[sT) SulTRAC

May 22, 2015

Mr. Thomas Alcamo Remedial Project Manager U.S. Environmental Protection Agency Region 5 77 W. Jackson Blvd. (SR-61) Chicago, Illinois 60604

Subject: Technical Memorandum Piezometer Data Review Lemon Lane Landfill CBS Multi-Sites, Monroe County, Indiana Work Assignment No.103-TATA-OSZZ

Dear Mr. Alcamo:

As requested by the U.S. Environmental Protection Agency (EPA) to support its Five-Year Review for the Lemon Lane Landfill site, SulTRAC and its subcontractor, AECOM Technical Services, Inc. (AECOM), prepared the enclosed technical memorandum reviewing historical water level piezometer data. The review evaluates the degree of ( 1) potential waste wetting resultant from precipitation or seasonal changes in groundwater level, and (2) wetting soil beneath the waste materials resultant from backflooding from the underlying limestone bedrock.

Please call me at (312) 201-7491 if you have any questions or would like to schedule a conference call with AECOM to discuss the data review.

Sincerely,

Jeffrey Litka, CHMM Project Manager

Enclosure

cc: Daniel Olsson, EPA Contracting Officer (letter only) J.D. Campbell, Ph.D., P.E., SulTRAC Program Manager Mindy Gould, SulTRAC John Bassett, LPG, AECOM

I S. Wacker Drive, 37•h Floor, Chicago, lL 60606 Tel 312.201.7700 Fax 312.201.0031

ENCLOSURE

TECHNICAL MEMORANDUM PIEZOMETER DATA REVIEW

LEMON LANE LANDFILL CBS MULTI-SITES

MONROE COUNTY, INDIANA

(Five Pages)

TECHNICAL MEMORANDUM PIEZOMETER DATA REVIEW

LEMON LANE LANDFILL CBS MULTI-SITES

MONROE COUNTY, INDIANA

As requested by the U.S. Euviromnental Protection Agency (EPA) to support its Five-Year Review for

the Lemon Lane Landfill site, Su!TRAC and its subcontractor, AECOM Technical Services, Inc.

(AECOM), prepared this technical memorandum reviewing Lemon Lane Landfill historical water level

piezometer data for evaluating:

I. The degree of potential waste wetting resultant from precipitation or seasonal changes in groundwater level

2. The degree of wetting soil beneath the waste materials resultant from backflooding from the underlying limestone bedrock

Tables and figures supporting this memorandum are included in Appendices A and B.

BACKGROUND

Groundwater level monitoring within the footprint of Lemon Lane Landfill is conducted at four

piezometers (PZ-AS, PZ-AD, PZ-BS, and PZ-BD) that were installed through the landfill cap (see

Figure I [Tetra Tech EM Inc. 2002] in Appendix B). These piezometers were installed by CBS

Corporation (CBS) inunediately after the source remediation of2000 for evaluating groundwater

conditions beneath the cap. Table I in Appendix A provides construction details of the piezometers. An

adjacent bedrock monitoring well (MW-6) is also monitored by CBS.

The four piezometers installed into the footprint of the landfill were placed into areas of deep bedrock or

sinkholes that were filled with waste materials during the old dump operations. There are two major

sinkholes at the site that were filled with waste materials, referred to as the North Sinkhole and the South

Sinkhole (see Figure I). Figure 2 (EPA 2010) provides a schematic cross-section showing the piezometer

configuration. The shallow PZ-AS piezometer is screened across the native soil/waste interface in the

deepest part of the South Sinkhole, whereas shallow "S" piezometer PZ-BS is screened across the native

soil/waste interface in the deepest part of the North Sinkhole (Figure 1). A low point in the bedrock

surface corresponds to each topographic sinkhole. Two "D" piezometers (PZ-AD and PZ-BD) are

screened across the native soil/bedrock interface at these low points to monitor for backflooding of the

natural soil materials by bedrock groundwater.

E-1

All of the piezometers are monitored by making periodic measurements of the maximum recorded water

level depth relative to the bottom elevation of the piezometer. These data are recorded by crest gages that

record the maximum water level depth above the bottom of the piezometer over a given period of time.

In essence, the gages provide a continuous record of the maximum water level that occurs between

measurement events, but no information concerning the frequency that wetting occurs. CBS records and

reports these crest gage data to EPA as apparent movement and these data are listed in Table 2 (CBS

2014).

As an example of how the apparent movement data in Table 2 are interpreted, refer to the data collected

on November 9, 2012. These data indicate that the maximum water level depth that occurred in

Piezometer PZ-AS between November 9 and the preceding October 2 observation was 0.14 foot, as

measured from the piezometer bottom.

ANALYSIS

One way to interpret the piezometer data is to determine the depth or elevation of the water column in the

piezometer ( detennined by crest gage, or direct measurement) and compare this elevation with a critical

depth or elevation necessary to saturate the native soil or waste material. Any water measured in the

piezometer could be interpreted to indicate groundwater movement along the monitored interface if it is

assumed that the piezometer bottom functions as a sump to trap and store the water. However, it could

also be interpreted that there is no significant movement unless the water elevation exceeds the critical

elevation, thereby indicating a more widespread and general saturated hydrologic condition. This

approach is used in the analyses presented below.

Data associated with the Lemon Lane Landfill piezometers were extensively reviewed in 2010 as part of

the Lemon Lane Landfill Five-Year review process (EPA 20 l 0). At that time, a considerable amount of

data exchange occurred between EPA and CBS, and the result of this process was a data table that allows

for meaningful interpretation of the repmied apparent movement data (Table I). As shown in Table I, the

rise in the piezometer water level necessary to saturate the waste materials or soil (see Column 9 in

Table 1) is calculated by subtracting the base of waste or bedrock elevation (Column 8) from the

piezometer bottom elevation (Column 4). These water depths then represent the critical depths that, if

exceeded, indicate that general saturation of the waste or native soil above bedrock likely occurred during

the observation time period. The critical depth values for each of the four landfill cap piezometers are

listed in the heading of Table 2 for reference and comparison to the recorded apparent movement values.

E-2

Piezometer PZ-AS is installed at a bottom elevation of 845. l feet above mean sea level (ams!), and

piezometer PZ-BS is installed at a bottom elevation of843.l feet ams!. The base-of-waste elevations at

these two locations are 848.1 feet and 846.0 feet ams! (see Figure 2). Apparent movement values less

than the critical values of 3 .0 feet for PZ-AS and less than 2.9 feet for PZ-BS indicate that no wetting of

the base of the waste has occurred. As shown in Table I, none of the recorded apparent movement values

exceeds the appropriate critical value. Therefore, there is no evidence from the Table 2 data that saturated

conditions at the base of waste have ever occurred at either piezometer location.

Similarly, bedrock piezometer PZ-AD is installed at a bottom elevation of 822.3 feet ams!, and bedrock

piezometer PZ-BD is installed at a bottom elevation of 823.9 feet ams!. The corresponding bedrock

elevations at these piezometers are 829.9 feet and 832.5 feet ams! (see Figure 2). From these data,

apparent movement values of7.6 feet for PZ-AD and 8.6 feet for PZ-BS are the critical values indicating

bedrock backflooding of the soil.

Initial monitoring of piezometer PZ-BD in early 2002 indicated significant response during rainfall events

(CBS 2012). As a result, CBS installed a data logger that recorded water movement measurements from

November 2001 until the end of March 2003. These data showed short-term response for a few storm

events, but very little response after May 2002. This situation was attributed to plugging of the

piezometer with clay. Jn March 2004, the piezometer was cleaned and a crest gage was installed. Data

collected since that time are shown in Table 2.

In general, the bedrock piezometer data for PZ-AD and PZ-BD in Table 2 indicate that there is minimal

storm response during the dry season from July to October, except for large storms. During the wetter

seasons, stonn response is more frequent (CBS 2012). However, as shown in Table 2, none of the

apparent movement data collected since March 2004 at piezometer PZ-BD indicate that any bedrock

backflooding of the soil has occurred. Bedrock backflooding at PZ-AD is indicated only during storm

events on June 5, 2008, and on May 14, 2009 (see Table 2). In no case do the bedrock piezometer data

indicate the groundwater levels rose into the base of the waste at either piezometer location (see Figure 2).

CBS has also monitored water levels in bedrock monitoring well MW-6 (see Figure J) because this well

(!)is located adjacent to the deepest part of the landfill, (2) has shown the largest water level response of

any near-site monitoring well, and (3) the well water level tracks consistently with the flow rate of the

karst groundwater discharge point at lllinois Central Spring, about 0.5 mile downgradient from the site.

With a few data gaps, the water level in well MW-6 was gaged almost continuously from J 994 to

E-3

January 24, 2011, when CBS removed the data logger equipment. A time-series plot ofMW-6 water

levels (CBS 2012) is shown in Figure 3. CBS (2012) notes that of the 104,730 hours logged between

November 2000 and January 24, 2011, the nominal soil base elevation of 830 feet ams! in the South

Sinkhole was exceeded for 380 hours or 0.3 percent of the time.

The maximum water level ever recorded at well MW-6 in its monitoring history is 837.6 feet ams!. This

level occurred during a large storm on January 5, 2005 (see Figure 3). This elevation is about 10 feet

lower than deepest part of the waste materials remaining on site. Therefore, there is no indication from

these data that backflooding of waste materials from the bedrock occurs.

For a period in November 2001 to May 2002, CBS recorded continuous water levels at both MW-6 and

PZ-BD (see Figure 4). Although the two largest responses in PZ-BD correlate with the two largest

responses in MW-6, there are no equivalent responses in PZ-BD to other responses in MW-6 that rise a

few feet above the 823.9 foot ams! bottom elevation of PZ-BD (CBS 2012). Overall, the magnitude of

stonn response at MW-6 appears to be greater than that at PZ-BD. This difference suggests that

observation of the MW-6 water level is not a good proxy substitute for water level observation at PZ-BD.

Backflooding of the soil by bedrock groundwater may cause soil piping erosion and sinkhole formation in

the overlying soil. However, CBS (2012) noted that quarterly cap inspections and detailed biennial cap

elevation surveys have shown very little landfill settlement and no indications of sinkhole formation.

These inspections will continue.

SUMMARY

In summary, a review of the Lemon Lane Landfill piezometer crest gage and MW-6 water level data

collected over the past I 0 years indicates the following:

I. There is no evidence that the native soil/waste interface is ever wetted at either the PZ-AS or PZ-

BS piezometer locations.

There is no evidence that the native soil/bedrock interface is ever backflooded at the PZ-BD

location, and is only rarely backflooded at the PZ-AD piezometer location. Therefore, there is no

reason to anticipate future problems with landfill settlement as a result of soil piping erosion in

the sinkhole bottom. CBS will continue quarterly inspections to monitor for settlement.

2. MW-6 water level is not a good proxy substitute water level observation at PZ-BD. Continued

water level observation by CBS at PZ-BD is therefore recommended in lieu of continued

monitoring ofMW-6.

E-4

REFERENCES

CBS Corporation (CBS). 2012. Long-Term Groundwater Monitoring Plan for Lemon Lane Landfill, Quality Assurance Project Plan (QAPP)- Volume XXXIII, Draft, Revision 1, September.

CBS. 2014. Surface Water and Water Level Monitoring, Fourth Quarter 2013, Lemon Lane Landfill, Monroe County, Indiana, December.

Tetra Tech EM Inc. 2002. Lemon Lane Landfill Addendum to the Revised Current Status Report Dated May 200 I. Bloomington, Monroe County, Indiana. July 26.

U.S. Environmental Protection Agency (EPA). 2010. Five-Year Review Report: Second Five-Year Review Report for the Lemon Lane Landfill, Monroe County, Indiana, May.

E-5

APPENDIX A

TABLES

(Five Sheets)

1 2

Ground TOG Riser Top Surface

State Plane State Plane Elevatlon1 Elevation Elevatlon Site Station Easting (ft) Northing (ft) (ft MSL) (ft MSL) (ft MSL)

LL PZ-AD 3100882 1429690 868.50 868.50 865.4 LL PZ-AS 3100974 1429785 882.56 882.47 879.1 LL PZ-BD 3100992 1430207 872.42 872.50 869.8 LL PZ-BS 3101054 1430137 880.27 880.31 877.9

Notes;

(1) TOC"' Top of Casing/Top of Outer Casing/Top of Pro cover from CBS revised spreadsheet (Mar 2010).

Table 1 Lemon Lane Landfill

Piezometer Construction Details

3 4 5 6

Screen- Bottom Original Base Riser Elevation Ground Waste/

Length (ft MSL) Elevation Bedrock (ft) (1) - (3) (ftMSL) (ft)

46.2 822.3 861.4 31.5 37.4 845.1 876.1 28 48.6 823.9 867.0 34.5 37.2 843.1 875.0 29

Page 1 of 1

7 8 9 10 11 12

Base Max Waste/ Water Level Recorded Max Bedrock Rise Needed Water Water

Elevation to Wet Level Level Interface (GWMP) Interface (ft) Rlse Rise Max

Type (5)-(6) (8) - (4) (ft) EL. Date

Soll/ Bdrk 829.9 7.6 9.42 831.7 5/14/2009 Waste I Soil 848.1 3.0 0.15 845.2 3/10/2007 Soil I Bdrk 832.5 8.6 6.15 830.1 5/14/2009

Waste I Soil 846.0 2.9 0.5 843.6 12/11/2008

Date

Critical Value

12/27/2013

11/21/2013

10/7/2013

9/3/2013

8/2/2013

6/27/2013

5/23/2013

3/28/2013

2/17/2013

1/11/2013

12/05/2012

11/09/2012

10/02/2012

9/07/2012

5/02/2012

4/09/2012

1/18/2012

12/5/2011

11/23/2011

10/28/2011

10/15/2011

9/26/2011

9/16/2011

6/28/2011

4/20/2011

4/12/2011

4/5/2011

2117/2011

12/3/2010

10/27/2010

9/28/2010

7/8/2010

2/18/2010

12/18/2009

10/22/2009

8/31/2009

7/23/2009

71612009

6/24/2009

5/14/2009

5/1/2009

Table 2 Lemon Lane Landfill Cap Piezometers

Apparent Crest Gage Movement

Apparent Movement (ft)

PZ-AD PZ-AS PZ-BD

7.6 3.0 8.6

None None None

None None None

None None None

None None None

None None None

None None None

None None None

None None None

None None 0.13

None None None

None None None

None 0.14 None

None None None

0.6 None 0.5

None None None

None None None

None None None

2.29 l7l None None

None None None

None None None None None None None None None

None None None

None None 0.17

None None None

None None None

None None None

None None None

None None None

None None None

None None None

N.R.l'l None 0.18

0.31 None 0.17

0.31 None 0.18

0.23 None 0.20

0.43 None 0.17

0.43 None 0.19

0.41 None 0.25

None None None

9.42 m None 6.15 l7l

None None None

Page 1 of 4

PZ-BS

2.9

None

None

None

None

None

None

None

None

None

None

None

0.15

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

Date

Critical Value

4/10/2009 41712009

2/14/2009 12/1112008 11/13/2008 7/18/2008 6/25/2008 6/5/2008 512012008

4/30/2008 4/18/2008 4/8/2008 212512008

10/19/2007 912812007

9/12/2007 812712007

8/3/2007 71612007

6/26/2007 6/12/2007 5/31/2007 51712007

4/24/2007 312312007

3/10/2007 2/21/2007 21912007

1/18/2007 1/2/2007

11/9/2006 9/15/2006 812212006

8/3/2006 712512006

7/12/2006 6/20/2006 6/12/2006 5/18/2006 5/2/2006 3/31/2006

Table 2 Lemon Lane Landfill Cap Piezometers

Apparent Crest Gage Movement

Apparent Movement (ft)

PZ-AD PZ-AS PZ-BD

7.6 3.0 8.6 0.14 None 0.17 0.13 None 0.18 0.27 None 0.27 None None None

None None None

0.27 None 0.24 New gage installed None New gage installed

>= 7.67 (7) None >= 5.38 (7)

> 2.8 None 0.53 None None 0.29 0.22 None 0.20 0.15 None 0.23 0.28 0.14 0.15 None None None

None None None

None None None

None None None None None None

None None None

None None None

None None None

None None None

None None None

0.15 None 0.11 N.R. (61 None 0.16 0.50 0.15 0.11 0.17 None 0.14 None None None

< 0.55 None < 0.73 0.52 None 0.72 0.30 None None

None None None

None None None

None None None

None None None

None None 0.17 0.08 None 0.14 0.18 None None

0.17 None 0.15 > 2.95 None 0.45 0.84 None None

Page 2 of 4

PZ-BS

2.9 None

None

None

0.5 None

None

None

None

None

None None

None

0.17 None

None

None

None

None None

None

None

None

None

None

None

None

0.23 None

None

None

None

None

None None

None

None

None

None

None

None

None

Date

Critical Value

3/14/2006

212812006

212012006

2/15/2006

2/3/2006

1/11/2006

1/5/2006

12/21/2005

11/4/2005

10/11/2005

912012005

81812005

7/19/2005

6/21/2005

6/1/2005

5/25/2005

4/15/2005

3/24/2005

2/18/2005

2/3/2005

12/7/2004

10/21/2004

10/6/2004

91912004

8/30/2004

8/10/2004

712912004

7/12/2004

612412004

6/10/2004

5/21/2004

5/10/2004

4/23/2004

41912004

3/12/2004

3/2/2004

2/13/2004

21412004

1/15/2004

12/31/2003

12/8/2003

Table 2 Lemon Lane Landfill Cap Piezometers

Apparent Crest Gage Movement

Apparent Movement (ft)

PZ-AD PZ-AS PZ-BD

7.6 3.0 8.6

> 2.95 None > 2.95

0.23 None 0.26

None None None

0.27 None 0.25

None None None

None None None

None None None

None None None

None None None

None None None N/A (5l None 0.21

None None 0.17

None None 0.22

None None 0.12

0.43 None None

N.R.('l None None

None None None

None None None

None None 2.53 (3)

None None 0.08

0.2 None 0.24

None None None

None None None

None None None

None None None

None None None

None None None

None None None

None None None

None None None

None None None

None None 0.28

None None None

None None None

None None None

None None (2)

None None (2)

None None (2)

0.46 None (2)

None None (2)

None None (2)

Page 3 of4

PZ-BS

2.9

None

None None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

Date

Critical Value

11/26/2003

11/7/2003

10/23/2003

10/9/2003

9/29/2003

9/11/2003

9/3/2003

8/14/2003

7/31/2003

7/16/2003

7/2/2003

6/20/2003

6/5/2003

5/19/2003

5/8/2003

4/23/2003

4/7/2003

3/21/2003

3/5/2003

2/20/2003

2/11/2003

1/28/2003

1/13/2003

12/30/2002

12/13/2002

12/2/2002

11/14/2002

Notes:

Table 2 Lemon Lane Landfill Cap Piezometers

Apparent Crest Gage Movement

Apparent Movement (ft)

PZ-AD PZ-AS PZ-BD

7.6 3.0 8.6

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

1.35 None (2)

None None (2)

0.35 None (2)

None None (2)

0.45 None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

None (1) (2)

None (1) (2)

None None (2)

None None (2)

None None (2)

None None (2)

None None (2)

(1) Crest gage could not be removed from Piezometer AS on this date, ice-bound.

(2) Datalogger was installed Nov. 2001 to Mar. 2003; Crest gage was installed in PZ-BD on 3/8/2004.

(3) This reading appears unreasonably high for a period of relatively normal precipitation.

(4) No record of a visit to this station on this date was found at the time this report was written.

(5) Crest gage became untied and fell to bottom of PZ-AD this day. No reading available.

(6) Crest gage unreadable

(7) Hand measured water level using a water level probe.

Page 4 of 4

PZ-BS

2.9

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

APPENDIXB

FIGURES

(Four Sheets)

MW-830

Oil MW-SS

~

MW-B4 i I

I

,.--:;:·::;:.:::::-_:_- -- -, ; __ ;;..--- I

MW-2 11

1 i w

:, z ' I :) I ., z ,o

MW-14-----.11 ~

I _J MW·17 I

MW-13

MW-3

0 PZ-C

0pz.o

LEMON LANE ••••• LANDFILL ...

I MW-40 I

MW-4S·, 1, MW-10 MW-21 1

MW-41 MW-20 .. ··· ····. .. ·. .. · ~

/,•' B-2 ~ . .

MW-180 ~_J-:;::i _:_- GRAY 1

STREET MW-190

MW-16 0 -·----~~~ RAILROAD

·---·---·-·-·----·-·---·-·-·-=·-=·-=-~-S. ~~======PZ~-F~LF~-7-L~F~-6-~8~0~P~Z-~E~ ·-·-·-·-

0 LF-6~ MW-15 NN-7000 NN~;;-·-·-----·---------·- lf-4

0 0 NN-300 ·-·-·--·-·-00-387 ·-·-·-·----0 QI NN-120 -·---...

MW-01 00-370 0 00-300 Ql · - •• MW-82

00-125 ~

MW-11 ~ MW-5

00-587~

0MS·1

VALHALLA CEMETERY

0 100 200 e:_ SCALE (FEET)

1 INCH = 200 FEET

'.EGEND

MW-6 0 MONITORING WELL OR PIEZOMETER LOCATION AND DESIGNATION

• SOIL BORING

..,,,.,---. CROSS SECTION LINE (FIGURE 2)

DIRECTION OF KK-112, 11-87, 11-112, AND res

LEMON LANE LANDFILL BLOOMINGTON, INDIANA

FIGURE 1 SITE MAP

i:JTetra Tech EM Inc .

C=:J SOkJFllL

~ ClAY

~ LIMeSTONE

?

"'~ d ~ ~ A ~ ~ 0 ~ 0 8 0 ~~6

u 1'l Q I &i.g f=-~~-.---- ,

MAXIMUM WATER LEVEL 1/5/05 837.6'

880

870 'I'

~

820

810

800

790

INFORMATION HOT AVAILA8LE FOR fll.UCLAV CONTACT AT l...OCATIONS 8-1, 8-2 AND 8-6

~o~- o~~~ N~~~~ ~~@~8 ~w -mw ~

NOT'E:

-1- WATER LEVEL ELEVATIONS ARE PRESENTED IN FEET AMSI.. THE E\.EVATIONS AND DATES SHCM'N REPRESENT TtE MAXIMUM ELEVATIONS MEASURED AT PIEZOMETERS Pz..AO AHO PZ-80.

SOR.. BORINGS 8-1, 8-2, M, ~ OTB-32. INERE DRUED PRIOR TO THE REMEDW..AC'TION ANO AAE PROJECTED ONTO THE SCHEMATIC DIAGRAM: TI-IEREFORE, nESE SOil BORINGS ARE INCLUDED OM. Y TO PROVIOE BEDROCK SURFACE ElEVATION CONTROL POtNTS.

A'

0 5 10

VERTICAL SCALE IN rEET AMSL 0 100 200

HORIZONTAL SCALE IN n:ET

NORTH

890

880

870

860

850

840

830

820

810

800

790

Ll!:MON LANE LANDFILL BLOOMINGTON, INDIANA

FIGURE 2 GEOLOGIC SCHEMATIC A-A'

11:' I .. _.. l llCM

-...J en :ii: <(

~ c: 0

~ > Cl) jjj ... Cl)

1U 3:

840

835

830

825

820

815

810 Dec-99

Figure 3. Monitoring Well MW-6 Water Levels. (Modified from CBS (2012), Figure 11 ).

Lemon Lane Landfill South Sinkhole Nominal Bedrock -Elevation 830 ft.

)

:1

~ "' ~ \ ~ !' \k ~~ I lj \lw \I ,.~

' ~ ~ ' ~ L, ~ ~ , . ij \W-- \., ~ '--.. I !\ ' '

I I I I

Apr-01 Sep-02 Jan-04 May-05 Oct-06 Feb-08 Jul-09 Nov-10 Apr-12

836

834 832.5 ft AMSL - PZ-BD Soil I Bedrock Interface

832

830

::i' Vl

~ <( 828 ~ c 0 ·~ ~ 826 Qj

w .... Qj

~ 824

822

820

818

816 11/5/2001

. .

J.

. .. II - . •

\ \ '--J ~

12/25/2001

- PZ-BD --MW-6

' . ' A. ~ .. j j .~~ jlJ ~ ·-. w . ... '11 r I '

I

\ A ""'

\ ~\ ~ \ \ \ v........J'-' '

2/13/2002 4/4/2002 5/24/2002 7 /13/2002 0:00 Date

Figure 4. Time-Series Plots Showing Correlation of MW-6 and PZ-BD Water Levels (Modified from CBS {2012), Figure 10A).