GROUNDWATER MODEL REPORT HAVERTOWN PCP SITE … · numeric simulations of those site...

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GROUNDWATER MODEL REPORTHAVERTOWN PCP SITE

HAVERFORD TOWNSHIP, PENNSYLVANIA

Prepared For:

Tetra Tech, Inc.56 West Main Street, Suite 400

Christiana, Delaware

Prepared By:

Val F. Britton, P.O.326 Conestoga RoadWayne, PA 19087

(610)964-1462

June 10,2004Revised July 29,2004

Val F. Britton, P.O.Technical Consultant

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Table of Contents

1.0 General 5

2.0 Site Characterization 6

3.0 Model Construction 8

3.1 General 8

3.2 Three-Dimensional Solid Model 8

3.3 Numeric Model 9

4.0 Model Simulations 13

4.1 General 13

4.2 Model Simulations 13

5.0 Summary and Conclusions 18

6.0 Recommendations 20

7.0 Limitations 22

Tables

Table 1 - Hydro-Geologic Flow Model Parameters

Table 2 - MT3DMS Parameter Estimations

Table 3 - Naylor's Run Flow Budget

Figures

Figure 1 - Site Topography (Map View)

Figure 2 - Site Topography (Oblique View)

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Figure 3 - Top of Bedrock (Oblique View)


Figure 5 - Bedrock Surface Contour

Figure 6 - Groundwater Contour (12/01/03)

Figure 7 - Groundwater Contour (12/01/03) with Bedrock

Figure 8 - Site Features with Groundwater Contour (12/01/03)

Figure 9 - Site Features with Groundwater Contour (12/01/03)

Figure 10 - Site Features with Geology



Figure 13 - Site Features with Geology and Groundwater Contours (12/01/03)

Figure 14 - Model Boundary

Figure 15 - Grid Layout (MODFLOW)

Figure 16 - Layer Array (MODFLOW)

Figure 17 - HUF to MODFLOW Conversion

Figure 18 - Drain Configuration (MODFLOW)

Figure 19 - Naylor's Run Stream Bed Locations

Figure 20 - Recharge Zones (MODFLOW)

Figure 21 - Sensitivity Analyses - Recharge Zones - Modeled Parameters

Figure 22 - Sensitivity Analyses - Recharge Zones - (20% Increase)

Figure 23 - Sensitivity Analyses - Recharge Zones - (20% Decrease)

Figure 24 - Calibration (MODFLOW)

Figure 25 - Simulated Groundwater Contours

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Figure 26 - Simulated Groundwater Contours (Pumps Off)

Figure 27 - Zoom Recovery System (All Pumps On)

Figure 28 - Simulated Groundwater Contours - Abandoned Sewer Line Plugged

Figure 29 - Capture Zone (All Pumps Off)

Figure 30 - Capture Zone (All Pumps On)

Figure 31 - Capture Zone - Trench Zoom (All Pumps On)

Figure 32 - Particle Path - Cross Section

Figure 33 - Forward Particle Path Tracking - Multi-Layer Release - Cross Section

Figure 34 - Simulation of CW-4D/CW-5D (Pumping at 8 gpm)

Figure 35 - Simulated PCP Fate and Transport (Ten Year Migration)

Figure 36 - Simulated PCP Fate and Transport (Ten Year Migration) Cross Section

Figure 37 - PCP Concentration - Shallow Wells (October 2002)

Figure 38 - PCP Concentration - Deep Wells (October 2002)

Figure 39 - PCP Concentration - Shallow Wells (March 2004)

Figure 40 - PCP Concentration - Deep Wells (March 2004)

Figure 41 - Simulated PCP Fate and Transport - Ten Year Migration Active Pumping

Figure 42 - Simulated PCP Fate and Transport -Ten Year Migration -X-Section

Figure 43 - 1950 to 1991 Transport Simulation

Figure 44 - 1991 to 2002 Transport Simulation

Figure 45 - 2002 to Present Transport Simulation

Appendices

Appendix A - Model Output Files

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1.0 General

The purpose of the groundwater model was to provide a numeric representation of thehydro-geologic conditions existing at the Havertown PCP site facility, subsequently,allowing a capture zone analyses of an existing remedial system. Additionally, the modelwill be used for simulations for the evaluation of modifications to the existing remedialsystem. It should be noted that this report is not intended to be a hydro-geologiccharacterization of the site, but rather, this report provides three-dimensional images andnumeric simulations of those site characteristics previously documented in formal hydro-geologic characterization report. The intent of the groundwater model was to provide anadditional tool, in conjunction with other more qualitative techniques, to help understandthe hydro-geologic characteristics of the site.

Groundwater Modeling Systems (GMS) software, Version 5.0, developed by the UnitedStates Department of Defense and distributed by Environmental Modeling Systems, Inc.(EMS-I) was utilized in the development of the groundwater model for the Havertownfacility. This modeling software consists of numerous modules that are interfaced toallow more accurate representation of hydro-geologic conditions and greater flexibility insimulating and evaluating flow and transport conditions on the site.

Data provided by Tetra Tech, Inc. (TTI) was incorporated into the model. The dataincluded drilling logs, static water levels, hydraulic conductivity data, pump test data,soils and groundwater chemical analytical data, site topography, and other physical sitecharacteristics.

The "site" generally encompasses the entire region of the groundwater model thatincorporates numerous properties along the general axis of Naylor's Run.

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2.0 Site Characteristics

Characteristics associated with the site were obtained from existing report documentationrelative to the Havertown PCP site, geologic literature, and additional informationprovided by TTI.

Site topography ranges from approximately 330 feet above mean sea level (msl) toapproximately 242 feet above msl. Generally, a topographic low exists along the axis ofNaylor's Run that acts as the primary drainage in the area of the site. Topographic highsexist on each side of Naylor's Run. Figures 1 and 2 present a three-dimensionalsimulation of the site topography. It should be noted that based on the topographicimages, no geologic features were apparent (i.e. fracture traces, etc.).

Numerous sanitary and storm sewers were located along the topographic low, apparentlyto take advantage of gravity drainage along this axis. Additionally, it should be noted thata portion of Naylor's Run was relocated utilizing underground conduits and open troughsto redirect the flow from the original location of the creek. A recently discoveredabandoned sewer line was also identified running along the axis of Naylor's Run.

The site consists of three mam hydro-geologic units that include a fill material, saprolite,and a fractured schist (Wissahickon Formation). The folding orientation of the schistbedding (strike) trends approximately N45E. Additionally, fractures associated with thebedrock appear to be perpendicular to the strike of the bedding at an orientation ofapproximately N45W. Based on the available data, a simulation of the top of bedrock wasconstructed and is presented as Figures 3 and 4. Figure 5 presents a bedrock elevationcontour map based on an interpolation of existing boring data and reported rock outcroplocations.

A geo-physical evaluation of the fracture patterns of the crystalline bedrock wasconducted. The evaluation suggested that high angle fractures existed within the bedrockmaterial further supporting the theory that one unconfmed water-bearing unit exists at thesite. This system is likely perched within the crystalline bedrock where water-bearingfractures eventually become absent at depth.

Groundwater at the site likely exists as an unconfined water table moving from thenorthwest to the southeast with a hydraulic gradient of approximately 0.015 ft/ft. For themost part, the water table exists within the saprolitic material. The water table used forcomparison in the ground water model was based on measurements collected onDecember 01, 2003 at which time the recovery system was not operating and no apparentpumping was occurring. Figure 6 presents a groundwater elevation contour map of thisdata and Figure 7 presents the data overlaying the bedrock contour, exposing thelocations where bedrock is likely above the water table. It should be noted that, based onthis data, the bedrock does not appear to have any significant impact on the groundwaterflow suggesting the unconfmed flow system within the saprolite and the fracturedbedrock.

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Figure 8 and 9 presents the relationship between the water table (12/01/03) and the othersite features (i.e. sewers, foundations, conduits, etc.). It should be noted that the elevationof the sewer line inverts at several locations are either at or below the ground surface. Itshould be noted that this has potential impact on both groundwater movement andpotential LNAPL migration.

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3.0 Model Construction

3.1 General

The model was constructed in two stages. The first stage consisted of developing a threedimensional solid model representing the physical characteristics of the site discussedabove in Section 2.0. The second stage consisted of converting the three-dimensionalsolid model into a numeric model for calibration and subsequent flow and transportsimulation. MODFLOW 2000, a finite difference model, was utilized for the numericmodel and MODPATH was utilized for the particle transport model. All model outputfiles are presented in Appendix A.

Review of existing site data suggested that the fractured bedrock system exhibitedunconfined hydro-geologic conditions. Additionally, it is apparent that preferential flowexists along fractured bedding planes predominately parallel to strike. For this reason, themodel was constructed with anisotropic conditions replicating the bedding on the site.This method of construction allowed site conditions to be more accurately represented. Itis understood that additional site characterization (i.e. pump test) is planned that maychange this interpretation of the site's hydro-geology, however, for the purpose of thisreport, the present flow conditions discussed above will remain the basis for the model.

3.2 Three Dimensional Solid Model

Geologic Characteristics

An initial geologic solid model of the site was constructed by incorporating existinggeologic site data into a three dimensional representation (solid model) of the site.Generally, this included three types of hydro-geologic units that included fill material,saprolite, and a crystalline fractured bedrock. The relationship, thicknesses, andelevations of these units were based on existing site boring data presented in drilling logs.In addition, strike and dip measurements collected on the site and in the region were alsoutilized in configuring the geologic framework of the model. The solid model surfaceswere built with triangular interpolated networks (TINs) on a grid cell size ofapproximately 20 feet by 20 feet. All surfaces were contoured based on scatter point datasets interpolated through inverse distance weighted averaging, kriging, or linearinterpretation. It should be noted that the actual thickness of the geologic units (i.e. fillmaterial and saprolite) in the north western portions of the site and in the south easternportion of the site were based on limited data and as a result a high amount ofinterpolation exists, however, the location of these beds likely have little impact on themodel simulations since they are on the outskirts of the areas of concern. Figures 10, 11,and 12 present the site features and site geology with fence diagrams.

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Drainage

Storm sewers, sanitary sewers, creek beds, and underground surface water conduits werealso incorporated into the model. Their diameters and invert elevations were obtainedfrom existing data. It should be noted, that although not evident in the solid model,leakage along these sewer lines through the annulus material and the lines wasincorporated into the numeric model. Rates were determined based on fieldmeasurements, assumptions, and model calibration (discussed in Section 3.3).

Water Table

A water table surface was also incorporated into the solid model. Groundwatermeasurements collected on December 01, 2003 were used to represent a non-pumpingcondition on the site. This groundwater elevation data was contoured utilizing geo-statistical kriging methods. Figure 6 presents a groundwater elevation contour map basedon this data. This groundwater surface (water table) was then incorporated into the solidmodel. Figure 13 presents an images of this data incorporated into the solid modelgeologic fence diagram. It should be noted that the majority of the water table surfaceexists within the saprolite material.

3.3 Numeric Model

Boundary Conditions

Figure 14 presents the boundaries of the model. The boundaries of the model werepositioned far enough from the area of interest to prevent interference from the boundaryconditions on the flow characteristics of the site. Specified heads were assigned to theboundary conditions based on groundwater elevation data collected on the site.

Model Grid

Six layers were incorporated into the model to allow modification to the deeper layersshould data (i.e. pump test results) suggest that different hydro-geologic conditions existat depth. The layers were divided into grids approximately 20 feet by 20 feet. The area ofthe trench system was divided into grids of approximately 5 feet by 20 feet to allow anappropriate level of detail of the groundwater flow proximate to the trench system.Figures 15 and 16 present the general structure of the numeric model.

Geologic Characteristics

The geologic solid model was incorporated into the numeric finite difference model(MODFLOW) utilizing the hydro-geologic unit flow (HUF) package available inMODFLOW 2000. The orientation of the model was adjusted to allow the Y-axis of themodel grid to parallel the strike of the bedrock bedding planes. This allowed hydro-

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geologic properties to be assigned and oriented along the strike direction to bettersimulate existing site conditions such as anisotropy. The HUF package allows specifichydro-geologic parameters to be assigned to each material type (i.e. fill material,saprolite, and crystalline rock). The hydro-geologic parameters that were assigned to eachgeologic unit are presented on Table 1. Figure 17 presents an image of a cross section ofthe HUF conversion.

The upper layer of the model incorporates all of the HUF units. The vertical anisotropyratio and the vertical dispersivity ratio for the crystalline bedrock material was increasedrelative to typical un-fractured rock to better represent the vertical fracturing evident fromthe geo-physical evaluation discussed in Section 2.0. The hydro-geologic parametersassigned to the bedrock in the upper most layer is consistent with the parameters in thelower layers. Hydro-geologic parameters utilized in the model are summarized in Table1.

Drains (Storm-water and Sanitary Lines)

Numerous drains were assigned to the numeric model to represent the storm sewers andsanitary sewers. Figure 18 presents the configuration and location of the drains that wereincorporated into the model. For the purpose of the model it was assumed that annularmaterial around the sewer lines likely had a higher conductivity than the native material.In addition, it was assumed that the sewer lines leaked to some degree. The amount ofleakage and flow through these drains was determined based on assumptions, fieldmeasurements, and model calibration. Generally, a rate of approximately 1 to 2 gallonsper minute through the drains was utilized. An exceptions to this flow rate was theabandoned sewer line (10 gpm) and the large storm drain running behind PhiladelphiaChewing Gum Factory (no flow), since actual flow measurements were known in thesedrains.

Drains (Naylor 's Run)

Numerous drains were utilized to represent Naylor's Run creek bed locations. It shouldbe noted that the present location and configuration of Naylor's Run is different thanwhat existed historically. Figure 19 presents the present configuration of Naylor's Runand the location of the past creek bed. It has been assumed that the historic creek bedlocation was filled in prior to the residential development of the area. It has also beenassumed that the previous creek bed likely consisted of at least a one-foot thick creek bedbottom consisting of highly conductive sands and gravels. Presently, it is postulated thatthis material may be acting as a long "French-type" drain. It should be noted that boringHAV-7 encountered a sand and gravel layer that could be associated with the formercreek bed location. This was the only location at which sand and gravel was encounteredduring the subsurface explorations.

The location of the historic creek bed of Naylor's Run, utilized in the groundwater model,was based on three drawings. The first was a detailed survey plan entitled "Plan ofProposed Subdivision, Oakmont Park" dated June 16, 1954. The other two plans, of less

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detail, were historic atlases dated 1908 and 1920. It should be noted that the historicatlases had numerous inconsistencies, one of which included the position of the roads(Eagle Road and Lawrence Road). Therefore, the accuracy of the exact location of thehistoric creek bed of Naylor's Run is questionable on the historic atlases.

For the purpose of the groundwater model, the historic creek beds were positioned inthere relative location based on the existing drawings. The specific location of the creekbed presented on the June 1954 drawing was used exactly as shown on the drawing.Extensions of the creek bed shown on the historic atlases were positioned in thereapproximate position based on an average of the two positions shown on the historicatlases. Figure 19 presents the locations of the creek beds utilized in the modelsimulations.

For the purpose of the model, the creek bed for Naylor's Run was subdivided intosegments based on elevations, and the conductance of the material lining the creek bed. Itwas assumed that a relatively low conductance exists where the creek bed has been linedwith concrete or has been completely re-directed with conduit. Segments that are notlined and are directly connected to the seepage face of the geologic formation have beenassigned higher conductance values. The conductance values were adjusted slightlyduring the calibration procedure to appropriately simulate the water table conditions.Figure 18 presents the drain segments and Table 3 presents the flow budget assigned toboth the historic and present creek channels for Naylor's Run.

Recharge

Groundwater recharge was based on the average annual precipitation in the region. As ageneral "rule of thumb", recharge of approximately 1/3 of the actual precipitation occursin relatively flat and porous terrain typical of what exists on the site. Figure 20 presentsthe aerial coverage of the recharge zones. Recharge values utilized in the model arepresented on Table 1.

A sensitivity analyses of recharge was conducted to better understand the impact that thisparameter has on the groundwater movement on the site. To evaluate recharge, a separatemodel simulation was run with an overall 20% increase in recharge (20% above what wascalculated based on annual precipitation) and a simulation was run with an overall 20%decrease in recharge (20% below what was calculated based on annual precipitation).Figure 21 presents the groundwater flow simulation based on the recharge values utilizedin the groundwater model. Figures 22 and 23 present the 20% increase and 20% decreasein recharge respectively. It is evident that recharge does not have a significant impact ongroundwater movement; the model remains calibrated throughout these parameterchanges.

Calibration

Static groundwater elevation data collected on December 01, 2003 was utilized as theobserved groundwater elevations for the calibration of the model. Minor adjustments to

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the boundary conditions, drain conductance, hydraulic conductivities, and anisotropyratios were made to allow groundwater to simulate the flow conditions observed onDecember 01, 2003. A 1-foot target deviation was allowed from the actual observedconditions. Wells utilized in the calibration along with the results of the calibration arepresented on Figure 24. The majority of the wells fell within a 95% or better match(indicated by the green color). Several of the wells were outside of the 95% match, butwithin a 90% match (indicated by the yellow color). Overall, the model calibrated well.Figure 25 presents the calibrated groundwater flow simulation representing steady stateflow with all of the remedial system pumps off. This steady state flow simulation and theassociate hydro-geologic parameters were used as the basis for all the remaining modelsimulations

It should be noted that numerous drains run along the central axis of the site, several ofwhich represent the past and present creek beds of Naylor's Run. To date, no formal flowbudget evaluation of Naylor's Run has been completed. However, a USGS gaugingstation located at the intersection of Naylor's Run and Route 3 (southeast of the site)indicated that Naylor's Run has an average net outflow of 60,480 cubic feet per day(about 314 gallons per minute). Based on the flow budget calculated from the model(Table 3), the average net outflow was 78,935 cubic feet per day (about 409 gallons perminute). Recent observations and estimates of the main- streambed discharge suggest thehigher discharge which at the specific point in time is higher than the USGS average. It isdifficult to determine the actual flow attributable to base flow (from the groundwaterdischarge). It should be noted that no formal flow rate evaluation of Naylor's Run hasbeen conducted. The flow budget utilized in the model does not correlate well to thevalue estimated based on the USGS data. When base flow values are brought into therange of the USGS values, the model will not calibrate properly suggesting the USGSvalue may not be representative site-specifically. For this reason, it is recommended thata formal flow budget evaluation of Naylor's Run be conducted.

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4.0 Model Simulations

4.1 General

At the completion of the calibration process, the simulated flow through the site has aclose match to observed site conditions indicating that the model is simulating siteconditions and has been appropriately calibrated. At this point in the modeling process,modifications can be made to the model to simulate remedial systems such as alteringpumping rates, simulating collection trenches, or evaluating capture zones. The nextsection describes the results of simulations that were run on the calibrated model.

4.2 Model Simulations

Steady State Ground-water Flow

Figure 25 presents the steady state groundwater flow through the site with all of theremedial recovery pumps turned off.

Remedial System Pumps On

Figure 26 presents an image of the simulated groundwater elevation contours with theremedial system pumps on (RW-1 through RW-4 and the trench sump). Figure 27presents a zoom image of the remedial system area.

Plugged Abandoned Sewer Line

Figure 28 presents the simulated groundwater elevation contour lines with the drainagethrough the abandoned sewer line (approximately 10 gpm) plugged. The remedial systemwas kept on during this simulation to represent existing site conditions. It should be notedthat no significant change in the contour elevations resulted in the plugging of the sewerline (when compared to Figure 26 - the open abandoned sewer line). This is likely theresult of other drains distributing the additional 10 gpm including the former Nay lor'sRun streambed that likely acts as a conduit.

Capture Zone Evaluation Under Static Non-Pumping Conditions

This simulation was created by releasing particles at known LNAPL locations proximateto Eagle Road to evaluate the migration of dissolved phase constituents. The simulationwas run forward to evaluate how particles would migrate under non-pumping conditions.Figure 29 presents the results of the simulation. Based on the simulation, the particlesinitially move toward the topographic low and eventually appear to follow various drains(sewers, historic stream beds, present stream beds).

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Capture Zone Evaluation of the Existing Recovery System

Figure 30 presents a map view of the simulated zone of capture resulting from theexisting remedial system. This simulation was created by releasing particles at the watertable surface at the groundwater recovery locations (RW-1 through RW-4 and the trenchsystem). The simulation was run backwards to reveal the area of capture. This simulationwas based on groundwater advection (flow) only. Figure 31 presents a zoom of thecapture zone proximate to the remedial system. Figure 32 presents a side view of thecapture zone superimposed over the geologic strata. It should be noted that a strong zoneof capture is evident to the west of the trench system.

For evaluation purposes, particles were also released at depth to determine if the activerecovery system would intercept particles in the deeper zones. Based on the simulation,the particles were all captured by the trench system. Figure 33 presents this simulation incross section.

Capture Zone Simulation with CW-4D and CW-5D Enhancement

Figure 34 presents the simulated zone of capture by adding CW-4D and CW-5D asrecovery wells pumping at 8 gpm each. Based on the simulation, these wells appear tocapture particles in a south to southwesterly direction.

Contaminant Solute Fate and Transport Simulation- Non-Pumping Conditions

To evaluate the dissolved fraction migration of PCP, a fate and transport simulation wascreated for non-pumping steady state conditions. MT3DMS was utilized as the softwarefor the simulation and was superimposed on the calibrated MODFLOW model discussedin Section 3.3. Locations of known LNAPL were utilized as point source locations for therelease of dissolved state PCP in the simulation. Concentrations of 14,000 ug/1 were usedat each source location since this is the approximate solubility of PCP in water atapproximately 20°C. The simulation was run for 10 years: the plume appears to reach asteady state (equilibrium) at approximately 4.5 years. Figure 35 and 36 present the resultsof the simulation. It should be noted that a transverse dispersivity ratio of 2.0 and avertical dispersivity of. 1 were used in the simulation. Flow parameters for the simulationare presented on Table 1 and the degradation and sorption parameters are presented onTable 2.

Based on this simulation, it is evident that the extent of dissolved PCP does not fullyextend to areas that have had observable PCP concentrations (i.e. CW-13D). Based on thehydrogeology of the site, known LNAPL source areas, and the physical characteristics ofthe site, it is difficult to explain how dissolved PCP contamination would migrate to CW-13D without an additional LNAPL source area up gradient of this location. It should benoted that cross contamination cannot be ruled out as a potential cause of theconcentrations of PCP observed in this well.

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For comparison purposes, actual groundwater chemical data collected on October 2002and March 2004 was compared to the results of the model simulation. Figures 37 and 38present the October 2002 data in the shallow and deep zone respectively. Figures 39 and40 presents the March 2004 data in the shallow and deep zones respectively. It should benoted that the general shape of the simulated plume is similar to the shape of the actualplume delineated from the groundwater data. Additionally, it is evident from thegroundwater chemical data that both the shallow and deep zones are similar, furthersuggesting an unconfmed hydro-geologic condition.

Contaminant Solute Fate and Transport Simulation- Pumping Conditions

To evaluate the dissolved fraction migration of PCP, a fate and transport simulation wascreated for pumping conditions (present remedial system configuration and pumpingrates). MT3DMS was utilized as the software for the simulation and was superimposedon the calibrated MODFLOW model discussed in Section 3.3. Locations of knownLNAPL were utilized as point source locations for the release of dissolved state PCP inthe simulation. Concentrations of 14,000 ug/1 were used at each source location since thisis the approximate solubility of PCP in water at approximately 20°C. The simulation wasrun for 10 years: the plume appears to reach a steady state (equilibrium or capture by theremedial system) at approximately 4.5 years. Figure 41 and 42 present the results of thesimulation. It should be noted that a transverse dispersivity ratio of 2.0 and a verticaldispersivity of .1 were used in the simulation. Flow parameters for the simulation arepresented on Table 1 and the degradation and sorption parameters are presented on Table2.

Based on the results of the simulation, it is evident that the existing remedial system iscapturing the simulated dissolved plume of PCP emanating from the known LNAPLsource areas.

1950 to 1991 Particle Transport Simulation

This simulation represents the site hydro-geologic conditions between 1950 and 1991when the abandoned sewer line was apparently leaking and acting as a potential conduitthrough the central axis of the site. Additionally, the present day groundwater recoverysystem was not installed or operating. The 30-inch diameter storm sewer that runs behindthe chewing gum factory had not been sealed and was leaking (inflow of groundwater) ata rate of approximately 20 gallons per minute.

The simulation was constructed by releasing particles at the known locations whereLNAPL was observed. The simulation was run forward and the particles were allowed tomove with the groundwater flow. Figure 43 presents the results of this simulation. It isapparent (see the inset box for detail) that the particles move into Naylor's Run historiccreek bed, the 30-inch diameter storm drain, and the abandoned sanitary sewer suggestingthat all of these are potential migration pathways for contamination. It should be notedthat no dispersion is applied to the particles. The particles track on the groundwateradvection (flow) only. Additionally, it should be noted that this simulation was run with

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the impermeable cap over the Havertown Super-fund site removed with standard rechargerates (See Figure 20) since the cap had not been constructed until 1997.


This simulation represents the site hydro-geologic conditions between 1991 and 1997when the abandoned sewer line was apparently leaking and acting as a potential conduitthrough the central axis of the site. Additionally, the present day groundwater recoverysystem was not installed or operating nor was the cap installed on the Superfund site. The30-inch diameter storm sewer that runs behind the chewing gum factory had been sealedand was no longer leaking.

The simulation was constructed by releasing particles at the known locations whereLNAPL was observed. The simulation was run forward and the particles were allowed tomove with the groundwater flow. Figure 44 presents the results of this simulation. It isapparent that the particles move into Naylor's Run historic creek bed and the abandonedsanitary sewer, however, they do not enter the 30-inch diameter storm drain. It should benoted that no dispersion is applied to the particles. The particles track on the groundwateradvection (flow) only. Additionally, it should be noted that this simulation was run withthe impermeable cap over the Havertown Superfund site removed with standard rechargerates (See Figure 20) since the cap had not been constructed until 1997.


This simulation represents the site hydro-geologic conditions between 1997 and 2002when the abandoned sewer line was apparently leaking and acting as a potential conduitthrough the central axis of the site. Additionally, the present day groundwater recoverysystem was not installed or operating nor was the cap installed on the Superfund site. The30-inch diameter storm sewer that runs behind the chewing gum factory had been sealedand was no longer leaking and the cap had been installed on the Havertown Superfundsite.

The simulation was constructed by releasing particles at the known locations whereLNAPL was observed. The simulation was run forward and the particles were allowed tomove with the groundwater flow. It should be noted that the recharge rate in the cap areawas changed to simulate an impermeable barrier, however, it did not create anysignificant change in the groundwater advection and subsequent particle tracking. As aresult, no change was evident from 1991-1997 simulation. Therefore, Figure 44 alsorepresents the results of this simulation. It is apparent that the particles move intoNaylor's Run historic creek bed and the abandoned sanitary sewer, however, they do notenter the 30-inch diameter storm drain. It should be noted that no dispersion is applied tothe particles. The particles track on the groundwater advection (flow) only. Additionally,it should be noted that this simulation was run with the impermeable cap over theHavertown Superfund site as an impermeable barrier (See Figure 20) since the cap wasconstructed in 1997.

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2002 to present Particle Transport Simulation

This simulation represents the site hydro-geologic conditions between 2002 and presentwith the abandoned sewer line apparently leaking and acting as a potential conduitthrough the central axis of the site. Additionally, the present day groundwater recoverysystem is operating. The 30-inch diameter storm sewer that runs behind the chewing gumfactory had been sealed.

The simulation was constructed by releasing particles at the known locations whereLNAPL was observed. The simulation was run forward and the particles were allowed tomove with the groundwater flow. Figure 45 presents the results of this simulation. It isapparent that the particles move into the intersection of Naylor's Run historic creek bedand the abandoned sanitary sewer. The simulation suggests that water is being pulledthrough the sanitary line or the former creek bed from the operation of the recoverytrench. It should be noted that no dispersion is applied to the particles. The particles trackon the groundwater advection (flow) only.

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5.0 Summary and Conclusions

Groundwater modeling is an additional tool that can be used in conjunction withconventional evaluation techniques to better understand groundwater flow conditions andcontaminant migration characteristics. It allows the integration of numerous hydro-geologic parameters simultaneously, ultimately providing a means for qualitative andquantitative evaluation of site characteristics. Based on the results of the groundwatermodel for the Havertown Superfund site and surrounding area, the following conclusionshave been reached:

Solid Model

• No geologic features (i.e. fault traces, bedding orientation, etc.) are evident basedon detailed evaluation of site topography.

• Simulated bedrock surface with peaks and valleys trending along the averagestrike and dip of the bedrock measured from several known outcrop locationsmatches the bedrock depths identified in the site soil borings.

• Many of the existing underground utilities (i.e. storm water sewer lines, sanitarysewer lines, etc.) are near the water table surface and could influence potentialLNAPL migration (past or present).

Numeric Model

• Calibration of the model with observed site data has indicated that the entire depthof the aquifer is acting as an unconfined system. This is likely the result of highangle fracturing that runs deep into the bedrock.

• The existing groundwater extraction system is adequately capturing the dissolvedcontaminant plume on the site. However, excessive amounts of clean groundwatermay be entering the extraction system ultimately lowering the efficiency of theremedial system.

• Historic contaminant migration pathways are evident in the model simulationsthrough the abandoned sewer line (recently plugged), the historic riverbed ofNaylor's Run, and the 30-inch storm drain (sealed in 1991). Presently, the historicstreambed of Naylor's Run could still be acting as a conduit for contaminantmigration, however, with the implementation and operation of the existinggroundwater extraction system, contaminants entering the historic streambedwould be pulled into the groundwater recovery system.

• Predictions made in the model have indicated there will be little impact togroundwater flow or static groundwater elevation change should the abandonedsanitary sewer line be plugged. It is evident that flow moving through this linewill easily be distributed to other drains and no flooding should occur.

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Dissolved contaminants have been observed at locations on the site (i.e. CW-7Dand CW-10D) where the model has not been able to show a clear transport pathfrom the known source areas to the existing contamination. This suggests thatadditional sources of LNAPL potentially exist outside of the presently knownareas.

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6.0 Recommendations

Based on the results of the model simulations, the following is recommended:

• Anisotropy appears to play a key role relative to the distribution of the capturezone of the existing recovery system. Values utilized in the model simulationswere assumed based on regional publications and general estimates since no site-specific data exists. To better replicate actual site conditions, a long-termdrawdown pump test is recommended at the site at an appropriate location toevaluate site-specific horizontal and vertical anisotropy.

• Results of the dissolved state PCP fate and transport simulation do not directlycorrelate to the observed groundwater concentrations on the site. Since several ofthe observed groundwater concentrations were well above the solubility of PCP, itmust be assumed that free product likely exists at these locations. The freeproduct (LNAPL) would likely migrate differently than the dissolved stateconstituents. As a result, it is recommended that the migration of the LNAPL bespecifically evaluated with a dual phase model simulation such as UTCHEM.This would require a more in depth evaluation of the release of LNAPL (theapparent carrier of PCP) on the site. Additionally, the actual source of the LNAPLrequires evaluation, especially in light of dissolved PCP contaminants existingwhere there is no recorded history of an up-gradient LNAPL source.

• Although a USGS stream gauging station is located south of the study area whichmonitors total flow through the stream bed for Naylor's Run, no site specificstream segment measurements have been taken to determine actual base flowthrough Naylor's Run. It is postulated that different base flow (from groundwateronly) rates will exist along different segments of Naylor's Run due to variablesubsurface conditions (i.e. former steam bed locations, etc.). It is recommendedthat formal stream flow measurements be collected during low precipitationevents utilizing stream weir or other quantitative methodologies.

• The historic location of Naylor's Run creek bed likely has had a significantimpact on the migration of contaminants across the site. These former creek bedslikely have sand and gravel associated with them, that when backfilled during sitedevelopment, are presently acting as long French drains. These were the naturaldrainage points and subsequently, still likely drain groundwater from the site. It isrecommended that a more detailed evaluation of these former creek bed locationsbe conducted.

• Based on observed PCP groundwater concentrations, there appears to be a strongmechanism moving contaminants from the source areas to the CW-9 and CW-10locations. Based on the flow simulation, this flow component does not exist. Itshould be noted that the model calibrated well in this area suggesting that someanomaly may exist in this area. One possible explanation may be a significant

20AR302298

seasonal groundwater fluctuation that significantly alters the groundwater flowdirections. It is recommended that the area between the site source areas andCW-9 and CW-10 be evaluated for possible factors that may cause the deflectionof contaminants toward these wells. Additionally, it is recommended that seasonalvariation in the groundwater elevations be further evaluated to determine anypotential impact on the migration of site contaminants.

21AR302299

7.0 Limitations

The modeling in this report was performed using a commercially available softwarepackage (Groundwater Modeling System-GMS, Version 5.0 developed by the UnitedStates Department of Defense) designed to simulate groundwater flow and the migrationof contaminants. Where available, actual data from the site was utilized to calibrate themodels and develop the graphical representations presented hi this document. In otherinstances, assumptions were necessary to complete the model and limitations associatedwith the site data result in a level of uncertainty in the model predictions. Therefore, theresults of the model predictions should be independently evaluated using actual sitemonitoring data.

The results of the model may differ from actual site conditions because of unknownsubsurface conditions. The results of the models presented in this document shall not beconstrued to create any warranty or representation with regard to the site. Theconclusions presented in this report were based on the services described, and not onscientific tasks or procedures beyond the described scope of services.

22AR302300

Table 1Hydro-Geologic Flow Model Parameters

Havertown PCP Site - Haverford Township, Pennsylvania

TransmissivityHorizontal Conductivity (K)Vertical Conductivity (K)Horizontal Anisotropy Kx/KyVertical Anisotropy Kh/KvSpecific StorageSpecific YieldAquifer PorosityLongitudinal DispersivityBulk DensityImmobile Porosity

=•* [ ^ : ii-;^";^ '".''.ifi':*.":•'• ji-i i^fij*: !>tkD'1'1i.

NA1NA11NANA23NANA

|UnItSr;

ft2/dft/dft/dNANANANANANANANA

iFiliMateriai:-

NA0.5NA11NANA0.38NANA

NA1.0NA .1.42NANA.255NANA

IGifystallineg.

NA12NA2.02NANA0.21NANA

IKetfhai-geiPatkage ' •''.'^^••: V - ; , . " --V^lV:' 'r' ^^^^-J^^^:-l!^^^^^ ••••^J^^^^SS^^^f^^^^^^^w^me(^,s^vM^^r^^M^^^^^Recharge Rate

y'REElt

4?UnitiS|£ft/d

S.'^Jv^^xS^.CKIjJ'IîKS-'r'iÔIlCM. ;;^"i(;J-=: !;•;•:

.01 .0001jrZo'ii"el3:|. l'if*.02

?pHv1-S^^fe;p®St;iSl§:ii«ISSiii î^SfsSifeasS

, Evapotranspiration" Package^ * *%\J. „" /•, *> .- "V^ ^_ ^ •/ "ft u ' - > \ - ' * ^ * \ . ' * ' " . - „ " . "^ • * " , ! '< r V y ' j *Parameter * -„ ^ " JtEvapotranspiration RateEvapotranspiration Extinction DepthEvapotranspiration Elevation

REFNANANA

UnitsNANANA

Zonel'j 'NANANA

Zone 2 -»NANANA

Zone 3 -, 'NANANA

i \ ' I T"•j •*

NA- Not ApplicableREF - Reference for Value (see reference page)

AR302301

Table 2 - Havertown PCP Site - MT3DMS Parameter Estimations

SorptionSolution: Linear Isotherm

'Iff} Partition

[Coefficient (1)

^SB^aSlS&SSghih •mrMSSf.:

. , Aquiferfpry /:jj IJiVCquifer Dry' -* . ~Aqujfef piy^'•p nl.ii, iri_; '_:i.-. J/*r\ *<o.'';n 'r tl—'j Til'.'/cv -i n"r:ii.,'in»—'—'—:*,.''/cv

PCP 0.1200 1000.0000 0.0010 0.0001 0.0001 0.2500 120.0000 1.9200 3.7302

0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00000.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00000.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

Decay (Biodegradation)Solution: First-Order Irreversible Kinetic Reaction CMS Chemical Reaction Package Input Parameters

Contaminant

PCPx

xX

X

1520.0000

0.0000

0.0000

0.0000

0.0000

&&1 Half Life (6)iliiia r'; lisa!! '

4.1644

0.0000

0.0000

0.0000

0.0000

','-.- Rate Constant.:. . Rate Constant i

:.... '(Dissolved):;:.:.' ^ :. (Sprbedj „.;

0.0007

#DIV/0!

#DIV/0!

. #DIV/0!

#DIV/0!

0.0007

#DIV/0!

#DIV/OI

#DIV/0!

#DIV/OI

J: •.; , : Bulk" ''•" : '' ' 1stSorption...V'- "' '~-':'Rate '- 'Rate:-; .

» 5 - : .;• -Density-:. 'Constant ' v: ".Constant ~ .-; CpnktaVit '>.-.--'-

PCP 3.7302 0.0001 0.0007 0.0007

x 0.0000 0.0000 #DIV/OI #DIV/OI

x 0.0000 0.0000 #DIV/OI #DIV/OI

x 0.0000 0.0000 #DIV/OI #DIV/OI

x 0.0000 0.0000 #DIV/OI #DIV/OI

References1 Technical Guidance Manual, Pennsylvania's Land Recycling Program, 1997, PADEP, Appendix A, Table 52 Based on general assumption for soils and saprolitic material of the Wissahickon Schist3 Howard, P.H. etal, 1991, Handbook of Environmental Degradation Rates, Lewis Publishers,4 Freeze, R.A. and Cherry, J.A., 1979, Groundwater, Prentice-Hall, Inc., p 6045 Nielsen, D.M.,1991, Practical Handbook of Ground-Water Monitoring, Lewis Publishers, p 400-401.6 Howard, P.H. et al, 1991, Handbook of Environmental Degradation Rates, Lewis Publishers,

AR302302

Table 3 - Havertown PCP Site- Naylor's Run Flow Budget

Existing Main

Drain Section37.0063.0027.0030.0031.0032.0034.0035.0029.0046.00

Historic Main

Drain Section76.0075.0036.0066.0067.0068.0062.0064.00

Historic West

Drain Section71.0077.0072.00

Channel

I.D. length (ft)1442.55162.60333.56491.32230.13373.79218.34563.16430.61365.95

4612.01

Channel

I.D. length (ft)753.61217.4790.5131.84536.32143.38459.12446.78

2679.03

Channels A and B

I.D. length (ft)1267.62368.02106.52

flow (ft/d)1006.025649.903993.94

0.350.00

64.9611722.887148.781033.821629.76

32250.41

Total Flow (gpm/ft)

flow (ft/d)6502.774991.111476.62392.845574.61

0.006610.839705.95

35254.73

Total Flow (gpm/ft)

flow (ft/d)11142.47287.37

0.00

flow(gpm)5.22

29.3220.730.000.000.34

60.8437.105.378.46

167.38

0.01

flow(gpm)33.7525.907.662.0428.930.0034.3150.37

182.97

0.07

flow(gpm)57.831.490.00

1742.16 11429.84 59.32

Total Flow (gpm/ft) 0.03

AR302303

Groundwater Model Reference Page

Based on measurements, tests, or other methodologies conducted in the fieldat the specific site. See the Hydro-geologic report.

Driscoll, Fletcher G., Groundwater and Wells Second Edition, JohnsonFiltration Systems, Inc., p. 67 (1989).

United States Department of Defense, Groundwater Modeling Systems(GMS) Technical Manual (Version 4.0) (2002)

Nielsen, David M., Practical Handbook of Groundwater Monitoring, LewisPublishers, p. 116-129, 389, (1991).

AR302304

Vertical Exaggeration: 4x

Havcrtown PCP Superfund SiteHavenown. Pennsylvania

Figure 1 - Site Topography (Map View)

AR302305


Havcrtown PCP Superflind SiteHavenown, Pennsylvania

Figure 2 - Site Topography (Oblique View)

Mvcftli.ltKM

AR302306

Explanation

Structure

| | Foundation/Storm Conduit

t^^ Recovery Trench

I I Fill Material

I I Saprolite

Crystalline Bedrock

Sanitary Sewer

I——I Abandoned Sewer

^™ Storm Sewer

I I Water Table

HH Unknown

I I Sand/Gravel


Havertown PCP Superfund SiteHavenown, Pennsylvania

Figure 3 -Top of Bedrock (Oblique View)

AR302307

Explanation

I 1 Structure

|—•] Foundation/Storm Conduit

HJH Recovery Trench

I I Fill Material

I I Saprolite

K3 Crystalline Bedrock

r"""3 Sanitary Sewer

I 1 Abandoned Sewer

^B storm Sewer

I I Water Table

i^H Unknown

I I Sand/Gravel


Havenown PCP Superfund SiteHavenown. Pennsylvania


AR302308

Bedrock Contour (Feet)

= 300

= 234

-— 288

IE 282

^ 276

= 270

= 264

= 258

^ 252

— 246Bedrock Anisotropy Ratioi (ky/kx): 2.0

Havertown PCP Superfund SiteHavenown. Pcniuylvonia

Figure 5 - Bedrock SurfaceContour

AR302309

L

Note: Groundwater elevation contoursare based on measurements collected on12/01/03

Havertown PCP Supcrfund SiteHavertown, Pennsylvania

Figure 6 - Groundwater Contour (12/01/03)

AR302310

Groundwater Elevation (feet)

300294

288

282

276

270264

258

252

245

L

Area where rock is above watertable



Figure 7 - Groundwater Contour (12/01/02)with Bedrock

AR302311

Note: Groundwatcr elevation contoursare based on measurements collected on12/01/03

Explanation

EH Structure

Foundation/Storm Conduit

•| 1 Recovery Trench

EH Fill Material

I I Saprolite

I I Crystalline Bedrock

I J Sanitary Sewer

' 1 Abandoned Sewer

I—J Storm Sewer

I I Water Table

f^^ Unknown

EH Sand/Gravel


Havertown PCP Superfund SiteHavtnovn, Pennsylvania

Figure 8 - Site Features with GroundwaterContour 12/01/03)

AR302312

Grounclwater Elevat ion (feet) CW-14D

Note: Groundwatcr elevation contoursare based on measurements collected on12/01/03

Explanation

EH Structure


| | Recovery Trench

I I Fill Material

I I Saprolite


I 1 Sanitary Sewer

I 1 Abandoned Sewer

I 1 Storm Sewer

EH Water Table

ESS Unknown

I I Sand/Gravel


Havcrtown PCP Supernind SiteHavertown, Pennsylvania

Figure 9 - Site Features with GroundwaterContour 12/01703)

| Mairti 23.2004

AR302313

Explanation

en Structurei 1| ] Foundation/Storm Conduit

| ' 1 Recovery Trench

I ] Fill Material

I I Saprolite

I J Crystalline Bedrock

I J Sanitary Sewer

I—I Abandoned Sewer

en Storm Sewer

en Water Table

IBSI Unknown

I I Sand/Gravel


'ertown PCP Superfund SiteHavenown. Pennsylvania

Figure 10- Site Features with Geology

AR302314

Explanation

I 1 Structure

| 1 Foundation/Storm Conduit

| 1 Recovery Trench

I I Fill Material

I I Saprolite

1 I Crystalline Bedrock

I I Sanitary Sewer

I 1 Abandoned Sewer

I 1 Storm Sewer

I 1 Water Table

rSBI Unknown

I I Sand/Gravel


irtown PCP Superfund Sitelavertown, Pennsylvania


AR302315

Explanation

Structure

Foundation/Storm Conduitenen| | Recovery Trench

I I Fill Material

I I Saprolite


I I Sanitary Sewer

I 1 Abandoned Sewer

I—'--I Storm Sewer

d] Water Tablel: a Unknown

I I Sand/Gravel


Havcrtown PCP Superfund SiteHavenown, Pennsylvania


AR302316

Groumlwater Elevation (feet)


Explanation

I - 1 Structure


Recovery Trench

I I Fill Material

I I Saprolite


I I Sanitary Sewer

> - 1 Abandoned Sewer

I - -I Storm Sewer

CZI Water Table

E3 Unknown

I I Sand/Gravel


Havertown PCP Superfiind SiteHavenown. Pennsylvania

Figure 13 - Site Features with Geology andGroundwater Contours (12/01 /03)

Mont) 2i. XKM

AR302317

Area of grid refinement (parallel torecovery trench)

Model Boundary

Havertown PCP Supcrfund SiteHavenown. Pennsylvania

Figure 14 - Model Boundary

AR302318



Havcrtown PCP Superfund SiteHavcrtown, Pennsylvania

Figure 15 - Grid Layout (MODFLOW)

AR302319


Note: Six layer model - the red layer represents the first layer


Havertown PCP Superfund SiteHavenown. Pennsylvania

Figure 16 - Layer Array (MODFLOW)

AR302320

Explanation

I "1 Recovery Trench

HZ] Fill Material

I I Saprolite

I 1 Crystalline Bedrock

Water Table

Vertical Exaggeration:3x

Havertown PCP Superfund SiteHavertown, Pennsylvania

Figure 17 - HUF to MODFLOW Conversion

ID*

AR302321

32Q CW-5D ^»-~

^Spfc5S

Explanation

X Specified Head Node

X Recovery Well0 Drain Node

^\ Drain Arc

"\ Specified Head Arc(Model Boundary)


Figure 18 - Drain Configuration (MODFLOW)

AR302322

Existing Stream Bed/Tributaries

Historic Stream Bed/Tributaries


Figure 19- Naylor's Run Stream Bed Locations

AR302323

4 ' 4

HII - I1Mmats NH - warwmort UH - HOOTcnuxttnanV VUWf WB UIC

17 Mnvr an uic

Explanation

1 Residential (homes, lawns,streets, sidewalks. Moderateinfiltration

2 Impervious surface (large pavedor covered area). Poorinfiltration.

3 Open space, minimal pavementor structures. Good infiltration.

Havcrtown PCP Superfiind SiteHavcrtown, Pennsylvania

Figure 20 - Recharge Zones (MODFLOW)

AR302324

Croundwaior [Elevui ions (feet)

Recharge Parameters

Zone 1 0.01 ft/day

Zone 2 0.0 ft/day

Zone 3 0.02 ft/day

Explanation

Calibration Target

* Observed Flow Target (12/01 /03 Data)

Q Witthin 1.0 foot tolerance

Outside 1.0 fooltolerance/within 2.0 foottolerance

Havertown PCP Superfund SiteHavertown. Pennsylvania

Figure 21 - Sensitivity Analyses -Recharge Zones - Modeled Parameters

[ M»cti 3V TOM

AR302325

Groundwater Elevat ions (feet)

|H 301H 296H 291= 236H 281g 276g 271g 266= 261§ 256= 251^ 246= 241

Recharge Parameters

Zone I 0.012 ft/day

Zone 2 0.0 ft/day

Zone 3 0.024 ft/day

Explanation

Calibration Target

• Observed Flow Target (12/01/03 Data)

U Within 1.0 foot tolerance

Q Outside 1.0 fooltolerance/within 2.0 fooltolerance


Figure 22 - Sensitivity Analyses -Recharge Zones - (20% increase)

AR302326

Grcnmclwalcr Ek-vntions ffcct)

^ 301H 296g| 291== 286s^ 281H 276H 271g 266j^ 261= 256Eg 251S 246^ 241

Recharge Parameters

Zone I 0.008 ft/day

Zone 2 0.0 ft/day

Zone 3 0.016 ft/day

Explanation

Calibration Target

- Observed Flow Target (12/01/03 Data)

U Within 1 .0 fool tolera

Outside 1.0 fooltolerance/within 2.0 foottolerance

Havcrtown PCP Superfund SiteHavertown. Pennsylvania

Figure 23 - Sensitivity Analyses -Recharge Zones - (20% decrease)

AR302327

Groiiiidwaler Elevations (feel)

=: 301H 296H 291|H 285H 281H 276jj= 271g] 266= 261jg 256g 251= 246^ 241

Explanation

Calibration Target

- Observed Flow larger (I2/OI/03 Dua)

Q Within 1.0 foot lolemnce

Q Outiide 1.0 fooltolerance/within 2.0 fooltolerance

Havertown PCP Superfund SiteHovenown. Pennsylvania

Figure 24 - Calibration (MODFLOW)

AR302328

GrOLindwntci Elevniions (feet)

^ 301= 236^ 291= 286^ 281== 27BH 271H 265^ 261^ 256^ 251^ 246^ 241 Aaisolropy Ratios (ky/kx)

Fill Material 1.0

Saproliie 1.4

Rock 2.0

Pumping Rates

p.w-iRW-2

RW-3

RW-4

Trench

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

Havcrtown PCP Superfund SiteHavenown, Pennsylvania

Figure 25 - Simulated Groundwater Contours

AR302329

Groundwalcr Elevnlions (feet)

= 301H 296= 291== 286^ 281= 276= 271= 266g 261Ijj 256^ 251S 246= 241

Aaisotropy Ratios (ky/kx)

FillMaleritl 1.0

Saprolite 1.4

Rock 2.0

Pumping Rates

RW-I

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm

Havertown PCP Superfimd SiteHavenown, Peniuylvania

Figure 26 - Simulated Groundwater Contours(Pumps On)

AR302330

HAVER70WN PSUPEP.FUND ;

Anisotropy Ritioi (ky/lu>

Fill Material 1.0

Saprolite 1.4

Rock 2.0

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm

Approximate Scale (Feet)

Havertown PCP Superfiind SiteHsvenown. Pennsylvania

Figure 27 - Zoom Recovery System(All Pumps On)

AR302331

\ J* IS

ned Sewer

- , / < ^^i£^ ,^-• r-~^?.' X i...-*£.9&<s

Aaisotropy Ritioa (ky/kx)

Fill Material 1.0

Saprolito 1.4

Rock 20

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm


Havertown PCP Superfiind SiteHavenown. Pennsylvania

Figure 28 - Simulated Groundwater Contours -Abandoned Sewer Line Plugged

AR302332

Groundwatcr Elevat ions (feet)


Anisotropy Ritios (ky/lu)

Fill Material 1.0

Saprolite 1.4

Rock 2.0

Explanation

•• Particle Path Direction(Space between Arrows is 100 days)

Capture Zone

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

Havenown PCP Superfund SiteHavertown, Pennsylvania

Figure 29 - Capture Zone (All Pumps Off)

AR302333

Groundwater Elevations (feet)

= 301H 296^ 291= 286H 281

H 276= 271g 266^ 261g 256JH 251g 246= 241

Anbolropy Ratio) (ky/kx)

FillMllcrill 1.0

Saprolite 1.4

Rock 2.0

Explanation

Panicle Path Direction(Space between Arrows is 100 days)

Capture Zone

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm

Havertown PCP Superfiind SiteHavcrtown, Pcniuylvanil

Figure 30 - Capture Zone (All Pumps On)

AR302334

Anisotropy Ratioi (ky/lu)

Fill Material 1.0

Saprolite 1.4

Rock 2.0

Explanation

Particle Path Direction(Space between Arrows is 100 days)

I Capture Zone

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm


Havenown PCP Superfund SiteHavcrtown, Pennsylvania

Figure 31 - Capture Zone - Trench Zoom(All Pumps On)

AR302335

Groundwater Elevations (feel)

havertwn_Heads

Particle Path Based on 5-Year Migration

Explanation

I '""I Recovery Trench

I I Fill Material

I I Saprolite

1——I Crystalline Bedrock

Water Table

E*" Particle Path Direction(Space between Arrows is 100 days)

Recovery Trench

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm



Figure 32 - Reverse Particle Path Tracking -Cross Section

AR302336


Particle Path Based on 5-Year Migration

Explanation

I 1 Recovery Trench

I I Fill Material

I 1 Saprolite

L—I Crystalline Bedrock

~~~ Water Table

Es=~ Particle Path Direction(Space between Arrows is 100 days)

Recovery Trench

Pumping Rates

RW-l 4.0 gpm

RW-2 1.0 gpm

RW-3 4.0 gpm

RW-4 4.0 gpm

Trench 18 gpm


Havcrtown PCP Superfund SiteHavenown. Pennsylvania

Figure 33 - Forward Particle Path Tracking -Multi-Layer Release - Cross Section

AR302337


Aaiiolropy Rilioi (ky/lu)

Fill Material 1.0

Saprolile 1.4

Rock 2.0

Explanation

Particle Path Direction(Space between Arrows is 100 days)

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

CW-4D

CW-5D

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm

8.0 gpm

8.0 gpm


Havertown PCP Superfund SiteHivenown, Pennsylvania

Figure 34 - Simulation of CW-4D / CW-5DPumping at 8gpm

AR302338

£ •' ' L- ^=

SAL-,

1$%?L. i * — • ">— i

^H^:

^'/L-LTfZ'''/</. cb:~'--/ ,/.-.• •• 3 .r>

Approximate Scale (Peet)

Aaisotropy Ratios (ky/kx)

FillMalerial 1.0

Saprcliu 1.4

Rock 2.0

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

Note: Source concentration of PCP at eachrelease location was 14 mg/l which is themaximum solubility of PCP in 20°C water.

Havertown PCP Supertund SiteHavenown, Pennsylvania

Figure 35- Simulated PCP Fate and TransportTen Year Migration - Non-Pumping

AR302339

PCP Concentration (mg/1)

I'I 13

11

10

8

Explanation

I '"I Recovery Trench

I I Fill Material

I I Saprolite


Water Table

T- -J- _• -ri.

_J -JU' _^ >sc


A'


Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

Note: Source concentration of PCP at eachrelease location was 14mg/l which is themaximum solubility of PCP in 20°C water.

Havertown PCP Supcrfund SiteHavertown. Pennsylvania

Figure 36- Simulated PCP Fate and TransportTen Year Migration-Cross Section

AR302340

Well Location

PCP Concentration(ug/l)

Data points were contoured using the geo-statistical method of natural neighborcorrelation with a gradient plane option. Thismethod allowed the most reasonabledistribution of contour lines based on theavailable number of data points.

Approximate Scale (Feel)


Vil K BrllluB, r.C

Figure 37 - PCP Concentration - Shallow Wells(October 2002)

AR302341

- .- 3*00Pj -2600|J .-24 00

7600

W/ '•••«T // -r-f =^*a' fI' =-?-!, "M- c .

PCP Conccntration(ug/l)




Figure 38 - PCP Concentration - Deep Wells(October 2002)

AR302342

PCP Concentration(ug/l)

Data points were contoured using the geo-statislical method of natural neighborcorrelation with a gradient plane option. Thismethod allowed the most reasonabledistribution of contour lines based on theavailable number of data points.

Approximate Scmle (Feet)

Havertown PCP Superfund SiteHaverlown, Pennsylvania

Figure 39 - PCP Concentration - Shallow Wells(March 2004)

AR302343

Well Location

PCP Conccntration(ug/l)



Havertown PCP Superfund SiteHavcnown. Pennsylvania

Figure 40 - PCP Concentration - Deep Wells(March 2004)

AR302344

•&V5AV


Anisolropy Ritioa (ky/lu)

FillMalehil 1.0

Saprolite 1.4

Rock 2.0

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18.0 gpm

Note: Source concentration of PCP at eachrelease location was 14 mg/1 which is themaximum solubility of PCP in 20°C water.


Figure 41- Simulated PCP Fate and TransportTen Year Migration Active Pumping

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PCP Concentration (m

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7 * t h i- . ' ' «e' ' - •, 4..-J/-5^7 ,-s$r: --y

Explanation

[ "' 1 Recovery Trench

d] Fill Material

I I Saprolite


Water Table

Pumping Rates

RW-1

RW-2

RW-3

RW-4 ;

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18.0 gpm

Nole: Source concentration of PCP at eachrelease location was 14mg/l which is themaximum solubility of PCP in 20°C water.

Havertown PCP Superfund SiteHavcrtown, Pemuylvania

Figure 42- Simulated PCP Fate and TransportTen Year Migration - Active Pumping X-Section

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=S 3*1 I *"

' m 246 .' / / JP 241 ; /;' HAVBRTOWN

~S ! I CI IDrDITI IMP

Aoisotropy Ratios (ky/ki)

FillMalcriil 1.0

Siprolite 1.4

Rock 2.0

Pumping

RW-l

RW-2 .

RW-3

RW^t

Trench

» Rates

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm


Havertown PCP Superftmd SiteHavenown, Pennsylvania

Figure 43 - 1950 to 1991 Transport Simulation(30-Inch Diameter Storm Sewer - 20 GPM)

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Grmmdwater Elevations (feet)

ft 7,«"

Aaiiolropy Ratioi (liy/ki)

FillMilcnil 1.0

Stprolite 1.4

Rock" 2.0

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm

0.0 gpm


73

Havertown PCP Superfund SiteHavenown, Pemuylvuiii

Figure 44 - 1991 to 2002 Transport Simulation(30-inch Diameter Storm Sewer Sealed)

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haven Ground water Elevations (feet) /

Aniaotropy Ration (ky/kx)

Fill Material 1.0

Saproliu 1.4

Rock 2.0

Pumping Rates

RW-l

RW-2

RW-3

RW-4

Trench

4.0 gpm

1.0 gpm

4.0 gpm

4.0 gpm

18 gpm


Havertown PCP Superfiind SheHavenown, Pennsylvania

Figure 45 - 2002 to Present (FrenchDrain/Recovery Wells/Leaking Sanitary Line)

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GROUNDWATER MODEL REPORT HAVERTOWN PCP SITE … · numeric simulations of those site...

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