ML21076A469

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Cimarron Environmental Response Trust Facility Decommissioning Plan, Revision 2, Appendix L, 2020 Groundwater Flow Model, Part 2
ML21076A469
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Site: 07000925
Issue date: 02/26/2021
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Environmental Properties Management, Enercon Services, Burns & McDonnell Engineering Co, Veolia Nuclear Solutions Federal Services
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Office of Nuclear Material Safety and Safeguards, Cimarron Environmental Response Trust, NRC Region 4
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APPENDIX A - 2016 GROUNDWATER FLOW MODEL UPDATE BURNS ~ M£DONNELL.

2016 Groundwater Flow Model Update Cimarron Remediation Site Cimarron Environmental Response Trust Project No. 89761 Revision 0 1/25/2017

2016 Groundwater Flow Model Update Cimarron Remediation Site Prepared for Cimarron Environmental Response Trust Crescent, Oklahoma Project No. 89761 Revision 0 1/25/2017 Prepared by Burns & McDonnell Engineering Company, Inc.

Kansas City, Missouri COPYRIGHT© 2017 BURNS & McDONNELL ENGINEERING COMPANY, INC.

2016 Groundwater Flow Model Update Revision 0 Table of Contents TABLE OF CONTENTS Page No.

1.0 INTRODUCTION

............................................................................................... 1-1 1.1 Background and Objectives ..................................... ......................... ................... 1-1 2.0 GROUNDWATER MODEL DESCRIPTION AND UPDATES ........................... 2-1 2.1 Conceptual Model .. .................................................. ........ .................................... 2-1 2.2 Groundwater Flow ............................................................................................... 2-1 3.0 GROUNDWATER MODEL CONSTRUCTION .................................................. 3-1 3 .1 Model Construction ............................................................................................. 3-1 3.2 Model Domain ...................................................................................... ............... 3-1 3.3 Model Layering .............................................................. ...................................... 3-2 3.3.1 WA Model ......... ................................................................................... 3-2 3.3.2 BA#l Model .......................................................................................... 3-2 3.4 Boundary Conditions ........................................................................................... 3-2 3.4.1 No Flow Boundaries ................................................................. .... .. ...... 3-3 3.4.2 General Head Boundary ........................................................................ 3-3 3.4.3 Constant Head Boundary ...................................................................... 3-3 3.5 Hydrogeologic Properties .................................................................................... 3-3 3 .6 Recharge .............................................................................................................. 3-4 3.7 Model Calibration ................................................................................................ 3-4

3. 7 .1 WA Model Calibration ......................................................................... 3-4 3.7.2 BA#l Model Calibration Check ........................................................... 3-5
3. 7 .3 Sensitivity Analysis .............................................................................. 3-6 3.8 Uncertainty ........................................................................................................... 3-6 4.0 REMEDIATION SIMULATIONS ........................................................................ 4-1 4.1 Model Simulation of Injection and Extraction ..................................................... 4-1 4.2 Particle Tracking .................................................................................................. 4-1 4.3 WA Remediation Simulation Setup ................................... .................................. 4-1 4.4 BA#l Remediation Simulation Setup .................................................................. 4-2 4.5 Remediation Simulation Results ............... ........................................................... 4-2 5.0

SUMMARY

AND CONCLUSION ...................................................................... 5-1

6.0 REFERENCES

.................................................................................................. 6-1 APPENDIX A GROUNDWATER FLOW MODEL REPORT (ENSR, 2006)

APPENDIX B GROUNDWATER FLOW MODEL UPDATE REPORT (BURNS

& MCDONNELL, 2014)

CIMARRON ENVIRONMENTAL RESPONSE TRUST TOC-1 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 Table of Contents LIST OF TABLES 3-1 Groundwater Model Input Values 3-2 Western Upland and Alluvial Area Water Level Measurements August 2016 3-3 Burial Area # 1 Water Level Measurements August 2016 3-4 Target Residuals Western Upland and Alluvial Areas 3-5 Target Residuals Burial Area# 1 CIMARRON ENVIRONMENTAL RESPONSE TRUST TOC-2 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 Table of Contents LIST OF FIGURES 1-1 Location of Cimarron Site 2-1 Western Upland and Alluvial Areas August 2016 Potentiometric Surface Map 2-2 Burial Area # 1 August 2016 Potentiometric Surface Map 3-1 Model Domain and Model Boundary Conditions Expanded Western Alluvial Area Model 3-2 Model Domain and Model Boundary Conditions Burial Area# 1 Groundwater Model 3-3 Model Predicted Potentiometric Surface with Calibration Target Residuals Expanded Western Alluvial Area Model 3-4 Model Predicted Potentiometric Surface with Calibration Target Residuals Burial Area# 1 4-1 Forward Particle Tracking Simulation Expanded Western Alluvial Area 4-2 Forward Particle Tracking Simulation for Burial Area #1 Groundwater Model CIMARRON ENVIRONMENTAL RESPONSE TRUST TOC-3 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 List of Abbreviations LIST OF ABBREVIATIONS Abbreviation Term/Phrase/Name Burns & McDonnell Burns & McDonnell Engineering Company, Inc.

amsl above mean sea level CSM Conceptual Site Model DCGL Derived Concentration Goal Level DEM Digital Elevation Model DEQ Oklahoma Department of Environmental Quality EPM Environmental Properties Management LLC Ft foot/feet GHB General Head Boundary in/yr inches per year KMNC Kerr-McGee Nuclear Corporation gpm gallons per minute MCL maximum contaminant level NRC Nuclear Regulatory Commission pCi/L picoCuries per liter Site Cimarron Site Trust Cimarron Environmental Response Trust USGS United States Geological Survey

% percent

µg/L micrograms per liter CIMARRON ENVIRONMENTAL RESPONSE TRUST Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 INTRODUCTION

1.0 INTRODUCTION

Environmental Properties Management LLC (EPM), Trustee for the Cimarron Environmental Response Trust (the Trust), submits this 2016 Groundwater Flow Model Update for the Cimarron site (the Site),

located at 100 N. Highway 74, Crescent, Oklahoma.

To evaluate groundwater remediation alternatives at two areas on the Cimarron Site, two existing groundwater flow models were updated. The areas include Burial Area # 1 (BA #1) and the Western Alluvial (WA) area. These two models were originally developed as part of the Groundwater Flow Modeling Report (ENSR, 2006) included as Appendix A, and the Groundwater Flow Model Update (Bums & McDonnell, 2014) included as Appendix B.

The models were updated with new geologic and hydrogeologic data, based on additional assessment performed in 2014 and 2016 . The WA model area was expanded to include a larger area including the Western Upland (WU). The WU hydrogeologic and water level information were added in the expanded model boundary area. The calibration of both models was confirmed using a comprehensive data set of groundwater elevations collected in August 2016. Accuracy of the model calibration was evaluated by comparing measured groundwater elevations, groundwater flow direction, and water budgets, with simulated elevations, flow paths, and budgets. Calibration goals included: 1) a mass balance error less than l % of the water budget, 2) low residual error from the statistical testing of modeled and measured groundwater elevations, and 3) a qualitative match of model simulated potentiometric surface and observed potentiometric surface.

The updated groundwater models were linked to a particle tracking model (MODPA TH) to evaluate alternative remediation scenarios. Groundwater extraction was modeled with both groundwater recovery trenches and extraction wells that were added to the models and will be used as the basis for design for the anticipated groundwater flow rates for the remediation efforts. Upon approval of these updated and revised flow models, they will be used for completion of the groundwater remediation design that will be included in a comprehensive license amendment request.

1.1 Background and Objectives The Cimarron facility was formerly operated by Kerr-McGee Nuclear Corporation (KMNC), a wholly owned subsidiary of Kerr-McGee Corporation. The Cimarron facility was utilized for the production of mixed oxide fuel and uranium fuel including enriched uranium reactor fuel pellets, and eventually fuel rods. Enriched uranium fuel was produced at the facility from 1966 through 1975. Process facilities included a main production building; several ancillary buildings, five process related collection ponds, CIMARRON ENVIRONMENTAL RESPONSE TRUST 1-1 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 INTRODUCTION two original sanitary lagoons, one new sanitary lagoon, a waste incinerator, several uncovered storage areas, and three burial grounds.

Licensed material still present onsite exceeds decommissioning criteria for unrestricted release only in groundwater. The concentration of uranium in groundwater must be reduced to achieve unrestricted release of the site and license termination. The Derived Concentration Goal Level (DCGL) for the site is 180 picoCuries per liter (pCi/L) total uranium, and the Oklahoma Department of Environmental Quality (ODEQ) has approved a toxicological concentration release criterion of 110 micrograms per liter (µg/L) for uranium in groundwater. In addition to uranium, groundwater in portions of the Site contains two non-radiological chemicals of concern (COCs): nitrate and fluoride. DEQ has approved site-specific risk-based concentration limits of 52 milligrams per liter (mg/L) for nitrate and 4 mg/L for fluoride.

Uranium exceeds the license release criterion of 180 pCi/L in three areas: BA #1, the WU Area and the WA Area (ENSR, 2006a and Cimarron, 2007). These areas are illustrated in Figure 1-1 . Uranium exceeds the DEQ criterion of 110 µg/L in these same areas, and the extent within those areas approximately matches the extent of uranium exceeding the NRC criterion. The extent of uranium impact to groundwater has been adequately delineated for the development of a groundwater remedy. Years of environmental monitoring have already demonstrated that nitrate and/or fluoride exceed DEQ criteria in the following areas: the WU Area, the WA Area, the Uranium Pond # 1 (UPl) Area, the Uranium Pond #2 (UP2) Area, and the uranium plant storage yard (Well 1319 Area). The flow model domain covers all of the areas that exceed the Maximum Contaminant Level (MCL) and that will eventually require remediation.

These groundwater flow models will be used as a tool to assist in the design of groundwater recovery and reinjection systems to reduce the concentrations of COCs in groundwater to less than their release criteria.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 1-2 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 Groundwater Model Description and Updates 2.0 GROUNDWATER MODEL DESCRIPTION AND UPDATES 2.1 Conceptual Model The Conceptual Site Model (CSM) of the Cimarron River flow system was developed and presented in the Conceptual Site Model-Rev-OJ Report (ENSR, 2006b) prior to the development of the original groundwater models for the WU and WA areas and the BA #1 area. The CSM was then incorporated into the 2006 groundwater models to ensure that the models used existing information and an accepted interpretation of the site-wide geology. Appendix A (Groundwater Flow Modeling Report [ENSR, 2006a]) provides a summary of information on the CSM.

2.2 Groundwater Flow The Site consists of gently rolling hills, leading northward to the floodplain of the Cimarron River.

Ground elevation varies from approximately 925 ft above mean sea level (amsl) at the northeastern property line to approximately 1,045 ft amsl near the southern property line. Three surface water reservoirs are present on the Site. Unnamed ephemeral streams feed these reservoirs, which discharge to the floodplain of the Cimarron River.

Groundwater flow in the WU area is generally to the northwest with a gradient that ranges from 0.02 foot/foot in the central and western portions of the property, to 0.05 foot/foot in the eastern portion of the property (down gradient of Reservoir 3). This groundwater flow pattern continues until groundwater reaches the interface with the alluvial aquifer of the WA area, where the hydraulic gradient steepens. The groundwater flow direction and hydraulic gradient change significantly once groundwater enters the alluvial aquifer. The WA groundwater flow is generally northeastward toward the Cimarron River; flow is driven by a relatively flat hydraulic gradient of 0.001 to 0.002 foot/foot. Figure 2-1 presents a potentiometric surface map of Sandstone B beneath the WU and alluvium for the WA area based on groundwater level measurements during August 2016.

Additional wells installed in the WU and WA area have provided a more refined understanding of the groundwater flow and direction than was provided in the 2006 Groundwater Flow Modeling Report (ENSR, 2006a). The current model update included the expansion of the domain to include the WU area where active remediation is planned. The August 2016 groundwater level measurements for upland wells screened in Sandstone B were used in the model expansion since Sandstone B and the alluvial deposits are in direct contact at the bluff that is the demarcation between the uplands and the WA area. Sandstone A was not included in this model since it is not in direct connection with the alluvial aquifer.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 2-1 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 Groundwater Model Description and Updates Groundwater in the vicinity of BA # 1 flows across an escarpment that is an interface for the Sandstone B water-bearing unit and the Cimarron River floodplain alluvium, and finally into and through the floodplain alluvium to the Cimarron River. Figure 2-2 presents a potentiometric surface map of Sandstone B and the alluvium for the BA # 1 area based on groundwater level measurements collected during August 2016. Flow in Sandstone Bis mostly northward west of the transitional zone and northeastward along the interface with the transitional zone.

Flow is driven by a relatively steep hydraulic gradient (0.10 foot/foot) at the interface between Sandstone B and the floodplain alluvium. Once groundwater enters the transition zone of the floodplain alluvium, the hydraulic gradient decreases to around 0.02 foot/foot and flow is refracted to a more northwesterly direction. Once groundwater passes through the transitional zone, it enters an area where the hydraulic gradient is relatively flat and groundwater flow is toward the north. Data indicates that the gradient in the sandy alluvium is approximately 0.001 foot/foot.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 2-2 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 GROUNDWATER MODEL CONSTRUCTION 3.0 GROUNDWATER MODEL CONSTRUCTION The two existing groundwater flow models developed for the Cimarron Site were updated as part of an effort to evaluate remedial alternatives at the Site. A detailed description of those groundwater models is provided in Appendix A (ENSR, 2006) and Appendix B (Burns & McDonnell, 2014). The primary modification to the existing groundwater models was the expansion of the model domain of the WA model to include the WU area. This model expansion was undertaken to better simulate the remedial activities that are proposed within the WU. No structural changes were made to existing groundwater models other than those related to the expansion of the WA model. No changes were made to the parameterization of input values in either model. The calibration of both models was checked using groundwater elevation data collected in August 2016. Once the model calibration check was completed, both models were used to evaluate the performance of the planned remedial system using injection and pumping rate data that are consistent with current remedial design concepts. Both groundwater models were run using steady state assumptions. The following sections describe the updates or new information in the model update.

3.1 Model Construction MODFLOW-2000 (Harbaugh et al, 2000), a three-dimensional, finite difference groundwater flow computer code, was selected to update the groundwater flow models. Pre- and post-processing was performed using Groundwater Vistas 6 (Rumbaugh, 2011 ). Groundwater Vistas was used to create standard format MODFLOW file sets from graphically input data.

Model output was evaluated using Groundwater Vistas, Surfer Version 12 (Golden Software, 2015),

ArcMap 10 (ESRI, 2010) and Microsoft Excel. Groundwater Vistas was used when possible to provide contoured model results (model predicted heads and drawdown) and numerical data output. Additional data contouring and evaluation was completed using Surfer. Surfer' is a grid-based contouring and three-dimensional surface plotting program. Surfer and ArcMap 10 were used to interpolate the irregularly-spaced, model-predicted data onto regularly spaced grids and to produce contoured results.

3.2 Model Domain The numerical model domain for the WU and WA areas is shown on Figure 3-1. The primary objective of this model update was to expand the model domain to include the WU area, where extensive injection and pumping remediation will occur. The grid size remains 10 feet by 10 feet, but the model now contains 270,366 active cells which is a substantial increase from the 2006 model. The model origin (left-bottom CIMARRON ENVIRONMENTAL RESPONSE TRUST 3-1 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 GROUNDWATER MODEL CONSTRUCTION corner) is located at X = 2,091 ,050 and Y = 319,455 in Oklahoma State Plane Coordinates. The model grid is rotated (minus) 20 degrees.

The numerical domain for BA # l is shown on Figure 3-2 and covers the same area as the 2006 groundwater model. The northern boundary of the model domain is the Cimarron River and the southern boundary of the model is the extent of the transition zone. The grid size is 10 feet by 10 feet and contains 267,440 active cells. The model origin (left-bottom corner) is located at X = 2094550 and Y = 322150 in Oklahoma State Plane Coordinates. There is no rotation of the model grid ..

3.3 Model Layering No adjustments were made to the number of model layers for either model. Some modifications to the layer elevations in the WA Model was required to accommodate the expansion of the model. The following section describes the layer development for both models.

3.3.1 WA Model The WU/WA model domain includes two layers: Layer l represents the alluvium and Sandstone B (in the WU portion of the model domain), while Layer 2 represents the underlying bedrock. New model surfaces were imported to represent the WU area that was previously not included in the model. The top of Layer 1 was developed from a 10 meter resolution digital elevation model (DEM) obtained from the United States Geological Survey (USGS). The base of Layer l for the area which underlies the WU area was set at a constant elevation of 920 feet msl. This value represents the base of Layer 1 used in the 2006 model in the transition zone, which is the contact between the alluvium and the uplands.

3.3.2 BA#1 Model Twelve layers are used to simulate the complex geology of the BA# l area. No adjustments were made to the number of layers or the layer elevations for BA # 1 model update. This complex model layering system setup was described in the 2006 Groundwater Flow Modeling Report (ENSR, 2006a) and was not modified during the model update.

3.4 Boundary Conditions The model boundary conditions represent the hydrologic interactions between the inside and outside of the model domain and simulate flow into and out of the groundwater model. The boundary conditions used in both the WA and BA# 1 groundwater models were summarized in detail in the Groundwater Flow Modeling Report (ENSR, 2006), and in the Groundwater Flow Model Update (Burns & McDonnell, 2014). These documents are included as Appendix A and Appendix B, respectively.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 3-2 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 GROUNDWATER MODEL CONSTRUCTION The model conditions presented in the Groundwater Flow Model Update (Burns & McDonnell, 2014) were used as the point of departure for the model update presented within this document. No changes to the model boundary conditions were made to the BA#l model. Boundary conditions for the WA model were not modified except in the portion of the model domain associated with the model expansion to include the WU area. Changes to the boundary conditions of the WA model are described below.

3.4.1 No Flow Boundaries No flow boundaries are used to simulate impermeable boundaries, groundwater divides, or streamlines.

Mathematically, no-flow boundaries occur when flux across a model cell is set to zero. The location of the active model domains are shown on Figures 3-1 and 3-2. Outside of the active domain are no flow cells that define the western and eastern boundary of both model domains. Within the active model domain all cells are active.

3.4.2 General Head Boundary A new General Head Boundary (GHB) condition was established to represent the upgradient boundary of the WA groundwater model. The upgradient boundaries for both the WA area and BA# l were represented as a GHB. This GHB was updated to account for the water level elevations observed in the wells during the August 2016 water level measurement event and to match the direction of groundwater flow observed with the recently installed wells in the WA area. No other GHBs were added to the WA model.

3.4.3 Constant Head Boundary A Constant Head Boundary was added to the expanded WA model in order to simulate the impact of leakage from Reservoir 3 (the reservoir shown on Figure 3-1) on the groundwater elevations within the WU area. The impact of the reservoir on groundwater elevations can be seen upon examination of the groundwater elevations presented on Figure 2-1. The reservoir was simulated with a water surface elevation of 95 8 feet msl. The water surface elevation was based on specific data collected and reported by the design project team.

3.5 Hydrogeologic Properties After review of new and existing data, no changes were made to the hydraulic conductivity parameters from the 2006 models. The WU expansion area within the WA model was simulated using the values presented in Table 3-1. These values are based on site-specific data or (where site data is not available),

on values obtained from published literature.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 3-3 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 GROUNDWATER MODEL CONSTRUCTION 3.6 Recharge Based upon a review of precipitation data, 2016 appears to be slightly drier than a normal precipitation year. However, water levels at the site were similar to the 2006 model. No changes were made to the recharge values originally presented in the 2006 model because 2016 does not represent a typical year and the recharge values are meant to represent a long term average condition.

3. 7 Model Calibration Table 3-2 and Table 3-3 present the most recent water level measurements available from August 2016 for the WU and WA area and BA # 1, respectively. All wells were used as calibration targets.

The WA model was recalibrated to water levels collected in August 2016 because the model domain was increased and new boundary conditions were added to the model. The calibration status of the BA# 1 model was checked using water levels collected in August 2016. The BA# 1 model was not recalibrated because no structural changes were made to that model. For both models, the calibration was evaluated by comparing measured groundwater elevations, groundwater flow direction, and water budgets, with simulated elevations, flow paths, and budgets. The calibration goals for the numerical model were as follows:

  • A less than one (1) percent water balance error, which is considered appropriate for a calibrated groundwater model (Anderson and Woessner, 1992). The water balance error is defined as the total inflow minus the total outflow, divided by either the inflow or outflow, whichever yields the highest error.
  • A Normalized Root Mean Square error (NRMS) of less than ten (10) percent. A NRMS of less than ten ( l 0) percent is generally considered appropriate for a calibrated groundwater model (Anderson and Woessner, 1992). A lower NRMS indicates a better statistical model calibration.
  • An Absolute Residual Mean (ARM) error of less than ten percent of the observed head change value across the model domain. The ARM can be described as the average error of the absolute value of the residuals.
  • A qualitative match of model simulated potentiometric surface and observed potentiometric surface, evaluated by comparing contours. When calibrated, the model should be able to reproduce the direction and magnitude of the hydraulic gradient observed within the study area.

3.7.1 WA Model Calibration The water level measurements that were collected in August 2016 were used to check the calibration status of the WU/WA model. The calibration data includes both alluvial wells and wells screened in CIMARRON ENVIRONMENTAL RESPONSE TRUST 3-4 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 GROUNDWATER MODEL CONSTRUCTION Sandstone B. Sandstone A wells were not included because the water level is significantly higher and this unit is not in direct connection with Sandstone B or the alluvial aquifer.

Approximately 70 water level measurements were available for comparison to the model predicted values for the August 2016 date. For comparison purposes, the previous WA area model (Burns & McDonnell, 2014) included water level measurements were collected from 43 wells. The results for these calibration checks are presented in Table 3-4 and are summarized below:

  • Mass balance error of 0.09 percent.
  • NRMS = 3 .4 percent
  • ARM= 0.6 feet The percent error in the water budget for the WA model is significantly less than l %, indicating a stable model. The calibration statistics are comparable to the statistics from the previous model (Burns &

McDonnell, 2014) and indicate that the model is calibrated. A visual comparison between the model predicted and observed groundwater gradient indicates the model is a good match to the observed potentiometric surface and a good match to observed groundwater flow. The model predicted potentiometric surface and the residual error for each monitoring well is presented on Figure 3-2.

3.7.2 BA#1 Model Calibration Check To check the calibration status of the BA# 1 model, water level measurements that were collected in August 2016 were used. This calibration dataset included 68 wells and the range in observed water level elevations is 17.5 feet. The calibration goals for the BA# I model were the same as those listed for the WA model:

The results for these calibration checks are presented in Table 3-5 and are summarized below:

  • Mass balance error of 0.00003 percent.
  • NRMS = 6.9 percent
  • ARM= 0.7 feet The percent error in the water budget for the BA# l model is significantly less than l %, indicating a stable model. The calibration statistics are comparable to the statistics from the previous model (Burns &

McDonnell, 2014) and indicate that the model is calibrated. A visual comparison between the model predicted and observed groundwater gradient indicates the model is a good match to the observed potentiometric surface and a good match to observed groundwater flow. The model predicted potentiometric surface and the residual error for each monitoring well is presented on Figure 3-4.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 3-5 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 GROUNDWATER MODEL CONSTRUCTION 3.7.3 Sensitivity Analysis No structural changes or changes to the parametrization of the inputs were made to the BA#l model as a result of this model update. Given these limited changes to the models, a sensitivity analysis was not performed as part of this modeling effort. A sensitivity analysis was conducted on the flow model for both the 2006 Groundwater Model (Appendix A) and the 2014 Groundwater Model (Appendix B). The parameterization of the WA model was not changed as part of this update; the only change was the expansion of the model domain. The conclusions presented in the 2006 Groundwater Model report regarding the sensitivity of the model to parameter inputs and boundary conditions remain valid for this update of the model.

3.8 Uncertainty Site conditions and hydrogeologic properties were estimated through extrapolation of measured or estimated properties or inferences from data measured or estimated based on existing site data and professional judgment. Groundwater models are by definition a simplified version of the aquifer system.

Therefore, these simplifications provide some model limitations.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 3-6 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 REMEDIATION Simulations 4.0 REMEDIATION SIMULATIONS Remediation system simulations were completed using both groundwater models with injection rates and pumping rates that are representative of a design basis of each remediation system. A summary of the remedial system simulations is presented below.

4.1 Model Simulation of Injection and Extraction Injection and extraction trenches were simulated as a line of boundary wells with the total pumping or injection flow rate was equally distributed amongst the wells. Injection or extraction wells were simulated as an individual boundary wells using their prescribed flow rate. Well boundaries in MODFLOW are specified flow boundary conditions, where the flow rate is assigned by the model. The impact to groundwater elevations that result from the injection or extraction of water in the well boundary cells is calculated by MODFLOW. The boundary wells were modeled using steady state conditions, meaning the extraction or injection flow rates are held constant through time.

4.2 Particle Tracking The particle tracking code MODPATH (Pollock, 1989) was selected to perform the particle tracking analysis for both the WA and BA# l models. MODPATH uses a semi-analytical particle tracking scheme and is based on the assumption that each directional velocity component for a particle of water varies linearly within a grid cell in its own coordinate direction (Pollock, 1989). This assumption allows an analytical expression to be derived that describes the flow path of water within a grid cell. Given the initial position of a particle anywhere in a cell, the pathline and travel time within the cell can be computed directly. Groundwater heads and intercell flow rates are first determined using MODFLOW.

This information is then input to MODP ATH along with effective porosity values and user-specified starting particle locations. MODP A TH then calculates three-dimensional pathlines and time-of-travel information as particles are tracked individually through the simulated flow system using the calculated distribution of velocity throughout the flow system. MODPA TH was selected for this modeling study because of its applicability and simple linkage with MODFLOW.

4.3 WA Remediation Simulation Setup All wells and trenches located in the WU area were simulated regardless of their installation layer (Sandstone A or Sandstone B). The primary reason the Sandstone A trenches were included in the remedial simulations was to evaluate the potential mounding affects within the WU area, as the hydraulic properties of the two sandstone units are similar. A secondary reason for including the Sandstone A CIMARRON ENVIRONMENTAL RESPONSE TRUST 4-1 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 REMEDIATION Simulations trenches in the remedial simulations was to evaluate the indirect travel path of injected water from Sandstone A into the alluvium. This approach is conservative, as it assumes that all water discharging from Sandstone A as a seepage face will eventually be captured by the wells installed in the alluvial transition zone. It should be noted that an unknown small percentage of the groundwater discharging at the seepage face will likely be lost to evaporation. The majority of this discharge however, will infiltrate into the alluvium after migrating down the seepage face surface or through joints and fractures.

4.4 BA#1 Remediation Simulation Setup All wells and trenches located in the BA# 1 model area were simulated in the model layer that corresponds to the geologic unit that the trench or well will be constructed in, based on the installation depth of the trench or well. A detailed cross section of the geology in the BA#l area was presented in the 2006 Groundwater Flow Model Report (see Figure 3 in Appendix A).

The location of remediation well GE-BA 1-04 was changed, compared to previous modeling efforts. This well was moved approximately 40 feet east to improve the capture of uranium impacted groundwater.

4.5 Remediation Simulation Results Forward particle tracking was used to ensure that all areas of concern would be hydraulically contained by extraction pumping. This includes make sure that all water injected is later captured by an extraction well.

Prior to running the MODPATH simulation, a MODFLOW simulation that includes pumping and injection at full design scale was run. This MODFLOW simulation was used as the flow field for the MODPA TH simulation. In the forward particle tracking simulations, particles were placed in each cell representing an injection trench and around specific areas of higher contaminant concentration that require containment. These particles were then tracked forwards using the MODPATH code. Particles were placed in the middle of a model cell and tracked forwards The results of the forward particle tracking model simulations are presented on Figure 4-1 (WA) and Figure 4-2 (BA# 1).

The particle tracking simulation results shown on Figure 4-1 include injection and extraction trenches in the Western Upland that will be constructed in Sandstone A but were simulated in Sandstone B.

Sandstone A is not included in the groundwater flow model since it is not directly interconnected with Sandstone B and the alluvium. The particle tracks depicted are nonetheless representative of groundwater and dissolved phase transport in Sandstone A, as the hydraulic properties of the two sandstone units are similar. All simulations show plume capture for the contaminants of concern.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 4-2 Burns & McDonnell

2016 Groundwater Flow Model Update Revision 0 Summary AND CONCLUSION 5.0

SUMMARY

AND CONCLUSION As presented in the 2006 modeling report and the 2014 model update for the WA and BA# 1 models, the purpose of this work was to conceptualize, develop, and calibrate numerical models to provide tools to better evaluate changes in groundwater flow for assessment of different remedial alternatives through simulations.

The objective of this report was to describe updates to the two models that included the expansion of the domain in the WA model to include the western upland and update of water level elevations for both models. In addition to these updates, remediation simulations were evaluated using potential extraction and injection configuration scenarios using MODP A TH forward particle tracking simulation.

Calibration targets including measured groundwater elevations and flow data were achieved in both models. Any variability between the observed and predicted groundwater elevations were acceptable and reasonable . The overall modeled simulations confirmed the hydrogeologic characteristics described in the Conceptual Site Model (ENSR, 2006). Sensitivity analysis was not performed since only limited changes were made to the models and did not impact the validity of the 2006 Groundwater Flow Model Report (ENSR, 2006) or the 2014 Groundwater Flow Model Update Report (Burns & McDonnell, 2014).

In conclusion the results of the updates to both numerical models have captured the characteristics of the hydrogeologic conditions in reference to groundwater flow and evaluation of potential remediation alternatives through generation of simulations of injection, pumping, and capture scenarios.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 5-1 Burns & McDonnell

2016 Groundwater Flow Model Update REFERENCES

6.0 REFERENCES

Anderson, M.P., and Woessner, W.W. 1992. Applied Groundwater Modeling Simulation of Flow and Advective Transport. Academic Press, Inc. San Diego, California.

Burns & McDonnell, 2014. Groundwater Flow Model Update Cimarron Remediation Site prepared for Cimarron Emergency Remediation Trust (CERT).

ENSR, 2006a. Groundwater Flow Modeling Report prepared for Cimarron Corporation (Tronox) October.

ENSR, 2006b. Conceptual Site Model (CSM)-Rev-01 Report prepared for Cimarron Corporation (Tronox)

Golden Software, Inc. 2009. Surface Mapping System: Golden Software, Inc. Golden Colorado.

Harbough, Arlen, Banta, Edward R., Hill, Mary C., and McDonald, Michael, 2000. MODFLOW-2000, The US. Geological Survey Modular Ground-Water Model.

Oklahoma Climatological Survey, 2013. www.climate.ok.gov. Accessed October, 2013.

Pollock, D. W., 1989. Documentation of Computer Programs to Compute and Display Pathlines Using Results.from the US. Geological Survey Modular Three-Dimensional, Finite-Difference, Groundwater Flow Model. USGS Open File Report no.89-391, 188 p.

Rumbaugh, J. 0. and D. B. Rumbaugh, 2011. Groundwater Vistas, Version 6. Environmental Simulations, Inc., Reynolds, PA.

CIMARRON ENVIRONMENTAL RESPONSE TRUST 6-1 Burns & McDonnell

TABLES CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-1 GROUNDWATER MODEL INPUT VALUES UPDATED WESTERN ALLUVIAL AREA MODEL Subsurface Units: Value Units Source a>

Horizontal Hydraulic Conductivity (KH) 3.00E+00 ft/day Calibration (U Vertical Hydraulic Conductivity 5% of KH

....J 1.S0E-01 ft/day (Kv) cc (l) Specific Storage 0.01 ----- Default, not used in steady state model C

0 en

-0 Specific Yield 0.01 ----- Default, not used in steady state model C

(U Porosity Freeze & Cherry, 1979 Table 2.4 Cf) 5  %

CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-2 WESTERN UPLAND and ALLUVIAL AREA WATER LEVEL MEASUREMENTS August 2016 Water Elevation (08/08/2016)

Well Easting Northing I (feet amsl)

T-51 2,091,962.33 322,775.32 929.40 T-52 2,092,329.67 322,774.93 929.33 T-53 2,092,658.89 322,773.47 929.20 T-54 2,092,870.51 321,927.51 929.90 T-55 2,093,119.60 322,069.59 928.46 T-56 2,093,377.95 322,211.21 927.75 T-57 2,092,460.78 321,788.04 930.23 T-58 2,092,165.08 321,742.39 930.42 T-59 2,092,954.88 322,773.96 929.18 T-60 2,093,281.83 322,773.99 929.20 T-61 2,093,609.54 322,774.36 929.03 T-62 2,091,852.83 321,470.61 930.69 T-63 2,091,976.65 321,623.17 930.50 T-64 2,091,690.89 321,341.87 930.85 T-65 2,091,814.49 321,568.90 930.65 T-66 2,091,841.97 321,712.17 930.53 T-67 2,091,742.89 321,657.32 930.61 T-68 2,091,713.09 322,052.25 930.25 T-69 2,091,871.69 321,961.92 930.35 T-70R 2,091,625.71 321,577.88 930.72 T-72 2,091,716.88 321,899.31 930.40 T-73 2,091,492.01 321,770.60 930.53 T-74 2,091,531.32 321,541.25 930.80 T-75 2,091,598.42 321,910.85 930.08 T-76 2,091,730.58 321,776.39 930.52 T-77 2,091,578.19 322,010.24 930.29 T-78 2,091,493.75 321,897.01 930.39 T-79 2,091,581.67 322,212.51 930.07 T-81 2,091,475.97 321,993.82 930.29 T-82 2,091,568.93 322,413.79 931.77 T-83 2,091,500.85 322,296.59 929.80 T-84 2,091,869.00 322,295.48 929.92 T-85 2,092,242.87 322,346.29 929.81 T-86 2,092,646.71 322,374.16 929.63 T-87 2,092,979.20 322,421.78 929.40 T-88 2,093,383.60 322,464.00 929.10 T-89 2,093,072.37 323,042.19 928.73 T-90 2,092,830.42 323,042.30 928.85 T-91 2,092,965.54 323,228.28 927.63 T-92R 2,093,120.51 323,143.29 925.85 Page 1 of 3

CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-2 WESTERN UPLAND and ALLUVIAL AREA WATER LEVEL MEASUREMENTS August 2016 Water Elevation

{08/08/2016)

Well Easting Northing (feet amsl)

T-93 2,093,413.80 323,104.00 928.66 T-94 2,093,266.80 323,409.22 928.31 T-95 2,092,457 .65 323,019.00 928.98 T-96 2091984.825 322557 .2606 929.56 T-97 2092124.72 323343.533 928.78 T-98 2092176.49 323514.234 928.61 T-99 2092589.7 323746.24 928.25 T-100 2093060.29 323821.155 927.05 T-101 2093507 .592 323599.274 927.99 T-102 2093581.063 323084.588 928.69 T-103 2094027.626 322867.406 928.86 Sandstone B Wells 1314 2095467.354 322412.2216 944.45 1315R 2095504.061 322756.5123 934.62 1316R 2095438.451 322776.9811 933.38 1319B-1 2092053.325 320128.3468 947.62 1319B-2 2092077.815 319999.5928 948.71 1319B-3 2092004.745 320105.0462 947.82 1319B-4 2092053.333 320206.8577 947.11 1319B-5 2091860.113 320322.067 945.37 1338 2093545.835 321818.8511 944.27 1341 2092542.171 321354.7241 937.68 1345 2092346.655 321461.4806 934.66 1346 2093200.273 321854.3517 938.38 1382 2093127.503 321735.55 938.76 1384 2093398.84 321601.975 945.03 1386 2093375.507 321918.247 939.89 1388 2093709.911 321837.355 946.55 1390 2093720.086 322017.061 942.47 1391 2093820.096 321752.383 951.88 1392 2093115.047 321860.652 936.82 1394 2093370.33 321825.993 941.12 Alluvial Wells 1342 2090179.195 322508.023 929.78 1343 2093597.568 323387.5216 928.27 1344 2095776.385 323500.3817 926.97 1361 2095439.831 323265.3712 927.53 1362 2095450.843 323186.9535 927.61 1363 2095357.605 323327.579 927.56 1364 2095504.527 323277.3096 927.51 Page 2 of 3

CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-2 WESTERN UPLAND and ALLUVIAL AREA WATER LEVEL MEASUREMENTS August 2016 Water Elevation (08/08/2016)

Well Easting Northing (feet amsl) 1365 2095455.832 323330.0953 927.49 1366 2095526.229 323327.8529 927.45 1367 2095208.626 323329.652 927.64 1368 2095262.386 323477.678 927.42 1372 2095590.485 323726.149 926.71 1373 2095689.267 323653.141 926.78 Page 3 of 3

CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-3 BURIAL AREA #1 WATER LEVEL MEASUREMENTS AUGUST 08, 2016 Well Easting Northing Water Elevation (08/08/2016) 02W02 2095455 .00 322885.00 930.53 02W03 2095375 .00 322885.00 928.42 02W04 2095335.00 322905.00 927.88 02W05 2095315.00 322955.00 927.88 02W06 2095305.00 323005 .00 927.87 02W07 2095345.00 323005 .00 927.87 02W08 2095395.00 323015 .00 927.85 02W09 2095595 .00 322765 .00 935 .13 02W10 2095575.00 322825.00 933 .81 02Wll 2095445.00 323055.00 927.74 02W12 2095455.00 323035 .00 927.73 02W13 2095475.00 322985 .00 927.93 02W14 2095395.00 323055.00 927.76 02W15 2095285.00 322895 .00 927.91 02W16 2095265.00 322945.00 927.90 02W17 2095255.00 323005.00 927.86 02W18 2095345.00 323095.00 927.74 02W19 2095325.00 323055.00 927.82 02W21 2095195.00 323055.00 928.41 02W22 2095215 .00 322935 .00 927.89 02W23 2095205.00 323005 .00 927.89 02W24 2095265 .00 323055.00 927.83 02W26 2095625.00 322715 .00 935.88 02W27 2095395 .00 322825 .00 932.18 02W28 2095535 .00 322835 .00 933.91 02W29 2095555.00 322755 .00 934.99 02W30 2095475.00 322765 .00 934.91 02W31 2095505 .00 322855 .00 933.53 02W32 2095435.00 322965.00 927.87 02W33 2095255.00 322915.00 927.96 02W34 2095185.00 323105.00 927.84 02W35 2095255.00 323155.00 927.75 02W36 2095255.00 323105.00 927.78 02W37 2095325 .00 323155.00 927.69 02W38 2095395 .00 323095.00 927.70 02W39 2095575 .00 322735.00 935.29 02W40 2095525 .00 322665 .00 939.37 02W41 2095575.00 322685 .00 937.77 02W42 2095475.00 322725.00 937.06 02W43 2095325.00 323205.00 927.66 02W44 2095375.00 323155.00 927.65 02W45 2095285.00 323195 .00 927.69 02W46 2095465.00 322905.00 929 .07 02W47 2095525.00 322625.00 940.39 02W50 2095525 .00 322565.00 940.91 02W52 2095555 .00 322565.00 940.25 02W53 2095385 .00 322825 .00 932.28 02W62 2095205.00 323145 .00 927.77 1314.00 2095465.00 322415.00 944.45 1344.00 2095775.00 323505 .00 926.97 1361.00 2095435.00 323265.00 927.53 1362.00 2095455.00 323185.00 927.61 1315R 2095505 .00 322755 .00 934.62 1316R 2095435 .00 322775 .00 933.38 TMW-01 2095505.00 322695.00 942.72 TMW-02 2095505.00 322595.00 940.77 TMW-05 2095555.00 322885.00 932.30 TMW-06 2095635.00 322795.00 934.64 TMW-08 2095535.00 322725.00 935.37 TMW-09 2095485.00 322825 .00 933.65 TMW-13 2095375.00 322955.00 927.90 TMW-17 2095495.00 322765.00 932.22 TMW-18 2095335.00 322865.00 928.12 TMW-19 2095335 .00 322865.00 928.99 TMW-21 2095435.00 322705 .00 937.22 TMW-24 2095435.00 323405 .00 927.44 TMW-25 2095625.00 322655.00 937.22 Page 1 of 1

CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-4 TARGET RESIDUALS WESTERN ALLUVIAL AREA Observed Computed Monitoring Well Target Residual Error X Coordinate Y Coordinate l ayer Groundwater Groundwater Name (feet)

Elevation (ft msl) Elevation (ft msl)

T-51 2091962.326 322775.3151 1 929.40 929.58 -0.18 T-52 2092407.077 321938.0561 1 929.33 930.03 -0.71 T-53 2092658.888 322773.4615 1 929.20 929.46 -0.26 T-54 2092870.502 321927.5107 1 929.90 929.95 -0.06 T-55 2093119.602 322069.5861 1 928.46 929.79 -1.33 T-56 2093377.955 322211.2088 1 927 .75 929.66 -1.91 T-57 2092460.776 321788.0348 1 930.23 930.11 0.12 T-58 2092165.082 321742.3992 1 930.42 930.19 0.23 T-59 2092954.879 322773 .9563 1 929.18 929.40 -0.22 T-60 2093281.825 322773.9903 1 929.20 929.37 -0.17 T-61 2093609.542 322774.3586 1 929.03 929.35 -0.32 T-62 2091852.827 321470.6111 1 930.69 930.35 0.34 T-63 2091976.646 321623.1701 1 930.50 930.27 0.24 T-64 2091690.893 321341.8723 1 930.85 930.60 0.25 T-65 2091814.49 321568.8962 1 930.65 930.30 0.35 T-66 2091841.967 321712.1639 1 930.53 930.24 0.29 T-67 2091742.889 321657.3199 1 930.61 930.27 0.33 T-68 2091713 .086 322052.2542 1 930.25 930.08 0.17 T-69 2091871.687 321961.9211 1 930.35 930.11 0.24 T-70R 2091625. 712 321577.8822 1 930.72 930.32 0.40 T-72 2091716.886 321899.31 1 930.40 930.16 0.24

  • T-73 2091492.007 321770.5945 1 930.53 930.24 0.29 T-74 2091531.319 321541.2486 1 930.80 930.34 0.46 T-75 2091598.425 321910.8499 1 930.08 930.16 -0.08 T-76 2091730.573 321776.3881 1 930.52 930.22 0.29 T-77 2091578.18 322010.2399 1 930.29 930.11 0.18 T-78 2091493.754 321897.016 1 930.39 930.18 0.21 T-79 2091581.67 322212.5118 1 930.07 929.99 0.08 T-81 2091475 .972 321993.8223 1 930.29 930.12 0.16 T-82 2091568.929 322413.793 1 931.77 929.87 1.90 T-83 2091500.849 322296.5901 1 929.80 929.95 -0.15 T-84 2091868.998 322295.488 1 929.92 929.91 0.01 T-85 2092242.869 322346.2933 1 929.81 929.81 0.00 T-86 2092646.71 322374.1661 1 929.63 929.71 -0.08 T-87 2092979.208 322421.7784 1 929.40 929.60 -0.20 T-88 2093383.607 322463.997 1 929.10 929.52 -0.42 T-89 2093072.365 323042.1849 1 928.73 929.22 -0.49 T-90 2092830.417 323042.2904 1 928.85 929.25 -0.40 T-91 2092965.543 323228.2829 1 927.63 929.11 -1.48 T-92R 2093120.509 323143.2884 1 925.85 929.15 -3.30 T-93 2093413.803 323104.0018 1 928.66 929.17 -0.51 T-94 2093266.797 323409.2196 1 928.31 928.95 -0.64 T-95 2092457.655 323018.9933 1 928.98 929.33 -0.35 T-96 2091984.822 322557.2589 1 929.56 929.72 -0.16 T-97 2092038.592 323318.4229 1 928.78 929.18 -0.40 T-98 2092176.486 323514.2345 1 928.61 929.02 -0.41 T-99 2092589.694 323746.2418 1 928.25 928.79 -0.54 T-100 2093060.294 323821.1539 1 927 .05 928.54 -1.49 T-101 2093507.595 323599.2793 1 927.99 928.83 -0.84 T-102 2093581.061 323084.5863 1 928.69 929.18 -0.49 T-103 2094027.623 322867.4018 1 928.86 929.34 -0.48 1319B-1 2092053.321 320128.3453 1 947.62 946.62 1.00 1319B-2 2092077.815 319999.588 1 948.71 947.85 0.86 1319B-3 2092004.75 320105.048 1 947 .82 946.51 1.31 lof 2

CIMARRON ENVIRONMENTAL RESPONSE TRUST TABLE 3-4 TARGET RESIDUALS WESTERN ALLUVIAL AREA Observed Computed Monitoring Well Target Residual Error X Coordinate Y Coordinate Layer Groundwater Groundwater Name (feet)

Elevation (ft msl) Elevation (ft msl) 13198-4 2092053.33 320206.8531 1 947.11 946.01 1.10 13198-5 2091860.112 320322.0669 1 945.37 943.99 1.38 1338 2093545.832 321818.8544 1 944.27 943.19 1.08 1341 2092542.176 321354.7234 1 937.68 937.35 0.33 1345 2092346.652 321461.4784 1 934.66 934.00 0.66 1346 2093200.273 321854.3468 1 938.38 936.44 1.94 1382 2093127.504 321735.5542 1 938.76 937.53 1.23 1384 2093398.846 321601.9725 1 945.03 944.18 0.85 1386 2093375.507 321918.2437 1 939.89 937.96 1.93 1388 2093709.908 321837.3578 1 946.55 946.71 -0.16 1390 2093720.092 322017 .0578 1 942.47 942.12 0.35 1391 2093820.098 321752.3799 1 951.88 952.16 -0.28 1392 2093115.048 321860.6481 1 936.82 934.86 1.96 1394 2093370.328 321825.9886 1 941.12 939.68 1.44 1342 2090179.201 322508.0204 1 929.78 929.66 0.12 1343 2093597.566 323387.5208 1 928.27 928.99 -0.72

SUMMARY

STATISTICS Residual Mean 0.072692 Absolute Residual Mean 0.622272 Residual Std. Deviation 0.879194 Sum of Squares 54.47864 RMS Error 0.882194 Min. Residual -3.301795 Max. Residual 1.960407 Number of Observations 70 Range in Observations 26.03 Scaled Residual Std. Deviati 0.033776 Scaled Absolute Residual M 0.023906 Scaled RMS Error 0.033891 Scaled Residual Mean 0.002793 2of 2

CIMARRON ENVRONMENTAL RESPONSE TRUST TABLE 3-5 TARGET RESIDUALS BURIAL AREA #1 Observed Computed Monitoring Well Target Residual Error X Coordinate Y Coordinate Layer Groundwater Groundwater Name (feet)

Elevation (ft msl) Elevation (ft msl) 02W02 2095455 322885 6 930.53 928.58 1.95 02W03 2095375 322885 5 928.42 928.51 -0.09 02W04 2095335 322905 6 927.88 928.42 -0.54 02W05 2095315 322955 5 927.88 928.23 -0.35 02W06 2095305 323005 7 927.87 928.06 -0.19 02W07 2095345 323005 7 927.87 928.05 -0.18 02W08 2095395 323015 7 927 .85 928.00 -0.15 02W09 2095595 322765 6 935.13 935.40 -0.27 02W10 2095575 322825 6 933.81 933.00 0.81 02Wll 2095445 323055 8 927 .74 927.83 -0.09 02W12 2095455 323035 8 927.73 927 .88 -0.15 02W13 2095475 322985 8 927.93 928.05 -0.12 02W14 2095395 323055 8 927.76 927.87 -0.11 02W15 2095285 322895 5 927.91 928.45 -0.54 02W16 2095265 322945 6 927.90 928.27 -0.37 02W17 2095255 323005 7 927.86 928.07 -0.21 02W18 2095345 323095 8 927.74 927.78 -0.04 02W19 2095325 323055 7 927.82 927.90 -0.08 02W21 2095195 323055 8 928.41 927.93 0.48 02W22 2095215 322935 6 927.89 928.31 -0.42 02W23 2095205 323005 8 927.89 928.07 -0.18 02W24 2095265 323055 8 927.83 927.91 -0.08 02W26 2095625 322715 5 935.88 936.93 -1.05 02W27 2095395 322825 6 932.18 930.41 1.77 02W28 2095535 322835 6 933.91 931.64 2.27 02W29 2095555 322755 5 934.99 935.63 -0.63 02W30 2095475 322765 7 934.91 934.82 0.09 02W31 2095505 322855 6 933.53 929.71 3.81 02W32 2095435 322965 7 927.87 928.18 -0.31 02W33 2095255 322915 6 927.96 928.38 -0.42 02W34 2095185 323105 8 927.84 927.80 0.05 02W35 2095255 323155 8 927.75 927.66 0.08 02W36 2095255 323105 8 927.78 927.78 -0.01 02W37 2095325 323155 7 927 .69 927.64 0.05 02W38 2095395 323095 8 927.70 927.76 -0.06 02W39 2095575 322735 5 935.29 936.36 -1.07 02W40 2095525 322665 7 939.37 939.35 0.03 02W41 2095575 322685 6 937 .77 937.97 -0.20 02W42 2095475 322725 7 937.06 937.05 0.02 02W43 2095325 323205 8 927.66 927.53 0.12 02W44 2095375 323155 8 927.65 927.62 0.04 02W45 2095285 323195 8 927.69 927.57 0.12 02W46 2095465 322905 6 929.07 928.49 0.58 02W47 2095525 322625 7 940.39 940.80 -0.41 02W50 2095525 322565 7 940.91 942.66 -1.75 02W52 2095555 322565 7 940.25 941.99 -1.75 02W53 2095385 322825 6 932.28 930.44 1.85 02W62 2095205 323145 8 927.77 927.70 0.07 1314 2095465 322415 8 944.45 947 .88 -3.43 1 of 2

CIMARRON ENVRONMENTAL RESPONSE TRUST TABLE 3-5 TARGET RESIDUALS BURIAL AREA #1 Observed Computed Monitoring Well Target Residual Error X Coordinate Y Coordinate Layer Groundwater Groundwater Name (feet)

Elevation (ft msl) Elevation (ft msl) 1344 2095775 323505 7 926.97 927.07 -0.10 1361 2095435 323265 8 927.53 927.38 0.15 1362 2095455 323185 10 927.61 927.14 0.47 1315R 2095505 322755 7 934.62 935.47 -0.85 1316R 2095435 322775 7 933.38 933.98 -0.60 TMW-01 2095505 322695 7 942.72 938.33 4.39 TMW-02 2095505 322595 7 940.77 942 .18 -1.42 TMW-05 2095555 322885 7 932 .30 930.35 1.95 TMW-06 2095635 322795 4 934.64 935.02 -0.37 TMW-08 2095535 322725 6 935.37 936.77 -1.41 TMW-09 2095485 322825 6 933.65 930.89 2.76 TMW-13 2095375 322955 6 927.90 928.24 -0.33 TMW-17 2095495 322765 12 932 .22 934.50 -2.28 TMW-18 2095335 322865 6 928.12 928.56 -0.45 TMW-19 2095335 322865 4 928.99 929.19 -0.20 TMW-21 2095435 322705 6 937.22 938.13 -0.91 TMW-24 2095435 323405 7 927.44 927.22 0.22 TMW-25 2095625 322655 5 937.22 938.40 -1.18

SUMMARY

STATISTICS Residual Mean -0.02604 Absolute Residual Mean 0.735811 Residual Std. Deviation 1.199928 Sum of Squares 97.954333 RMS Error 1.20021 Min. Residual -3.434028 Max. Residual 4.388739 Number of Observations 68 Range in Observations 17.4756 Scaled Residual Std. Deviatio, 0.068663 Scaled Absolute Residual Me, 0.042105 Scaled RMS Error 0.068679 Scaled Residual Mean -0.00149 2 of 2