d e o f th e si m u lated, long-term net flow in C&D Canal with various am ount of datum shift

. ........................................... 2 5 Table 4-5: The summ ary of the r e g r ession results between the observed data and the sim u lated tidal h e i g h t s . .............................................................. 2 7LIST OF FIGURES
Figure 1-1: Water Quality Zones of the Delaware River Estuary

. ........................... 1 Figure 4-1(a): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2

. 0 ) : Z o n e 2

........................................................... 7 Figure 4-1(b): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2

. 0 ) : Z o n e 3

........................................................... 8 Figure 4-1(c): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2

. 0 ) : Z o n e 4

........................................................... 9 Figure 4-1(d): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2

. 0 ) : Z o n e 5
.......................................................... 1 0 Figure 4-1(e): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2

. 0 ) : Z o n e 6

.......................................................... 1 1 Figure 4-1(f) : Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0) for all Zones: Boundaries are m arked in red colored letters and drinking water intakes ar e m ark e d i n g r e e n c o l o r e d l e tt e r s . ........................................ 1 2 F i g ur e 4

- 2 : M a p o f l o c at i o n s o f th e t i d e g a g e s t a t i o n s i n th e D e l aw ar e R i v e r E s tu ary . ......... 1 7 Figure 4-3: Daily average flow for the Delaware Ri ver at Trenton during the m odel calibration period.

.................................................................... 1 9 Figure 4-4: Assigned Manning’s coeffici en t s fo r the m a in channel of the m odel segm e nts. Only the m a i n s t e m o f th e D e l aw ar e E s tu ary i s s h o w n . ................................ 2 1 Figure 4-5: Tem poral variations of the sim u lated chlo ride at RM 54 related to the inflows at Trenton.

.................................................................... 2 3 Figure 4-6: Tem poral variations of the sim u lated and the observed chloride concentration at RM 54.

.................................................................... 2 3 Figure 4-7: Sensitivity sim u lation results: Imp act on chlo ride concentrations by the datum shift at the Chesapeake City

. ...................................................... 2 4 Figure 4-8: Com p arison between th e o b served and the si m u lated current velocity : (a) Spatial plot; (b) Linear regression results

. ................................................ 2 6 Figure 4-9: The observed and the sim u lated tidal height s at Reedy Point (River Mile 5 8

. 6 ) : (a) fo r the entire calibration period; (b) from the period March 10, 2003 to March 31, 2003

. .... 2 8 Figure 4-9: The observed and the sim u lated tidal hei g h t s at Reedy Point (River Mile 58.6): (c) Linear regression results (n=13,777); (d) cum u lative frequency distribution curve

. ........ 2 9Figure 5-1: Schem atic diagram of the segm e ntation for the water quality m odel

. .............. 3 1 Figure 5-2: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlori de data at the Reedy Island station

. ...... 3 4 Figure 5-3: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlo ride data at the Chester station

. ........... 3 4 Figure 5-4: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlori de data at the Fort Mifflin station

. ....... 3 5 Figure 5-5: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlori de data at the Ben Franklin station

. ...... 3 5 Figure 5-6: Assigned dispersion coefficients for the water quality m odel. The m a in stem of Delaware E s tu ary i s o n l y s h o w n i n th e s c h e m a t i c . .................................... 3 7 F i g ur e 5

- 7 : C u mu l a t i v e f r e qu e ncy distributions o f the observed and the simu lated chloride c o n c e n tr a t i o n s : D at a f r o m th r e e s e g m e n t s (N o d e 2 , 1 2 an d 1 7 ) w e r e c o m b i n e d

. ..... 3 8 Figure 5-8: Spatial com p arison between the observed data (DRBC_BoatRun) and the sim u lated chloride concentrations throughout the Estuary

. ..................................... 3 9 Figure 5-9: Tem poral com p arison between the observed data (derived from specific conductance from USGS Fort Mifflin Station) and the sim u lated chloride concentr a tions for (a) entir e sim u lation period; (b) first week of Septem ber 2002

. .......................... 4 1 Figure 5-10: Tem poral com p arison between the observed data (derived from specific conductance from USGS Chester Station) and the sim u lated chlo ride concentrations for (a) entire sim u lation period; (b) first week of Septem ber 2002

. ................................... 4 2 Figure 5-11: Tem poral com p arison between the observed data (derived from specific conductance from USGS Reedy Is. Station) and the sim u lated chlo ride concentrations for the calibration period

.................................................................... 4 3 Figure 5-12: Tem poral com p arison between the observed data (derived from specific conductance from USGS Reedy Is. Stat i o n ) a n d the sim u lated ch loride concentrations for the first week of Septem ber, 2002

. ...................................................... 4 3 Figure 5-13: Linear regression results bet w e e n derived and sim u lated chloride concentrations at Reedy I s . U S G S s t ation ( n = 1 3,660). Both datas e t s w e r e hour ly tim e inte rv a l thr oughout the c a l i b r a t i o n p e r i o d

. ..................................................... 4 4 F i g ur e 5

- 1 4 : Cu mu lative frequency distributions of the observed and the simu lated ch lo rid e c o n c e n tr a t i o n s f o r th e R e e dy I s l an d s t a t i o n . ................................. 4 41. INTRODUCTION 1.1 Background A new hy drody nam i c m odel was needed as a part of the d e v e lo pm ent of Stage 1 TMDLs for the poly c hlorinated bipheny ls (PCBs) for the Delaware Ri ver Estu ary . Even though the developm ent of the TMDLs for PCBs only covers Zones from 2 to 5 of the tidal portion of the Delaware River, the need to set the downstream boundary at the m outh of th e Delaware Bay was inevitable (Figure 1-1). The purpose of inclusion of the Bay area or the setting the downstream boundary at the mo u t h o f th e b a y is to generate realistic boundary conditions betweenZones 5 and 6. Delaware River Basin Comm i ssion (DRBC) currently m a intains two hy drody nam i c m odels. One is DYNHYD5 (DRBC, 1995) and the other is ECOM (Hy droQual, Inc., 1998). The d o w n s tream boundary for both of the m odels were set at the head of the Delaware Bay (Liston Point, DE at River Mile 49). The biggest difference between two m odels are the m odel dim e nsions. The DYNHYD5 m o d e l i s basically a one dim e nsional m odel with available branching to sim u late around the islands, and the E C OM is a z-level, three-dim e nsional m odel. The DYNHYD5 hy drody nam i c m odel was linked with the water quality m odel (TOXI5) to develop the Total Maxim u m Daily Loads (TMDLs) for the volatile organic compounds in 1998 (DRBC, 1998a; 1998b). The DYNHYD5 m odel was chosen to be updated and used as a hy drody nam i c m odel for the Stage 1 TMDLs for PCBs because of the lim ited data availability and the well known character istics of the relatively well m i xed Delaware Estuary sy stem (Wong and Garvine, 1984). The existing DYNHYD5 m odel was renam e d for Versi on 1.0 and the newly developed DYNHYD5 is nam e d Version 2.0 of the DYNHYD5 hy drody nam i c m ode l for the Delaware River Estuary

.

Figure 1-1: Water Quality Zones of the Delaware River Estuary

. 

### 1The segm e ntat i o n o f the existing DYNHYD5 hy drody nam i c m odel has been extended to include the Delaware Bay (Zone 6) in this versio n of the DYNHYD5 hy drody nam i c m odel (Version 2.0). In addition to the extension to the m outh of the Bay , one of th e m a jor differences in this newly developed hy drody nam i c m odel is the length of the calibration period. Versi on 1.0 was calibrated over nine day s and validated over six day perio d wh ile Version 2.0 w as calibrated over 19 m onths (577 day s ) covering wide range of flow conditions. 1.2 Study Objectives As described in the Section 1.1, the hy drody nam i c and water quality m odels were requiredt o b e ex t e nded to the m outh of the Delaware Bay to obtain the bette r t e mp o r a l a n d spatial gradients of the chem icals of concern for the rest of the Estuary

. The m a jor objectives for this study are described below. 1. Developm ent of the m odel segm e ntation to cover the Zone 6 of the Delaware Bay

. 2. Calibration of the hy drody nam i c m odel against the tidal heights to ensure that the m odel correctly sim u lates the advective water m ovem e nts within the Estuary

. 3. Calibration of the water quality m odel, linked with hy drody nam i c m odel, against chloride to ensure that the m odel sim u lates the dispersive m ovem e nt properly

. 2. CONCEPTUAL APPROACH FOR THE MODEL CALIBRATION Th e calibration of the hy drody nam i c m odel basically re quires two steps followed by a link with the w a t e r quality m odel to com p lete the calibration process. The detailed description of the two step calibration approach is discussed in this section. Step 1 The DYNHYD5 m odel w a s c a l i b r a t e d against tidal heights. The hy drody nam i c m odel was set up with all the forcing tides at the open boundaries and inflo w s from the tributaries and discharges. Groups of Manning’ s coefficients were determ ined to obtain the b est m a tch with the observed tidal heights at the gaging stations. Because of the lack of velocity data, the current velocities were not a calibration param e ter in this calibration process. Rather, the current velocities and flows were checked and conf i rmed u s i n g best professional judgem e nt and the lim ited available data. At the end of this process, the advective m ovem e nts are set and calibrated. Step 2 Once the hy drody nam i c m odel is calibrated, the outputs of the calibrated hy drody nam i c m o d e l are then linked with the water quality m odel as a part of the hy drody nam i c m odel calibration process. The m a in purpose of this process is to set the proper dispersion coefficients and also to find the proper com putational tim e step of the water quality m odel. It was alm o st inevitable th at certain levels of t h e n u m erical dispersions were introduced into the water quality m odel because of the size of the segm e nts and the com putational tim e step. Dispersion coefficients and the advection factor were adjusted until the water quality m odel results were well m a tched with known, spatially and tem porally vary ing, observed conservative c h em ical concentrations. Like m any other estuary m odel calibrati on proces s e s , c h l o ride (or salinity ) concentrations were used as a calibration param e ter. The m a jor sources of chlo ride were the two open boundaries. The dispersion coefficients between segm e nts and an advection factor were then adjusted to obtain the best fit wit h the observed data sets. Calibrated dispersion coefficients and the advection factor were thus established at the end of this step. Utilizing the hy drody nam i c m odel results along with these dispersion coefficients properly 

### 2sim u lated both the advective and dispersive m ovem e nt of the chem icals of concern in the water column . Iterative approach using step one and two m i ght be required to finalize the hy drody nam i c m odel calibration, which was the case for this study

. 2.1 Constraints for the Extension of the Model Segments Version 1.0 of the DYNHYD5 h y drody nam i c m odel c onsists of 94 junctions and 100 channels. The downstream boundary was extended to the m outh of the De laware Bay (Zone 6) in the newer version of the hy drody nam i c m odel. The extended m odel com p rises a total of 105 junctions and 111 channels. A num ber of constraints were considered in this m odel dom ain exte nsion. The m a jor constraints of the inclusion of the Delaware Bay into the m odel dom ain are the stabilityof the m odel, the data availability , and overall sim u lation tim e. Because the PCB water quality m odel w ill have additional sedim ent lay e rs, and there is a slower interaction between sedim ent lay e r and water co lumnchem ical exchanges, the overall sim u lation tim e was one of the critical elem ents in determ ining th e num ber of extended portions of the m odel segm e nts. Because the purpose of the inclusion of the Delaware Bay was to generate reasonable tem poral variations of chem ical concentrations at the intersection of the Zon es 5 and 6, it was not required to have a relatively fine scale of segm e ntation in Zone 6. It was determ ined th at nine segm e nts would cover the Zone 6. This coarse segm e ntation will fulfill the m a in purpose of this work while m i nim i zing the overall com putational tim e in both hy drody nam i c and water quality m odel sim u lations. 2.2 Concept of the Rolling Calibration and the Calibration Period The newly segm e nted hy drody nam i c m odel was then calibrated against tidal heights and chloride by utilizing the water quality m odel over a longer tim e period than u sed with Version 1.0. The final calibration covers the period from Septem ber 1, 2001 to March 31, 2003, whic h lasted for 19 m onths or 577 day s . The concept of rolling calibration was used. In rolling calibration, as m o re data becom es available, the sim u lation period of the m odel is sequentially extended, and the m odel is re-calibrated or va lidated to the full available data set for each extension. Thus, rather than splitting the tim e period for the m odel calibration and validation period, a longer and single tim e period was used as a calibration tim e period. In consequence, a num ber of sensitivity runs perform ed before March 31, 2003 did not cover the whole calibration tim e period.
3. OVERVIEW OF THE MODELS 3.1 Overview of DYNHYD5 Hydrodynamic Model The DYNHYD5 h y d r o d y n a m i c m odel solves the one dim e nsional equations of continuity and m o m e ntum for a branching or ch an n e l-junction (link-node), com putational network. The resulting unsteady hy drody nam i cs are averaged over larger tim e intervals and stored fo r l a t e r u s e by the water quality m odel (Am b rose et. al., 1993a). 3.1.1 Governing Equations Even though m o re detailed descriptions of the gove rning equations for the DYNHYD5 hy drody nam i c m odel are available from the User’s Manual (Am b rose et. al, 1993a), a num ber o f key equations are listed in this section to help understand the DYNHYD5 m odel. Th e hy drody nam i c m odel solves one-dim ensional equations describing the propagation of a long wave through a shallow water sy stem while conserving both m o m e ntum and volum e. The equation of m o tion, based on the conservation of m o m e ntum , predicts water 

### 3velocities and flows. The equation of continuity , based on the conservation of volum e, predicts water heights (heads) and volum es. This approach assum es that flow is predom inantly one- dim e ns ional, Coriolis and other accelerations norm a l to the direction of flow are neg ligible, channels can be adequate l y represented by a constant top width with a variable hy draulic depth, wave length is significantly greater than the depth, and that bottom slopes are m oderate. 3.1.2.1 The Equation of Motion The equation of m o tion is given by : 

### ∂ U ∂ U ∂ t = − U ∂ x + a g , λ 

### + a f 

### + a w , λ where, 

### ∂ U ∂ t = the local inertia term , or the velocity rate of change with respect to tim e, m / sec 2 

### ∂ U U ∂ x = the Bernoulli acceleration, or the rate of m o m e ntum change by m ass transfer; also defined as the conservative inertial term from Newton’s second law, m / sec 2


## a g , λ = gravitational acceleration along the λ axis of the channel, m / sec 2


### a f = frictional acceleration, m / sec 2 

## a w , λ = wind stress acceleration along axis of channel, m / sec 2
x = distance along axis of channel, m t = tim e, sec U = velocity along the axis of channel, m / sec λ = longitudinal axis Gravitational acceleration is driven by the slope of th e water surface. The acceleration along the longitudinal axis is 

## a g , λ 

## = − g sin S where, g = acceleration of gravity = 9.81 m / sec 2 S = water surface slope, m /m with sm all water su rface slope (S), the term [ s in S] can be replaced with S. The slope can be expressed as the water su r f ace elevation changes along the distance of the channel. The gravitational acceleration term can be now expressed as: 

### ∂ H a g , λ 

### = − g ∂ x where, H = water surface elevation, or head (height above an arbitrary datum ) , m


### 4The frictional acceleration term can be expressed us ing the Manning equation for steady uniform flow: / 

### R 23 

### ∂ H 1 / 2 

### U = n ∂ x where, R = hy draulic radius (approxim ately equa l to the depth for wide channel), m n = Manning roughness coefficient, sec/m 1/3 

### ∂ H ∂ x = the energy gradient, m /m
The wind effect was not considered in the hy drody nam i c m odel calibration for the Delaware River Estuary

. 3.1.2.2 The Equation of Continuity The equation of continuity is given by : 

### ∂ A
= − ∂ Q ∂ t ∂ x where, A = cross sectional area, m 2 Q = flow rate m 3 /sec For rectangular channels of constant width B, the equation of continuity can be expressed as: 

### ∂ H
= − 1 ∂ Q ∂ t B ∂ x where, B = width, m H = water surface elevation (head), m 

### ∂ H ∂ t = rate of water elevation change with respect to tim e, m / sec 

### 1 ∂ Q B ∂ x = rate of water volum e change with respect to distance per unit width, m / sec
3.1.2 Model Network The solutions of the equations give velocities (U) and heads (H) throughout the water body over the duration of the sim u lation. The “link-node (or channel-j unction)” network solves the equations of m o tion and continuity at alternating grid points. At each tim e st ep, the equation of m o tion is solved at the links, giving velocities for m ass transport calculations, and the equation of continuity is solved at the nodes, giving heads for pollutant concentration calculations. 3.2 Overview of TOXIWASP5 (see DRBC, 2003a, b, c; Am brose et. al., 1993b, c; for the detailed m odel description)


### 54. CALIBRATION OF THE HYDRODYNAMIC MODEL 4.1 Model Bathym etry and Geom etry 4.1.1 Bathy m etry The bathy m etry data for the extended portion was dow nloaded from the National Ocean Service (NOS) web site (http://spo.nos.noaa.gov/servlet/BuildPa ge?tem plate=bathy

. txt&parm1 = M090 )

. This hy drographic inform ation for the Zo n e 6 was established using the Digital Elevation Model (DEM) and GIS. The downloaded bathy m etry data was based on the m ean low water (MLW) datum whereas, the existing m odel’ s datum was National Geodetic Vertical Datum of 1929 (NGVD1929). Because of lack of a inform ation on the relationship between MLW and NGVD29 for the Bay area, lim ited station inform ation w a s u s e d to convert the datu m o f the downloaded bathy m etry to NGVD29 datum

. Another note to the downloaded bathy m etry data was that the bathy m etry data were derived from seventeen hy drographic survey s conducted between 1945 and 1993. On the other hand, the existi ng m odel’s bathy m etry was derived from single shore to s hor e s urv e y pe r f o rm e dby U

. S. A rmy C o r p s of Engine e r s ( U SA C E ) in la te 1980s to e ar ly 1990s. The bathy m etry data for the Version 2.0 of the h y drody nam i c m odel was from the USACE for the Zones 2 through 5 and from the NOS for the Zone 6. 4.1.2 Model Geom etry and the Segm entation The newer version of th e h y d r o d y n a mic m odel exte nds the downstream boundary to the m outh of the Delaware Bay (Zone 6), and consis ts of 105 junctions and 111 channels

. The m i nim a l num ber of junctions were added to represent the Zone 6 of the Delaware River Estuary to im prove the sim u lation results and to m i nim i ze im pacts on the overall com putational tim e. Minor m odifications were also perform ed to junctions and channels of the Versi on 1.0 m odel to im prove the m odel stability

. Most of the num bering sy stem s were ke pt to m a intain the com p arability between the m odels. One of m odifications in Version 2.0 m odel was the a ddition of boundary junctions fo r all four drinking water intake withdrawals. By assigning the boundary junctions for the intake withdrawals, the m ass of chem ical of concern would be withdrawn along with the wate r m ass in the hy drody nam i c and water quality m odeling. Another m odification to the Version 1.0 hy drody nam i c m odel was the re l o c a t i o n o f the Chesapeake and Delaware Canal (C&D Canal) downstream boundary

. The downstream boundary for th e C&D Canal was at the Old Town Point Wharf, MD in the earlier versi on of the m odel. In this version, the boundary was m oved about 9 km east from the Old Town Point to the Chesapeake City , MD for several reasons. First, the Chesapeake City location has a mo r e c o n f i n e dchannel configuration com p ared to the location at the Old Town Point Wharf, which is potentially influenced by the Elk River. Second, tidal heights were not gaged for both o f the locations, rather, relationships to estim ate the tidal heights for both locations were already developed by NOAA. The tidal heights for the Old To wn Point Wharf were derived from the observed tidal heights at Baltim ore, MD, which is over 80 km away . Whereas, t h e t i d al h e i g hts for the Chesapeake City w e r e d e r i v e df r o mth e R e e dy I s l an dS t at i o n ’ s o b s e rv e dd a t a , w h i c h is only about 2 1 kma p art
. T h e r e f o r e , Chesapeake City would be based on m o re accurate tidal he ight calculations. Junctions and channels of the C&D Canal were redefined, while the total num ber of segm e nts and the num bering sy stem rem a ined sam e as the Version 1.0 Model. The finalized segme n t a t i o n f o r

the Version 2.0 of the DYNHYD5 hy drody nam i c m odel for each Zone is presented in Figure 4-1 (a) to (e). The schem atic di agram of segm e ntation for the entire Delaware Estuary is presented in Figure 4-1 (f). The individual junction in form ation for the m odel input is summ arized in Table 4-1 and the channel geom etries are summ arized in Table 4-2. 

### 6Figure 4-1(a): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0): Zone 2 

### 7Figure 4-1(b): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0): Zone 3 

### 8Figure 4-1(c): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0): Zone 4 

### 9Figure 4-1(d): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0): Zone 5 

### 10Figure 4-1(e): Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0): Zone 6 

### 11RM Tr e n t o n RM
133. 3 132. 0 130. 6 129. 0

67

53

41 39 37 35

21 20 18 19 13 14 90 76 75 74 72 71 70 69 68

64 63 62

55

2 60 59 58 56

51 49 48 44 43

38 42

23 36

77 34 33 32 31 66

52

22

12 78 11 25 24

92

95 96 97 17 102

100 98 99 101 73 89 C r os s w ic k s 127. 3 124. 9 L o w e r Bu ck s I n tak e 105 122. 6 120. 7 Bri s t o l & Bur l i n gt on I n t a k e 104 118. 6 119. 0 

### Zo n e 2 Nes h am iny 8 8 65 116. 8 115. 0 113. 2 61 87

57 8 6
54 85 T o rre s d ale I n tak e 103 111. 5 R a n c oca s 109. 5 107. 8 105. 4 P e nskn 104. 0 

### Zo n e 3 101. 6 101. 7 C ooper 99. 4 96. 9 50 84 Ne wt on 95. 5 S c huylk i ll 8 3 47 46 45 92. 3 89. 7 87. 7 87. 0 

### Zo n e 4 Darby 8 2 40 86. 5 84. 8 82. 2 82. 0 81. 0 93 94 R a c c oon 80. 0 81 30 8 0 29 28 27 26 Br an dyw i n e 77. 3 75. 1 72. 2 Ch r i sti n a 70. 8 

### Zo n e 5 68. 1 65. 5 63. 0 60. 6 60. 6 60. 2 60. 1 C& D Ca n a l 9 1 1 4 5 6 7 8 9 1 0 3 58. 6 58. 7 15 16 79 S a lem 54. 9 53. 3 51. 9 50. 5 48. 3 46. 9 45. 0 42. 6 39. 6 35. 8 28. 7 

### Zo n e 6 18. 6 13.5 8. 0 1. 2 M o uth o f B ay Figure 4-1(f) : Schem atic diagram of the segm e ntation for the DYNHYD5 hy drody nam i c m odel (Version 2.0) for all Zones: Boundaries are m arked in red colored letters and drinking water intakes are m arked in green colored letters. 

### 12Table 4-1: Summ ary of the junction data.
Node No. River Mile Surface Area (m 2 ) Bottom Elevation a (m) 1 58.6 558800 -8.64 2 48.3 11926900 -5.54 3 58.6 438900 -8.64 4 58.6 375980 -8.91 5 58.6 336160 -9.18 6 58.6 429880 -9.23 7 58.6 523600 -9.28 8 58.6 583660. -9.24 9 58.6 664180. -9.25 10 58.6 685410. -9.23 11 51.9 9341080. -5.52 12 54.9 12758070. -5.08 13 58.6 8766871. -6.45 14 58.7 5064157. -1.35 15 58.6 2351584. -2.18 16 58.6 6374031. -1.23 17 45.0 24912800. -5.07 18 60.2 5167297. -3.97 19 60.1 5177611. -1.33 20 60.6 6157438. -5.61 21 63.0 7034125. -2.14 22 63.0 10221140. -5.04 23 65.5 9519791. -5.59 24 68.1 7735475. -5.64 25 70.8 7384800. -5.99 26 70.8 660094. -5.01 27 70.8 587896. -2.29 Node No. River Mile Surface Area (m 2 ) Bottom Elevation a (m) 5 4 101.6 330047. -1.48 5 5 104.0 2898224. -6.41 5 6 105.4 2508300. -6.93 5 7 105.4 190491. -1.86 5 8 107.8 2487769. -7.40 5 9 109.5 2735115. -7.09 6 0 111.5 2526880. -6.46 6 1 111.5 693730. -3.18 6 2 113.2 2186401. -4.89 6 3 115.0 1672200. -7.19 6 4 116.8 1791112. -5.70 6 5 116.8 255475. -3.19 6 6 118.6 1435770. -8.05 6 7 119.0 417771. -3.29 6 8 120.7 1435770. -7.76 6 9 122.6 1219777. -7.16 7 0 124.9 1575120. -6.93 7 1 127.3 1672200. -6.74 7 2 129.0 1207700. -5.16 7 3 129.0 156351. -1.29 7 4 130.6 969504. -3.86 7 5 132.0 650300. -4.81 7 6 133.3 646500. -1.67 7 7 50.5 9839210. -5.22 7 8 53.3 8672718. -5.30 7 9 58.6 7173807. -1.68 8 0 70.8 8500. -1.20 

### 13Node No. River Mile Surface Area (m 2 ) Bottom Elevation a (m) Node No. River Mile
28 70.8 29 70.8 30 70.8 31 72.2 32 75.1 33 77.3 34 80.0 35 81.0 36 82.2 37 82.0 38 84.8 39 86.5 40 86.5 41 87.7 42 87.0 43 89.7 44 92.3 45 92.3 46 92.3 47 92.3 48 95.5 49 96.9 50 96.9 51 99.4 52 101.6 53 101.7 567268. 587896. 206279. 7993324. 7065067. 6704078. 5517972. 1897769. 3228271. 1165478. 4352494. 1392385. 515698. 1443955. 2980736. 4548459. 5507658 711663. 825117. 433186. 3733656. 2887910. 268163. 2722887. 2403154. 1340552. -1.20 8 1 70.8 -1.20 8 2 86.5 -3.24 8 3 92.3 -5.30 8 4 96.9 -5.93 8 5 101.6 -5.43 8 6 105.4 -5.83 8 7 111.5 -2.82 8 8 116.8 -8.32 8 9 129.0 -1.07 9 0 134.0 -5.46 9 1 58.6 -2.42 9 2 46.9 -2.80 9 3 82.2 -2.38 9 4 82.2 -6.46 9 5 39.6 -8.41 9 6 35.8 -7.17 9 7 28.7 -7.43 9 8 18.6 -7.21 9 9 8 .0 -5.13 100 13.5 -6.42 101 1.2 -10.67 102 42.6 -1.87 103 111.5 -8.95 104 118.6 -6.70 105 122.6 -1.67 Surface Area (m 2 ) Bottom Elevation a (m) 11900. -3.24 9100. -2.80 16900. -5.13 5100. -1.87 9100. -1.48 9100. -1.86 18300. -3.18 10200. -3.19 10200. -1.29 26300. -1.67 655600. -8.25 14443000. -5.01 433547. -1.87 495482. -1.87 45906200. -5.51 86887700. -5.02 286164000. -4.24 401974000. -5.79 462987600. -8.83 335131600. -2.64 92928860. -12.57 31825000. -5.32

10000. -6.50 10000. -6.50 10000. -6.50

a- The datum for the bottom elevations was NGVD1929.



### 14Name Channel No. Length meter C&D 1 2093 MAIN 2 1889 C&D 3 1528 C&D 4 1528 C&D 5 2380 C&D 6 2380 C&D 7 2926 C&D 8 3111 C&D 9 2285 C&D 1 0 2285 MAIN 11 4570 MAIN 12 3120 MAIN 13 5890 MAIN 14 4000 Salem 1 5 2742 Salem 1 6 2742 MAIN 17 4163 MAIN 18 4164 MAIN 19 2742 MAIN 20 4164 MAIN 21 3250 MAIN 22 2945 MAIN 23 3352 MAIN 24 4265 MAIN 25 4164 Christina 2 6 3656 Christina 2 7 3656 Christina 2 8 2844 Christina 2 9 2844 Table 4-2: Summ ary of the channel geom etry
. Width Angle meter d e gree Name

220 90 220 90 220 90 220 90 220 90 220 90 220 90 220 90 4381 330 3796 15 2347 5 1372 90 518 40 7129 320 305 60 1320 50 1625 355 1158 315 1410 320 1036 320 1871 320 1494 280 2316 30 1189 330 2747 45 2501 30 2080 20 239 315 230 255 Pennsauken 5 7 1930 427 MAIN 58 2742 53 MAIN 59 3656 932 MAIN 60 2437 762 Rancocas 61 2949 871

MAIN 62 2745 65 MAIN 63 2949 851 MAIN 64 2949 966 Neshaminy 6 5 2949 848

MAIN 66 2745 181 M AIN 6 7 2745 766 MAIN 68 2745 712 MAIN 69 2898 652 MAIN 70 1930 89 MAIN 71 2898 649 MAIN 72 3356 466 Crosswicks 73 2389 296

MAIN 74 2389 307 MAIN 75 2949 433 MAIN 76 3305 415 MAIN 77 3660 433 MAIN 78 2745 406 Salem 7 9 1830 91 Christina 8 0 2288 430 Brandy wine 81 2438 363 Darby 8 2 2438 239 Schuy lkill 83 2980 220 Newton 84 2714 5664 Cooper 8 5 3000 6530 

### 15 Channel No. Length Width meter meter Angle d e gree

110 150 60 45 80 90 75 85 75 90 80 85 90 300 90 70 90 10 40 125 90 70 60 355 330 355 90 330 325Name Channel No. Length meter Width meter Angle d e gree Name Channel No. Length meter Width meter Angle d e gree Brandy wine 30 2844 169 225 Pennsauken 8 6 1472 102 255 MAIN 31 2844 102 225 Rancocas 87 1472 179 320 MAIN 32 2844 179 320 Neshaminy 8 8 1421 98 20 MAIN 33 3656 2086 10 Crosswicks 89 1675 142 45 MAIN 34 3656 2225 30 Trenton 9 0 1421 37 105 MAIN 35 3656 2107 40 C&D 9 1 1421 53 150 MAIN 36 4062 2095 45 MAIN 92 1422 65 90 MAIN 37 3656 1236 45 Raccoon 93 1422 181 90 MAIN 38 3250 1185 60 Raccoon 94 1015 89 300 MAIN 39 3656 1320 45 MAIN 95 965 91 60 Darby 4 0 2234 754 60 MAIN 96 1269 239 355 MAIN 41 2234 1059 25 MAIN 97 2285 4816 330 MAIN 42 1930 792 45 MAIN 98 2285 3795 15 MAIN 43 3656 1506 90 MAIN 99 2438 203 315 MAIN 44 2742 98 20 MAIN 100 9754 102 315 Schuy lkill 45 1930 417 90 Mouth of the Bay 101 5000 7794 320 Schuy lkill 46 3656 417 90 MAIN 102 6900 8636 320 Schuy lkill 47 3656 1248 80 Torresdale Intake 103 10880 15362 322
MAIN 48 4750 1156 60 Bristol Intake 104 14941 22981 336 MAIN 49 3250 195 330 LowBucks Intake 105 16803 25824 330
Newton 50 3250 173 10 MAIN 106 11167 25025 325 MAIN 51 3250 142 45 MAIN 107 24041 14351 29 MAIN 52 3656 1152 90 MAIN 108 21563 13281 253 MAIN 53 3656 912 35 MAIN 109 4563 581 270 Cooper 5 4 2742 37 105 MAIN 110 4563 581 270 MAIN 55 3656 786 350 MAIN 111 4563 581 270 MAIN 56 3148 1014 10



### 164.2 Data Com p ilation 4.2.1 Tidal Height Available water su rface elevation ( tidal height) data were obtained from National Oceanic Atm o spheric Adm i nistration (NOAA) web-site ( http://www.co-ops.nos.noaa.gov/data_r es.htm l ) for the period from Septem ber 1, 2001 to March 31, 2003, which coincides with the calibration period of the PCBs water quality mo d e l. Seven tide gaging stations we re available with the verified hourly tidal heights within the mo d e l dom ain (Figure 4-2). Hourly tidal heights were dow nloaded based on Local Standard Tim e (LST), units of m e ters, and Mean Lower Low Water (MLLW) datum

. Re trieved water surface elevation data sets were then converted to the NGVD1929 datum

. The data for the wa ter surface elevation at Burlington, New Jersey were obtained from the US Geological Survey (USGS) by personal contact (pers onal contact with Robert Schopp,USGS, NJ District, 2003). A summ ary of the av ailable water surface elevation data with m odel node inform ation is contained in Table 4-3.

Figure 4-2: Map of locations of the tide gage stations in the Delaware River Estuary

. 

### 17Table 4-3: Summ ary of available water surface elevation data from NOAA and USGS for the Delaware River Estuary

. Station ID River Mile Station Name Available Period NODE No. MLLW - NGVD29 meter Lewes 8557380 1.5 9 /1/01 ~ 3/31/03 101 0.6523 Brandy wine Shoal 8555889 15 7/1/02 ~ 3/31/03 99 0.6800 a Reedy Point 8551910 58 9/1/01 ~ 3/31/03 10 0.7681 Philadelphia 8545240 100 9/1/01 ~ 3/31/03 51 0.7010 b Tacony

Palmy r a Bridge 8538886 107 6/11/02 ~ 3/31/03 58 0.8400 a Burlington 01464598 119 6/20/02 ~ 1/16/03 C 3/1/03 ~ 3/31/03 66 Reported with NGVD29 datum Newbold 8548989 127 11/15/01 ~ 3/31/03 71 0.9700 a a - Inform ation on the difference between m ean lower low water (MLLW) an d NGVD1929 was not available. The difference was assum e d to correct the NOAA’ s verified data into the m odel’ s datum of NGVD1929. b - There were two tidal st ations for Philadel phia under NOAA’s web site. One station (Station ID 8545240) contained tidal height data for the m ode ling period and the other station (Station ID 8545530) only contained the MLLW to NGVD29 relationship. The station 8545240 had NAVD88 height related to MLLW. A downloadable software (called VERTC ON) was used to calculate the relationship between NAVD88 and NGVD29 using the latitud e an d longitude

. Using the location inform ation and the ‘VERTCON’ , t h e vertical relationship betweenNAVD88 and NGVD29 was calculated to be 0.332 m e ters. NAVD88 from MLLW for this station was report e d as 1

. 033 m e ters. Thus, the calculated relationship between MLLW and NGVD29 becam e 0.701 m e ters. c - The data gap was caused by an ice jam at the gaging station.
4.2.2 Inflows 4.2.2.1 Inflows from Tributaries Daily flows from twenty -two (22) tributaries, includi ng the Delaware River at Trenton and Schuy lkill River, were input into the m odel. Daily average flows for the Delaware River at Trenton for the entire calibration period are shown in Figure 4-3. The flow at Trenton varied from 69 to 2,237 m 3 /sec (or 2,420 to 79,000 ft 3 /sec) during the calibration period. The annual aver age freshwater inflows from Trenton m akeup m o re than 60% of total freshwater inflows into the Delaware Ri ver Estuary
. Daily flows for the ungaged trib u t aries 

### 1825 00

m^ 3 / s e c ft^ 3 /sec 90, 0 0 0Flow, m3/sec 80, 0 0 0 20 00 70, 0 0 0 60, 0 0 0 15 00 50, 0 0 0 40, 0 0 0 10 00 30, 0 0 0

50 0 20, 0 0 0 10, 0 0 0 0

- 09/ 01/ 01 1 1 / 01/ 01 01 /0 1/0 2 03 /03 / 0 2 05/ 03 /02 0 7/0 3 / 0 2 0 9 / 0 2 / 0 2 1 1 / 0 2 /0 2 01/ 02/ 03 0 3 / 04/ 03 Da t e Figure 4-3: Daily average flow for the Delaware Ri ver at Trenton during the m odel calibration period. were extrapolated from nearby gaging stations with drainage area adjustm e nts. Detailed m e thods and assum p tions on tributary flow calculations are summ arized in DRBC (2003b).
4.2.2.2 Inflows from Discharges Seventeen (17) NPDES pe rm ittees with discharges that contribute to the top 90 percent of the cum u lativeFlow, ft3/sec

flows am ong 144 discharges were requested to subm it the daily average effluent flows. These daily average inflows (577 data points per discharge) were used in the m odel for the calibration period. For the rest of the discharges, a m ean flow value per discharge for the entire calibration period was calculated using the Perm it Com p liance Sy stem (PCS) data, and used in the m odel. More detailed description can be found in the m odel calibration report (DRBC, 2003b). Four water intake wi th d r awals were also incorporated into the m odel. Those four intakes were: the City of Philadelphia, Torresdale; City of Burlington; Bristol Borough; and Lower Bucks County JMUA. Daily average intake flow data were obtained from the City of Ph ilad e lphia for the Torresdale intake and incor porated into the m odel. The o t h e r, three intakes were assigned their average intake flow rate value. 4.2.3 Current Velocity Limited current velocity data we re available during the m odel calib ration period. The Acoustic Doppler Current Profiler (ADCP) w a s d e ploy ed in the m i d sec tion of the Estuary to m easure the current velocity 

### 19profiles in a num ber of transects by the University of Delaware. The data were obtained through the personal contact and used to confirm the perform ance of the m odel. (Personal comm unication with Dr. Christopher S o mme r f i e l d )

. 4.3 Calibration of the DYNHYD5 Hydrodynamic Model 4.3.1 Code Modification The original DYNHYD5 source codes had been m odified to reduce the sim u lation tim e in the earlier version of DYNHYD5 m odel for the Delaware River Estuary

. Mo st of the m odifications were perform ed to comm e nt out the linkage with the graphic output processing subroutin es. In this version, additional m odifications were required to incorporate the larger num ber of junctions and channels, larger num ber of variable inflows, and longer tim e series inputs. The dim e nsions of the co rresponding variables in ‘Dy nhy d.CMN’ file were therefore updated. 4.3.2 Assignm ent of Open Boundaries With Forcing Tides and the Com putational Tim e Step Two downstream boundaries were assigned with the forcing tidal heights. One was located at the Mouth of the Bay (Lewes , D E ) and the other was at the West ern end of C & D canal (Chesapeake City , MD). A com b ination of the m easured high and low tidal heights and hourly observed tidal heights were input into the m ode l a l ong w ith the c o rresponding ti m e s f o r

the m a ins t e m dow ns tr e am boundary a t Le w e s , D E
. The derived hourly tidal heights from the hourly observed data at the Reedy Island gaging station were assigned as forcing tides at the C&D Canal boundary

. The rela tionshi p for tidal heights at Chesapeake City from Reedy Island station was obtained from the NOAA (Intern ational Marine, 2001). The average phase lag was about 55 m i nutes (high and low tides at Chesapeake City were 55 m i nutes ahead of Reedy Is. Station’ s) and am plitude correction factor was 0.5 (m ultiply 0.5 to th e Reedy Is. Station’s tidal heights). The forcing tidal heights at both boundaries were adjusted to NGVD1929 datum before incorporated into the m odel. The com putational tim e step for the DYNHYD5 hy drody nam i c m odel was set to 30 seconds to m a intain the stability of the m odel. 4.3.3 Determ ination of Manning’s Coefficients The Manning’ s coefficient (n) play s an im portant role on water m ovem e nt in the DYNHYD5 hy drody nam i c m odel. Manning’ s coefficient was the key factor in calibrating the advective m ovem e nt of the water m ass. The basic sensitivity of the m odel’ s responses to th e assigned Manning’ s coefficients revealed that assigning a larger Manning’ s coefficient slowed down the tidal propagation and decreased the tidal am plitude. Sm aller Manning’ s coefficients resulted in faster tidal pr opag a t i o n and increased tidal am plitude, as expected. Assignm ent of too large or too sm all of Manning’s co efficients could cause the instability of the m odel. To have a better fit in the regression between the sim u lated and the observed tidal h e i g h t s , n u m e r ous com b inations of Manning’ s coefficients sets were t ested. From these, acceptable values were assigned for the sections of the m odel’ s dom ain. The assigned Manning’ s coefficients are summ arized graph i c a lly in Figure 4-4.



### 20Lo w er B u ck s I n ta k e B r ist o l & B u rl in gt o n In ta k e Ne s h am i n y 

### Zo n e 2
T o rres d a l e I n ta k e



### Zo n e 3

S c hu ylkill

Dar b y 

### Zo n e 4

B r an dy w i ne Ch ristina



### Zo n e 5 C&D C a nal



### Zo n e 6 RM

C r o ssw ic k s

67

Ran c oc as

Pe n s au k e n 53 Coop e r

Ne w t on

41 39 37 35 Rac c oon

21 2 0 18 19 13 1 4 Sal e m

101 98 10 0 99 102 95 96 97 77 2 92 17 22

12 78 11 31 25 24 23 36 34 33 32 44 43 42 38 52

51 49 48 59 58 56 55 64 63 62 60 69 68 66

74 72 71 70 90 76 75 Trent o n M a nning 's n 133. 3 Se c/ m 1/3 132. 0 130. 6 129. 0 127. 3 

### 0.040 124. 9 122. 6 120. 7 118. 6 116. 8 115. 0 113. 2 

### 0.035 111. 5 109. 5 107. 8 105. 4 104. 0 101. 6 99. 4 96. 9 95. 5 92. 3 

### 0. 020 89. 7 87. 7 86. 5 84. 8 82. 2 80. 0 77. 3 75. 1 

### 0.016 72. 2 70. 8 

### 0. 010 68. 1 65. 5 63. 0 

### 0.015 60. 6 60. 2 58. 6 54. 9 53. 3 

### 0.010 51. 9 50. 5 48. 3 46. 9 45. 0 42. 6 39. 6 35. 8 28. 7 

### 0.017 18. 6 8. 0 1. 2 M o ut h o f B a y Figure 4-4: Assigned Manning’ s coefficients for the m a in channe l o f t h e mo d e l segm e nts. Only the m a in stem of the Delaware Estuary is shown. 

### 214.3.4 Influence of the C&D Canal While calibrating the hy drody nam i c m odel, it was found that the C&D Canal play ed a very im portant role in chloride concentration profiles in the lower part of the Delaware Estuary

. The direction and the m a gnitude of the net f l o w b e t w e e n t h e Chesapeake and Delaware Estuary m a de a significant im pact on the chem ical transport in the Delaware Estuary

. The Manning’ s co efficient for the channels within the C&D Canal was assigned with a value of 0.030, which was com p arable with the earlier study result (n=0.026) perform ed by G ardne r and Pritc hard (1974). In a ddition, the pre d ic te d am plitude of the tida l ve loc ity w a s m a inta ine da t about 1.0 m / sec within the C&D Canal an d this was confirm e d by Dr. Kuo-Chuin Wong of the University of Delaware and Dr. William Boicourt of the Un iversity of Mary land (personal comm unications). 4.3.4.1 Issue Statem ent Direction of net flow and m a gnitude Durin g t h e e arly stage of the calibration process, the di rection of the net flow within the C&D Canal was predicted to be westward (from the Delaware into the Chesapeake Estuary ) with an average flow rate of about 300 m 3 /sec by the m odel. These results were contradictory to the num ber of earlier study results (Gardner and Pritchard, 1974; Pritchard and Gardner, 1974; Thatcher and Najarian, 1981; Johnson et. al., 1999). All of the previous field and m odeling study results reveal ed that the long-term net flow within C&D Canal had eastward flow direction with net flow rates ranging from 30 to 259 m 3 /sec in their studies. Chloride Gradient in the Delaware Estuary The water quality m odel was run with the hy drody nam i c m odel output which contained the westward C&D net flow condition. Dispersion coefficients in the water quality m odel were set to zero for the whole estuary in this run. The chloride concentration for the downstream boundary at Lewes, DE was set at 16,000 m g /L. Note that the sim u lation period was from August 2001 to Novem b er 2002 for these calibration runs (See the Section 2.2 of the concept of the rolling calibration regarding the differences in the sim u lation period). The tem poral variations of the sim u lated chloride c oncentrations at River Mile (RM) 54 were plotted along with the daily freshwater inflows at Trenton, NJ (F ig u r e 4-5). As shown in Figure 4-5, the chloride concentrations in the Delaware Estuary were greatly influenced by the upstream freshwater inflows. During the low freshwater inflow period, a significant ocean w a t e r intrusion was sim u lated. The chloride concentrations were dropped significantly du r ing the high freshwater inflow conditions, as expected. The sim u lated chloride concentrations were com p ared with the observed data at River Mile 54 (Figure 4-6). The m odel over-predicted the chloride concentrations, especi ally during the low freshwater inflow period. One of the m a in reasons was that the C&D Canal withdrew water from the Delaware Estuary , causing water from the ocean m oving up during the low freshwater inflow pe riod. Because the m odel was already set with zero dispersion coefficients, there was no other m echanism s to depress the chloride intrusion from the ocean.



### 22

### 23 - 2,0 0 0 4,0 0 0 6,0 0 0 8,0 0 0 10 , 0 0 0 12 , 0 0 0 14 , 0 0 0

8/1 / 01 10 /1/01 12/1 / 01 1 / 31/0 2 4/ 2/0 2 6 / 2/02 8/2/ 0 2 10/ 2/02 12/2/0 2Chloride Conc.,mg/L

- 20 0 40 0 60 0 80 0 1,000 1,200 1,400Flow at Trenton, m3/sec

S i m u late d c h l o ride c o nc entration Dai l yfl ow atTrent o n, N J

0 20 00 40 00 60 00 80 00 100 00 120 00 140 00 160 00

8/ 1/ 01 10/ 1/ 01 1 2 / 1 /0 1 1 / 31/ 02 4/ 2/0 2 6 / 2/ 02 8/ 2/ 02 10/ 2/0 2 12 /2/ 0 2Chloride Conc., mg/L

Ob s e r v e d

_

U S G S S i m u late d Figure 4-5: Tem poral variations of the sim u lated chlo ride at RM 54 related to the inflows at Trenton.

Figure 4-6: Tem poral variations of the sim u lated and the observed chloride concentration at RM 54.

### 24 0 20 00 40 00 60 00 80 00 100 00 120 00 140 00

8/ 1/ 01 10/ 1/ 01 1 2 / 1 /0 1 1 / 31/ 02 4/ 2/0 2 6 / 2/ 02 8/ 2/ 02 10/ 2/0 2 12 /2/ 0 2ChlorideConc., mg/L

0c m s h if t 10 c m S h if t 20 c m S h i f t 4.3.4.2 Approach and Modification to the Tidal Datum at Chesapeake City , MD Because the m anipulation of dispersion coefficients could not resolve the intrusion of chloride, an advective m ovem e nt correction was perform ed within the C&D Cana l. adjustm e nt was required to correctly sim u late the direction and m a gnitude of the net flow through the C&D Can a l. The m a jor com ponents that determ ined the direction and the m a gn itude of the flows within the C&D Canal were the tidal heights at both ends of the Canal, Chesapeake City and Reedy Point, in this m odel. adjustm e nts on the tidal heights at the Chesapeake City would be m a de and not to m ake any adjustm e nt on tidal heights at Reedy Point Station, because the tidal he ights at Reedy Point were actually observed. On the other hand, the tidal heights at the Chesapeake City were derived from the Reedy Point station’ s observed data. To force the net flow direction eastward (from Chesapeake to Delaware Estu ary ) , the tidal heights at the west end (Chesapeake City ) were raised. datum at Chesapeake City was shifted up at different levels and com p ared to the results of the sensitivity si m u lations on chloride concentrations (Figure 4-7). ( 1 0 ) cen t i m eters up-shift of the tidal datum at th e Chesapeake City was chosen based upon the sim u lated chloride concentration profiles.

Figure 4-7: Sensitivity sim u lation resu l t s : Im pact on chlo ride concentrations by the datum shift at the Chesapeake City

. A certain level of
It was decided that

The tidal Ten4.3.4.3 Confirm a tion of the Datum Adjustm e nt Even though the m onitoring of the lon g - t e rm flow, or the actual tidal heights at Chesapeake City with a survey of the station’s datum would be the only way to clearly justify this adjustm e nt, a num ber of previous studies and the m odeling results reenforced th e approach we took in this m odeling work. With 10 centim eter of up-shift of the datum at Chesapeak e City , the m odel sim u lated the net flow direction of eastward. This result agreed with the earlier studies d escribed in the Section 4.3.4.1. In addition, Thatcher and Najarian (1981) applied sam e approach to force the net flow direction to east in their previous m odeling work. Lastly , a crucial justification m ay be observe d in the setup in the recently developed Chesapeake Bay Mode l ( W ang and Johnson, 2002)

. I nthe i r m ode l, the C & D C ana l w a s tr e a t e da s ar i ve r boundary and a constant flow rate of 21.24 m 3 /sec was assigned. The direction of fl ow was from the Chesapeake toward the Delaware Bay

. The sensitivity sim u lation results on datum shift for the entire calibration period (577 day s ) are summ arized in Table 4-4. The direction of the long-term net flow changes at a point between 5 and 10 centim eters datum shift. With 10 centim eter shift, th e net flow am ount for the entire calibration period was sim u lated to be 20.6 m 3 /sec, which was alm o st exact am ount of flow rate assigned in Chesapeake Bay Model.

T a b l e 4

- 4 : T h e d i r e c t i o n an dm a g n i tu d e o f th e s i m u l a t e d , long-term net flow in C&D Canal w i th various am ount of datum shift. Scenario Direction of net flow Magnitude of the net flow (m 3 /sec) Datum Up-shift am ount cm Calibration period (577 day s ) Feb 2002 to Jan 2003 (365 day s ) 0 W est 246 257 5 W est 114 126 10 East 20.6 19.1 15 East 158 148 20 East 298 297



### 254.4 Calibration Results The input file for DYNHYD5 hy drody nam i c m odel for the calibration period is provided in Appendix A. Because of the file size, portions of the daily infl ows and forcing tide input sections were shortened. 4.4.1 Com p arisons with Current Velocity ADCP results from eleven transects we re selected to com p are with the hy drody nam i c m odel outputs. The current velocity profile data for those 11 transects were post-processed to obtain the average velocity and then the results were com p ared with the sim u lated current ve locity

. Review of the plots and results of regression (a)

(b)

Figure 4-8: Com p ariso n b e tween the observed and the si m u lated current velocity : (a) Spatial plot; (b) Linear regression results. 

### 26analy ses confirm s that the m odel reproduces the current velocity relatively well both spatially and tem porally (Figures 4-8 (a) and (b)). 4.4.2 Calibration Results of the Tidal Heights The sim u lated tidal heights are com p ared with the observed t i d a l heights at six tide gaging stations. The observed data and the sim u lated tidal heights are presented in four ty pes of plots per station. The four plots are: (a) tem poral plot for the entire calibration period; (b ) tem poral plot for the last 3 weeks of the calibration period; (c) linear regression plot; (d) cum u lative frequenc y d i s t r i b u tion plot. Figures 4-9 a, b, c and d represent the com p arison plots at the Reedy Point Stati on as an exam ple. The tidal height com p arison plots for the rest of the stations are presented in the A ppendix C. The tem poral com p arison plot s showed good agreem ent between the observed data and the sim u late d results for both the am plitudes and the phases of the tidal heights. The results of the linear regression betw een the observed data and the sim u lated tidal heights are su mm arized in Table 4-5. If sim u lated and observe d data are equal, then the slope would be one and intercept would be zero. The slopes were ranged fro m 0.945 to 1.027 and the intercepts were ranged from

- 0 .087 to 0.035. The squar e of the c o rr e la tion c o e f f i c i e n ts ( R 2 ) were varied from 0.930 to 0.994. The cum u lative frequency distribution plots show a good agr eem ent between the sim u lated and the observed tidal heights throughout the ranges of the tidal heights.
Table 4-5: The summ ary of the regression results between th e o b served data and the sim u lated tidal heights. Station Name River Mile Slope I ntercept R 2 Brandy wine Shoal 8 .0 0.973 0.005 0.994 Reedy Point 58.6 0 .961 0.035 0.937 Philadelphia 99.4 1 .027 -0.087 0.941 Tacony -Palmy ra 107.8 1 .026 0.012 0.934 Burlington 118.6 0 .979 -0.075 0.942 Newbold 127.3 0 .945 0.010 0.930 The calibrated DYNHYD5 hy drody nam i c m odel successfully reproduced t h e t i d al heights. The m odel generated the tidal heights reasonably well on both the am plitudes and the phases of the tidal heights. Along with the current velocity confirm ation results and tidal height com p arison results, the calibrated DYNHYD5 hy drody nam i c m odel for the Delaware Riv e r E s t u ar y c o r r e c tly ge ne rates the advective m ovem e nt of the water m ass.



### 27

### 28 Tidal heigh t co m p arison at Re edy P o in t (Node 10: RM 58.6)

-1

. 5 -1

. 0 -0

. 5 0.0 0.5 1.0 1.5 2.0 2.5

09/01/ 01 1 1 /01/01 01/01/02 03/ 03/02 05/03/02 07/0 3 /02 09/02/02 11/02 /02 0 1/02/03 03/04/0 3 Dat eTidalheight, meter

Obs e rv ed (NOAA) S i mulated

Tid a l heigh t com p aris o n at Reed y Po in t (Node 10: RM 5 8 .6 )

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5

03/1 0 /0 3 0 3 / 12 /03 03/ 14/0 3 0 3 /1 6/03 03/ 18/ 03 0 3 /2 0/03 03 /22/ 03 03/2 4 /0 3 0 3/26 /03 03/ 28/ 03 Da t eTidalheight,meter

Obs e rv ed ( N O AA) Sim u l ated (a)

(b)

Figure 4-9: The observed and the sim u lated tidal heig h t s at Reed y P o int (River Mile 58.6): (a) for the entire calibration period; (b) from the period March 10, 2003 to March 31, 2003.

### 29 O b sr ved v s . Si m u l a t e d Ti da l H e i g h tatR e e d y P o in t ( N ode 10: RM 5 8 . 6 )

y = 0 . 9 608 x + 0. 0 347 R2 =0. 93 74

-1. 5 -1. 0 -0. 5 0. 0 0. 5 1. 0 1. 5 2. 0

- 1 .5

- 1 .0

- 0 .5 0

. 0 0 .5 1. 0 1 .5 2

. 0

Obs e r v e d ti da l he ig ht , mSimulated tidal height,m

Si mul ated 1:1 Line L i n e ar ( S imu l at ed )

Cum u lati ve P l ot of Ti dal Hei g hts at R eedy P t . (N ode 10: RM 58.6)

-2 -1 0 1 2 3

0% 2 0 % 4 0% 60% 80% 100% C u mulative P erc enta ge, %Tidal Height,meter

Ob se rv e d S i m u late d (c)

(d)

Figure 4-9: Th e o b s erved and the sim u lated tidal hei ghts at Reedy Point (River Mile 58.6): (c) Linear regression results (n=13,777); (d) cum u lative frequency distribution curve.5 CALIBRATION OF WATER QUALITY (CHLORIDE) MODEL As a part of the hy drody nam i c m odel calibration, the original TOXI5 m odel was linked with the outputs from the calibrated DYNHYD5 m odel. Fifteen (15) m i nutes of the com putational tim e step was used for the water quality m odel. TOXI5 m odel was then calibrated ag ai ns t the chloride concentrations to determ ined the dispersive m i xing within the Estuary

. Chloride c oncentrations were traced throughout the m odel dom ain and com p ared with the observed data with various sets of assigned dispersion coefficients. The m a in objective in this calibration process was to determ ine a set of adv ection factor and dispersion coefficients for the water quality m odel. 5.1 Water Quality Model Segm entation The segm e ntatio n o f the water quality m odel was established through one to one m a pping with the segm e ntation of the DYNHYD5 hy drody nam i c m odel. Because the water quality m odel (TOXI5) required boundary flows from outside its network, one juncti on above each of the TOXI5 boundary segm e nts was not m a pped. Thus, the total num ber of segm e nts for the water quality m odel becam e 87. The schem atic diagram of the water quality m odel segm e ntation is depicted in Figure 5.1.



### 30RM Tr e n t o n R M 133.3 132.0 130.6 129.0 Zo n e2 127.3 124.9 122.6 120.7 119.0 118.6 Ne sha m iny 65 116.8 115.0 113.2 111.5 109.5 107.8 105.4 Zo n e3 104.0 101.6 67

53

41 39 37 35

21 20 18 19 13 14 76 75

17 74 72 71 70 69 68 66

64 63 62 60 59 58 56 55
52

51 49 48 44 43
42 38 36 34 33 32 31 25 24 23

80

81 87 22

12 78 11

82 83 84 86 85 77 2 101.7 99.4 96.9 95.5 92.3 89.7 S c huyl k i l l 47 46 4 5 Zo n e4 87.7 Dar

b y 40 86.5 87.0 84.8 82.2 82.0 81.0 80.0 77.3 Bran dywi n e 75.1 72.2 70.8 30 Chr i sti n a 29 28 2 7 26 Zo n e5 68.1 65.5 63.0 60.7 60.6 60.2 60.1 58.6 58.7 54.9 53.3 51.9 50.5 48.3 46.9 45.0 42.6 39.6 35.8 C&D Ca n a l 1 3 5 6 7 8 9 1 0 4

Zo n e6 28.7 18.6 13. 5 8.0 Mo uth o f B a y
Figure 5-1: Schem atic diagram of the segm e ntation for the water quality m odel. 73 Cr o sswicks

61 R a n c ocas

57 Pen s auk e n
54 Co o p e r

50 Ne w t on

79 R accoon

15 16 Salem



### 315.2 Data Compilation and Processes One of the biggest m e rits in calibrating a hy drody nam i c m odel in an estuarine sy stem is the existence of the natural conservative chem ical. Salt content is usuallyused as a part of the hy drody nam i c m odel calibration process in an estuarine sy stem
. Because of our rolli ng calibration approach (i.e., longer tim e period), using the salt content as a calibration param e ter seem ed to be a logical choice rather than perform ing a dy e study

. The salt content can be expressed in a num ber of way s . The direct expression of the salt content, salinity , was usually in units of parts per thousand (ppt). The chlo ride concentration in m illigram s per liter is another way of expressing the salt content. The chloride concentrati on is ty pically obtained by laboratory testing. On the other hand, the specific conductance (or conductivity ) is another way to express salinity

. The specific conductance is basically a m e asu r emen t o f the electrical transm isivity (in a unit of m i cro Siem ens per centim eter), which can be affected by other m i nerals in am bient water. However, in highly sal i n e water environm ent, the im pact from other m i neral content is m u ch sm aller than that from the chloride content. The lim itation of using the specific conductance as a surrogate m easurem e nt f o r sal i n i t y is not clearly defined. All three ty pes of available salt content data were co m p iled for the Delaware Estuary from late 90s to March 2003. Th e chloride concentration was chosen to be th e form of salt content in this m odel calibration, thus all the com p iled data were converted into chloride concentration before use. 5.2.1 DRBC (BoatRun) Monitoring Data Boatrun data, which is the water quality m onitoring pr ogram run by DRBC throughout the Estuary , were used in the chloride calibration. Water sam ples were collectedat a depth of three feet below the water surface and were targeted for the slack tide conditions. Because of slack t i d e sam pling, it could be assum e d that the collected data represented the f u ll range of chloride c oncentrations for the m onitoring station. A total of twenty -two (2 2 ) st at i o n s were m onitored and the sam pling frequency was either 12 or 7 tim es per y ear, depending on the location of the station. The benefit of these data sets was that chloride concentration was actually m easured in the laboratory

. Therefore, any conversion process was not required. The observed chloride data sets were used as calibration t a rgets and also used to assign the m a instem upstream and downstream boundary conditions. 5.2.2 USGS Continuous Monitoring Stations Water tem p erature and specific conductance were m easure d using a utom atic m onitor s hour ly at f

our locations along the Estuary by USGS. Those four stations are: (1) Reedy Is. Station (RM 54); (2) Chester Station (RM 82); (3) Fort Mifflin Station (RM 92); and (4) Ben Frank lin Station (RM 100). No data were collected during the winter season wi t h ex cep tion of the Reedy Island Station. Hourly specific conductance and water t e mp e r a ture data were downloaded from the USGS Autom a ted Data Processing Sy stem (ADAPS). T h e hourly observed specific conductance were then convertedinto chloride concentration for use with the hy drody nam i c m odel calibration. 5.2.3 Other Sources of Data 1. Chloride data collected in Schuy lkill River by Academy of the Natural Science: Measured chloride data for the Schuy lkill River were available fo r the tim e period of 1999 and 2000. These data sets were used to assign the boundary conditions at the Schuy lkill River. 2. The chloride concentration data within the C& D Canal were provided by DNREC (Richard Greene, DNREC, personal comm unication), and thes e data sets were used in assigning the C&D Canal boundary

. 

### 325.2.4 Data Process DRBC’s (BoatRun) chloride concentration data were di rectly com p ared with the m odel outputs without any data m anipulation. However, the continuous m onitored data collected by USGS required conversions. Using tim e series specific conductivity and water tem p erature data, the salinity was calculated using a relationship provided by DNREC (Greene, 1998). This specific c onductance to salinity relationship was claim e d to be valid over a wide range of the salinity (0 to 40 ppt). The calculated salinity values were then converted into chloride concentration by apply i ng the sim p le relationship (APHA, 1995)

. Chloride concentration (m g/L) = Salinity (ppt) x 1000 / 1.80655 These converted tim e series chloride data at f o u r US GS stations were then com p ared with the observed BoatRun chloride concentration data to validate the conv ersio n relationship. The com p arison results are provided in the Fi g u r e s 5

- 2 t h r o u gh 5-5. Note that the y

- axis scales are different in all four figures. The derived and observed chloride concen trations show a good agreem ent for the data collected at the Reedy Island station. Because the locations did not coin ci d e b e tween the DRBC and the USGS stations, the observ e d d a t afrom two DRBC m onitoring stations we re used to bound the derived data for both Chester (Figure 5-3) and Fort Mifflin (Figure 5-4) USGS sta tions. During the high flow period (March to June 2002), both the observed and derived ch loride concentrati ons were below 200 m g /L except at the Reedy Island station. The conversion relationship between chlori de concentration and salinity appeared to breakdown where the chloride con cen trations are less than 200 m g /L. The derived chloride concentrations were sy stem atically higher than the concentrations observed by DRBC m onitoring program (Figures 5-3, 5-4 and 5-5). For this reason, a caution is needed in interp reting the m odel perform ance when the converted chloride data are used to com p are with the m odel outputs. Both the derived and observed ch loride concentrations were below 200 m g /L at all time fo r th e Ben Franklin Bridge Station. Figure 5-5 shows a clear discrepancy between the derived and the observed chloride concentrati ons collected at Ben Franklin Bridge station. With this observation, the derived chloride concentration data at the Ben Franklin Bridge station were not used in this m odel calibration. Further developm ent of a relationshi p is required between salinity and ch loride concentration in low regim e of chloride concentrations in order to utilize all the data collected at the four USGS stations in the Delaware Estuary
.



### 33120 00

100 00

80 00

60 00

40 00

20 00

0 8/ 1/ 01 10/ 1/ 01 12/ 1/ 01 1 / 3 1 / 0 2 4 / 2 / 0 2 6 /2 /0 2 8 / 2 / 0 2 1 0/ 2/0 2 12/ 2/ 02 Chl o ri de Co nc. co nvert ed fr o m Reedy Is. Sta t i o n D RBC Mo ni to r e d D at a Figure 5-2: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlori de data at the Reedy Island station.

18 00 16 00
14 00 12 00 10 00 80 0 60 0 40 0 20 0

0 8/1/0 1 1 0 /1/01 1 2/1/0 1 1/31 /0 2 4 /2 /02 6 /2/02 8 /2/02 1 0/2/0 2 1 2 /2/0 2 Chloride Con c . c onv erte d from Ch est e r St at i o n Boa tru n-8 4 .0 Boatrun

- 78

. 1 Figure 5-3: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlo ride data at the Chester station.ChlorideConc., mg/LChloride Conc., mg/L



### 3450 0 45 0 40 0 35 0 30 0 25 0 20 0 15 0 10 0 50 0 8 / 1/01 10 /1/01 1 2/1/0 1 1/31 / 0 2 4 /2/0 2 6 /2 / 0 2 8 /2/02 1 0 / 2/02 1 2 /2/0 2 C h loride C o n c . c onv erted from F t
. M i fflin Station B o atru n- 93

. 2 B o a t ru n- 87

. 9 Figure 5-4: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlori de data at the Fort Mifflin station.

18 0 16 0
14 0
12 0 10 0 80 60 40 20 0 8/1/01 1 0 /1/0 1 12/1/01 1/31/02 4/2/02 6/ 2/02 8 / 2 / 02 10 /2 /02 1 2/2 / 0 2 Chloride Co nc. conv er te d fr om Ben F r anklin S t atio n Boa trun-10 0

. 2 Figure 5-5: Tem poral com p arison of chloride concen trations derived from the USGS m onitored specific conductance data and the m onitored chlori de data at the Ben Franklin station.ChlorideConc.,mg/LChlorideConc.,mg/L



### 355.3 Calibration of the Chloride Water Quality Model 5.3.1 Assignm ent of the Boundary Conditions Because of the lack of observed tim e series chloride c oncentration data, constant values were assigned at the boundaries throughout the calibration period. Detailed descriptions of determ ining the boundary conditions are listed below. 1. The segm e nt for the downstream boundary o f th e main stem Delaware Estuary occupied from River Mile 3 to 12.6, which is a re lativel y l a r g e s i ze. The observed chloride concentration te m por a lly var i e d f

r o m 9,000 to 18,000 m g /L w ithinthe downstream boundary segm e nt according to the DRBC’ s four y ears of m onitoring data. With the lack of the tim e series data points at the boundary , the m e dian value of 15,000 m g /L of chloride concentration was assigned. 2. The boundary condition for the C&D Canal wa s set at 550 m g /L after reviewing the available data and the previous m odeling work. 3. The observed chloride data at the m o st upstream sam pling station of the DRBC’ s m onitoring program (BoatRun) were used to determ ined the upstream boundary condition. T h e data was tightly bounded with m e dian chloride concentration of 21 m g /L. For the m a instem upstream boundary , the Delaware River at Trenton, th e boundary chloride concentration was assigned with 21 m g /L. 4. The chloride concentration at Fairm ount Dam , the upstream boundary for the Schuy lkill River, varied from 20 to 59 m g /L with a m e dian value of 34 m g /L. The upstream boundary chloride concentration for the Schuy lkill River was assigned with 34 m g /L. 5. The rest of the m i nor tributaries were assigne d with the chloride concentrations ranging from 7 to 24 m g /L after reviewing the previous m odeling works (DRBC, 1998; Hy droQual, Inc., 1998). 5.3.2 Determ ination of the Advection Factor (ADF) and Dispersion Coefficients Two par am e t e r s were adjusted during the calibration pr ocess, the advection factor and longitudinal dispersion coefficients. The adv e c t i o n f actor (0 to 0.5) is used by TOXI5 m odel to m odify the finite difference approxim a tion of the advection term in the m ass balance differential equation. A non-zero ADF reduces the num erical dispersion produced by a particular velocity , channel length, and tim e step com b ination. However, assignm ent of non-zero ADF could cause instability of the m odel. ADF of 0.3 was assigned in the Version 1.0 m odel, while 0.37 was assigned for this version of the mo d e l t o r e du c e the num erical dispersion. The increase of the ADF was necessary to reduce the num eri cal dispersi o n i n t h e B ay (Zone 6) segm e nts with large segm e nt sizes. The com putational tim e step was determ ined to be 15 m i nutes. Along with the advection factor adjustm e nt, sets of th e disper si o ncoefficients were tested. The assigned dispersion coefficients for the TOXI5 m odel are graphi cally summ arized in Figure 5-6. Because of the large segm e nt sizes, zero dispersion coefficient was assigned fo r the segm e nts in the lower portion of the Bay

.



### 36RM Tr e n t o n RM 1 33.3 1 32.0 1 30.6 Cr o s sw i c ks

67 11 9.0

Ra nc o c a s

P e ns auke n 53 10 1.7 C o oper

New t o n

41 39
37 82.0 35 81.0 R accoo n

21 20 60.6 18 19 60.1 13 14 58.7 Sa le m 76 75 74 72 71 70 69 68
66

64 63 62 60 59 58 56 55
52

51 49 48 44 43
42 87.0 38
36 34 33 32 31 25 24

77 2 80 23 22

12 78

83 84 86 13 .5 85 17 87 81 82 11 Dispersi o n Coef ficient s , m 2 /sec 1 29.0 1 27.3 1 24.9 Lo w e r B u c k s I n t a k e 1 22.6 1 20.7 B r is t o l & B ur lingto nI n ta ke 1 18.6 Nes h am i ny 1 16.8 1 15.0 Zone 2 1 13.2 T o rr e s d a le I n ta ke 1 11.5 1 09.5 1 07.8 

### 30 1 05.4 1 04.0 Zone 3 1 01.6 99.4 96.9 95.5 Sc huy lkil l 92.3 89.7 87.7 Darb y 86.5 Zone 4 84.8 82.2 80.0 77.3 75.1 

### 50 Br a n d yw i n e 72.2

C hr i stina 70.8 68.1 Zone 5 65.5 63.0 60.6 60.2 

### 100

C& D Can a l 58.6 54.9 53.3 51.9 50.5 

### 25 0 48.3 46.9 45.0 42.6 

### 14 0 39.6 35.8 Zone 6 28.7 18.6 0

8. 0 Mouthof Bay Figure 5-6: Assigned dispersion coefficients for the water quality m odel. The m a in stem of Delaware Estuary is only shown in the schem atic. 

### 375.4 Calibration Results of Chloride Concentrations 5.4.1 Com p arison with the DRBC Data The m odel input file for the chloride calibration is p r o v ided in Appendix B. The sim u lated chloride concentrations at 19 segm e nts were com p ared with th e observed DRBC Boatrun data . The tem poral chloride com p arisons are presented in the Appendix D. Figures D- 3 and D-4 show that the m odel tends to over-predict the chlori d e co n cen t r at ions in a lower portion of the Bay (River Miles between 20 and 36). This overprediction m i ght be associated with the coarse grid seg m e ntation in the lower portion of the Bay

. Num e rical d i sp ersion is believed to be the m a in cause for this over-prediction. However, the m a in objective in the developm ent of Version 2.0 of the hy drody nam i c m odel were (1) to generate an acceptable tem poral chem ical trend at the Zone 5 / Zone 6 interface; (2) to sim u late proper advective and dispersive transport of chem ical mass within the Estuary

. The sim u lated chloride results at the Liston Point (River Mile 48.2; boundary between Zones 5 and 6) show a strong positive relations hip with th e observed chloride data (Figure D-5). Cum u lative frequency distributions for the observed and the sim u lated chloride co ncentrations were calculated for the segm e nts around the Zones 5 and 6 inte rface. The three segm e nts used in calculations were node 17 (RM 45), node 2 (RM 48), and node 12 (RM 55) and their corr esponding observed data from Smy rna R., Listo n Pt., and Reedy Is. m onitoring stations. The calculated results were then plotted in Figure 5-7. Figure 5-7 clearly shows that the m odel reproduces th e observed chloride concentrations around the Zones 5 and 6 interface correctly

. As shown in t h e F i g u res D-6 through D-19 from the Appendix D, there was a good agreem ent between the sim u lated chloride concen trations and the observed data at the individual

10 0,00 0

10 , 0 00

1,00 0

10 0

10

1 0 % 10 % 2 0% 30 % 40% 50 % 6 0% 7 0 % 8 0 % 90 % 1 0 0 % C u mu lative Pe rce n t a g e Ob s e r v e d S i m u late d Figure 5-7: C u mu l a t i v e f r e qu e n c y distributions of the observe d and the simu lated ch lo rid e concentrations: Data from three segm e nt s (Node 2, 12 and 17) were com b ined.ChlorideConcentration, mg/L



### 38m onitoring stations throughout the Estuary
. The observe d and the sim u lated chloride concentration data were re-organized to check the m odel perform ance on the spatial scale. The m onitoring data and the m i nim u m , m a xim u m and m e dian values of the m odel outputs for th e m a in channel segm e nts of the Estuary are com p ared in Figure 5-8. River Mile (RM) zero indicates the M outh of the Delaware Bay at Lewes, DE., and RM 133 is the location o f h ead o f th e tid e at Trenton, NJ
. The observed chloride data were well bounded by the m i nim u m and m a xim u m values of the m odel outputs, a nd the m e dian values of m odel outputs generally split the observed data. All of the com p arison plots between the observed and th e sim u lated chloride concentrations indicat e d t h a t t h e m odel was able to reproduce the tem poral and spatial trends, and the m a gnitude of the chlo rid e concentrations within a reasonable range throughout the tidal portion of the Delaware River. The calibrated m odel therefore properly sim u lates the advective and di spersive m ovem e nt of the chloride fo r t h e entire Estuary
.

2 000 0 1 800 0 1 600 0 1 400 0 1 200 0 1 000 0 800 0 600 0 400 0 200 0 0 0 1 0 2 0 3 0 4 0

Sim u late d ( M i n im um)chloride conc., mg/L Zon e 6 Z on e 5 Zone 4 Z one 3 Z one 2

5 0 6 0 7 0 8 0 9 0 1 0 0 Ri v er M i l e Sim u lat e d (Max im um ) Sim u late d(Me d i an) 110 1 2 0 1 30 14 0

O b serv ed (0 1-02)
Figure 5-8: Spatial com p arison between the observed data (DRBC_BoatRun) and the sim u lated chloride concentrations throughout the Estuary

.



### 395.4.2 Com p arison with USGS Data Sim u lated chloride concentrations were com p ared withchloride concentrations which were derived from the hourly observed specific conductance data m easured by USGS. Becau se the data obtained from USGS stations are long-term continuous (hourly interval) m easurem e nts, the com p ariso n wi t h m odel outputs provides the perform ance check on the ph ase of the chloride m ovem e nt in the estuary

. The derived chloride concentration data from Ben FranklinBridge station were not u sed in this com p arison because of the low chloride concentration an dt h e conversion issues describ ed in the section 5.2.4. For the sam e reason, only the graphical com p arison was perform ed for two stations : Fort Mifflin (River Mile 91.8) and Chester (River Mile 82.4). The com p arisons of the sim u lated and the derived chloride concentrations over tim e are presented on Figure 5-9 for Fort Mifflin station and Figure 5-10 for Chester Station. The m odel successfully reproduces the tem poral trend of the chloride concentrations in both locations. Again, the m odel tends to over-predict above 200 m g /L of chloride concentration regim e and under-predict when the chloride concentrations were below 200 m g /L. A further investigation is required on the conversion issue to assess the m odel output results in a lower regim e of chloride concentrations. S till, the mo d e l g e n e ral l y m a tches the peaks, as shown on Figures 5-9(b) and 5-10(b). The derived and the sim u lated chloride concentrations were presented in four ty pes of com p arisons for the Reedy Island station. The four plots were: (a) tem poral plot for the entire calibration period; (b) tem poral plot for the first week of Septem ber, 2002; (c) linear re gression plot; (d) cum u lative frequency distribution plot. Figures 5-11, 5-12, 5-13, and 5-14 represent the com p aris on plots at the Reedy Island station which is located at River Mile 54.2. Figures 5-11 and 5-12 are the com p arison plots to check the perform ance of the m odel on tem poral variations of chloride concentrations. As shown on Figure 5- 11, the m odel predicted the general trend of the tem poral variation properly

. In a ddition, Figure 5-12 shows a reasonable predictio n o n the m a gnitude and the phase of the chloride variation. The linear regression result is shown on Figure 5-13 with slope of 1.036, intercept of -130 m g /L and R 2 of 0.87. Com p ared to the wide range of chloride concentrations (60 to 9,500 m g /L) during the calibration period, an in tercep t o f -130 m g /L is a negligible bias. The cum u lative frequency d i stribution plot shows a good ag reem ent between the observed and the predicted results (Figure 5-14). The m odel slightly under-predict ed in th e low chloride range and over-predicted in high chloride concentration range. The m e dian value for the USGS station at Reedy Is. was 3,000 m g /L while the m odel predicted 2,840 m g /L for the calibration period. This result y i elds -5.3 percent of relative error in the m e dian chloride concentration prediction at the Reedy Is. station. Overall, the calibrated m odel successfully reproduces the t e m poral trend of the chloride concentration at three USGS continuous m onitoring stations.



### 40

### 41 0 10 0 20 0 30 0 40 0 50 0 60 0

9/ 1/0 1 12 /1/0 1 3 / 2 /0 2 6 /1 /02 8 /31 / 02 11 /30 / 02 3/ 1/0 3ChlorideConc.,mg/l

Deri ved

_

USGS Sim u lated

0 100 200 300 400 500 600

9/1/02 9/2/02 9/3/02 9/4/02 9/5/02 9/6/02 9/7/02 9/8/02ChlorideConc.,mg/l

D e r i ved_US G S Sim u la ted (a)

(b)

Figure 5-9: Tem poral com p arison between the observed data (derived from specific conductance from USGS Fort Mifflin Station) and the sim u lated chlo ri d e co n c entrations for (a) entire sim u lation period; (b) first week of Septem ber 2002.(a) 2 , 000 1 , 800 1 , 600Chloride Conc., mg/LChloride Conc., mg/l 1 , 400 1 , 200 1 , 000

800 600 400 200

- 9/1/ 0 1 12 / 1 /01 3 /2/02 6 /1/02 8 / 3 1 / 0 2 11/30/02 3/1/03 Si m u l at e d D e r i ve d_U S G S (b) 20 00 18 00 16 00 14 00 12 00 10 00 80 0 60 0 40 0 20 0

0 9/1 / 02 9/2/0 2 9 / 3/02 9/4 / 0 2 9 / 5/02 9/6 / 02 9/7/0 2 9 / 8/02 De ri v e d

_

USGS Sim u lated Figure 5-10: Tem poral com p arison between the observed data (derived from specific conductance from USGS Chester Station) and the sim u lated chlo ride concentrations for (a) entire sim u lation period; (b) first week of Septem ber 2002. 

### 42

### 43 - 2,000 4,000 6,000 8,000 10,000 12,000

9/ 1/01 12/1/ 01 3/ 2/02 6/1/ 02 8/ 31/02 11/30/ 02 3/ 1/03Chloride Conc.,mg/L

D e rived_U S G S S i m u lated

- 2,000 4,000 6,000 8,000 10,000 12,000

9/1/02 9/2/02 9/3/ 0 2 9/4/02 9/5/02 9/ 6/02 9 / 7/02 9/8/02ChlorideConc.,mg/L

D e rived_US G S Si mu la t e d Figure 5-11: Tem poral com p arison between the observed data (derived from specific conductance from USGS Reedy Is. St at i o n ) an d th e s i m u l at e d c h l o r i de concentrations for the calibration period.

Figure 5-12: Tem poral com p arison between the observed data (derived from specific conductance from US GS Reed y Is. Station) and the sim u lated ch loride concentrations for the first week of Septem ber, 2002.

### 44 y = 1.0 357x - 130 .36 R

2 = 0 . 873 3

- 2, 0 0 0 4, 0 0 0 6, 0 0 0 8, 0 0 0 10 ,00 0 12 ,00 0

- 2 , 000 4, 000 6 , 00 0 8 ,00 0 1 0 ,0 00 12,0 0 0 Obse rved chl o ri de c o nce n tr ati o n. , m g /LSimulated chlor. Conc.,mg/L

R eed y Is Line ar (R eed y Is)

- 2, 000 4, 000 6, 000 8, 000 10, 000 12, 000

0% 10 % 2 0% 30% 40 % 5 0% 60% 70 % 8 0% 90% 100 % C u m u lativeper c e n tage , %ChlorideConc.,mg/L

D e rive d_U SGS Sim u late d Figure 5-13: Linear regression results between d e r i ved and sim u lated chloride concentrations at Reedy I s . U S G S s t ation ( n = 13,660)

. o th data s e t s w e r e hour ly tim e in te rv a l throughout the calibration period.

F i g ur e 5

- 1 4 : Cu mu lative frequency distributions of the observed and the simu lated ch lo rid e concentrations for the Reedy Island station. B6. FUTURE REFINEMENTS The perform ance of the Version 2.0 DYNHYD5 hydr odynam ic m odel will be increased by incorporating following future works: 1. Refin e m e nt of the segm e ntation in Zone 6. U se of sm aller segm e ntation in zone 6 to redu ce th e num erical dispersion and increase the resolution of the concentration gradients. 2. Use of the observed tidal heights at the C&D Canal boundary for forcing tides. 3. Measurem e nts of the long-term flo w i n C&D Can a l to identify the direction and m a gnitude of exchanges between Chesapeak e and Delaware Estuary

. 4. More frequent tim e series data collection of ch loride concentrations at the m a jor boundaries. 5. Developm ent of the relationship between the chlori de and salinity to cover the low regim e of salinity inform ation derived from specific conductance data. 6. Measurem e nts of current velocities and incorporating into the calibration process.



### 457 REFERENCES
Am brose, R.B., Wool, T.A., and Martin, J.L. 1993a. The Dy nam i c Estuary Model Hy drody nam i cs Program , DYNHYD5 Docum e ntation and User Manual. US Environm ental Protection Agency

. Am brose, R.B., Wool, T.A., and Martin, J.L. 1993b. The Water Quality Analy s is Sim u latio n Pro g r am, WASP5. Part A: Model Docum e ntation. US Environm ental Protection Agency

. A m bros e , R.B., Wool, T.A ., and Martin, J

. L. 1993c. The Wate r Q u a lity A n a l ys is Sim u la tion Program , WASP5. Part B: The WASP5 Input Dataset. US Environm ental Protection Agency

. Am erican Public Health Association. 1995. Standard Methods for the Exam ination of Water and Wastewater. APHA, Washington, DC. DRBC. 1995. Calibration and Validation of the DYNHYD5 Hy drody nam i c Model for the Delaware River Estuary
. Estuary Toxics Managem e nt Program . Delaware River Basin Comm i ssion. West Trenton, New Jersey . Decem ber 1995. DRBC. 1998a. Calibration and Validation of a Water Quality M o d e l fo r Volatile Organics and Chronic Toxicity i n t h e Delaware River Estuary

. Estuary Toxics Managem e nt Program . Delaware River Basin Comm i ssion. West Trenton, New Jersey . Decem ber 1998. DRBC. 1998b. Wasteload Allocations for Volatile Organics and Toxicity : Phase I TMDLs for Toxic Pollutants in the Delaware River Estuary

. Estuary Toxics Managem e nt Program . Delaware River Basin Comm i ssion. West Trenton, New Jersey . Decem ber 1998. DRBC. 2003a. PCB Water Quality Model for Delaware Estuary (DELPCB). Delaware River Basin Comm i ssion. West Trenton, New Jersey

. DRBC. 2003b. Calibration of the PCB Water Quality Mode l for the Delaware Estuary for Penta-PCBs and Carbon. Delaware River Basin Comm i ssion. West Trenton, New Jersey

. DRBC 2003c. Total Maxim u m Daily Loads for Poly chlori nated Bipheny ls (PCBs) for Zones 2

- 5 o f t h e Tidal Delaware River. Delaware River Basin Comm i ssion. West Trenton, New Jersey

. G ar d e n e r , G

. B
. an dP r i t c h ar d , D
. W. 1974. T e c h n i c a l R e p o rt8 7 : H y dr o g r a p h i c an dE c o l o g i c a l E f f e c t s o f Enlargem ent of the Chesapeake and Delaware Canal: Appendix XV. Verification and Use of a Num e rical Model of the C & D Canal. Final Report to The Phila delphia District, U.S. Army Corps of Engineers. Greene, R.W. 1998. Procedure for Com puting Salin ity from Tem p erature and Conductance Measurem e nts. Delaware Departm e nt of Natural Resources and Environm ental Control. Hy droQual, Inc. 1998. Developm ent of a Hy drody nam i c and Water Quality Model for the Delaware River. Delaware River Basin Comm i ssion, West Trenton, N.J. International Marine. 2001. Tide Tables 2002: East Coast of North and South Am erica. Johnson, B. H., Heath, R. E., Hsieh, B. B., Kim , K. W
. , an d M a rt i n , B. L. 1999. Assessm ent of Channel 

### 46Deepening in the Chesapeake and Delaware Canal and Approach Channels in Upper Chesapeake Bay : Three-Dim e nsional Num e rical Model Study . Draft Report. Waterway s Experim e nt Station. Prepared for U.S. Army Engineer District, Philadelphia. National Ocean Service. Estuarine Bathy m etry Data. URL: http://spo.nos.noaa.gov/servlet/BuildPa ge?tem plate=bathy

. txt&parm 1=M090 National Oceanic and Atm o spheric Adm i nistration. Retrieve Observed Water Levels and Associated Ancillary Data. URL: http://www.co-ops.nos.noaa.gov/data_res.htm l Pritchard, D. W., Gardner, G. B. 1974. Technical Report 85: Hy drography of the Chesapeake and Delaware Canal. Chesapeake Bay Institute, The Johns Hopkins Un iversity . U.S. Army Corps of Engineers Contract No. DACW 67-71-C-0062. Philadelphia, PA. February 1974. Thatcher, L. M., Najarian, T. O. 1981. Com p arison of Salt Intrusion in the Delaware Estuary Under the Influence of Pre- and Post- Enlargem ent Flows in C & D Canal. U.S. Army Corps of Engineers Contract No. DACW 61-80-C-0080. Najarian, Thatcher & Associates Inc. Closter, NJ. March 1981. 51pp. Wang, H. V., Johnson, B. H. 2002. Validation and App lication of the Second Generation Three Dim e nsional Hy drody nam i c Model of Chesapeake Bay

. Water Qualityand Eco s y s t e m M o d e l i n g , 1

. , Kluwer Academ ic Publishers. The Netherlands. 2002. pp. 51-90. Wong, K-C, Garvine, R. W. 1984. Observations of Wind-Induced, Subtidal Variability in the Delaware Estuary
. Journal of Geophy sical Research, Vol. 89, No. C6. pp. 10589-10597.



### 47APPENDIX A. Input File of the Calibrated DYNHYD5 Hydrodynamic Model (Version 2.0) B. 

### Input File of the Calibrated Water Quality (chloride) Model C. Calibration Results of the DYNHYD5 Hydrod ynamic Model for the Delaware River Estuary D. Calibration Results of the Water Quality (c hloride) Model for the Delaware River Estuary



### 48