thermal dynamics of lake powell and its inflow: patterns during the lssf experiment and beyond grand...

Thermal Dynamics of Lake Powell and its Inflow:

Patterns during the LSSF Experiment and Beyond

Thermal Dynamics of Lake Powell and its Inflow:

Patterns during the LSSF Experiment and Beyond

Grand Canyon Monitoring and Research CenterGrand Canyon Monitoring and Research CenterSusan HueftleSusan HueftleGrand Canyon Monitoring and Research CenterGrand Canyon Monitoring and Research CenterSusan HueftleSusan Hueftle

•TidBiT Study Findings–LSSF hydrograph Effects•Seiche Effects

– Inflow Dynamics–Model Calibration

•Monitoring Findings–Hydrograph summary–3rd Year of lake underflow

–Near Mixing of Lake

•PEP Results

•TidBiT Study Findings–LSSF hydrograph Effects•Seiche Effects

– Inflow Dynamics–Model Calibration

•Monitoring Findings–Hydrograph summary–3rd Year of lake underflow

–Near Mixing of Lake

•PEP Results

Overview:Overview:Overview:Overview:

• TidBiT® thermistors– Sensitivity ± 0.08°C – Resolution from –4 to +37°C – Sealed in epoxy, good to any

depth– Infrared download to 32 Kb– 15’ interval readings for 11 months– Purchased 66 for $91 each– Demonic intrusion

• 4 downlake stations• Sheep/Cataract Canyon inflow• Hourly Met data from Page:

– Mean wind speed– Wind gusts– Air temperature

• GCD data from B. Vernieu

• TidBiT® thermistors– Sensitivity ± 0.08°C – Resolution from –4 to +37°C – Sealed in epoxy, good to any

depth– Infrared download to 32 Kb– 15’ interval readings for 11 months– Purchased 66 for $91 each– Demonic intrusion

• 4 downlake stations• Sheep/Cataract Canyon inflow• Hourly Met data from Page:

– Mean wind speed– Wind gusts– Air temperature

• GCD data from B. Vernieu

TidBiT ExperimentTidBiT Experiment

Deployment Problems

• Tampering decreased with distance from dam

• Water, rust

• Lake action, houseboats

Deployment Problems

• Tampering decreased with distance from dam

• Water, rust

• Lake action, houseboats

Wahweap: May ‘00-present discontinuousWahweap: May ‘00-present discontinuous

Padre bayMay-June

’00

Padre bayMay-June

’00

EscalanteMay-July ‘00Escalante

May-July ‘00

OakAug ‘00-Mar ‘01

OakAug ‘00-Mar ‘01

SheepMay ‘00-present

SheepMay ‘00-present

San Juan InflowMar 01-presentSan Juan InflowMar 01-present

Tidbit Tidbit DeploymentsDeployments

Padre tidbit recovery

Initial boat-buoy interface

Comes

to res

t

on sho

re

Returns toBosom ofGCMRC lab

Recovery roomNPS water lab

NPS retrieves buoy & tidbits,Ride around in cart for 2 days

Hap

pily s

am

plin

gA

way o

n s

tati

on

Houseboaters struggle with moral& practical dilemma of restoring tidbits to original position

TidBiT Study Findings : Seiche effectsTidBiT Study Findings : Seiche effects

A Seiche is a submarine oscillation of lake strata caused by external disturbances. Seiching increases dispersive and mixing of strata, particularly in the hypolimnion. It can create short-term oscillations in water quality parameters in dam discharges; and create a trace for detecting downstream flow velocities and mixing.

• Seiche typically followed wind event 3-12 hours• Seiche period average 3-6 hours, up to half day• Displacement greater at surface• Signature from dam was insufficient to override any wind seiching• A weakness of the experiment was the degree of homogeneity in

the lake during the study• Wahweap oscillations noisier than uplake stations

A Seiche is a submarine oscillation of lake strata caused by external disturbances. Seiching increases dispersive and mixing of strata, particularly in the hypolimnion. It can create short-term oscillations in water quality parameters in dam discharges; and create a trace for detecting downstream flow velocities and mixing.

• Seiche typically followed wind event 3-12 hours• Seiche period average 3-6 hours, up to half day• Displacement greater at surface• Signature from dam was insufficient to override any wind seiching• A weakness of the experiment was the degree of homogeneity in

the lake during the study• Wahweap oscillations noisier than uplake stations

15-S

ep

17-S

ep

19-S

ep

21-S

ep

23-S

ep

25-S

ep

27-S

ep

29-S

ep

1-O

ct

3-O

ct

5-O

ct

7-O

ct

9-O

ct

11-O

ct

13-O

ct

15-O

ct

17-O

ct

19-O

ct

21-O

ct

23-O

ct

25-O

ct

27-O

ct

29-O

ct

31-O

ct

2-N

ov

8 °

1 0 °

1 2 °

1 4 °

1 6 °

1 8 °

2 0 °

2 2 °

2 4 °

2 6 °

2 8 °

3 0 °

H2O

Temp

°C

0510152025303540W

ind Sp

eed (K

PH

)

8,00010,00012,00014,00016,00018,00020,00022,00024,00026,00028,00030,00032,00034,000

GC

D D

ischarge (cfs)

4 03 53 02 52 01 51 050

Pa

ge A

ir Tem

p (°C

)

25 m

35 m

1 m

Air Temp

W ind gusts

penstocks

40 m

80 m

20 m

15 m

70 m

Discharge

WahweapOak

TidBiT Study Findings : Inflow DynamicsTidBiT Study Findings : Inflow Dynamics

• Inflows respond to temperature changes

faster than the down-lake

•Both response to the same weather patterns

• Inflow conditions are critical for a well-

calibrated model, lake levels can influence

Sheep canyon

• Inflows respond to temperature changes

faster than the down-lake

•Both response to the same weather patterns

• Inflow conditions are critical for a well-

calibrated model, lake levels can influence

Sheep canyon

TidBiT Study Findings : Inflow DynamicsTidBiT Study Findings : Inflow Dynamics

•Inflows responses faster to temperature changes than the lake

•Both response to the same weather patterns•Inflow conditions are critical for a well-

calibrated model, lake levels can influence Sheep canyon

•Inflows responses faster to temperature changes than the lake

•Both response to the same weather patterns•Inflow conditions are critical for a well-

calibrated model, lake levels can influence Sheep canyon

1-M

ay-0

0

31-M

ay-0

0

30-J

un-0

0

31-J

ul-00

30-A

ug-0

0

30-S

ep-0

0

30-O

ct-0

0

30-N

ov-

00

30-D

ec-0

0

29-J

an-0

1

1-M

ar-0

1

10000

20000

30000

0

5

10

15

20

25

30

0

10

20

30

40

4 0

3 0

2 0

1 0

0W

ind S

pee

d (k

ph)

Dis

char

ge (cf

s)

Discharge

Page

Air

Tem

p (°C

)

H2O

Tem

p

(

°C)

W ahweap 1m

Cataract @ Sheep

Diamond Ck

Air Temp

W ind gusts

GCD penstocks

•Peaks every year between late January and mid-February

•Decreasing salinity and increasing temps in the lake have reduced vertical density gradients

•Bottom strata becomes unstable and is subject to mixing

•Mixing could introduce higher concentrations of nutrients and other components to water column





TidBiT Study Findings : Winter Mixing




8,00012,00016,00020,00024,00028,00032,000

GC

D D

ischarge (cfs)

26-A

ug

9-S

ep

23-S

ep

7-Oct

21-O

ct

4-N

ov

18-N

ov

2-D

ec

16

-Dec

30-D

ec

13-Ja

n

27-Ja

n

10

-Fe

b

24

-Fe

b

10-M

ar

24-M

ar

7-A

pr

8 °

9°

10°

11°

12°

13°

14°

15°

16°

17°

18°

19°

20°

21°

22°

23°

24°

25°

26°

27°

28°

29°

30°

Temp

°C

0

5

10

15

20

25

30

35

40

45

50

55

60

65

Wind

Speed

(KP

H-

run hrly avg 21)

4 0

3 5

3 0

2 5

2 0

1 5

1 0

5

Page A

ir Tem

p (°C

)

WindWind

Air TempAir Temp

Q cfsQ

cfs

Water temps1-80 m

Water temps1-80 m









TidBiT Study Findings : Winter Mixing Detail: Jan- Apr 01

TidBiT Study Findings : Winter Mixing Detail: Jan- Apr 01

8,00010,00012,00014,00016,00018,00020,00022,00024,00026,00028,00030,00032,00034,000

GC

D D

ischarge (cfs)

6-Ja

n

13-

Jan

20-

Jan

27-

Jan

3-F

eb

10-F

eb

17-

Fe

b

24-F

eb

3-M

ar

10-M

ar

17-

Mar

24-

Mar

31-

Ma

r

7-A

pr

14-

Apr

8°

8.5°

9°

9.5°

10°

10.5°

H2O

Temp

°C

0

5

10

15

20

25

30

35

40

Wind

Speed

(KP

H)

4 0

3 5

3 0

2 5

2 0

1 5

1 0

5

0

Pa

ge A

ir T

emp

(°C)

WindWind

Air TempAir Temp

Bottom water temps50-80 m

Bottom water temps50-80 m

Q cfsQ

cfs

Wahweap forebay, Sept 1990 to Apr 2001Wahweap forebay, Sept 1990 to Apr 2001

• Most thermally mixed: Feb ’73, Jan ’91 come close• Underflow evident

• Most thermally mixed: Feb ’73, Jan ’91 come close• Underflow evident

0 . 01 . 02 . 03 . 04 . 05 . 06 . 07 . 08 . 09 . 01 0 . 01 1 . 01 2 . 0Dissolved Oxygen (m g/ L )

975

1000

1025

1050

1075

1100

1125

5506006507007508008509009501000105011001150C onductivity (µS/ cm )

975

1000

1025

1050

1075

1100

1125Dep

th in

Elev

ation

(m)

6.0°

7.0°

7.5°

8.0°

9.0°

10.0°

12.0°

14.0°

16.0°

20.0°

24.0°

28.0°T em perature (°C )

975

1000

1025

1050

1075

1100

1125

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 '01

Lake Findings: December 2000Lake Findings: December 2000

• Low hydrograph of 2000 produces more saline conditions• Antecedent conditions relatively dilute & mixed• Low hydrograph of 2000 produces more saline conditions• Antecedent conditions relatively dilute & mixed

0.0

0.5

1.0

2.0

4.0

6.0

8.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 25 50 75 100 125 150 175 200 225 250 275

Kilom eters from Glen Canyon Dam

Turbidity (NTU)

3.54.04.55.05.56.06.57.07.58.08.59.09.510.010.511.011.512.0

Dissolved Oxygen (mg/L)

++

++

++

++

+ + ++

+

+

+ + ++ ++

Pad

re

SJR

Co

nf

Iceberg

Bu

llfrog

Kn

ow

les

Sco

rup

No

rth G

ap

Dark

550

600

650

700

750

800

850

900

950

1000

1050

1100

1150

0 25 50 75 100 125 150 175 200 225 250 275

975

1000

1025

1050

1075

1100

1125

Dep

th as E

levation

(m)

Conductivity (µS/cm )

3.04.0

5.06.06.56.8

7.07.58.0

8.59.09.5

10.011.012.0

13.0

(°C)Temperature

++

++

+

++

+

++

+

++

+

++

++

++

+

++

++

++

Wah

Pad

re

Oak

SJR

Co

nf

Escalan

te

Iceberg

Lake

Bu

llfrog

Mo

ki K

no

wles

LG

HB

Sco

rup

Hite

No

rth G

ap S

heep

Dark

0255075

100125150

Main Channel of Lake Powell, Decem ber 8-12, 2000

Lake Findings: March 2001Lake Findings: March 2001

•Third year of winter DO underflow•Thermally nearly homogeneous•Third year of winter DO underflow•Thermally nearly homogeneous

0112468102030405060708090100200300400450500

0 25 50 75 100 125 150 175 200 225 250 275

Kilom eters from Glen Canyon Dam

Turbidity (NTU)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

14.0

16.0

Dissolved Oxygen (mg/L)

++

++

++

++

+ + ++

+

+

+ + ++ ++

Pad

re

SJR

Co

nf

Iceberg

Bu

llfrog

Kn

ow

les

Sco

rup

No

rth G

ap

Dark

400

450

500

550

600

650

675

685

700

750

800

850

900

950

1000

1050

1100

1150

1200

0 25 50 75 100 125 150 175 200 225 250 275

975

1000

1025

1050

1075

1100

1125

Dep

th as E

levation

(m)

Conductivity (µS/cm)

0.01.02.03.04.05.06.06.56.87.07.58.08.59.09.510.011.012.013.014.015.016.018.020.022.024.026.028.030.0

(°C)Temperature

++

++

++

++

+ + ++

+

+

+ + ++ ++

Pad

re

SJR

Co

nf

Iceberg

Bu

llfrog

Kn

ow

les

Sco

rup

No

rth G

ap

Dark

M ain C hannel of Lake Powell, M arch 4-8, 2001

0255075

100125150

Conclusions:Conclusions:• TidBiT inflow/stratification data critical input for

future modeling efforts• Current TidBiT results track winter mixing

– hypolimnetic mixing unprecedented in the lake’s history – Only approached <1°C 2 other years: 1991 & 1973

– Hypolimnetic mixing could introduce higher concentrations of nutrients, other ions to dam withdrawals

• Seiche effects dominated by wind, no detectable signature from dam operations

• Seiche signature greatest in open bays, oscillation seen from downstream to upstream

• 3rd Year of lake underflow and hypolimnetic oxygenation

• TidBiT inflow/stratification data critical input for future modeling efforts

• Current TidBiT results track winter mixing– hypolimnetic mixing unprecedented in the lake’s history – Only approached <1°C 2 other years: 1991 & 1973

– Hypolimnetic mixing could introduce higher concentrations of nutrients, other ions to dam withdrawals

• Seiche effects dominated by wind, no detectable signature from dam operations

• Seiche signature greatest in open bays, oscillation seen from downstream to upstream

• 3rd Year of lake underflow and hypolimnetic oxygenation

thermal dynamics of lake powell and its inflow: patterns during the lssf experiment and beyond grand...

Documents