Groundwater Contaminant Plume Stability Analysis Joe A

Groundwater

Contaminant

Plume Stability

Analysis

Joe A. Ricker, P.E.

A member of the Earth Consulting Group, Inc. family of companies

Ricker Plume Stability Analysis

�Background

�Ricker Plume Stability Analysis Methodology

�Example Site Analyses

Plume Stability –MDNR

Appendix H

Definition

�Stable Groundwater Plume: a groundwater plume is

“stable”when data representative of the entirety of the

plume dem

onstrates that the plume is not expanding and

that, overall, concentrations of chemicals of concern

(COC) are not increasing.

�Shrinking Groundwater Plume: A groundwater

plume is “shrinking”when data dem

onstrates that the

arealextent of the plume is decreasing and

concentrations of COCs, overall, are decreasing.

�Expanding Groundwater Plume: A groundwater

plume is “expanding”when either the physical extent of

the plume is increasing or concentrations of COCsare

increasing.

Plume Stability

�A condition where the plume is no longer expanding in

size, AND the plume footprint is not moving.

�Plume is at dynamic equilibrium

�R

ate

of c

hem

ical

mas

s in

to t

he

plu

me

is e

qu

al t

o th

e ra

te o

f ch

emic

al m

ass

lost

fro

m t

he

plu

me

Why Evaluate Plume Stability?

�An increasing plume could migrate to sensitive receptors

�Evaluate rem

edial progress

�Answ

er Environmental Indicator Code (EI) CA 750 –

“Has the migration of contaminated groundwater

stabilized?”

�Primary line of evidence when implementing M

NA

�“H

isto

rica

l gr

oun

dw

ater

…d

ata

that

dem

onst

rate

a c

lea

r an

d

mea

nin

gfu

l tr

end

of

dec

reas

ing

con

tam

ina

nt

mas

s a

nd

/or

con

cen

trat

ion

ov

er t

ime…

”

�Dem

onstrate low risk to close sites

-USEPA OSWER Directive 9200.4-17P

How is Plume Stability

Determined?

�Qualitative M

ethods

�C

once

ntr

atio

n v

s. T

ime

Plo

ts

�C

once

ntr

atio

n v

s. D

ista

nce

Plo

ts

�C

once

ntr

atio

n I

sop

leth

Ma

ps

�Statistical Methods

�W

ell

by

wel

l tr

end

an

alys

is

�M

ann-K

endall

�Lin

ear R

egre

ssio

n

�Plume-Based M

ethods

�P

lum

e A

rea

�P

lum

e M

ass

�P

lum

e C

ente

r of

Mas

s (C

OM

)

�M

ass

Flu

x


Determined?

�Qualitative M

ethods

Plume Stability Analysis Method

High

Moderate

Low

Concentration vs. Time Plots

Trends in most wells

visually stable and/or

increasing

No discernable

trends in many

wells, trends in

some relevant wells

Trends in all relevant

wells visually decreasing

Concentration vs. Distance Plots

Moderate or no visual

decrease in

concentration along

the plume centerline

and generally stable

trends in plots over

time. Sentinel wells

above DRCLs.

Moderate visual

decrease in

concentration along

the plume

centerline and

generally stable


time. Sentinel

Significant visual

decrease in

concentration along the

plume centerline and

general decreasing


time. Sentinel wells

with nondetects.

Concentration Isopleth Maps

Generally increasing

plume size over time.

Sentinel wells above

DRCLs.

Relatively

unchanged plume

size and extent over

time. Sentinel

wells with less than

Discernable decrease in

plume size and extent

over time. Sentinel

wells with nondetects.

Probability of Significant Risk


Determined?

�Statistical Methods


High

Moderate

Low

Mann-Kendall

Linear Regression


Concentrations trends

in any relevant

monitoring wells are

statistically

Increasing or Probably

Increasing

Concentration

trends in all

relevant monitoring

wells are

statistically

Decreasing,

Probably

Concentration trends in

all relevant monitoring

wells are statistically

Decreasing or Probably

Decreasing

Mann-Kendall Trend Analysis Criteria

Linear Regression Trend Analysis Criteria

Mann-Kendal

Confidence in

Concentration Trend

Statistic

Trend

Confidence in Trend

Positive

Negative

S>0

> 95 %

Increasing

COV < 1 Stable

S>0

90-95 %

Probably Increasing

COV > 1 No Trend

S>0

< 90 %

No Trend

Probably

Probably

S<0

< 90% and COV > 1

No Trend

Increasing

Decreasing

S<0

< 90% and COV < 1

Stable

> 95 %

Increasing

Decreasing

S<0

90-95 %

Probably Decreasing

S<0

0.95

Decreasing

Ln Slope

< 90%

No Trend

90-95 %


Determined?

�Plume-Based M

ethods


High

Moderate

Low

Plume Area

Increasing or probably

increasing trend in

plume area.

Stable trend in

plume area.

Decreasing or probably

decreasing trend in

plume area.

Plume Mass


increasing trend in

plume mass.

Stable trend in

plume mass.


decreasing trend in

plume mass.

Plume Center of Mass (COM)


increasing trend in

COM location.

Condition should be

verified with visual

analysis to verify that

plume is truly

Stable trend in

plume COM

location.


decreasing trend in

plume COM location.

Mass Flux


increasing trend in

mass flux at any

transect location.

Decreasing,

probably

decreasing, or

stable trend in mass

flux at each

transect.


decreasing trend in mass

flux at each transect.


Plume Stability -Existing

Methods

�Most Common M

ethod to Evaluate Plume Stability

�W

ell

by

wel

l tr

end

an

alys

is

�“T

he p

rim

ary

concern

in a

sta

bility

dem

onstration is w

heth

er C

OC

concentrations a

re incre

asin

g o

r decre

asin

g a

t in

div

idual m

onitoring

wells

.”

�“…

a s

table

or shrinkin

g c

onditio

n c

an b

e identified b

y a

sta

ble

or

decre

asin

g c

oncentration tre

nds o

ver tim

e. For th

is a

naly

sis

, an

overa

ll plu

me c

onditio

n w

as d

ete

rmin

ed for each C

OC

based o

n a

sta

tistical trend a

naly

sis

of concentrations a

t each w

ell…

”

-Indiana RISC Technical Guide –

Appendix 3

-AFCEE M

AROS User’s Guide


Methods


Methods


Methods

�Naphthalene

Plume

�52 W

ells

1

10

100

1,000

10,000

100,000

Concentration (µg/l)

Year

DB-18

DB-21

DB-22

DB-25

DB-27

DB-28


Methods

�Other Common M

ethod to Evaluate Plume Stability

�E

val

uat

e p

lum

e co

nto

urs

ov

er t

ime

�“O

ne m

eth

od o

f evalu

ating p

lum

e s

tatu

s is to p

lot plu

me

concentrations fro

m four or m

ore

events

on the s

am

e fig

ure

.”

-Washington Guidance on Remediation by Natural Attenuation


Methods

From State of Washington Guidance on Remediation of Petroleum-Contaminated Ground

Water By Natural Attenuation (Publication No. 05-09-091 [Version 1.0])


Methods

TW-02

TW-03

TW-04

MW-01

MW-02

MW-04

MW-05

MW-06

MW-08

MW-12

MW-14

MW-15

MW-16

MW-17 MW-18

MW-19

VCCP-01

VCCP-02

MW-03

MW-20

Interm

ediate Aquifer Zone

R² = 0.51

0

50

100

150

200

250 1997

1998

1999

2001

2002

2004

2005

2006

2008

2009

Area (Acres)

Date

Carbon Tetrachloride Plume Area


Methods

R² = 0.47

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000 1997

1998

1999

2001

2002

2004

2005

2006

2008

2009


Date

Carbon Tetrachloride Plume Average Concentration

R² = 0.58

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000 1997

1998

1999

2001

2002

2004

2005

2006

2008

2009

Mass (lbs)

Date

Carbon Tetrachloride Plume Mass


Methods x

x

xx x

xx

xx

xx

x

x

xxx

xxxx

AB-3D

AB-8D

AB-9D

AB-15D

AB-20D

AB-1S

OW-2A

AB-13DAB-17D

AB-19D

AB-21D

SCALE: 1 INCH = 600 FEET

0300

600

900

1,200

River

TDOT Facility

Site

Plume Boundary = 1 ug/L

PCP Plume Evaluation

Plume Area: 35.1 Acres

Plume Average Concentration: 92.5 ug/l

Plume M

ass: 86.0 Pounds

1550

100

500

1000

PCP Conc.

(ppb)

CENTER OF M

ASS

1993 PCP Plume

2008 PCP Plume

x

x

x xx

xx

xx

xx

x

x

xxxx

xxx

AB-3D

AB-8D

AB-9D

AB-15D

AB-20D

AB-1S

OW-2A

AB-13DAB-17D

AB-19D

AB-21D

SCALE: 1 INCH = 600 FEET

0300

600

900

1,200

River

TDOT Facility

Site

Plume Boundary = 1 ug/L

PCP Plume Evaluation


Plume Average Concentration: 9.6 ug/l

Plume Mass: 7.4 Pounds

1550

100

500

1000

PCP Conc.

(ppb)

CENTER OF MASS


Methods

�PCP Plume

�11 W

ells

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008


Date

AB-13D

AB-19D

AB-20D

AB-21D

DECREASING

TREN

D

DECREASING

TREN

D

STABLE

TREN

D

INCREASING

TREN

D


Methods

R² = 0.12

05

10

15

20

25

30

35

40 Oct-92

Jan-94

Apr-95

Jul-96

Sep-97Dec-98Mar-00Jun-01

Sep-02Nov-03Feb-05May-06Aug-07Oct-08

Area (Acres)

Date

PCP Plume Area Trend


Methods

R² = 0.48

0

10

20

30

40

50

60

70

80

90

100 Oct-92

Jan-94

Apr-95

Jul-96

Sep-97Dec-98Mar-00Jun-01

Sep-02Nov-03Feb-05May-06Aug-07Oct-08

Average Concentration (µg/l)

Date

PCP Plume Average Concentration Trend

R² = 0.46

0

10

20

30

40

50

60

70

80

90

100 Oct-92

Jan-94

Apr-95

Jul-96

Sep-97

Dec-98Mar-00

Jun-01

Sep-02

Nov-03Feb-05May-06Aug-07

Oct-08

Mass (lbs)

Date

PCP Plume MassTrend

Ricker Plume Stability

Analysis Method

�Effective method to evaluate trends in plume

characteristics using visual and statistical methods.

�A

rea

�A

ver

age

con

cen

trat

ion

�M

ass

�L

ocat

ion

of

plu

me

cen

ter

of m

ass

�M

ass

Flu

x

�Efficiently assim

ilates large volume of historical data into

concise and meaningful analysis


Analysis Method

�Excellent groundwater managem

ent tool

�T

erm

inat

ion

of

rem

edia

tion

sys

tem

s w

her

e lo

w r

isk

is

dem

onst

rate

d

�B

asis

for

MN

A

�M

onit

or p

rogr

ess

of r

emed

iati

on s

yste

m

�Ricker M

ethod H

ighlighted by USEPA Region IV

�R

CR

A S

how

case

Pil

ot

�http://w

ww

.epa.g

ov/c

orrectiveaction/s

how

case/rcra

_pdf/r4

_vels

i.pdf

�Methodology published in G

rou

nd

wat

er M

onit

orin

g &

R

emed

iati

on 28, no. 4/ Fall 2008/pages 85–94


Analysis Method

�Methodology

�Se

lect

ion

of

ind

icat

or c

omp

oun

d(s

)

�D

evel

op c

once

ntr

atio

n i

sop

leth

map

s

�Each indic

ato

r com

pound

�Each a

quifer le

vel (s

hallo

w, deep, etc

.)

�Plu

me b

oundary

defined b

y M

CL o

r site-s

pecific

level

TW-02

TW-03

TW-04

MW-01

MW-02

MW-04

MW-05

MW-06

MW-08

MW-12

MW-14

MW-15

MW-16

MW-17 MW-18

MW-19

VCCP-01

VCCP-02

(66,000)

(7,790)

(61,300)

[161**

]

[ND

**]

[19,8

05**

]

[ND

]

[86.2

]

[16,1

00]

[ND

]

[69,6

00]

[160,0

00]

[18,3

00]

[ND

]

[ND

]

[ND

]

[ND

*]

[ND

*]

[NS

]MW-03

[10.1

]MW-20

DIESEL

RECON

FACILITY

SG-13

MW-1

MW-2

MW-4

MW-8

MW-9

MW-10

MW-11

MW-15

MW-16

MW-18

MW-19

MW-20

MW-25

MW-26

MW-27

MW-31

MW-3

MW-12

MW-21

MW-22

MW-24

MW-30

MW-32

DMW-1

DMW-3

CFMW-1

CFMW-2

CFMW-3

CFMW-4

CFMW-6

CFMW-7

CFMW-8

CFMW-9

CFMW-11

CFMW-12

MW-5

MW-6

MW-7

MW-14

MW-17

MW-23

MW-28

MW-29

[12,000]

[12,000]

[20,000]

[140,000]

[3,700]

[820]

[ND]

[ND]

[ND]

[ND]

[NS-0]

[NS-0]

[NS]

[ND-34]

[140]

[ND-6.8]

[NS]

[NS]

[NS]

[NS]

[0.41]

[NS]

[NS]

[2,500]

[NS]

[NS]

[NS]

[3,900]

[NS-1.7]

[NS-110]

[NS-22]

[23]

[8.9]

[NS-78]

[NS]

[NS]

[NS-6,600]

[NS-11,000]

[NS-1,000][NS]

[NS-13]

General Gr

oundwa

ter Flow

DMW-4

DMW-2

MW-13

[ND]

[140]

[0.38]

[ND]

[NS]

[12,000]

Sump 2R

Sump 3

MW-1A

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-10

MW-11

MW-15S

MW-16

MW-2

MW-12

MW-14

MW-17S

RW-1

DW-2

DW-4

MW-15D

DW-1

DW-3

DW-6

MW-17D

WW-1

WW-3

[0.032]

[7.52]

[ND]

[ND]

[0.037]

[ND]

[ND]

[ND]

[ND]

[60.5]

[156]

[49.5]

[NS]

[NS]

[NS-69.6]

[130]

DW-5

Dry Dock 1

Dry Dock 2

Drum

Storage

Bldg.

Tank Farm

#200

Tank Farm

#100

Tank Farm

#300

Tank Farm

#500

Tank Farm

#400

Boiler

Room

Tank Farm

#600

Operations

Office

Property Boundary

Earthen Ber m

Wastewater Treatment Plant

Dock 2

Dock 3

Dock 1

Dock 4

Dock 5

Gas

Front

Office

Estimated Historical

Limits of Former Surface

Impoundment

River


Analysis Method

�Methodology

�C

alcu

late

plu

me

stab

ilit

y ch

arac

teri

stic

s

�Are

a

�Avera

ge c

oncentration

�M

ass

�C

ente

r of m

ass

TW-02

TW-03

TW-04

MW-01

MW-02

MW-04

MW-05

MW-06

MW-08

MW-12

MW-14

MW-15

MW-16

MW-17 MW-18

MW-19

VCCP-01

VCCP-02

(66,000)

(7,790)

(61,300)

[161**

]

[ND

**]

[19,8

05**

]

[ND

]

[86.2

]

[16,1

00]

[ND

]

[69,6

00]

[160,0

00]

[18,3

00]

[ND

]

[ND

]

[ND

]

[ND

*]

[ND

*]

[NS

]MW-03

[10.1

]MW-20

DIESEL

RECON

FACILITY

SG-13

MW-1

MW-2

MW-4

MW-8

MW-9

MW-10

MW-11

MW-15

MW-16

MW-18

MW-19

MW-20

MW-25

MW-26

MW-27

MW-31

MW-3

MW-12

MW-21

MW-22

MW-24

MW-30

MW-32

DMW-1

DMW-3

CFMW-1

CFMW-2

CFMW-3

CFMW-4

CFMW-6

CFMW-7

CFMW-8

CFMW-9

CFMW-11

CFMW-12

MW-5

MW-6

MW-7

MW-14

MW-17

MW-23

MW-28

MW-29

[12,000]

[12,000]

[20,000]

[140,000]

[3,700]

[820]

[ND]

[ND]

[ND]

[ND]

[NS-0]

[NS-0]

[NS]

[ND-34]

[140]

[ND-6.8]

[NS]

[NS]

[NS]

[NS]

[0.41]

[NS]

[NS]

[2,500]

[NS]

[NS]

[NS]

[3,900]

[NS-1.7]

[NS-110]

[NS-22]

[23]

[8.9]

[NS-78]

[NS]

[NS]

[NS-6,600]

[NS-11,000]

[NS-1,000][NS]

[NS-13]

General Gr

oundwa

ter Flow

DMW-4

DMW-2

MW-13

[ND]

[140]

[0.38]

[ND]

[NS]

[12,000]

Sump 2R

Sump 3

MW-1A

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-10

MW-11

MW-15S

MW-16

MW-2

MW-12

MW-14

MW-17S

RW-1

DW-2

DW-4

MW-15D

DW-1

DW-3

DW-6

MW-17D

WW-1

WW-3

[0.032]

[7.52]

[ND]

[ND]

[0.037]

[ND]

[ND]

[ND]

[ND]

[60.5]

[156]

[49.5]

[NS]

[NS]

[NS-69.6]

[130]

DW-5

Dry Dock 1

Dry Dock 2

Drum

Storage

Bldg.

Tank Farm

#200

Tank Farm

#100

Tank Farm

#300

Tank Farm

#500

Tank Farm

#400

Boiler

Room

Tank Farm

#600

Operations

Office

Property Boundary

Earthen Ber m

Wastewater Treatment Plant

Dock 2

Dock 3

Dock 1

Dock 4

Dock 5

Gas

Front

Office

Estimated Historical

Limits of Former Surface

Impoundment

River

Interm

ediate Plume Evaluation

Plume Area: 149 Acres

Plume Average Concentration:

9,399 ug/l

Plume Mass: 23,832 Pounds

Plume Evaluation


Plume Average Concentration: 5,610 ug/l

Plume M

ass: 1,512 Pounds

CVOC Plume Evaluation


Plume Average Concentration: 19.5 m

g/l

Plume M

ass: 1,615 Pounds

Documents

Groundwater Contaminant Plume Stability Analysis Joe A