HIGH ROCK LAKE DATA REVIEW

Jing Lin

Division of Water Resources – Water Planning

NC Department of Environment & Natural Resources

NCDP - Aug 18, 2015

Acknowledgement

Tetra Tech, 2004, Water Quality Data Review

Report (1973 – 2001)

Chris Wu, 2007, Scoping Study Data Review

(2005-2006)

Limno Tech, 2010, Intensive Monitoring Final Report

(April 2008 – March 2010)

Tetra Tech, 2012, Watershed Model Report

Tetra Tech/DWR, 2015, Nutrient Response Models

http://portal.ncdenr.org/web/wq/ps/mtu/specialstudies

Hydrology Representation (2005-2010)

2005

2006 2007

2008

2009 2010

0%

20%

40%

60%

80%

100%

1000 2000 3000 4000 5000

Perc

ent L

ess

Than

Annual Mean Daily Flow (cfs)

2005

2006 2007 2008

2009 2010

0%

20%

40%

60%

80%

100%

100 200 300 400 500 600

Perc

ent L

ess

Than

Annual Mean Daily Flow (cfs)

Yadkin River

Yadkin College

1963-2013

(57.4%)

South Yadkin River

Near Mocksville

1939-2013

(7.7%)

Outline

High Rock Watershed

Lake Physical Characteristics

Lake Biochemical Characteristics

Introduction

Yadkin-Pee Dee

1928 - Dam construction completed

Dam owned and operated by Alcoa Power Generating, Inc

www.gorowan.com

Yadkin

High Rock

Lake

Watershed

Population: 850,000

2007 Land Cover

47% Forest 30% Pasture/Crop 18 % Developed

Soil Type

Hydrologic Soil GroupHigh Rock Lake Watershed

NAD_1983_StatePlane_North_Carolina_FIPS_3200

Map produced 03-22-2011 - C. Carter

0 10 20 305Miles

0 10 20 305Kilometers

Legend

Major Roads

River/Stream

Water

Watershed Boundary

County

State Boundary

Hydrologic Soil Group

A

B

C

Virginia

North Carolina

I40

I77

I85

South Yadkin River

Yadkin River

High Rock Lake

Hydrologic

Soil Group

Soil Texture

B Silt loam or

loam

C Sandy clay

loam

Groundwater to the lake

Direct groundwater inflow is not measured or

known;

however, the contribution is expected to be

relatively small because

regional groundwater flow systems are of limited

extent in the Piedmont, and

the watershed model is fit without a significant

component of “deep” groundwater losses that do not

show up at stream gages.

Point Sources

Municipal and Industrial

Wastewater

Watershed Monitoring (focused flow and enhanced ambient monitoring 08-10)

TP, TSS and Flow

Nitrogen and Flow

Q281 and Yadkin College

R2 = 0.14

R2 = 0.44

R2 = 0.33

Outline

High Rock Watershed

Lake Physical Characteristics

Lake Biochemical Characteristics

High Rock Lake

Crane Creek

Abbotts Creek

Swearing Creek

Yadkin River

Grants Creek

South Yadkin River

Avg. Depth = 17 ft

Max Depth = 62 ft

Surface Area =15,180 acres

Volume = 239,672 acre-feet

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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Dissolved Oxygen (mg/L) Temperature (°C)

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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7.6

7.8

8

8.2

8.4

8.6

8.8

pH

Physical Profiles: Station HRL051

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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Conductivity (umhos/cm)

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3/05 7/05 11/05 3/06 7/06

3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06 3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06

3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06 3/05 7/05 11/05 3/06 7/06

3/05 7/05 11/05 3/06 7/06 3/05 7/05 11/05 3/06 7/06

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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Physical Profiles: Station YAD152A

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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-5

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6

6.2

6.4

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8.4

8.6

8.8

9

9.2

9.4

9.6

9.8

10

Conductivity (umhos/cm)

Dissolved Oxygen (mg/L) Temperature (°C)

pH

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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3/05 7/05 11/05 3/06 7/06

3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06 3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06

3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06

3/05 7/05 11/05 3/06 7/06

3/05 7/05 11/05 3/06 7/06 3/05 7/05 11/05 3/06 7/06

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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20

30

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50

60

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38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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0

6

6.2

6.4

6.6

6.8

7

7.2

7.4

7.6

7.8

8

8.2

8.4

8.6

8.8

9

9.2

9.4

9.6

9.8

10

Physical Profiles: Station YAD169F

Conductivity (umhos/cm)

Dissolved Oxygen (mg/L) Temperature (°C)

pH

38450 38500 38550 38600 38650 38700 38750 38800 38850 38900

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-8

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3/05 7/05 11/05 3/06 7/06

3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06 3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06

3/05 5/05 7/05 9/05 11/05 1/06 3/06 5/06 7/06

3/05 7/05 11/05 3/06 7/06

3/05 7/05 11/05 3/06 7/06

3/05 7/05 11/05 3/06 7/06

Residence Time

www.gorowan.com

High Rock Lake*: 4 – 50 days

Falls Lake# annual average (05-07):

4 – 7 months

* APGI (2006) # Lin et al (2011)

Outline

High Rock Watershed

Lake Physical Characteristics

Lake Biochemical Characteristics

Chl a and other problem indicator?

Chl a and nutrients?

HRL051

HRL052

YAD1561A

YAD152C

YAD152A

YAD169A

YAD169E YAD169F

YAD169B

YAD152

2008-2010 % greater than 40 μg/l standard

Upstream Dam 2008-2010

HRL051

HRL052

YAD1561A

YAD152C

YAD152A

YAD169A

YAD169E YAD169F

YAD169B

YAD152

YAD1391A

2008-2010 % greater than 40 μg/l standard

2005 – 2006 (37)

2008 – 2010 (97)

Algal Data Stations

Algal Unit Density vs. Chl-a (08-10)

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

Avg. U

nit D

en

sity

(u

nits/

ml)

Chl -a (µg/L)

Bluegreens

Chrysophytes

Cryptomonads

Diatoms

Euglenoids

Greens

Prymnesiophytes

Total

10 20 30 40 50 60 70 80 90

Extreme Blooms

Severe Blooms

Moderate Blooms

Mild Blooms

Algal Unit Density vs. Chl-a(05-10)

Dominant Algal Groups

30,000

(severe bloom?)

R2 = 0.35

Chl a All

Data

Bluegreens

Dominate

% Bluegreens

Dominate

0 - 30 54 5 9.3%

30 - 40 28 13 46.4%

> 40 52 32 61.5%

Algal Biovolume vs. Chl-a(05-10)

(bloom?)

R2 = 0.25

Chl a and %Algal Unit Density (08-10)

Turbidity pH DO

Surface Negative

(all stations)

Positive

(significant

middle to lower

lake stations)

Negative (winter)

Positive

(Summer & Spring)

Positive (Temp>20)

Bottom Negative

(Winter & Spring)

Correlations between Chlorophyll a and

Other Problem Indicators

Surface DO

Summer

Bottom DO and Surface Chl a

Negative (Physical)

Higher T, lower DO saturation, lower DO

Higher T, higher Chl a

Positive (Biological)

Higher PP, higher surface DO bottom DO (mixing!)

Higher PP, higher Chl a

Negative (Biological)

Higher PP, higher OM lower bottom DO (Stratification)

Higher PP, higher Chl a

(BOD, runoff, SOD)

Outline

High Rock Watershed

Lake Physical Characteristics

Lake Biochemical Characteristics

Chl a and other problem indicator?

Chl a and nutrients?

Upstream Dam

IN TN IP TP Temp Flow

Winter -0.59 -0.32 -0.57 0.11 0.40 -0.38

Spring -0.46 -0.25 -0.54 0.07 0.28 -0.41

Summer -0.04 0.25 -0.07 -0.04 0.17 -0.06

Fall -0.38 0.003 -0.45 0.16 0.47 0.04

Correlations between Chlorophyll a and

Other Parameters

Impacts of Turbidity and Flow on Chl a

R2 = 0.06

Summer

P limited

N limited

P limited

N limited

N-limited

P-limited

NP = 14

High Rock Lake: 2005 Algal Growth Potential

High Rock Lake Algal Growth Potential

June 15, 2005

13.9

6.6

2.6 2.1

5.7

9.8

32.8 32.2

2.7 2.3

30.3

20.2

14.0

6.6 5.63.3

5.0

9.5

0

10

20

30

40

50

60

YAD1391A YAD152C YAD169F YAD169A YAD156A YAD152A

Station

Dry

Weig

ht

(mg

/L)

Control

C+N

C+P

C+N = Control + 1.0 mg/L Nitrate-N C+P = Control + 0.05 mg/L Phosphate-P

Upper-Lake Mid-Lake Lower-Lake Lower-Abbotts Lower-Second Mid-Lake

High Rock Lake: 2006 Algal Growth Potential

High Rock Lake Algal Growth Potential

July 19, 2006

19.3

0.32.7

9.3

2.4 2.2

36.4

9.2

4.8

26.4

17.7 17.519.3

1.8 2.7

10.1

2.4 2.6

0

10

20

30

40

50

60

HRL051 YAD152 YAD1561A YAD152C HRL052 YAD169B

Station ID

AG

PT

- M

SC

, m

g/L

(D

ry W

t) Control(1)

C+N

C+P

C+N = Control + 1.0 mg/L Nitrate-N C+P = Control + 0.05 mg/L Phosphate-P

Summary:

Chl a – indicator for algal density and community

Chl a concentrations are influenced by physical factors such as flow and turbidity

High pH is likely caused by high algal growth

Bottom Hypoxia mainly controlled by physical parameters such as depth, temperature, flow, and vertical stratification.

Summer Chl a is positively correlated with TN

Overall, HRL appear to be N abundant, but during summer phytoplankton growth tends to be N-limited or co-limited by both N and P.

Questions?

Jing Lin

Jing.lin@ncdenr.gov

919-807-6410

R2 = 0.46

Tasks for SAC

1. What concentration/frequency/duration of chlorophyll-a is right to protect aquatic life? How to express N&P?

2. Is chlorophyll-a standard enough as a response indicator? Are other response indicators appropriate?

3. Is resulting criteria translatable to other lakes?

High Rock Lake

Watershed Model

Pam Behm

3rd NCDP SAC Meeting

August 18, 2015

Watershed Model

• Estimates what is happening on land that results in nutrient export to receiving water (i.e. High Rock Lake)

• Provides relative loading by source (agriculture, developed, point sources, etc.)

Project Background

• EPA Region 4 contracted Tetra Tech to support then-DWQ

• HSPF chosen for watershed model

• Approximately 40 dischargers were considered in the combined modeling.

• Watershed model simulates 2000 – 2010

• Considers range of sources including point source, MS4, DOT, septic, atmospheric, agriculture

Hydrologic Simulation Program -

FORTRAN (HSPF)

High Rock

Watershed

• 3,974 acres in NC and VA

• Area above W. Kerr Scott Reservoir omitted from model (represented as a boundary condition)

High Rock Lake Watershed

NAD_1983_StatePlane_North_Carolina_FIPS_3200Map produced 03-22-2011 - C. Carter

Guilford

Winston-Salem

High Point

Trinity

Lexington

Salisbury

Statesville

Elkin King

Lewisville

Mooresville

Clemmons

Thomasville

Tobaccoville

Kernersville

Mount Airy

Walkertown

Mocksville

Wilkesboro

Landis

North Wilkesboro

Spencer

Rural Hall

Yadkinville

Dobson

Troutman

Jonesville

Faith Rockwell

Taylorsville

Ronda

China Grove

Harmony

Cleveland

Granite Quarry

Pilot Mountain

East Spencer

East BendBoonville

Bethania

Cooleemee

Love Valley

Arlington

Woodlawn

Cana

Patrick Springs

Fancy Gap

Sparta

Wilkes

Surry

Iredell

Rowan

Stokes

Patrick

Davidson

Carroll

Forsyth

Yadkin

Davie

Catawba

Grayson

Lincoln

Ashe

Cabarrus

Alexander

Stanly

Alleghany

Henry

Randolph

Gaston

Guilford

Caldwell

Mecklenburg

Montgomery

Smyth FloydWythe

Rockingham

Burke

Galax

Cleveland

Legend

Major Road

River/Stream

Water

Watershed Boundary

Municipality

County Boundary

State Boundary

Virginia

North Carolina

South Yadkin River

Yadkin River

High Rock Lake

0 10 20 305Miles

0 10 20 305Kilometers

I40

I77

I85

NC

VA

SC

TN

GA

Subbasins

• Divided into 145 subbasins

• Allows use of multiple weather stations

• Assignment of source loads to specific areas and jurisdictions

SubbasinsHigh Rock Lake Watershed

NAD_1983_StatePlane_North_Carolina_FIPS_3200Map produced 03-07-2011 - S. Sarkar

I85I77

I40

9

79

5

36

3

4

97

47

86

69

48

1

65

6

93

17

80

67

51

63

78

58

61

21

59

2

16

68

98

95

8

89

39

46

85

7662

40

41

5244

25

53

37

125

74

49

32

124

138

56

50

99

109

26

11096

24

101

129

92

22

77

106

103

120

54

12

84

23

121

111

15

35 43 139

141

42

55

104

127

94

87

137

130

31

123

72

75

126

71

91

145

119

88

140

108

116

66

20

112100

10

81

107

102

70

113

27

83

45

34

60

118

13430

144

142

143

128

115

19

73

29

14

82

5738

18 132

133

13

33136

11

7

122

131

135

64

114

90

28

117

105

Legend

Major Roads

River/Stream

Water

Subwatershed Boundary

County Boundary

State Boundary

0 9 18 274.5Miles

0 9 18 274.5Kilometers

Virginia

North Carolina

2007 Land Cover 47% Forest 30% Pasture/Crop 18 % Developed

High Rock

Lake

Watershed

Population: 850,000

Wastewater Discharges and Withdrawals

• 22 major discharges (> 1 MGD)

• 18 minor discharges

• Onsite wastewater load estimates

• 21 water withdrawals

NC0021121

NC0026646

NC0020567NC0005312

NC0005266NC0020761

NC0021717

NC0020338

NC0037834

NC0005126NC0024228NC0050342

NC0024112

NC0024872

NC0031836 NC0055786

NC0020591

NC0004774

NC0023884

NC0004944

Legend

Major Discharge

Major Road

River/Stream

Water

Subwatershed Boundary

County Boundary

State Boundary

Point Sources (Major)High Rock Lake Watershed

NAD_1983_StatePlane_North_Carolina_FIPS_3200

Map produced 03-22-2011 - C. Carter

Virginia

North Carolina

0 10 20 305Miles

0 10 20 305Kilometers

I40

I77

I85

Watershed Model

• TAC Review – Jan 25/Mar 9 – Apr 25, 2012 ▫ Resulted in additional information/clarification added

to report. No model changes.

• Uncertainties ▫ Discharger data (frequency, reporting of nitrogen

species)

▫ Flow gage spatial distribution

▫ Precipitation coverage

• Model finalized August 2012

Watershed Model Results

Spatial Distribution of Flow and Nutrient Loading to High Rock Lake

Sources of Loading 2000 - 2009

Sources of Loading 2000 - 2009

Fraction of Total

Phosphorus Load

Delivered to High

Rock Lake

Fraction of Total

Nitrogen Load

Delivered to High

Rock Lake

High Rock Lake

Town Creek

Abbotts Creek

Swearing Creek

Second Creek

Yadkin River

Questions

• Where are the nutrients coming from and how much? ▫ Tool: Watershed Model

• What reductions in nutrient loading are necessary to achieve water quality standards in the lake? Nitrogen? Phosphorus? Both? ▫ Tool: Nutrient Response Model

Questions?

Pam Behm

pamela.behm@ncdenr.gov

919-807-6419

HIGH ROCK LAKE NUTRIENT

RESPONSE MODEL

Jing Lin

Division of Water Resources – Water Planning

NC Department of Environment & Natural Resources

NCDP - Aug 18, 2015

Development of Models

TetraTech under contract for both watershed and nutrient response model development

EPA revised WASP model according to TAC comments

HSPF

(watershed)

USGS Flow EFDC

(flow, temp)

WASP (Water Quality)

High Rock Lake

EFDC (Environmental Fluid Dynamics Code)

Developed by Tetra Tech, Supported by EPA

1, 2, 3- dimensional Hydrodynamic Model

Flow, Surface Elevation, and Water Temperature

Curvilinear-orthogonal

Sigma – Hybrid (generalized vertical grid)

http://www.epa.gov/athens/wwqtsc/html/efdc.html

WASP(Water Quality Analysis Simulation Program )

EPA

State Variables:

WQ state variables simulated in WASP

http://www.epa.gov/athens/wwqtsc/html/wasp.html

EFDC/WASP

Vertical LayersHigh Rock Lake Watershed

NAD_1983_StatePlane_North_Carolina_FIPS_3200Map produced 05-25-2012 - P. Cada

0 2 4 61Miles

0 2 4 61Kilometers

Legend

Major Road

River/Stream

Number of Vertical Layers

2

3

4

5

¢

§̈¦I85

GrantsCreek

YadkinRiver

Town/CraneCreek Arm

SwearingCreekArm

AbbottsCreekArm

Flat SwampCreek ArmDutch Second

Creek Arm

538 horizontal grids

Up to 5 layers

11 tributaries

Surface Boundary

Specified SOD, Nutrient Flux

WASP Model

Two Algal Groups: Warm-water Algae and

Cold-water Algae

One sediment class – silt and clay

Spatial varying background light extinction

coefficient

Model will not be used to address Turbidity

Dynamic Memory Allocation - Model Run time

Calibration/Validation Criteria

Type of Calibration/Validation

EPA guidance Criteria

Challenges

Hydrodynamic Chemical

Water Quality

Chlorophyll a

Relative Error

(RE)

±30% ±45% ±16% (±25%)

Coefficient of

Variation (CV)

≤10% ≤90% ≤70%

Correlation

Coefficient (r)

≥0.94 ≥0.60 ≥0.70

(EPA, 1990)

EFDC calibration/validation (original) W

ate

r Sur

face

Ele

vation

Wate

r Te

mpera

ture

WASP results

Model-Simulated and

Observed TSS

time series

WASP results

Model-Simulated and

Observed TP

time series

WASP results

Model-Simulated and

Observed TN

time series

WASP results

Model-Simulated and

Observed NOx

time series

WASP results

Model-Simulated and

Observed DO

time series

WASP results

Model-Simulated and

Observed Chl a

time series

Model Calibration Statistics – Chl a

Station Count Observed

Mean

(µg/L)

RE RAE CV r RMSE

HRL051 (Upper HRL above Swearing Cr) 45 23.56 12.0% 57.1% 0.76 0.78 17.97

YAD152A (Middle HRL at Town/Crane Cr) 45 37.04 0.7% 41.9% 0.56 0.64 20.85

YAD152C (Middle HRL below Town/Crane Cr) 45 41.56 -14.3% 32.7% 0.44 0.72 18.38

YAD169B (Lower HRL below Abbotts Cr) 45 35.84 -12.1% 40.4% 0.54 0.49 19.18

YAD169F (Lower HRL at forebay) 45 30.06 1.1% 39.8% 0.54 0.58 16.13

YAD152 (Town/Crane Cr Arm) 45 46.22 -12.4% 42.9% 0.52 0.34 23.91

YAD1561A (Second Cr Arm) 45 47.09 -23.1% 40.0% 0.48 0.42 22.83

HRL052 (Upper Abbotts Cr Arm) 45 36.95 -12.8% 45.7% 0.57 0.10 20.96

YAD169A (Lower Abbotts Cr Arm) 44 33.58 -2.2% 48.0% 0.62 0.17 20.78

YAD169E (Flat Swamp Cr Arm) 45 30.44 3.0% 42.8% 0.62 0.46 18.83

84

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Phyt

opla

nkto

n gr

owth

Lim

itHRL051

Light

Nitrogen

Phosphorus

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Phyt

opla

nkto

n gr

owth

Lim

it

YAD152C

Light

Nitrogen

Phosphorus

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Phyt

opla

nkto

n gr

owth

Lim

it

YAD169F

Light

Nitrogen

Phosphorus

Upper Lake

Middle Lake

Lower Lake

Phytoplankton

Growth Limit

EXAMPLE: Falls Lake Model Results

Nitrogen and Phosphorus Reduction Curve

Questions?

Jing Lin

Jing.lin@ncdenr.gov

919-807-6410

HIGH ROCK LAKE:

CLASSIFICATION, DESIGNATED

USES, AND IMPAIRMENT

Pam Behm - NC Division of Water Resources

NC NCDP SAC

3rd Meeting

August 18, 2015

Classification 89

Designated Uses

• Aquatic Life • Fishing • Fish consumption • Wildlife • Secondary Recreation (e.g. wading, boating) • Agricultural uses (e.g. irrigation) • Water Supply • Lower lake: Primary Recreation – full human

body contact (e.g. swimming, water skiing)

90

What USE(s) do we know are

impacted?

Aquatic Life – biological integrity

Existing evidence:

High chlorophyll-a

Elevated surface dissolved oxygen

High pH

Phytoplankton assemblages - blue-green algae dominated blooms

91

IMPAIRMENTS Source: 2014 303(d) List

Chlorophyll-a Standard:

40 μg/L

92

Proposed Water Quality Goal

Decrease the severity of algal blooms in High Rock Lake to protect for aquatic life.

93

Discuss…

94