VA0024899 2012 fact sheet revised 11.26.2012

Attachment F

1988 Stream Sanitation Modeling Memoranda Qual2K Water Quality Model

FINAL REPORT | Prepared for

Hanover County Department of

Public Utilities

Dissolved Oxygen Modeling of the North Anna, South Anna, and Pamunkey River System

November 25, 2020

3454 West Clay Street

Richmond, VA 23230


Prepared for

Hanover County, V i rg inia

November 25, 2020

ii

Table of Contents

List of Figures .............................................................................................................................................. iii

List of Tables ............................................................................................................................................... iii

List of Abbreviations ................................................................................................................................... iv

ES Executive Summary ..................................................................................................................... 1

1. Introduction .......................................................................................................................................1-1

2. Data Sources and Methods ..............................................................................................................2-1

2.1 Model Code Selection .............................................................................................................2-1

2.2 Model Domain and Set-Up .....................................................................................................2-1

2.2.1 Reach Properties ......................................................................................................2-1

2.2.2 Water Column Rates ................................................................................................2-5

2.2.3 Algal Parameters ......................................................................................................2-6

2.2.4 Light and Heat Parameters ......................................................................................2-6

2.3 Calibration and Corroboration Scenarios ..............................................................................2-6

2.3.1 Headwater and Diffuse Inflows ...............................................................................2-7

2.3.2 Point Source Inputs ..................................................................................................2-7

2.3.3 Conversion of CBOD5 to CBODU .............................................................................2-8

2.3.4 Bioavailable Organic Nitrogen .................................................................................2-9

2.3.5 Meteorological Data .................................................................................................2-9

2.4 Model Calibration and Corroboration Results .......................................................................2-9

2.4.1 Model Calibration Results ........................................................................................2-9

2.4.2 Model Corroboration Results ................................................................................ 2-10

3. Management Scenario Descriptions ................................................................................................3-1

3.1 Overview of Model Scenarios .................................................................................................3-1

3.2 Management Scenario Model Input Parameters .................................................................3-2

3.2.1 Headwater and Diffuse Inflows ...............................................................................3-2

3.2.2 Point Source Flows ...................................................................................................3-3

3.2.3 Temperature .............................................................................................................3-3

3.2.4 Dissolved Oxygen ......................................................................................................3-4

3.2.5 pH ..............................................................................................................................3-5

3.2.6 Headwater and Diffuse Inflow Water Quality ..........................................................3-6

3.2.7 Biochemical Oxygen Demand ..................................................................................3-6

3.2.8 Nitrogen Species ......................................................................................................3-6

3.2.9 Meteorological Data .................................................................................................3-7

4. Management Scenario Results ........................................................................................................4-1

5. References ........................................................................................................................................5-1

Appendix A: Field and Lab Data ............................................................................................................... A-1

Dissolved Oxygen Modeling of the North Anna, South Anna, and Pamunkey River System Table of Contents

iii

Calibration Data Set: September 26-27, 2012 ............................................................................... A-1

Corroboration Data Set: October 10-11, 2012 ............................................................................... A-1

Appendix B: Calibration and Corroboration Charts ................................................................................ B-1

Appendix C: Detailed Point Source Inputs for Management Scenarios ................................................C-1

Appendix D: Dissolved Oxygen Profiles for Management Scenarios .................................................... D-1

Appendix E: Average DO and Delta DO by Segment and Scenario ........................................................ E-1

List of Figures

Figure 2-1. QUAL2K Schematic ................................................................................................................2-2

List of Tables

Table 2-1. QUAL2K Reach Data ...............................................................................................................2-3

Table 2-2. QUAL2K Hydraulic Model Components .................................................................................2-3

Table 2-3. QUAL2K Sediment Oxygen Demand ......................................................................................2-4

Table 2-4. Oxidation, Nitrification, and Hydrolysis Rates .......................................................................2-5

Table 2-5. Algal-Related Parameters .......................................................................................................2-6

Table 2-6. Headwater and Diffuse Inflows ..............................................................................................2-7

Table 2-7. Point Sources in the Doswell Water Quality Model ...............................................................2-8

Table 2-8. Carbonaceous Biochemical Oxygen Demand Inputs for the Calibration and Corroboration

Scenarios ............................................................................................................................................2-8

Table 2-9. Nitrogen Inputs for the Calibration and Corroboration Scenarios .......................................2-9

Table 3-1. Overview of Exploratory Management Scenarios ..................................................................3-2

Table 3-2. Headwater Streamflows and Diffuse Inflows ........................................................................3-3

Table 3-3. Temperature Inputs for Management Scenarios ..................................................................3-3

Table 3-4. Dissolved Oxygen Inputs for Management Scenarios ..........................................................3-4

Table 3-5. pH Inputs for Management Scenarios ...................................................................................3-5

Table 3-6. BOD5 Inputs for Management Scenarios ..............................................................................3-6

Table 3-7. Nitrogen Inputs for Management Scenarios .........................................................................3-7

Table 4-1. QUAL2K Model Results by Critical Model Element ...............................................................4-1

Table 4-2. QUAL2K Model Results by Critical Model Segment Average................................................4-2

Table C-1. Point Source Inputs for the Bear Island Facility ....................................................................C-1

Table C-2. Point Source Inputs for the Doswell WWTP ...........................................................................C-1

Table C-3. Point Source Inputs for Other Point Sources .........................................................................C-2

Table E-1. Average DO and Delta DO by Segment and Scenario ........................................................... E-1

Dissolved Oxygen Modeling of the North Anna, South Anna, and Pamunkey River System Table of Contents

iv

List of Abbreviations

BOD5 biochemical oxygen demand (five-day)

CBOD5 carbonaceous biochemical oxygen

demand (five-day)

CBODU carbonaceous biochemical oxygen

demand (ultimate)

cfs cubic feet per second

DEQ Department of Environmental Quality

DO dissolved oxygen

DWQ division of water quality

gph gallons per hours

JCC Juvenile Correction Center

km kilometer

lf linear feet

lb/day pounds per day

MGD million gallons per day

mg/L milligrams per liter

mg/m2 milligrams per meter squared

SOD sediment oxygen demand

TKN Total Kjeldahl Nitrogen

ug/L microgram per liter

USEPA United States Environmental Protection

Agency

USGS United States Geological Survey

VPDES Virginia Pollutant Discharge Elimination

System

VIMS Virginia Institute of Marine Science

WLA wasteload allocation

WWTP wastewater treatment plant

ES-1

Executive Summary

This report describes the development and application of a QUAL2K water quality model to simulate

dissolved oxygen in the North Anna River, South Anna River, and Pamunkey River to Nelson’s Bridge.

Point sources in the model include the Doswell wastewater treatment plant, the future Bear Island

paper manufacturing facility and other permitted discharges such as the Ashland, Hanover

Courthouse, and Hanover Juvenile Correction Center (JCC) wastewater treatment plants. The model

was calibrated and corroborated to water quality data collected during September and October

2012.

After calibration, the QUAL2K model was used to evaluate four seasonal low flow (7Q10) conditions

corresponding to July-October, November-December, January-March, and April-June. Including the

exploration of alternative dissolved oxygen concentrations in selected effluents, a total of twelve

management scenarios were developed to identify average monthly point source loads of oxygen-

demanding substances that would comply with water quality endpoints. Water quality endpoints that

were examined include compliance with dissolved oxygen criteria (5.0 mg/L) and attainment of no

more than 0.2 mg/L difference in dissolved oxygen from an unloaded condition. All twelve

management scenarios were predicted to achieve the water quality endpoints.

1-1

Section 1

Introduction

The North Anna and South Anna Rivers are located in the York River watershed north of Richmond,

VA and flow in an east-southeasterly direction. About 3.5 miles northwest of Hanover Courthouse, VA,

these rivers converge to form the Pamunkey River, which flows into the York River at West Point, VA.

The Hanover County Department of Public Utilities holds Virginia Pollutant Discharge Elimination

System (VPDES) permits for three wastewater treatment plants (WWTPs) that discharge to the North

Anna-South Anna-Pamunkey River system. These include the Doswell WWTP (permit no.

VA0029521) on the North Anna River, the Ashland WWTP (VA0024899) on the South Anna River,

and Hanover County Courthouse WWTP (VA0062154) on the Pamunkey River. Outfall 001 of the

permit VA0029531 represents the combined discharge of the Doswell WWTP and the Bear Island

paper manufacturing facility. That facility was previously operated by White Birch Paper, Co. but

became inactive in 2017 and was sold to Cascades, Inc. in 2018. Cascades is currently planning

future operations at the Bear Island facility. Although the Doswell WWTP and the Bear Island facility

share an outfall structure, they are expected to receive separate VPDES permits in the next renewal.

This technical memorandum presents the methods and results of a modeling project to aid in the

development of wasteload allocations of oxygen-demanding substances for the major discharges to

this river system. A QUAL2K model was developed for the North Anna, South Anna, and Pamunkey

River system, and calibrated/validated to water quality data collected in September and October of

2012. This memorandum presents the model structure, inputs, and calibration/corroboration results

and also describes how the model was used to identify management scenarios for meeting water

quality endpoints under four seasonal low flow conditions. Management scenarios include two

different effluent flows for the Doswell WWTP: 1.0 MGD and 2.0 MGD. Water quality endpoints that

were examined include: (1) meeting water quality criteria for dissolved oxygen and (2) causing no

more than a 0.2 milligram per liter (mg/L) drop in dissolved oxygen from an unloaded condition.

2-1

Section 2

Data Sources and Methods

This section describes the model selection, set-up, calibration approach, and calibration results.

2.1 Model Code Selection

For this project, it was desired to select a modeling code that is well-documented, publicly available,

supported by the United States Environmental Protection Agency (USEPA), and well suited for

modeling dissolved oxygen in a branched river system. QUAL2K was selected because it meets these

requirements and is one of the most commonly used models for wasteload allocation (WLA)

modeling in the nation. The USEPA includes QUAL2K in its toolbox of water quality modeling codes as

compiled in the Watershed & Water Quality Modeling Technical Support Center

(http://epa.gov/athens/wwqtsc/index.html). The version 2.11b8 was applied for this project.

QUAL2K is specifically used for modeling branched rivers and stream networks under steady-state

conditions. As a one-dimensional model, channels are assumed to be well-mixed both vertically and

laterally. QUAL2K simulates two species of carbonaceous oxygen demand (CBOD): fast CBOD and

slow CBOD. It also simulates oxygen demand from nitrogenous sources and sediment. The user can

choose between various reaeration algorithms and thus tailor reaeration rates to the receiving water

body type. Full documentation of QUAL2K is provided by Chapra et al. (2012).

2.2 Model Domain and Set-Up

The model domain and set-up include the reach segmentation/properties and initial

parameterization for water column processes, algae, and light/heat.

2.2.1 Reach Properties

Reach properties in QUAL2K include both the geometry, hydraulic properties, and sediment oxygen

demand of major river segments.

2.2.1.1 Segmentation

The QUAL2K model was constructed to represent the North Anna-Pamunkey River as the

“mainstem,” and the South Anna River as a tributary. As a one-dimensional stream network model,

QUAL2K requires the user to conceptually divide the stream into reaches of similar hydraulic

characteristics. Those reaches are further divided into equally-spaced elements for computational

purposes. A total of 20 reaches were defined for this model: five on the North Anna River, seven on

the South Anna River, and eight on the Pamunkey River. The headwater segment of the North Anna

River begins approximately one km upstream of the Doswell-Bear Island outfall, and the headwater

segment on the South Anna River begins approximately two km upstream of the Ashland WWTP. The

average reach length is 2.48 kilometers. The entire model domain consists of 41.24 km on the North

Anna-Pamunkey River and 8.29 km on the South Anna River. Table 2-1 shows the reaches and

associated length, location, and elevations. Reach segmentation corresponds closely to the locations

of the sampling stations established by EEE Consulting, Inc. (2012), as shown in Figure 2.1

http://epa.gov/athens/wwqtsc/index.html

Dissolved Oxygen Modeling of the North Anna, South Anna, and Pamunkey River System Section 2

2-2

Figure 2-1. QUAL2K Schematic

Ashland WWTP Outfall

Hanover CH

WWTP Outfall


2-3

Table 2-1. QUAL2K Reach Data

Reach

Label

Downstream

(end of reach label)

Reach

Length

(km)

Location Element

Number

>=1

Elevation

Upstream

(km)

Downstream

(km)

Upstream

(m)

Downstream

(m)

NA1 NA2 0.90 41.24 40.34 5 12.06 11.89

NA2 NA3 2.29 40.34 38.05 12 11.89 10.98

NA3 NA4 2.28 38.05 35.77 12 10.98 10.67

NA4 NA5 1.27 35.77 34.50 6 10.67 10.40

NA5 PR1A 0.16 34.50 34.34 1 10.40 10.37

SA1 SA2 0.53 8.29 7.76 3 18.29 13.42

SA2 SA3 1.31 7.76 6.46 7 13.42 13.42

SA3 SA4 1.72 6.46 4.74 9 13.42 12.81

SA4 SA5 1.03 4.74 3.71 5 12.81 11.74

SA5 SA6 1.47 3.71 2.24 7 11.74 10.98

SA6 SA7 1.72 2.24 0.52 9 10.98 10.67

SA7 PR1 0.52 0.52 0.00 3 10.67 10.37

PR1A PR1B 0.20 34.34 34.14 1 10.37 10.06

PR1B PR2 2.69 34.14 31.45 14 9.45 8.38

PR2 PR3 2.98 31.45 28.47 15 9.45 8.38

PR3 PR4 3.30 28.47 25.17 16 8.38 7.47

PR4 PR5 0.74 25.17 24.43 4 7.47 7.32

PR5 PR6 5.05 24.43 19.38 25 7.32 6.10

PR6 PR7 (Norman’s Bridge) 4.01 19.38 15.37 21 6.10 5.35

PR7 (Norman’s

Bridge)

Nelson’s Bridge

(Terminus) 15.37 15.37 0.00 35 5.35 3.00

2.2.1.2 Hydraulic Models

Each reach within QUAL2K is required to have an associated hydraulic model that quantifies the

relations between streamflow, velocity, and depth. Two basic hydraulic model options include

utilizing rating curves or the Manning’s equation. For this model, rating curves developed by AWARE

were used to model the hydraulic characteristics of each element.

Table 2-2. QUAL2K Hydraulic Model Components

Reach

Label

Rating Curves

Velocity Depth

Coefficient Exponent Coefficient Exponent

NA1 0.09 0.43 0.40 0.45

NA2 0.06 0.43 0.45 0.45

NA3 0.06 0.43 0.40 0.45

NA4 0.06 0.43 0.40 0.45

NA5 0.08 0.43 0.40 0.45

SA1 0.18 0.43 0.26 0.45

SA2 0.18 0.43 0.40 0.45

SA3 0.17 0.43 0.40 0.45

SA4 0.17 0.43 0.27 0.45


2-4

Table 2-2. QUAL2K Hydraulic Model Components

Reach

Label

Rating Curves

Velocity Depth

Coefficient Exponent Coefficient Exponent

SA5 0.25 0.43 0.28 0.45

SA6 0.25 0.43 0.28 0.45

SA7 0.40 0.43 0.20 0.45

PR1A 0.14 0.43 0.29 0.45

PR1B 0.13 0.43 0.26 0.45

PR2 0.13 0.43 0.26 0.45

PR3 0.10 0.43 0.32 0.45

PR4 0.10 0.43 0.32 0.45

PR5 0.10 0.43 0.32 0.45

PR6 0.10 0.43 0.32 0.45

PR7 0.10 0.43 0.32 0.45

2.2.1.3 Sediment Oxygen Demand

Values for prescribed sediment oxygen demand (SOD) and bottom SOD coverage were initially set at

QUAL2K’s default values and were adjusted based on previous modeling efforts and during

calibration as necessary. The SOD values were informed by SOD measurements taken by VIMS in

1985 and AWARE in 2011. Final SOD values by reach are shown in Table 2-3.

Table 2-3. QUAL2K Sediment Oxygen Demand

Reach

Label

Bottom

SOD

Coverage

Prescribed

SOD

gO2/m2/d

NA1 50.00% 2.60

NA2 50.00% 2.60

NA3 50.00% 2.50

NA4 50.00% 2.50

NA5 50.00% 2.50

SA1 50.00% 2.50

SA2 50.00% 2.50

SA3 50.00% 2.50

SA4 50.00% 2.50

SA5 50.00% 2.50

SA6 50.00% 2.50

SA7 50.00% 2.50

PR1A 50.00% 2.00

PR1B 50.00% 2.00

PR2 50.00% 2.00

PR3 50.00% 2.00

PR4 50.00% 2.00

PR5 50.00% 2.00

PR6 50.00% 2.00

PR7 (Normans Bridge) 50.00% 2.00


2-5

2.2.2 Water Column Rates

This section describes the initial parameterization of the QUAL2K model.

2.2.2.1 Reaeration Models

QUAL2K allows the user to choose among preset reaeration algorithms, or to specify reaeration by

river reach. For the Doswell water quality model, various reaeration algorithms were evaluated during

model calibration, and algorithms were selected based on which gave the best calibration for each

tributary. The Owens-Gibbs reaeration model provided the best calibration for the South Anna River,

and the United States Geological Survey (USGS) “pool-riffle” model provided the best results for the

North Anna-Pamunkey River. Because QUAL2K only allows the use of a single reaeration model for

each model run, a two-step procedure was utilized whereby the model was first run with the Owens-

Gibbs model to obtain the reaeration coefficients for the South Anna. The prescribed reaeration

coefficients for the South Anna were then manually entered in the Reach Rates tab while the model

was run again using the USGS “pool-riffle” model.

2.2.2.2 CBOD Oxidation, Nitrification, and Hydrolysis Rates

Hydrolysis, oxidation, and nitrification rates defined on the Rates tab of QUAL2K represent reactions

associated with different parameters. These rates were initially set at values based on the literature

and were adjusted during calibration as necessary. Slow and fast CBOD were modeled as two

separate pools. The oxidation rate for slow CBOD was set to a value typical of pulp and paper mill

wastewaters (NCASI, 1982) and confirmed for the Bear Island facility effluent (AquAeTer, 2016a).

The oxidation rate for fast CBOD was set to a value typical for municipal secondary effluent (Lung,

2001). The final rates of the calibrated model are shown in Table 2-4.

Table 2-4. Oxidation, Nitrification, and Hydrolysis Rates

Parameter Value Units

Slow CBOD:

Hydrolysis rate 0.0 /d

Temp. correction 1.047 --

Oxidation rate 0.020 /d


Fast CBOD:

Oxidation rate 0.115 /d


Organic N:

Hydrolysis 0.1 /d


Settling velocity 0.01 m/d

Ammonium:

Nitrification 0.32 /d


Nitrate:

Denitrification 0.5 /d



2-6

Table 2-4. Oxidation, Nitrification, and Hydrolysis Rates


Sediment denitrification

transfer coefficient 0.05 m/d


2.2.3 Algal Parameters

The QUAL2K model simulated both suspended phytoplankton and bottom algal growth. Due to the

predominantly unconsolidated nature of the river bottom sediments in most of the model domain,

the bottom algae coverage was set to only five percent. Table 2-5 lists the algal-related parameters

of the final model.

Table 2-5. Algal-Related Parameters


Phytoplankton

Max. growth rate 3.8 /d

Respiration rate 1.07 /d

Excretion rate 0.3 /d

Death rate 0.01 /d

Ext. N half saturation const. 15 ug/L

Ext. P half saturation const. 2 ug/L

Settling velocity 0.15 m/d

Bottom algae

Growth model Zero-order

Max. growth rate 200 mg/m2/d

Respiration rate 0.2 /d

Excretion rate 0.2 /d

Death rate 0.2 /d



2.2.4 Light and Heat Parameters

The model uses the light and heat parameters to account for heat transfers between the

atmosphere and the model components. QUAL2K model default values were used for these

parameters. The selected submodels were as follows:

• Solar short wave radiation model: Bras

• Longwave emissivity model: Koberg

• Wind speed function: Brady-Graves-Geyer

2.3 Calibration and Corroboration Scenarios

The calibration and corroboration scenarios were based on water quality and effluent data collected

by EEE Consulting on September 26-27, 2012 and October 9-10, 2012, respectively. The purpose of

the sampling was to collect samples at least a week apart, with the first sampling event to be used to


2-7

calibrate the model, and the second to validate the model (EEE Consulting, 2012). Each sampling

event took a span of two days to collect the desired field data and samples for lab analysis. During

both sampling events, the North Anna-Pamunkey was sampled on the first day and the South Anna

was sampled on the second day. The field and lab data for the calibration and corroboration

datasets are tabulated in Appendix A. The following subsections describe how major inputs for these

scenarios were derived.

2.3.1 Headwater and Diffuse Inflows

Headwater flows to the North Anna and South Anna Rivers were based on daily streamflow at USGS

gauges for the calibration and corroboration periods. Specifically, gauge 01671025 (North Anna

River above Little River) was used to specify headwater flows to the North Anna River, and gauge

01672500 (South Anna River near Ashland) was used to specify headwater flows to the South Anna

River.

Diffuse inflows along North Anna, South Anna, and the Pamunkey Rivers were calculated based on

the difference between measured streamflows at the headwater gauges and flow at gauge

01673000 (Pamunkey River near Hanover), after subtracting known point source inflows. These

inflows were proportionally distributed over the length of the model study area according to reach

lengths and were input into the QUAL2K model under the Diffuse Sources tab. The model expressed

the diffuse sources across three reaches: the North Anna-Pamunkey River down to Norman’s Bridge

(river kilometer 15.37), the Pamunkey River between Norman’s Bridge and Nelson’s bridge, and the

South Anna within the model extents. Water quality parameters for the headwater flows and diffuse

inflows were based on data from the most upstream sampling stations on the North Anna River

(station NA1) and South River (station SA1). Headwater and diffuse inflows used in the QUAL2K

model are displayed in Table 2-6.

Table 2-6. Headwater and Diffuse Inflows

USGS Gauge Drainage

Area

(mi2)

Flow (cfs) Flow (m3/s)

Sep 26-27,

2012

Oct 10-11,

2012

Sep 26-27,

2012

Oct 10-

11, 2012

01671025 - North Anna River above Little River 467 31 32 0.877 0.906

01671100 - Little River near Doswell 107 5.4 3.7 0.153 0.105

01672500 -South Anna River near Ashland 395 45 59 1.274 1.670

01673000 - Pamunkey River near Hanover 1,078 116 139 3.283 3.934

North Anna-Pamunkey Diffuse Inflows -- -- -- 0.5662 0.7990

South Anna Diffuse Inflows -- -- -- 0.1804 0.2499

Pamunkey River, Norman’s Bridge to Nelson’s Bridge

Diffuse Inflows -- -- -- 0.6880 0.9535

2.3.2 Point Source Inputs

Five permitted point sources were defined in this model: the Doswell WWTP, the Bear Island facility,

Ashland WWTP, Hanover Courthouse WWTP, and the Juvenile Correction Center (JCC). They are listed

in Table 2-7. Because Doswell WWTP and the Bear Island facility share an outfall structure, the

QUAL2K model accepts the loadings from those two facilities as a single combined discharge.

However, the model pre-processing worksheet allows the user to specify the characteristics of the

individual discharges, and then uses a simple mixing equation to calculate the properties of the

combined discharge.


2-8

Lab data from samples collected by EEE Consulting in September and October of 2012 and permit

data were used as inputs for the water quality characteristics for the point sources. The Little River

was also treated as a point source inflow in QUAL2K, with streamflow derived from gauge 01671100

(Little River near Doswell) and water quality parameters set to the same values as headwater flows

on the North Anna River.

Table 2-7. Point Sources in the Doswell Water Quality Model

Point Source Name Headwater Location

(km)

Sept 26-27

Inflow

(m3/s)

Oct 10-11

Inflow

(m3/s)

Doswell/Bear Island Outfall North Anna-Pamunkey 40.28 0.205 0.195

Little River North Anna-Pamunkey 40.19 0.153 0.105

Ashland WWTP South Anna 6.50 0.029 0.028

Hanover Courthouse WWTP North Anna-Pamunkey 25.06 0.003 0.002

Juvenile Correction Center North Anna-Pamunkey 13.63 0.001 0.001

2.3.3 Conversion of CBOD5 to CBODU

QUAL2K requires inputs of BOD expressed as slow and fast carbonaceous biochemical oxygen

demand – ultimate (CBODU). The measured water quality data express BOD in terms of BOD5 or

CBOD5, requiring conversion to CBODU. For the calibration and corroboration scenarios, BOD5 was

converted to CBOD5 using a literature factor of 1.1 (Muirhead et al., 2006). DEQ’s default f-ratio of

2.5 was used to convert CBOD5 to CBODU for North Anna, South Anna, Ashland WWTP, Hanover

Courthouse, and JCC. For the Bear Island effluent, the f-ratio of 5.77 was used, based on literature

values for the pulp and paper industry (AWARE, 2011). The default DEQ f-ratio of 2.5 was used for

the other municipal discharges. The Bear Island facility discharge, headwater inflows, and

incremental inflows were considered to have slow CBOD, whereas the Doswell WWTP, Ashland

WWTP, Hanover Courthouse WWTP, and JCC were modeled as discharging fast CBOD. The CBOD

model inputs are shown in Table 2-8.

Table 2-8. Carbonaceous Biochemical Oxygen Demand Inputs for the Calibration and Corroboration Scenarios

Discharge

Measured CBOD5 Slow CBOD5 Fast CBOD5

Sep 26-27,

2012

Oct 10-11,

2012

Sep 26-27,

2012

Oct 10-11,

2012

Sep 26-

27, 2012

Oct 10-11,

2012

North Anna Headwater -- -- 2.27 2.27 -- --

South Anna Headwater -- -- 2.27 2.27 -- --

Little River -- -- 2.5 2.5 -- --

Doswell-Bear Island 10.9 23.3 66.4 121.6 0.081 0.908

Bear Island 11.9 22 -- -- -- --

Doswell 1 8.7 -- -- -- --

Ashland WWTP 1 4.3 -- -- 2.5 10.8

Courthouse WWTP 3.6 5.8 -- -- 9.0 14.5

Juvenile Correction Center 5.0 5.0 -- -- 12.5 12.5


2-9

2.3.4 Bioavailable Organic Nitrogen

The water quality data sets for the September-October 2012 sampling events included values for

TKN, nitrate + nitrite nitrogen, and ammonia nitrogen. QUAL2K requires inputs for ammonia

nitrogen, nitrate+nitrite nitrogen, and bioavailable organic nitrogen. For the Doswell-Bear Island

effluent, it was assumed that 46% of the TKN is bioavailable, based on a previous TKN bioavailability

study done for the Doswell-Bear Island combined effluent (HDR, 1988). For the other effluents, it

was assumed that 60% of the organic nitrogen would be potentially subject to hydrolysis within the

model domain (Chen et al., 2011). The resulting bioavailable organic nitrogen values are shown in

Table 2-9.

Table 2-9. Nitrogen Inputs for the Calibration and Corroboration Scenarios

Discharge

TKN (mg/L)

Bioavailable Organic N

(mg/L) Ammonia N (mg/L) Nitrate + Nitrite N (mg/L)

Sep 26-27,

2012

Oct 10-

11,

2012

Sep 26-

27, 2012

Oct 10-11,

2012

Sep 26-27,

2012

Oct 10-11,

2012

Sep 26-27,

2012

Oct 10-

11, 2012

North Anna

Headwater 0.24 0.34 0.11 0.17 0.05 0.05 0.05 0.05

South Anna

Headwater 0.37 0.21 0.19 0.10 0.05 0.05 0.05 0.05

Doswell-Bear Island 4.28 12.60 1.58 0.17 0.39 5.11 2.80 5.56

Ashland WWTP 1.23 2.22 0.71 1.14 0.05 0.32 14.60 19.70

Hanover WWTP 1.23 3.26 0.64 1.82 0.17 0.23 21.40 24.80

2.3.5 Meteorological Data

Meteorological data was obtained from the National Climatic Data Center. Meteorological data was

collected for the same days as the calibration (September 26-27, 2012) and corroboration (October

10-11, 2012) data. Air temperature, dewpoint, and shade were varied by hour to represent a diurnal

cycle. Cloud cover was set to 30% during the entire day.

2.4 Model Calibration and Corroboration Results

2.4.1 Model Calibration Results

Model calibration was conducted by visual comparison of model results to data collected by EEE

Consulting on September 26 and 27, 2012. Figures showing the results of the calibration run are

included in Appendix B. Key model calibration parameters include the reaeration algorithm, the

CBOD oxidation rate, the nitrification rate, and sediment oxygen demand. The first steps of the

calibration were to verify that streamflow and temperature estimates were reasonable, and then

water quality was examined. In some cases, discrepancies between the model and calibration data

appeared to be the result of (1) high control of model results from the single sample collected at the

Bear Island-Doswell outfall; or (2) the fact that the North Anna and South Anna Rivers were sampled

on two different days. These results caused limitations on the degree to which model parameters

were adjusted to match in-stream water quality measurements. Calibration results for individual

parameters are discussed below.

Streamflow: The model shows an excellent streamflow calibration on the North Anna-Pamunkey

River, especially to the headwater values and the downstream most-point which represents USGS

gauge 01673000 (Pamunkey River near Hanover). The model appears to slightly overestimate


2-10

streamflow on the Pamunkey River above the Hanover gauge, and to underestimate streamflow on

South Anna River. Individual field streamflow measurements may not be as accurate as daily

streamflow values from USGS gauges, and so the USGS results were given priority for model

calibration.

Temperature: Overall, the model shows a very good calibration to temperature on both the North

Anna-Pamunkey and South Anna Rivers.

Conductivity: The calibration to conductivity on the North Anna-Pamunkey River system was poor.

The model predicted a significant increase in conductivity below the Doswell-Bear Island effluent,

which was not observed. Conductivity is a conservative parameter and is affected by the magnitude

and conductivity of model input flows rather than any rate coefficient. The model result was largely

driven by a single conductivity measurement of the Doswell-Bear Island effluent collected on

September 26, 2012. Because the flow calibration was good, the simplest explanation for the poor

conductivity calibration is that the Doswell-Bear Island effluent measurement was not representative

of the daily condition. The corroboration dataset shows excellent agreement with observed

conductivity, suggesting that the calibration issue is not a fundamental problem with the model.

Measured conductivity was highly variable on the South Anna River. Model predictions were accurate

for the upstream and downstream portions of the South Anna River. The model also correctly

predicted the approximate magnitude of the step trend in conductivity caused by the mixing of the

South Anna and North Anna Rivers.

Dissolved Oxygen: The model reproduced the location and approximate magnitude of the DO sag on

the North Anna River, below the Doswell-Bear Island outfall, and also showed good agreement with

the DO profile on the South Anna River. Calibration charts appear to show that the model

underestimates the DO on the Pamunkey River, below the confluence of the North Anna River and

South Anna River. This is partially due to difficulties in matching the exact shape of the DO sag below

the Doswell-Bear Island outfall, but also affected by the fact that the North Anna-Pamunkey Rivers

and the South Anna River were sampled on two different days. The model correctly predicted the

approximate magnitude of the step trend in DO caused by the mixing of the South Anna and North

Anna Rivers.

Nitrogen and Phosphorus Species: The calibration plots for nitrogen species (ammonia, TKN, NO3,

and total N) and phosphorus species (inorganic P, total P) are all strongly influenced by results of the

sample of the Doswell-Bear Island effluent collected on September 26, 2012, which largely controls

the predicted magnitude of the “spike” in concentrations below the Doswell-Bear Island outfall. The

predicted increases are in good agreement with river data for parameters such as NO3, total N,

inorganic P, and total P. Ammonia and TKN appear to be underestimated on the North Anna River.

However, the longitudinal variation and step trends associated with North Anna-South Anna

confluence appear to be reasonable.

Chlorophyll-a: The model predicts consistently low phytoplankton chlorophyll-a (1-2 ug/L) through the

river system, which agrees with observation. The model predicted moderate accumulations of

bottom algae (90-120 mg/m2) on available substrate under steady-state low flow conditions.

2.4.2 Model Corroboration Results

Model corroboration was conducted by comparing model results to data collected by EEE Consulting

on October 10 and 11, 2012. Figures showing the results of the calibration run are included in

Appendix B. The model corroboration plots show very good agreement with streamflow and

conductivity. Temperature appears to be oversimulated, possibly due to variability in cloud cover and

other meteorological factors. The corroboration run correctly predicted the approximate maximum

depth of the DO sag on the North Anna River, although the shape of the sag was more difficult to


2-11

reproduce. As with the calibration run, the model was reasonably accurate for DO on the South Anna,

but discrepancies in the DO concentrations on Pamunkey River were strongly influenced by the fact

that that the North Anna–Pamunkey River was sampled on a different day than the South Anna

River. Nutrient species showed similar results as with the calibration run, with strongly influenced

results from the Doswell-Bear Island effluent samples, but reasonable longitudinal and step trends.

Summary of calibration/corroboration: The QUAL2K water quality model was calibrated using

parameter values that are well within the accepted literature range, and also reflect special studies

of the Doswell-Bear Island effluent BOD and TKN characteristics. As with most models, the model

shows better agreement to the calibration dataset than the corroboration dataset for most

constituents. Some apparent discrepancies between model predictions and observed values were

strongly influenced by the fact that the North Anna-Pamunkey River and South Anna River were

sampled on different days, and that the sample of the Doswell-Bear Island effluent has a strong

control on model results for the North Anna River. Overall, the model calibration was deemed

acceptable for its intended purpose.

3-1

Section 3

Management Scenario

Descriptions

Twelve potential management scenarios were run to explore the effects of oxygen-demanding

substances on water quality endpoints during seasonal low flow (7Q10) conditions. The modeled

management scenarios reflect monthly average point source inputs (Virginia DEQ, 2016). The four

seasonal scenarios corresponded to four different seasonal conditions (Jul-Oct, Nov-Dec, Jan-Mar,

and Apr-Jun) and two different levels of Doswell WWTP effluent flow (1 and 2 MGD). The two water

quality endpoints of interest were (1) attaining water quality criteria (5.0 mg/L) and (2) causing no

more than a 0.2 mg/L decrease in DO from an unloaded condition.

Reaction rates of all exploratory management scenarios were based on the calibration scenario, but

system inputs (headwater/diffuse flow parameters and point source loading) were altered to reflect

the respective seasonal and management conditions. A few additional modifications to the original

(calibrated) model were made in response to discussions between Hanover County Utilities, DEQ,

and the modeling team in 2020. This section describes the assumptions, modifications, and results

of each management scenario.

3.1 Overview of Model Scenarios

The basic approach taken for analysis of the management scenarios was first to configure the

models for the four seasonal conditions under unloaded conditions. To simulate the unloaded

condition, flows from permitted point sources were set to zero. Results of each of the twelve

management (”loaded”) scenarios were examined directly to ensure there were no violations of the

DO criterion (5.0 mg/L). Results of the management scenarios were also compared to the unloaded

condition to identify the change in dissolved oxygen in each river element and segment. This allowed

estimation of the maximum change in DO between the unloaded and loaded conditions.

The twelve management scenarios presented in this document are derived from a much larger

number (>100) of scenarios that were used to explore different combinations of assumptions

regarding seasonal conditions, point source inflows, and other environmental characteristics. These

twelve scenarios were selected as the most relevant scenarios for exploring the assimilative capacity

of the river system. As shown in Table 3-1, the scenarios differ primarily in season, the Doswell

WWTP flow, the BOD5/CBOD5 loading of the Bear Island facility and Doswell WWTP, and the effluent

DO concentrations. Other conditions and point source inputs were kept constant for each season. All

scenarios presented in this document comply with both the DO criterion and the antidegradation-

based goal of no more than a 0.2 mg/L decrease in DO from an unloaded condition. Detailed model

inputs for point sources are provided in Appendix C.


3-2

Table 3-1. Overview of Exploratory Management Scenarios

Scenario Season

Effluent Flow

(MGD) Bear Island

BOD5

(lb/d)

Doswell

WWTP

CBOD5

(lb/d)

Dissolved Oxygen

(mg/L)

Doswell

WWTP

Bear

Island

Doswell

WWTP

Bear Island Ashland

WWTP

1 Jul-Oct 1.0 1.5 679 41.7 6.5 6.5 7.0

2 Jul-Oct 2.0 1.5 634 83.4 6.5 6.5 7.0

3 Jul-Oct 1.0 1.5 679 41.7 6.5 6.5 6.5

4 Jul-Oct 2.0 1.5 634 83.4 6.5 6.5 6.5

5 Nov-Dec 1.0 1.5 1,078 41.7 7.1 7.1 7.0

6 Nov-Dec 2.0 1.5 911 83.4 7.1 7.1 7.0

7 Nov-Dec 1.0 1.5 963 41.7 6.5 6.5 7.0

8 Nov-Dec 2.0 1.5 634 83.4 6.8 6.8 7.0

9 Jan-Mar 1.0 1.5 1,126 41.7 6.5 6.5 7.0

10 Jan-Mar 2.0 1.5 1,126 83.4 6.5 6.5 7.0

11 Apr-Jun 1.0 1.5 1,126 41.7 6.5 6.5 7.0

12 Apr-Jun 2.0 1.5 1,126 83.4 6.5 6.5 7.0

3.2 Management Scenario Model Input Parameters

3.2.1 Headwater and Diffuse Inflows

Headwater and diffuse inflows used in management scenario model runs are summarized in Table

3-2. The 7Q10 streamflows were provided by DEQ. The approach taken estimating diffuse inflows

was similar to the approach taken for the calibration and corroboration scenario, with the difference

that it was desired to make the diffuse inflows for the management scenarios consistent with the

7Q10 yields (i.e., cfs per mi2 of contributing watershed) provided by DEQ. To calculate diffuse inflows,

the seasonal 7Q10 flows per unit drainage area were calculated for the major gages in the study

area, and these values were multiplied by the watershed drainage area between the headwater

inflow locations and downstream locations in the model domain.

Diffuse inflows for the mainstem (North Anna-Pamunkey) model segments were based on unit 7Q10

values from USGS gage 1673000 (Pamunkey River near Hanover). Specifically, the diffuse inflow to

the mainstem were calculated as the 7Q10 yield at the gage, multiplied by the watershed area

between the upstream and downstream ends of the mainstem model extent. The contributing

watershed area of the Little River was subtracted because the 7Q10 of that stream was specified

separately as a point source to the model. Similarly, the contributing watershed area of the South

Anna River was subtracted from the mainstem diffuse flow calculation because diffuse flows were

estimated separately for that stream, based on unit 7Q10 values from USGS gage 1672500 (South

Anna River near Ashland). These inflows were proportionally distributed over the length of the model

study area according to reach lengths. Unless otherwise noted below, the water quality

characteristics of headwater flows and diffuse inflows were set to the average values of the

September and October 2012 sampling events.


3-3

Table 3-2. Headwater Streamflows and Diffuse Inflows

Season

7Q10 Streamflow (cfs) Diffuse Inflows (cfs)

1671025

(N Anna abv

Little R.)

1671100

(Little R. nr

Doswell)

1675200

(South

Anna R. nr

Ashland

1671100

(Pamunkey R. nr

Hanover)

Mainstem

(North Anna-

Pamunkey to

Nelsons

Bridge)

South Anna

River

Jan-Mar 59.4 19.7 96.1 238.3 37.8 17.5

Apr-Jun 47.0 6.7 48.4 123.1 19.5 8.8

Jul-Oct 27.2 0.5 10.1 39.8 6.3 1.8

Nov-Dec 38.3 4.4 40.0 107.0 17.0 7.3

3.2.2 Point Source Flows

As shown in Table 3-1, the Doswell WWTP flow was set to 1.0 MGD in six of the twelve scenarios and

2.0 MGD in the other six scenarios. Other point source flows were set constant design flow rates as

follows:

• Bear Island = 1.5 mgd

• Ashland WWTP = 2.0 mgd

• Courthouse WWTP = 0.08 mgd

• JCC = 0.035 mgd

3.2.3 Temperature

Headwater, diffuse inflow, and point source temperatures used in management scenario model runs

are summarized in Table 3-3. The headwater temperatures were based on 90th percentile values at

stream gaging stations for each season, and were provided by DEQ. The temperatures of diffuse

inflows and the Little River were set to the same values as the South Anna River headwater.

Table 3-3. Temperature Inputs for Management Scenarios

Source Temperature (deg C)

Jul-Oct Nov-Dec Jan-Mar Apr-Jun

North Anna Headwaters 26.0 14.0 10.8 25.2

Little River 25.9 11.4 9.9 24.0

South Anna Headwaters 25.9 11.4 9.9 24.0

Diffuse Inflows 25.9 11.4 9.9 24.0

Bear Island Effluent 32.0 32.0 32.0 32.0

Doswell WWTP Effluent 24.4 16.8 16.8 24.4

Ashland WWTP Effluent 24.4 16.8 16.8 24.4

Courthouse WWTP Effluent 24.4 15.0 15.0 24.4

Juvenile Correction Center Effluent 22.0 18.7 18.7 22.0

The temperature of the Bear Island facility was set to 32.0 deg C for all seasons, based on

information provided by Cascades. Other point source temperatures were set to the 90th percentile

of available daily (Ashland and Doswell WWTPs) or monthly (Courthouse WWTP) data as reported in

the facility Discharge Monitoring Reports (DMRs). The period of record for the WWTP DMR data was

as follows:


3-4

• Ashland WWTP: January 2006 to June 2016

• Doswell WWTP: December 2007 to June 2016

• Courthouse WWTP: February 2014 to June 2016

The temperature at the JCC point source was defined as the maximum daily summer (22.0°C) and

winter (18.7°C) temperatures reported by the facility in the VPDES permit application and included

in Attachment E of the VPDES Permit VA0020664 Fact Sheet.

In 2020 discussions, DEQ noted that warm season (Apr-Jun and Jul-Oct) versions of model predicted

that temperature decreased about 5 deg. C along the mainstem. DEQ therefore requested model

revisions to attain a flatter temperature profile. Investigation by the modeling team revealed that the

predicted temperature decrease was primarily caused by the combination of high headwater inflow

temperature with more typical air temperatures, such that the water was predicted to lose heat to

the air. This issue was addressed by increasing the air temperature to achieve a relatively flat

temperature profile in the management scenarios.

3.2.4 Dissolved Oxygen

Headwater, diffuse inflow, and point source DO used in management scenario model runs are

summarized in Table 3-4. Headwater and Little River dissolved oxygen data were collected from the

same gauges and period of record as presented in Section 3.2.3. Little River dissolved oxygen was

set to the 10th percentile of available DO data.

Table 3-4. Dissolved Oxygen Inputs for Management Scenarios

Source Dissolved Oxygen (mg/L)



Little River 7.40 9.20 9.20 7.40


North Anna-Pamunkey Diffuse Inflows 7.05 8.99 8.99 7.05

South Anna Diffuse Inflows 6.77 9.23 9.23 6.77

Bear Island Effluent 6.5 6.5-7.1a 7.1 6.5

Doswell WWTP Effluent 6.5 6.5-7.1a 7.1 6.5

Ashland WWTP Effluent 6.5/7.0b 7.0 7.0 7.0



aTable 3-1 lists the Doswell and Bear Island DO concentrations by scenario.

bThe more appropriate monthly average DO value for the Ashland WWTP is 7.0 mg/L; however, 6.5

was tested for some Jul-Oct scenarios (3 and 4) to confirm that even this low value would not

cause violation of the antidegradation threshold.

Headwater DO was calculated for the North Anna and South Anna Rivers using a DO saturation

method rather than taking a percentile of the available DO data. For all sample dates that included

coincident temperature, DO, and conductivity data, a percent saturation value was calculated. The

dissolved oxygen model input was calculated from the 10th percentile percent saturation, and model

input values for temperature (90th percentile) and conductivity (average of 2012 field data). For a

previous version of the model (Brown and Caldwell, 2016), the modeling team developed DO values

for annual and wet season scenarios. For the 2020 version of the model, the DO values for the

annual scenario were applied to the warm season scenarios (Apr-Jun, Jul-Oct), and DO values of the


3-5

wet season scenario were applied to the cool season scenarios (Nov-Dec, Jan-Mar). Diffuse inflow DO

for the mainstem and South Anna segments were set equal to the respective North Anna and South

Anna River headwater DO values.

Point source dissolved oxygen was set to daily permit limits for the Courthouse WWTP (5 mg/L) and

JCC (6 mg/L). The Bear Island and Doswell effluents were set to different DO concentrations for

different seasons and scenarios. For the Nov-Dec seasons (scenarios 4 through 7), three effluent DO

concentrations (6.5, 6,8, and and 7.1 mg/L) were explored for the Bear Island and Doswell WWTP

effluents (Table 3-1). For the Ashland WWTP effluent, DO concentration was set to 7.0 mg/L for most

scenarios, as a conservatively low estimate of the monthly average DO value that would result from

compliance with daily permit limits. However, for two Jul-Oct scenarios (scenarios 3 and 4), the

Ashland WWTP DO concentration was set to 6.5 mg/L to confirm that even this low value would not

cause violation of the antidegradation threshold.

3.2.5 pH

Headwater, diffuse inflow, and point source pH used in management scenario model runs are

summarized in Table 3-5. Headwater and Little River pH values were set to the median of data from

the following gauges:

• North Anna River at Harts Corner (USGS Gauge 01671020), period of record 2006–2016.

• Little River (DEQ Gauge 8-LTL002.69), period of record 2003–2012.

• South Anna River (DEQ Gauge 8-SAR001.11), period of record 1979-2013.

For a previous version of the model (Brown and Caldwell, 2016), the modeling team developed pH

values for annual and wet season scenarios. For the 2020 version of the model, the pH values for

the annual scenario were applied to the warm season scenarios (Apr-Jun, Jul-Oct), and pH values of

the wet season scenario were applied to the cool season scenarios (Nov-Dec, Jan-Mar). Diffuse

inflow pH values were set equal to the respective South Anna and North Anna River headwater

values.

Table 3-5. pH Inputs for Management Scenarios

Source pH (s.u.)



Little River 7.10 7.10 7.10 7.10


North Anna-Pamunkey Diffuse Inflows 7.00 7.00 7.00 7.00

South Anna Diffuse Inflows 7.00 6.90 6.90 7.00

Bear Island Effluent 7.57 7.57 7.57 7.57

Doswell WWTP Effluent 7.57 7.57 7.57 7.57

Ashland WWTP Effluent 7.39 7.39 7.39 7.39



Point source pH values were set to permit limits for the Courthouse WWTP (pH of 7.6) and JCC (90th

percentile pH of 7.3) for the annual scenario and a 10th percentile pH of 6.4 for the wet weather

scenario. Bear Island/Doswell WWTP, and Ashland WWTP pH values were set equal to field data

collected at the respective discharge sites in September and October 2012.


3-6

3.2.6 Headwater and Diffuse Inflow Water Quality

Unless otherwise discussed in the temperature, DO and pH sections above, the water quality

characteristics of headwater flows and diffuse inflows were set to the average values of the

September and October 2012 sampling events. Phytoplankton and inorganic solids concentrations

were set during model calibration and corroboration.

3.2.7 Biochemical Oxygen Demand

As discussed in section 2.3.3, the model requires inputs of biochemical oxygen demand (BOD)

expressed as slow and fast CBODU (carbonaceous biochemical oxygen demand – ultimate). In

contrast, permit limits and treatability studies generally express values as BOD5 or CBOD5. For

headwater inflows, diffuse inflows, and most point sources, the default f-ratio of 2.5 was used to

convert between CBOD5 and CBODU. An f-ratio of 5.77 was used for the Bear Island facility, in

recognition that pulp and paper effluents exhibit higher f-ratios than municipal effluent (AWARE,

2011). As in the calibration scenario, municipal effluent was assumed to discharge fast CBODU,

whereas the Bear Island facility, headwater inflows, and diffuse inflows were assumed to contain

slow CBODU.

The derivation of BOD5 values from CBOD5 values (or vice versa) requires assumptions regarding

the proportion of the BOD5 that is carbonaceous vs. nitrogenous. This proportion is partially

dependent upon the ammonia and organic nitrogen concentrations of each source. The modeling

team used simple calculations to explore how different concentrations of ammonia and organic

nitrogen would affect the ratio of BOD5 to CBOD5. Based on this analysis, a ratio of 1.85 was chosen

for the JCC and Hanover Courthouse WWTP. This value is the average value cited for secondary

treatment by USEPA (1997). A lower ratio of BOD5 to CBOD5 (1.3) was used for the Bear Island

facility, based on lower concentrations of nitrogenous oxygen demand in that effluent. Limits for the

Doswell and Ashland WWTPs are expressed in units of CBOD5, and so no conversion was necessary

for those facilities. Table 3-6 lists the assumptions regarding oxygen demand for each facility and

model scenario.

Table 3-6. BOD5 Inputs for Management Scenarios

Discharge

Apr-Jun and Jul-Oct Seasons

mg/L lb/d

Headwaters and Diffuse Flows 1 NA

Bear Island BOD5 loading varies by scenario; see Table 3-1

Doswell WWTP CBOD5 loading varies by scenario; see Table 3-1

Ashland WWTP 20 (CBOD5) 337 (CBOD5)

Courthouse WWTP 30 20

Juvenile Correction Center 30 8.7

3.2.8 Nitrogen Species

QUAL2k accepts inputs of nitrite-plus-nitrate, ammonia, and organic nitrogen. Within the model,

100% of the organic nitrogen is assumed to be bioavailable. Hence, poorly-bioavailable organic

nitrogen should be subtracted from the organic nitrogen prior to input to the model. Table 3-7 lists

the assumptions regarding nitrogen species for each major source and scenario. As in the calibration

scenario, it was assumed that 46% of TKN for the Bear Island facility was bioavailable, and 60% of

organic nitrogen is bioavailable for most other point source effluents. The exception was the Ashland


3-7

WWTP, which was assumed to contain 1 mg/L of poorly-bioavailable organic nitrogen based on an

evaluation of effluent monitoring results.

Table 3-7. Nitrogen Inputs for Management Scenarios

Discharge NO2+NO3 N NH4-N Org. N TKN

mg N/L mg /L mg N/L mg/L lb/day

Headwaters and Diffuse Inflows 0.050 0.050 0.144 0.194 NA

Bear Island Facility 1.8 1.0 12.5 10.0 125.1

Doswell WWTP 1.0 1.0 2.0 3.0 25.0 (1 MGD scenarios)

50.0 (2 MGD scenarios)

Ashland WWTP 14.6 1.0 4.0 5.0 83.4

Courthouse WWTP 21.4 2.5 14.5 14.5 15.2

Juvenile Correction Center 18.0 17.5 6.3 10.5 3.1

3.2.9 Meteorological Data

Meteorological data was obtained from the National Climatic Data Center for the same days as the

calibration (September 26-27, 2012) data. Air temperature, dewpoint, and shade were varied by

hour to represent a diurnal cycle. As discussed in section 3.2.3, the air temperature was increased

for the warm weather seasons (Apr-Jun, Jun-Oct) in order to achieve a flat temperature profile for the

mainstem model segments. Cloud cover was set to 30% during the entire day.

4-1

Section 4

Management Scenario Results

Tables 4-1 and 4-2 provide the minimum DO and maximum delta DO values that were observed in

the model domain for each scenario. Table 4-1 provides these values based on individual model

elements, whereas Table 4-2 provides the values based on segment averages. Appendix D includes

charts of DO profiles for each scenario, and Appendix E provides the average DO and delta DO for

each segment and scenario.

On the mainstem (North Anna-Pamunkey River) segments, the DO sag compliance occurs 0-5 km

downstream of the Bear Island – Doswell outfall and upstream of the confluence of the North Anna

River with the South Anna River. On the South Anna, the DO sag occurs about just downstream of the

Ashland WWTP outfall and upstream of the confluence of the South Anna River with the North Anna

River. DO concentration was not predicted to decrease below the water quality criterion of 5 mg/L at

any location in any scenario. Similarly, DO concentration was not predicted to be more than 0.2 mg/L

(rounded to the single decimal place of the target in DEQ guidance) below an unloaded condition at

any location in any scenario.

Table 4-1. QUAL2K Model Results by Critical Model Element

Scenario Season

Minimum DO

(mg/L)

Maximum ΔDO

(mg/L)

North Anna –

Pamunkey South Anna

North Anna –

Pamunkey South Anna

1 Jul-Oct 5.8 6.8 0.212 0.164

2 Jul-Oct 5.8 6.8 0.212 0.164

3 Jul-Oct 5.8 6.8 0.212 0.248

4 Jul-Oct 5.8 6.8 0.212 0.248

5 Nov-Dec 8.1 9.2 0.248 0.201

6 Nov-Dec 8.1 9.2 0.248 0.201

7 Nov-Dec 8.1 9.2 0.249 0.201

8 Nov-Dec 8.1 9.2 0.245 0.201

9 Jan-Mar 9.0 9.2 0.172 0.084

10 Jan-Mar 9.0 9.2 0.202 0.084

11 Apr-Jun 6.6 6.8 0.206 0.048

12 Apr-Jun 6.5 6.8 0.222 0.048


4-2

Table 4-2. QUAL2K Model Results by Critical Model Segment Average

Scenario Season

Minimum DO (mg/L)

Maximum ΔDO (mg/L)

North Anna – Pamunkey

South Anna North Anna –

Pamunkey South Anna

1 Jul-Oct 5.8 7.4 0.210 0.125

2 Jul-Oct 5.8 7.4 0.210 0.125

3 Jul-Oct 5.8 7.4 0.210 0.151

4 Jul-Oct 5.8 7.4 0.210 0.151

5 Nov-Dec 8.1 9.5 0.246 0.181

6 Nov-Dec 8.1 9.5 0.247 0.181

7 Nov-Dec 8.1 9.5 0.245 0.181

8 Nov-Dec 8.1 9.5 0.243 0.181

9 Jan-Mar 9.0 9.4 0.172 0.084

10 Jan-Mar 9.0 9.2 0.199 0.084

11 Apr-Jun 6.6 7.1 0.206 0.045

12 Apr-Jun 6.5 7.1 0.222 0.045

5-1

Section 5

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HDR Infrastructure, Inc. January 1988. Water Quality Modeling: North Anna and Pamunkey Rivers; York River Basin,

Virginia. Prepared for Bear Island Paper Company

Lung, W. 2001. Water Quality Modeling for Wasteload Allocations and TMDLs. Wiley Press, p. 352

Muirhead, W.M., Farmer, G., Walker, S., Robb, L., Elmnedorf, H., Matthews, R., Butler, R., and Melcer, H., 2006.

Study of raw wastewater BOD5 and cBOD5 relationship yields surprising results. Proceedings of WEFTEC 2006,

pp. 840-853

National Council of the Paper Industry for Air and Stream Improvement. 1982. A Review of Ultimate BOD Estimation

and Its Kinetic Formulation for Pulp and Paper Mill Effluent. Technical Bulletin No. 382, p. 42

National Oceanic and Atmospheric Administration National Climatic Data Center. Land Based Station Data.

http://www.ncdc.noaa.gov/cdoweb/datasets/GHCND/stations/GHCND:USW00013740/detail

U.S. Environmental Protection Agency. 1997. Technical Guidance Manual for Performing Wasteload Allocations,

Book II: Streams and Rivers – Part 1: Biochemical Oxygen Demand/Dissolved Oxygen and

Nutrients/Eutrophication. EPA-823-B-97-002. 254 p

Virginia Dept. of Environmental Quality. 2016. DEQ Comments on the Dissolved Oxygen Modeling of the North Anna,

South Anna, and Pamunkey River System, October 7, 2014. Letter from Emilee C. Adamson to David Van Gelder.

3 p.

http://www.ncdc.noaa.gov/cdoweb/datasets/GHCND/stations/GHCND:USW00013740/detail


A-1

Appendix A: Field and Lab Data

Calibration Data Set: September 26-27, 2012

Corroboration Data Set: October 10-11, 2012


B-1

Appendix B: Calibration and Corroboration Charts

September 2012 Field Data

Site Date Time Temp Specific

Conductivity

DO

Concentration

DO

Concentration pH ORP

m/d/y hh:mm C mS/cm % mg/L mV

DOS1 9/27/2012 11:32 30.91 2.36 82.5 6.1 7.57 98.3

DOS2 9/27/2012 11:38 21.79 0.457 86.8 7.56 7.48 96

DOS3 9/27/2012 11:30 30.94 2.356 87 6.42 7.52 102

COURT1 9/27/2012 12:11 22.19 0.492 106.2 9.24 7.48 96

ASH1 9/27/2012 10:06 23.2 0.457 110.1 9.41 7.39 166.5

NA1 9/28/2012 9:24 20:00 0.56 87.6 7.83 6:44 231

NA2 9/27/2012 9:02 19.03 0.108 --- 8.51 6.29 247

NA3 9/27/2012 10:11 20.12 0.494 --- 7.07 7.45 197

NA4 9/27/2012 11:02 20.22 0.491 --- 7.23 7.47 192

NA5 9/27/2012 11:40 20.66 0.486 84 7.52 7.51 220.5

PR1 9/27/2012 12:25 20.83 0.358 94 8.4 7.59 232

PR2 9/27/2012 1:25 20.73 0.309 98.4 8.86 7.63 192

PR3 9/27/2012 2:48 20.86 0.296 100.1 8.9 7.56 212

PR4 9/27/2012 3:00 21.64 0.293 98 8.56 7.55 233

PR5 9/27/2012 3:25 21.78 0.297 95 8.31 7.61 254

SA1 9/26/2012 9:48 17.28 0.6 83.1 7.98 29

SA2 9/26/2012 10:30 17.59 0.67 88.9 8.49 6.77 4.6

SA3 9/26/2012 11:14 17.74 0.8 92.5 8.81 6.88 126.5

SA4 9/26/2012 12:30 18.5 0.85 96.2 8.99 6.98 102

SA5 9/26/2012 1:01 19.09 2 98.4 9.11 7.03 129.9

SA6 9/26/2012 1:50 19.49 1.2 99.8 9.17 6.96 146

SA7 9/27/2012 12:05 19.72 0.137 106 9.74 7.05 254

September 2012 Lab DataSeptember 2012 Lab DataSeptember 2012 Lab DataSeptember 2012 Lab Data

Site ID Sampling

Date Lab Sample ID Ammonia CBOD COD Nitrate

Nitrate+

Nitrite Nitrite Orthophosphate

Phosphorus,

Total

Specific

Conductance TKN Chlorophyll A

m/dd/yyyy mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L umhos/cm mg/L mg/m3

SA1 9/26/2012 12090471-001 <0.1 <2 12.5 <0.1 <0.1 <0.05 0.04 0.05 111 0.37 <0.100

SA2 9/26/2012 12090471-002 <0.1 <2 10.8 <0.1 <0.1 <0.05 0.04 0.04 110 0.31 <0.100

SA3 9/26/2012 12090471-003 <0.1 <2 <10 0.4 0.40 <0.05 0.12 0.14 120 0.32 2.90

SA4 9/26/2012 12090471-004 <0.1 <2 10.1 0.2 0.16 <0.05 0.05 0.10 115 0.30 <0.100

SA5 9/26/2012 12090471-005 <0.1 <2 <10 0.2 0.15 <0.05 0.05 0.08 115 0.31 <0.100

SA6 9/26/2012 12090471-006 <0.1 <2 <10 0.2 0.16 <0.05 0.06 0.09 115 0.30 3.70

SA7 9/27/2012 12090502-002 <0.1 <2 <10 0.3 0.34 <0.05 0.13 0.10 Not measured 0.33 1.10

COURT1 9/27/2012 12090479-001 0.17 3.6 13.2 21.3 21.4 0.09 2.51 2.50 Not measured 1.23 <0.100

DOS1 9/27/2012 12090479-004 0.39 10.9 105 1.6 2.80 1.16 0.64 0.73 Not measured 4.28 <0.100

DOS2 9/27/2012 12090479-002 <0.1 <2 16.2 20.2 20.2 <0.05 1.34 1.36 Not measured 1.23 2.40

DOS3 9/27/2012 12090479-003 0.38 11.9 101 0.4 1.63 1.27 0.60 0.58 Not measured 3.71 0.830

ASH1 9/27/2012 12090480-001 <0.1 <2 15.2 14.6 14.6 <0.05 3.74 3.77 Not measured 1.23 <0.100

NA1 9/28/2012 12090502-011 <0.1 <2 10.1 <0.1 <0.1 <0.05 <0.01 0.12 Not measured 0.24 0.300

NA2 9/27/2012 12090502-003 <0.1 <2 <10 <0.1 <0.1 <0.05 0.03 0.02 Not measured 0.30 <0.100

NA3 9/27/2012 12090502-005 0.13 <2 25.1 0.3 0.39 0.09 0.14 0.13 Not measured 0.67 <0.100

NA4 9/27/2012 12090502-001 0.14 <2 27.8 0.3 0.41 0.07 0.13 0.14 Not measured 0.70 1.60

NA5 9/27/2012 12090502-004 0.11 <2 22.0 0.4 0.42 0.06 0.13 0.16 Not measured 0.62 5.80

PR1 9/27/2012 12090502-010 <0.1 <2 21.0 0.4 0.40 <0.05 0.12 0.28 Not measured 0.53 2.20

PR2 9/27/2012 12090502-006 <0.1 <2 14.9 0.4 0.41 <0.05 0.12 0.09 Not measured 0.47 <0.100

PR3 9/27/2012 12090502-007 <0.1 <2 16.6 0.4 0.37 <0.05 0.11 0.09 Not measured 0.41 2.20

PR4 9/27/2012 12090502-009 <0.1 <2 14.2 0.4 0.36 <0.05 0.13 0.09 Not measured 0.41 <0.100

PR5 9/27/2012 12090502-008 <0.1 <2 11.5 0.4 0.38 <0.05 0.12 0.06 Not measured 0.42 1.10

October 2012 Field DataOctober 2012 Field DataOctober 2012 Field DataOctober 2012 Field Data

Site Date Time Temp Specific

Conductivity

DO

Concentration

DO

Concentration pH ORP

m/d/y hh:mm C mS/cm % mg/L mV

DOS1 10/11/2012 10:20 26.35 2.317 88.2 7.04 7.57 179.4

DOS2 10/11/2012 10:31 19.26 0.709 90.7 8.3 7.7 127.5

DOS3 10/11/2012 10:45 27.01 2.444 84.7 6.67 7.54 184.6

COURT1 10/11/2012 11:10 19.44 0.48 99.1 9.09 7.36 115.8

ASH1 10/11/2012 11:52 20.34 0.497 102.1 9.25 7.67 98.8

NA1 10/10/2012 3:17 16.9 0.066 82.8 7.09 7.61 44.7

NA2 10/10/2012 9:26 16.2 0.069 82.2 7.95 7.29 63.5

NA3 10/10/2012 10:17 16.1 0.431 73.2 6.42 7.54 131.6

NA4 10/10/2012 10:56 16.1 0.413 70.3 6.39 7.55 109.3

NA5 10/10/2012 11:27 16.4 0.415 82.2 7.86 7.63 2.2

PR1 10/10/2012 12:08 16.6 0.346 79.8 6.59 7.64 14.4

PR2 10/10/2012 12:43 16 0.248 79.1 6.48 7.73 -72.2

PR3 10/10/2012 1:23 16.2 0.251 85.8 7.13 7.72 -52.3

PR4 10/10/2012 2:04 16.7 0.249 85.9 7.24 7.75 -83.3

PR5 10/10/2012 2:20 17.1 0.247 81.2 7.4 7.81 -97.7

SA1 10/11/2012 9:05 15.1 0.125 88 7.48 7.16 169.9

SA2 10/11/2012 9:35 14.8 0.124 87.1 7.41 7.26 75.1

SA3 10/11/2012 9:55 14.4 0.129 91.3 8.42 7.33 42.7

SA4 10/11/2012 10:35 14.3 0.127 89.8 8.31 7.38 44.3

SA5 10/11/2012 10:40 14.1 0.127 90.6 8.91 7.39 -48.8

SA6 10/11/2012 11:15 14.2 0.128 92.7 8.98 7.41 -51.4

SA7 10/10/2012 11:45 15.3 0.106 91.4 8.62 7.78 0.6

October October October October 2012 Lab Data2012 Lab Data2012 Lab Data2012 Lab Data

Site ID Sampling

Date Lab Sample ID Ammonia CBOD COD Nitrate

Nitrate+

Nitrite Nitrite Orthophosphate

Phosphorus,

Total TKN

Chlorophyll

A

m/dd/yyyy mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/m3

SA1 10/11/2012 12100248-001 <0.1 <2 14.6 <0.1 <0.1 <0.05 0.04 0.06 0.21 <0.100

SA2 10/11/2012 12100248-002 <0.1 <2 16.0 <0.1 <0.1 <0.05 0.09 0.11 0.45 <0.100

SA3 10/11/2012 12100248-003 <0.1 <2 10.7 0.2 0.24 <0.05 0.14 0.10 0.23 <0.100

SA4 10/11/2012 12100248-004 <0.1 <2 14.2 0.2 0.19 <0.05 0.06 0.16 0.22 <0.100

SA5 10/11/2012 12100248-005 <0.1 <2 16.0 0.2 0.20 <0.05 0.08 0.17 0.23 0.700

SA6 10/11/2012 12100248-006 <0.1 <2 15.7 0.3 0.26 <0.05 0.09 0.16 0.24 <0.100

SA7 10/10/2012 12100238-007 <0.1 <2 12.4 0.3 0.29 <0.05 0.13 0.14 0.24 0.400

COURT1 10/11/2012 12100245-004 0.23 5.8 45.4 24.7 24.8 0.14 3.01 3.52 3.26 <0.100

DOS1 10/11/2012 12100245-002 0.70 23.3 318 2.8 5.56 2.74 0.75 0.99 12.6 0.200

DOS2 10/11/2012 12100245-001 0.18 8.7 87.6 41.2 41.2 <0.05 2.62 0.13 4.46 4.30

DOS3 10/11/2012 12100245-003 0.67 22.0 303 0.5 3.36 2.86 0.61 1.92 12.1 <0.100

ASH1 10/11/2012 12100246-001 0.32 4.3 36.4 19.3 19.7 0.42 4.38 4.71 2.22 6.90

NA1 10/10/2012 12100238-002 <0.1 <2 13.5 <0.1 <0.1 <0.05 0.04 0.04 0.34 0.600

NA2 10/10/2012 12100238-005 <0.1 <2 11.0 <0.1 <0.1 <0.05 <0.01 0.02 0.59 1.90

NA3 10/10/2012 12100238-004 0.22 3.0 38.2 0.6 0.89 0.32 0.12 0.16 1.02 2.50

NA4 10/10/2012 12100238-006 0.16 2.1 37.5 0.6 0.81 0.21 0.12 0.16 0.82 0.800

NA5 10/10/2012 12100238-003 0.20 <2 33.9 0.7 0.84 0.18 0.15 0.16 0.89 1.70

PR1 10/10/2012 12100238-008 0.12 <2 29.6 0.6 0.70 0.13 0.14 0.14 0.70 4.30

PR2 10/10/2012 12100238-009 <0.1 <2 22.5 0.5 0.62 0.08 0.14 0.17 0.52 2.80

PR3 10/10/2012 12100238-011 <0.1 <2 23.5 0.5 0.63 0.09 0.15 0.17 0.48 3.50

PR4 10/10/2012 12100238-001 0.13 <2 16.4 0.6 0.69 0.10 0.14 0.17 0.46 1.80

PR5 10/10/2012 12100238-010 <0.1 <2 22.5 0.6 0.71 0.11 0.15 0.14 0.48 2.70


C-1

Appendix C: Detailed Point Source Inputs for

Management Scenarios


C-1

Table C-1. Point Source Inputs for the Bear Island Facility

Table C-2. Point Source Inputs for the Doswell WWTP

Nitrate N Inorg P Org P

MGD m3/s lbs/day mg/L lbs/day mg/L lbs/day mg/L lbs/day mg/L lbs/day mg/L mg/L mg/L mg/L

1 Test 81 Jul-Oct 1.5 0.1 32.0 6.5 679.3 54.3 522.5 41.8 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

2 Test 82 Jul-Oct 1.5 0.1 32.0 6.5 634.3 50.7 487.9 39.0 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

3 Test 78 Jul-Oct 1.5 0.066 32.0 6.5 679.3 54.3 522.5 41.8 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

4 Test 79 Jul-Oct 1.5 0.066 32.0 6.5 634.3 50.7 487.9 39.0 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

5 Test 47 Nov-Dec 1.5 0.066 32.0 7.1 1078.4 86.2 829.5 66.3 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

6 Test 53 Nov-Dec 1.5 0.066 32.0 7.1 910.7 72.8 700.6 56.0 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

7 Test 66 Nov-Dec 1.5 0.066 32.0 6.5 963.0 77.0 740.8 59.2 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

8 Test 74 Nov-Dec 1.5 0.066 32.0 6.8 634.3 50.7 487.9 39.0 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

9 Test 67 Jan-Mar 1.5 0.066 32.0 6.5 1125.9 90.0 866.1 69.2 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

10 Test 70 Jan-Mar 1.5 0.066 32.0 6.5 1125.9 90.0 866.1 69.2 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

11 Test 49 Apr-Jun 1.5 0.066 32.0 6.5 1125.9 90.0 866.1 69.2 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

12 Test 55 Apr-Jun 1.5 0.066 32.0 6.5 1125.9 90.0 866.1 69.2 125.1 10.0 12.5 1.0 45.0 3.6 1.8 1.0 1.0

CBOD5 (slow) TKN NH4-N Bioavail. Org N

SeasonScenario

Previous

Name

Bear Island Facility

Flow Temp

(dec. C)

DO

(mg/L)

BOD5


MGD m3/s

Temp

(dec. C)

DO

(mg/L) lbs/day mg/L lbs/day mg/L lbs/day mg/L lbs/day mg/L lbs/day mg/L mg/L mg/L mg/L

1 Test 81 Jul-Oct 1.0 0.044 24.4 6.5 Not used Not used 41.7 5.0 25.0 3.0 8.34 1.0 10.0 1.2 1.0 0.15 0.15




5 Test 47 Nov-Dec 1.0 0.044 16.8 7.1 Not used Not used 41.7 5.0 25.0 3.0 8.34 1.0 10.0 1.2 1.0 0.15 0.15




9 Test 67 Jan-Mar 1.0 0.0 16.8 6.5 Not used Not used 41.7 5.0 25.0 3.0 8.34 1.0 10.0 1.2 1.0 0.15 0.15

10 Test 70 Jan-Mar 2.0 0.1 16.8 6.5 Not used Not used 83.4 5.0 50.0 3.0 16.68 1.0 20.0 1.2 1.0 0.15 0.15

11 Test 49 Apr-Jun 1.0 0.044 24.4 6.5 Not used Not used 41.7 5.0 25.0 3.0 8.34 1.0 10.0 1.2 1.0 0.15 0.15

12 Test 55 Apr-Jun 2.0 0.088 24.4 6.5 Not used Not used 83.4 5.0 50.0 3.0 16.68 1.0 20.0 1.2 1.0 0.15 0.15

SeasonScenario

Previous

Name

Doswell WWTP

Flow BOD5 CBOD5 (fast) TKN NH4-N Bioavail. Org N


C-2

Table C-3. Point Source Inputs for Other Point Sources


MGD m3/s lbs/day mg/L lbs/day mg/L lbs/day mg/L lbs/day mg/L lbs/day mg/L mg/L mg/L mg/L

Apr-Jun & Jul-Sept, Ashland WWTP 2.0 0.0876 24.4 7.00a

Not used Not used 338.7 20.3 83.4 5.0 16.68 1.00 50.0 3.00 14.6 4.38 0.17

Apr-Jun & Jul-Sept, Hanover Courthouse WWTP 0.08 0.0035 24.4 5.00 30.00 10.8 16.2 11.3 17.0 1.668 2.50 5.8 8.70 21.4 3.01 0.17

Apr-Jun & Jul-Sept, JCC 0.035 0.0015 22.0 6.00 30.00 4.7 16.2 8.2 28.0 5.10825 17.50 1.8 6.31 18.0 3.70 0.08

Nov-Dec & Jan-Mar, Ashland WWTP 2.0 0.0876 16.8 7.00 Not used Not used 338.7 20.3 83.4 5.0 16.68 1.00 50.0 3.00 14.6 4.38 0.17

Nov-Dec & Jan-Mar, Hanover Courthouse WWTP 0.08 0.0035 15.0 5.00 30.00 10.8 16.2 11.3 17.0 1.668 2.50 5.8 8.70 21.4 3.01 0.17

Nov-Dec & Jan-Mar, JCC 0.035 0.0015 18.7 6.00 30.00 4.7 16.2 8.2 28.0 5.10825 17.50 1.8 6.31 18.0 3.70 0.08aThe exception was for scenarios 3 and 4, for which Ashland DO was set to 6.5 mg/L to explore effects on delta DO in the South Anna River.

Bioavail. Org N

Seasonal Scenarios - Facility

Other Facilities

Flow Temp

(dec. C)

DOa

(mg/L)

BOD5 CBOD5 (fast) TKN NH4-N


D-1

Appendix D: Dissolved Oxygen Profiles for

Management Scenarios

Bear Island/Doswell Hanover CH JCC Ashland

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 1

Mainstem Point Source

S. Anna Point Source

DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 2



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 3



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 4



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 5



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

051015202530354045

De

lta

Dis

solv

ed

Oxy

ge

n (

mg

/L)

Dis

solv

ed

Oxy

ge

n (

mg

/L)

River Kilometer

Scenario 7



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 8



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

051015202530354045

De

lta

Dis

solv

ed

Oxy

ge

n (

mg

/L)

Dis

solv

ed

Oxy

ge

n (

mg

/L)

River Kilometer

Scenario 9



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

051015202530354045

De

lta

Dis

solv

ed

Oxy

ge

n (

mg

/L)

Dis

solv

ed

Oxy

ge

n (

mg

/L)

River Kilometer

Scenario 10



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 11



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

051015202530354045

Del

ta D

isso

lved

Oxy

gen

(mg/

L)

Dis

solv

ed O

xyge

n (m

g/L)

River Kilometer

Scenario 12



DO-Mainstem

DO-South Anna

Delta DO-Mainstem

Delta DO-S. Anna


E-1

Appendix E: Average DO and Delta DO by Segment

and Scenario


E-1

Table E-1. Average DO and Delta DO by Segment and Scenario

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

DO

mg/L

ΔDO

mg/L

NA1 7.0 0.000 7.0 0.000 7.0 0.000 7.0 0.000 8.9 0.000 8.9 0.000 8.9 0.000 8.9 0.000 9.0 0.000 9.0 0.000 7.0 0.000 7.0 0.000

NA2 6.7 -0.123 6.7 -0.134 6.7 -0.123 6.7 -0.134 8.7 -0.197 8.7 -0.231 8.7 -0.226 8.7 -0.243 9.1 -0.143 9.1 -0.183 7.0 -0.097 7.0 -0.112

NA3 6.2 -0.193 6.2 -0.196 6.2 -0.193 6.2 -0.196 8.4 -0.238 8.4 -0.247 8.4 -0.245 8.4 -0.232 9.1 -0.166 9.1 -0.198 6.8 -0.170 6.8 -0.186

NA4 5.8 -0.210 5.8 -0.210 5.8 -0.210 5.8 -0.210 8.1 -0.246 8.1 -0.242 8.1 -0.243 8.2 -0.215 9.0 -0.172 9.0 -0.199 6.6 -0.202 6.6 -0.218

NA5 5.8 -0.207 5.8 -0.207 5.8 -0.207 5.8 -0.207 8.1 -0.244 8.1 -0.237 8.1 -0.238 8.1 -0.206 9.0 -0.171 9.0 -0.197 6.6 -0.206 6.5 -0.222

PR1 6.8 -0.120 6.7 -0.135 6.8 -0.120 6.7 -0.135 9.3 -0.151 9.3 -0.162 9.3 -0.148 9.3 -0.148 9.9 -0.107 9.9 -0.122 7.5 -0.108 7.4 -0.123

PR2 6.9 -0.127 6.9 -0.133 6.9 -0.127 6.9 -0.133 9.4 -0.134 9.4 -0.140 9.4 -0.130 9.4 -0.128 10.0 -0.097 10.0 -0.109 7.5 -0.097 7.5 -0.108

PR3 7.0 -0.138 7.0 -0.139 7.0 -0.138 7.0 -0.139 9.4 -0.124 9.4 -0.127 9.4 -0.120 9.4 -0.115 10.0 -0.090 10.0 -0.100 7.6 -0.098 7.5 -0.106

PR4 6.9 -0.155 6.9 -0.154 6.9 -0.155 6.9 -0.154 9.4 -0.128 9.4 -0.128 9.4 -0.123 9.4 -0.116 10.0 -0.090 10.0 -0.099 7.5 -0.105 7.5 -0.112

PR5 6.8 -0.164 6.8 -0.160 6.8 -0.164 6.8 -0.160 9.3 -0.127 9.3 -0.126 9.3 -0.122 9.3 -0.112 9.9 -0.087 9.9 -0.095 7.5 -0.112 7.5 -0.119

PR6 6.7 -0.158 6.7 -0.153 6.7 -0.158 6.7 -0.153 9.2 -0.123 9.2 -0.120 9.2 -0.117 9.2 -0.105 9.9 -0.082 9.8 -0.088 7.4 -0.116 7.4 -0.122

PR7 6.7 -0.142 6.7 -0.134 6.7 -0.142 6.7 -0.134 9.1 -0.113 9.1 -0.107 9.1 -0.106 9.2 -0.092 9.7 -0.072 9.7 -0.076 7.4 -0.111 7.4 -0.116

SA1 7.4 -0.001 7.4 -0.001 7.4 -0.001 7.4 -0.001 9.5 0.000 9.5 0.000 9.5 0.000 9.5 0.000 9.4 0.000 9.4 0.000 7.1 0.049 7.1 0.049

SA2 7.8 -0.028 7.8 -0.028 7.8 -0.040 7.8 -0.040 9.9 -0.030 9.9 -0.030 9.9 -0.030 9.9 -0.030 9.7 -0.012 9.7 -0.012 7.5 0.058 7.5 0.058

SA3 7.8 -0.125 7.8 -0.125 7.7 -0.151 7.7 -0.151 9.9 -0.181 9.9 -0.181 9.9 -0.181 9.9 -0.181 9.8 -0.084 9.8 -0.084 7.7 -0.028 7.7 -0.028

SA4 7.9 -0.070 7.9 -0.070 7.9 -0.071 7.9 -0.071 10.1 -0.141 10.1 -0.141 10.1 -0.141 10.1 -0.141 10.0 -0.082 10.0 -0.082 7.9 -0.045 7.9 -0.045

SA5 8.0 -0.046 8.0 -0.046 8.0 -0.047 8.0 -0.047 10.2 -0.102 10.2 -0.102 10.2 -0.102 10.2 -0.102 10.3 -0.074 10.3 -0.074 8.0 -0.035 8.0 -0.035

SA6 8.0 -0.045 8.0 -0.045 8.0 -0.045 8.0 -0.045 10.3 -0.083 10.3 -0.083 10.3 -0.083 10.3 -0.083 10.4 -0.068 10.4 -0.068 8.1 -0.029 8.1 -0.029

SA7 8.1 -0.031 8.1 -0.031 8.1 -0.031 8.1 -0.031 10.3 -0.068 10.3 -0.068 10.3 -0.068 10.3 -0.068 10.5 -0.061 10.5 -0.061 8.1 -0.022 8.1 -0.022

Min (Mainstem) 5.8 -0.210 5.8 -0.210 5.8 -0.210 5.8 -0.210 8.1 -0.246 8.1 -0.247 8.1 -0.245 8.1 -0.243 9.0 -0.172 9.0 -0.199 6.6 -0.206 6.5 -0.222

Min (South Anna) 7.4 -0.125 7.4 -0.125 7.4 -0.151 7.4 -0.151 9.5 -0.181 9.5 -0.181 9.5 -0.181 9.5 -0.181 9.4 -0.084 9.4 -0.084 7.1 -0.045 7.1 -0.045

Scenario 12Scenario 6 Scenario 7 Scenario 8 Scenario 9 Scenario 10 Scenario 11Scenario 5

Segment

Scenario 1 Scenario 2 Scenario 3 Scenario 4


Office

3454 West Clay Street

Richmond, VA 23230

T 804.763.9135

Documents

VA0024899 2012 fact sheet revised 11.26.2012