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Home My WebLink About03A Workshop Pumping Reduction 3M Woodbury City Council Action Request Form Meeting Date 7/20/2016 Department Community Development Agenda Category Workshops - Open to Public Title Workshop - Proposed Pumping Reduction Plan at 3M Woodbury Landfill Staff Recommendation Detailed Staff Recommendation Budget Implication N/A Attachments Letter from Stantec � Stantec July i3,2oi6 File:i93go22g3 Attention: Jennifer Levitt Ciry of Cottage Grove i2800 Ravine Parkway South Cottage Grove, MN 55oi6 Dear Ms.Levitt, Reference:Proposed Pumping Reduction Plan at gM Woodbury Landfill At your request, we have reviewed 3M's proposed plan to reduce the pumping rate to the barrier well system for the 3M Woodbury landfill site. We have put together this letter to summarize the planned changes and to note any concerns or recommendations we have regarding the proposed plan. Back�round • The pumping reduction proposal relates to four barrier wells that the 3M Company has been operating at the 3M Woodbury Site since the late 1960s and early 1970s. A layout of the 3M Woodbury Site is presented in the attached figure,taken from the pumping reduction proposal. • The purpose of these wells is to capture contaminants from the landfill before they can migrate through groundwater and reach the private and public water supply wells in the Cottage Grove area. • The average pumping rate of these four wells has ranged between 2500 and 3100 gallons per minute (gpm) since 2005. • Based on studies performed by the 3M and their consultants,they believe that the current barrier well network pumping rates can be reduced,while still maintaining adequate capture of the contaminants present at the 3M Woodbury Site. • The first phase of the pumping reduction proposal would be to reduce pumping in one of the barrier wells (Well B1)from an average rate of 800gpm to a new rate of 400gpm.This reduction is proposed to take place this month (July 2016). • The pumping reduction proposal also includes a schedule of increased water quality and water level sampling in the period after the pumping reduction takes place. • If results of the pumping reduction are favorable, a second phase of pumping reduction may be proposed by 3M in the future. � July 13,2016 Jennifer Levitt Page 2 of 4 Reference: Proposed Pumping Reduction Plan at 3M Woodbury Landfill The reason for the proposed pumping reduction proposal is that it will not only save 3M in operational costs to run the barrier wells, but it will reduce the amount of withdrawal from the Prairie du Chien- Jordan aquifer. Current Met Council projections show that groundwater withdrawals in southern Washington County could result in significant aquifer drawdown by the year 2030, if steps aren't taken to reduce excess pumping and promote greater water conservation. If less water is required from the 3M barrier well network to maintain capture,the reduction in the pumping rate will help the long-term sustainability of the aquifer. Comments and Recommendations We have reviewed the proposed pumping reduction proposal and are providing the following comments, concerns, and recommendations which we believe should be addressed by 3M before any planned reduction in the pumping rate occurs. 1. The hydrographs from December 2015 appear to show that groundwater levels never reached equilibrium during the periods in which different pumping scenarios were tested.This is to be expected with short-term pumping test data. We are interested in knowing how long is it predicted that it would take to achieve equilibrium, so the steady state conditions represented by a pumping reduction could be observed? If the established water levels at the barrier wells (and nearby observation wells) end up being higher than predicted (and therefore representing less capture of groundwater), 3M should have a plan in place to address this discrepancy. 2. The report indicates that the pumping wells provide a redundancy in the capture of contaminated groundwater. For a complex groundwater flow system,this redundancy helps to offset some unknown aspects of the complicated site hydrogeology. Reducing the pumping rate will also reduce the amount of redundancy, giving less margin for error in maintaining capture. 3M should attempt to quantify how much redundancy will remain in the system to ensure that capture is being maintained and that sufficient overlap of well capture zones is sufficient to capture all contaminants of concern. 3. Sampling key wells every six weeks for the first six months, results in four samples during this period instead of the usual two quarterly samples.We recommend a higher sampling frequency during the first six months, sampling at intervals no less than monthly for the first six months.This increased sampling rate is also favored by Gary Krueger of the MPCA. If a failure of the barrier wells occurs in which capture is not maintained, discovering that failure sooner, rather than later, will be critical for protecting both private and municipal wells down-gradient of the site. � July 13,2016 Jennifer Levitt Page 3 of 4 Reference: Proposed Pumping Reduction Plan at 3M Woodbury Landfill 4. We recommend long term installation of pressure transducers at additional wells, providing a better indication of changes in groundwater elevations and flow directions. Since the new flow rates will offer less redundancy in capture of the contaminants, higher resolution water level data will help shows fluctuations in groundwater levels that manual water levels measurements may not capture. Additionally,with multiple aquifers involved it would appear that more wells are needed to get a better representation of hydrogeologic flow changes across all layers. 5. We recommend more frequent manual water level measurements of all groundwater wells, especially during the early portion of the pumping reduction period could better measure the changes that occur to groundwater flow across the entire site. For example, weekly manual measurements during the first month of reduction period would provide better resolution of the initial groundwater elevation changes. 6. Better definitions of the thresholds that would activate the contingency plan should be provided by 3M. While "anomalies" in PFC data have been observed in the past, 3M should address how many wells will need to show contaminant increases before the threshold before the contingency plan is enacted. For example, will a single spike in one well be sufficient to trigger the contingency plan, or will multiple spikes over multiple samples be needed before the contingency plan is enacted? 7. Upon observation of any potential anomalies in the water quality data,we recommend that the contingency plan should include an automatic measure to re-sample the affected well(s), with or without requiring input from the MPCA first. Additionally, an increase in sampling frequency for the wells where anomalies have been observed (along with any surrounding wells) should be carried out until multiple samples are observed where the anomaly is absent. Increased sampling will help to more rapidly define whether the increased concentrations are resultant from changes in pumping rates. 8. The contingency plan should also address how a potential well outage would be handled. With reduced barrier well pumping rates in place,the level of redundancy will also be less.Therefore, the loss of a well due to mechanical failure, however temporary, should be immediately addressed with increased pumping in the other barrier wells to ensure capture is being maintained while the well outage is being addressed. Communications with Gary Krueger from the MPCA also indicate that"action levels" be better defined in the Contingency Plan, so it is known what events will trigger a response from 3M. � July 13,2016 Jennifer Levitt Page 4 of 4 Reference: Proposed Pumping Reduction Plan at 3M Woodbury Landfill 9. Some monitoring wells, particularly MW-2, have shown a spike in PFC levels towards the end of 2015. 3M should address the suspected cause of this new spike in concentrations.The previous spike at this well was attributed to activities related to landfill excavation and increased infiltration.The current spike would suggest that other unknown factors are still at play within the site. 3M should also address whether the wells with increased concentrations at the end of 2015 been re-sampled and, if so,what the latest results indicate. 10. The communication plan should notify stakeholders when an anomaly in the groundwater samples or measurements is observed and/or if the contingency plan is enacted.This communication should occur immediately instead of waiting for the next scheduled round of reporting.That way all parties can be assured that any anomalies are being addressed in a timely manner. It also gives other parties an opportunity to increase sampling of other nearby wells which could be impacted by a loss of capture. 11. Some sort of inetrics for success or failure of the pumping reduction proposal should be provided, so it can be determined what changes, if any, are appropriate for future pumping withdrawals. Assuming the results of the Phase 1 pumping reduction show acceptable level of capture are being maintained as well as predicted by the modeling,what would the proposed amount of pumping reduction be for Phase 2?3M should be more transparent in supplying their long-term plan for pumping reductions beyond Phase 1. We hope the above input provides you with some direction in responding to 3M's pumping reduction proposal.We would be happy to meet with you, along with representatives of 3M and the MPCA,to further discuss these concerns, along with any other concerns you have about the proposed changes to the management of the 3M Woodbury landfill. Regards, STANTEC CONSULTING SERVICES, INC. � Mark Janovec,PG Senior Scientist Phone: 65�-604-4831 Fax:651-636-i3ii mark.j anovec @ stantec.com _,,y= . _ �„ _ : � � T e_ _ , � a _ — t � � , � � - �;, . ,1•� �i �• � . f n .E c--�' • 7 �y 1 �' � , �... ,_ :,: , , ..� ! p +. , e .� � - G � � l. , :? ` +8►:. . �.��.. • r ..i ��_� �.�_ �. ��A �-�C�► 't, - — �� `n r - � � � i , � � � �s�s t ` a� S 07 JS �6 PC � > - • � � �07 PC � � � , � o � . 07SP + � i v � y„ �► '` � � �05PC a.. , - -•- --z r�( �4S �� Former Northeast S 05 SP � �� Disposal Area . . fVlit`. � � a� . > MW-(D�SI� . . �nra�re,� _ � a� �.�R`�� 0 .` ' Former Main `�SP � . . Disposal Area Former Municipal � �` ��,�-�B�� _ FiII Areas . . _ o r MW-11 I� f • j � .�IR-08 , °' .. � �� ' S03PC' i06 - � �� M1f�-�� ` 1 MW_�� ' � � �$g� \_ � '3 JS WOODBURY CORPORATE BOUND ,,.,..- CD �j , CqTTAGE GROVEtCORPORATE BOUN[ r`�,'�,��1 ��< „. � ��,�"'` �.� �... � � � g� ' .�i.ri.... 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' Aerial Source: ESRI,Bing Mapping Service. 2011� Legend: � Monitoring Well Locations N � Sentinel Well Locations FIGURE 1-1 Barrier Well Locations W E � � GROUNDWATER MONITORING Q� DNR Well Locations S NETWORK Approximate Paleochannel Location 3M WOODBURY SITE Approximate DisposalArea 0 500 1,000 WOODBURY, MN Boundaries Feet Site Boundary File:Y:\3MWoodbury\MXD\GW_Approx_Piezometer_DNRWeII_Locs.mxd,4/1/201 6 1 2:51:20 PM,johna 3M Center 224-5W-17 St. Paul, MN 55144-1000 July 15, 2016 Electronic Delivery Mr. Gary Krueger Remediation Division Minnesota Pollution Control Agency 520 Lafayette Road North St. Paul, MN 55155 Re: Response to Comments on the Proposal to Reduce Barrier Well Pumping Rates, 3M Woodbury Site, May2016 and Revised Proposal to Reduce Barrier Well Pumping Rates,3M Woodbury Site, July 2016 Dear Mr. Krueger: This letter provides responses to Minnesota Pollution Control Agency (MPCA) and City of Cottage Grove comments received by 3Mon the Proposal to Reduce Barrier Well Pumping Rates (Plan) at the former 3M Woodbury Site (Site) dated May 2016. The MPCA comments were submitted to 3M in an e-mail dated June 28, 2016. The City of Cottage Grove comments were provided to 3M during a meeting held on June 3, 2016, between representatives from 3M, the City of Cottage Grove and the City of Woodbury. The MPCA comments were provided in narrative form. Specific items from the MPCA comments are presented below and the city of Cottage Grove comments are also provided along with 3M’s responses. The responses to MPCA and City of Cottage Grove comments have been incorporated into Sections 4, 5 and 6 of the Revised Proposal to Reduce Barrier Well Pumping Ratesdated July 2016which is included inthis transmittal. MPCA Comments MPCA Comment 1: Overall, the phase one reduction rate/amount does appear to be reasonable as proposed. However, as discussed at our meeting, we want to see more details as to the communication/contingency plan once the reduction plan is implemented. One concern we do have is the “action level” for when a response by 3M will be triggered. The action level proposed may be appropriate for interior well results, but could allow unacceptable high PFC levels (in some cases many times above MDH levels of health concern) in wells near the site property boundary without any response occurring. 3M Response to MPCA Comment 1:More details on the communication/contingency plan and communication have been added to Sections 5 and 6 of the Plan. As statedin Section 5 of the Plan, “Since variability in PFC concentrations is occurring under current pumping conditions, establishing a PFC concentration as the sole criterion for termination or modification of the pumping reduction program is not appropriate as a contingency measure. Rather, a more broad, weight-of- evidence approach to such decision making will be employed considering the anomalous PFC concentration(s) encountered, the historical database, site hydrogeologic conditions, and other relevant factors.” Mr. Gary KruegerPage 2of 6 MPCA Therefore, should an anomalous PFC concentration be encountered, the PFC analytical data in conjunction with the Site hydrogeologic datawill be analyzed to ensure that groundwater capture is beingmaintained. Provided that groundwater elevationdata indicates that groundwater capture is maintained, 3M will immediately resample the well(s) where an anomaly is encountered. In the event groundwater elevation data does not indicate capture, the pumping reduction program will be modified or terminated. As stated in the Plan, an anomaly is defined as a PFC concentration detected at a concentration greater than two standard deviations over the arithmetic mean(i.e. PFCconcentrations). This “action level” is primarily less than the historical detected maximum PFC concentration for all wells that are located along the southern and western property boundary. MPCA Comment 2: As was discussed, we believe a more frequent monitoring schedule for the barrier/list one wells be considered. While the recommendation to sample the barrier wells for PFCs weekly the first month once reduction is implemented is appropriate, sampling of the barrier and list one wells for PFCs approximately every 4 weeks once the reduction is implemented would be more appropriate than every 6 weeks. In addition, we are requesting additional wells be sampled for PFCs during the August quarterly sampling event than what normally would have been done. Those wells include the following: S03JS, S03PC, S04PC, S05JS, S05PC, S05SP, S06JS, S06PC, MW-12, S08JS, S08PC, S09JS, MW-04 and MW-04L. The annual sampling event could be scheduled for October instead of November, with the November sampling being the barrier/list one wells. Once the results from the November sampling event are known, we could re-evaluate the monthly sampling events for the remainder of phase one. 3M Response to MPCA Comment 2:Section 4 has been modified to reflectmonthly sampling of the list onewells for the first four months after the reduction in pumping is implemented.In addition, the wells referenced above will be added to the third quarter monitoring event in August. Following receipt of the November analytical data, a determination will be made with respect to the sampling frequency going forward. Section 4and Table 4-1 in the Plan have been revised to incorporate these modifications the sampling program. City of Cottage Grove Comments City of Cottage Grove Comment 1: The hydrographs from December 2015 appear to show that groundwater levels never reached equilibrium during the periods in which different pumping scenarios were tested. This is to be expected with short-term pumping test data. How long is it predicted that it would take to achieve equilibrium, so the steady state conditions represented by apumping reduction could be observed? If the established water levels at the barrier wells (and nearby observation wells) end up being higher than predicted (and therefore representing less capture of groundwater), how will this be addressed? 3M Response to City of Cottage Grove Comment 1:3M agrees that the groundwater levels during the December 2015 short-term (24-hour) pumping tests had not reached equilibrium; however, the change in water level data collected during the short-term pumping testswas the data used in the Plan to predictthe effect of a reduction in pumping of the barrier wells at the Site. The predictions providea Mr. Gary KruegerPage 3of 6 MPCA conservative approach sincegroundwater levels would continue to declineafter 24 hours of pumping; therefore, the extent of groundwater capture for the barrier well is expected to exceed that as shown in the Plan. Previous water level data collected during hydraulic testing at the Site indicates that steady-state conditions will be reached within approximately oneweek. Steady-state conditions are reached in a shorter time frame in the bedrock aquifers (e.g. Jordan sandstone) compared to the shallow unconfined aquifer. If hydraulic data indicate that capture is not being achieved over the necessary area, the Contingency Plan will be implemented. City of Cottage Grove Comment 2: The report indicates that the pumping wells provide a redundancy in the capture of contaminated groundwater. For a complex groundwater flow system, this redundancy helps to offset some unknown aspectsof the complicated site hydrogeology. Reducing the pumping rate will also reduce the amount of redundancy, giving less margin for error in maintaining capture. Can you quantify how much redundancy will remain in the system to ensure that capture is being maintained and that sufficient overlap of well capture zones is sufficient to capture all contaminants of concern? 3M Response to City of Cottage Grove Comment 2:The amount of redundancy has not been quantified but is presented visually in several figures of the Plan. As shown in Figures 2-7 through 2-9 of the Plan, the direction of groundwater flow under non- pumping conditions is from barrier well B1 toward barrier wells B3 and B4. This direction of groundwater flow creates a redundancy in the capture zones for barrier wells B1, B3 and B4. The redundancy in the barrier well network is shown in the groundwater elevation contour maps constructed using the water level data collected during the short-term pumping tests performed at barrier wells B2, B3 and B4, and provided in the Plan in Attachments 3A, 5A and 6A, respectively. Comparing the extent of groundwater capture of each of these barrier wells (especially barrier wells B3 and B4) in the shallow aquifer, upper Prairie du Chien and Jordan Sandstone aquifers, indicatesconsiderable overlap. Coupled with the capture zone for barrier well B1 operating at approximately 50 percent of its current average flow rate, the overlap of well capture for each barrier well is predicted tobe more than sufficient to capture all contaminants of concern at the Site. City of Cottage Grove Comment 3: Sampling key wells every six weeks for the first six months results in four samples during this period instead of the usual two quarterly samples. A higher sampling frequencyduring the first six months would appear to be more appropriate, sampling at intervals no less than monthly for the first six months. If a failure of the barrier wells to ensure capture occurs, discovering that failure sooner, rather than later, will be critical to protecting both private and municipal wells down-gradient of the site. 3M Response to City of Cottage Grove Comment 3:Please see response to MPCA Comment 2. City of Cottage Grove Comment 4: Long term installation of pressure transducers at additional wells would provide a better indication of changes in groundwater elevations and flow directions. Since the new flow rates will offer less redundancy in capture of the contaminants, higher resolution water level data will help show fluctuations in groundwater levels that manual water levels measurements may not capture. Additionally, with multiple Mr. Gary KruegerPage 4of 6 MPCA aquifers involved it would appear that more wells are needed to get a better representation of hydrogeologic flow changes across all layers. 3M Response to City of Cottage Grove Comment 4:Transducers are currently installed in seven wells (MW-06, MW-06LR, MW-H, WR-03, PZ01DR, PZ03DR and PZ04DR) at the Woodbury Site to record groundwater elevations. Prior to initiating the pumping reduction additional transducerswill be installedin wells PZ01JS and PZ02DR to record water levels. Transducers installed in these nine wells will provide continuous monitoring of water levels along the southern property boundary of the Site to ensure groundwater capture is maintained. City of Cottage Grove Comment 5: More frequent manual water level measurements of all groundwater wells, especially during the early portion of the pumping reduction period could better measure the changes that occur to groundwater flow across the entire site. For example, weekly manual measurements during the first month of reduction period would provide better resolution of the initial groundwater elevation changes. 3M Response to City of Cottage Grove Comment 5:As discussed in the response to City of Cottage Grove Comment 1, steady-state groundwater conditions are expected to be reached within approximately oneweek after the implementation of the pumping reduction program. A round of water levels will be collected a day prior to the reduction in pumping and then one and two weeks later. These groundwater elevation data will be compared to verify that after steady-state conditions have been established. Another round of depth-to-groundwater measurements will be collected four weeks after the reduction in pumping. Theincrease in water level measurements is reflected in the revisedSection 4 of thePlan. In addition to increasingthefrequency thatwater level measurements will be taken during the first month, water level data from the transducers will be downloaded at the same time that depth-to-groundwater measurement are taken. The water level data collected by the transducers will also be evaluated to determine when steady-state conditions have been reached. City of Cottage Grove Comment 6: Better definitions of the thresholds that would activate the contingency plan should be provided. While “anomalies” in PFC data have been observed in the past, how many wells need to show contaminant increases before the contingency plan is enacted? Will a single spike in one well be sufficient to trigger the contingency plan, or will multiple spikes over multiple samples be needed before the contingency plan is enacted? 3M Response to City of CottageGrove Comment 6:Please see response to MPCA comment 1 for additional information on the contingency plan. Typically, the contingency plan would not be activated by only one “spike” in one well, but the well location and,most important, the hydraulic information collected at the Site will be evaluatedin activating the contingency plan. City of Cottage Grove Comment 7: Upon observation of any potential anomalies in the water quality data, the contingency plan should include an automatic measure to re-sample the affected wells(s), with or without requiring input from the MPCA first. Additionally, an increase in sampling frequency for the wells where anomalies have been observed (along with any surrounding wells) should be carried out until multiple samples are observed where the Mr. Gary KruegerPage 5of 6 MPCA anomaly is absent. Increased sampling will help to more rapidly define whether the increased concentrations are resultant from changes in pumping rates. 3M Response toCity of Cottage GroveComment 7:The last sentence in the first paragraph on page 5-2 of the Plan has been revised as follows: 3M will notify and discuss the response plan with MPCA which will include resampling of the well (and possibly other nearbywells) with expedited analysis. City of Cottage Grove Comment 8: The contingency plan should also address how a potential well outage would be handled. With reduced barrier well pumping rates in place, the level of redundancy will also be less. Therefore, the loss of a well due to mechanical failure, however temporary, should be immediately addressed with increased pumping in the other barrier wells to ensure capture is being maintained while the well outage is being addressed. 3M Response to City of Cottage Grove Comment 8:The following provision has been added to the Contingency Plan: In the event that a barrier well is temporarily shut downfor maintenance or repair, the flow rates in the barrier wells B1, B3 and/or B4 can be increased to compensate for the barrier well that is not operating. City of Cottage Grove Comment 9: Some monitoring wells, particularly MW-2, have shown a spike in PFC levels towards the end of 2015. Whatis the suspected cause of this new spike in concentrations? The previous spike at this well was attributed to activities related to landfill excavation and increased infiltration. The current spike would suggest that other unknown factors are still at play within the site. Have the wells with increased concentrations at the end of 2015 been re-sampled and, if so, what do the latest results indicate? 3M Response to City of Cottage Grove Comment 9:As noted in the comment, the concentration spikes in monitoring well MW-02 may be related to above normal precipitation in 2015 that caused an increase in infiltration and may have mobilized PFCs remaining beneath the former Northeast Disposal Area at the Site. Regardless of the cause for the increase in PFC concentrations, groundwater elevation data has consistently shown that groundwater in the vicinity of monitoring well MW-02 is captured by the barrier well network. City of Cottage Grove Comment 10: The communication plan should notify stakeholders when an anomaly in the groundwater samples or measurements is observed and/or if the contingency plan is enacted. This communication should occur immediately instead of waiting for the next scheduled round of reporting. That way all parties can be assured that any anomalies are being addressed in a timely manner. 3M Response to City of Cottage Grove Comment 10:The revisedContingency Plan in Section 5 contains additional details on notifications and response to anomalies. Key performance data includes groundwater level measurements and analytical data. Groundwater sampling results are dependent upon the turnaround time of laboratory analytical data. Analytical data for PFCs will be reported when it is available and will lag groundwater elevation measurements. Mr. Gary KruegerPage 6of 6 MPCA City of Cottage Grove Comment 11: Assuming the results of the Phase 1 pumping reduction show acceptable level of capture are being maintained as well as predicted by the modeling, what would the proposed amount of pumping reduction be for Phase 2? 3M Response to City of Cottage Grove Comment 11:The reporting of Phase 1 pumping reduction results and possible plans for a Phase 2 reduction are discussed in the amended Section 6of the Communication Plan. Plans and details for a possible Phase 2 are dependent upon the Phase 1 results. If you have any questions regarding this information, please call me at (651) 737-3477. Sincerely, Karie Blomquist, P.E. Environmental Engineering Specialist Corporate Environmental Programs Building 224-5W-17 Enclosure cc:Mr. Timothy Lockrem –MPCA Mr. Fred Campbell –MPCA Ms. Virginia Yingling –MDH Ms. Jennifer Levitt –City of Cottage Grove Ms. Charlene Stevens –City of Cottage Grove Mr. Klayton Eckles –City of Woodbury Mr. Jim Westerman –City of Woodbury REVISED PROPOSAL TO REDUCE BARRIER WELL PUMPING RATES 3M WOODBURY SITE WOODBURY, MN JULY 2016 Prepared for: 3M Company Prepared by: WESTON SOLUTIONS, INC. 1400 Weston Way West Chester, Pennsylvania 19380 W.O. No. 02181.222.031.0002 TABLE OF CONTENTS Section Page 1.BACKGROUND ....................................................................................................... 1-1 1.1Purpose ................................................................................................................ 1-1 2.DECEMBER 2015 HYDRAULIC EVALUATION ................................................. 2-1 2.1Barrier Well B2 ................................................................................................... 2-5 2.2Barrier Well B1 ................................................................................................... 2-6 2.3Barrier Well B3 ................................................................................................... 2-7 2.4Barrier Well B4 ................................................................................................... 2-8 2.5Summary ............................................................................................................. 2-8 3.OPTIMIZED PUMPING PLAN ................................................................................ 3-1 4.PLAN IMPLEMENTATION AND SCHEDULE ..................................................... 4-1 5.CONTINGENCY PLAN ........................................................................................... 5-1 5.1Groundwater Elevation Data ............................................................................... 5-1 5.2PFC Analytical Data ............................................................................................ 5-1 6.COMMUNICATION PLAN ..................................................................................... 6-1 7.REFERENCES ........................................................................................................... 7-1 ii 2016-07-WBMN-Krueger_BW_Reduction-Rev.docx LIST OF FIGURES Title Page LIST OF TABLES Title Page LIST OF ATTACHMENTS ATTACHMENT 1 HYDROGRAPHS ATTACHMENT 2 METRO-MODEL GROUNDWATER ELEVATION CONTOUR MAPS ATTACHMENT 3 BARRIER WELL B2 GROUNDWATER MAPS ATTACHMENT 4 BARRIER WELL B1 GROUNDWATER MAPS ATTACHMENT 5 BARRIER WELL B3 GROUNDWATER MAPS ATTACHMENT 6 BARRIER WELL B4 GROUNDWATER MAPS ATTACHMENT 7 METRO-MODEL PREDICTIVE SIMULATIONS ATTACHMENT 8 GROUNDWATER PFC ANALYTICAL DATA OCTOBER - NOVEMBER 2015 ATTACHMENT 9 TREND GRAPHS 1. BACKGROUND 1.1 PURPOSE Quarterly Groundwater Report – Third Quarter 2013 Further Delineation of a Paleochannel at the Former 3M Woodbury Disposal Site, Woodbury, MN, 2. DECEMBER 2015 HYDRAULIC EVALUATION o o o o 2.1 BARRIER WELL B2 2.2 BARRIER WELL B1 2.3 BARRIER WELL B3 2.4 BARRIER WELL B4 2.5 SUMMARY (2) Change in Water Level (feet) 15 (AM) Groundwater B4 On 24 hrs Elevation- (ft MSL) 12/7/2015 (AM)12/10/2015 (AM)12/11/2015 (AM)12/12/2015 (AM)12/13/2015 (AM)12/14/2015 (AM)12/15/2015 (AM)12/16/2015 (AM)12/17/20 Groundwater All Wells Off Elevation- (ft MSL) (2) Change in Water Level (feet) Groundwater B3 On 24 hrs Elevation- (ft MSL) aluation, December 2015 Groundwater All Wells Off Elevation- (ft MSL) (2) Change in Water Level rrier Well Hydraulic Ev (feet) Woodbury Site, Woodbury, MN Groundwater B1 On 24 hrs Elevation- (ft MSL) Table 2-1 Summary of Groundwater Elevation Data - Ba Groundwater All Wells Off Elevation- er level is a positive value. (ft MSL) (2) - Change in Water Level calculated by subtracting pumping from non-pumping groundwater elevation. Therefore, a decrease in wat Change in Water Level (feet) Groundwater B2 On 24 hrs. Elevation- (ft MSL) (2) Change in Water Level - Monitoring well MWG-DR is screened within a possible perched zone. (feet) Groundwater All Wells Off Elevation- (ft MSL) OSTP - St. Peter Sandstoneft MSL = feet above mean sea level. NA - Not Accessible. CJDN - Jordan Sandstone Groundwater All Wells On Elevation- (ft MSL) (1) (2) Monitored OPDC - Prairie du Chien Group Former Residential Wells Unit Sentinel Wells Monitor Wells Barrier Wells WELL ID DNR Wells Notes: 3. OPTIMIZED PUMPING PLAN o o o o recognized that the ability of the current version of the metro groundwater flow model to predict groundwater flow across the Site is limited due to the discretization of the model domain (i.e. grid node size) and hydrostratigraphic units; however, the groundwater flow model provides another line of evidence that groundwater capture is currently being achieved and will be achieved with a reduction in pumping at barrier well B1. In summary, reducing the flow rate for the Site barrier well network for this Phase 1 reduction as described, is predicted to maintain groundwater capture and result in preserving approximately 210 million gallons of the groundwater resource per year. 3-5 2016-07-WBMN-Krueger_BW_Reduction-Rev.docx Table 3-1 Barrier Well Flow Rates January 2014 - December 2015 Woodbury Site, Woodbury, MN Combined Barrier Well Barrier Well Barrier Well Barrier Well Flow (gpm)B1B2B3B4 Date/Month Jan-1428697921206531304 Feb-1428557881176481301 Mar-1429377861226811348 Apr-1429617951196801367 May-1427776791116501338 Jun-1429317851336781335 Jul-1429507841326751359 Aug-1429497881316751355 Sep-1426727141196171223 Oct-1429807991336901358 Nov-1429217951296751323 Dec-1429447951276751348 2014 Average28967751246661330 Jan-1528737901236621298 Feb-1528727901216581303 Mar-1528817901236591309 Apr-152843794336741341 May-152651726826201223 Jun-1529277761656581328 Jul-1529247741636571330 Aug-1528427051546711312 Sep-1529287671586721331 Oct-1529137771556581323 Nov-1529497761516711351 Dec-151986530101447908 2015 Average27997501276421280 1 2014-2015 Average 29127821306691331 Reduction Target Flow Rate: 25004001306701300 1 -Flow rates for May 2014, September 2014, May 2015 and December 2015 were not used to calculate the 2014-2015 average. Barrier well maintenance activities were performed in May 2014 and May 2015, and barrier well shutdown tests were performed in September 2014 and December 2015. As shown in the data reported, these activities lowered the average flow rates calculated for these months. NOTE: • All flow values reported in gallons per minute (gpm). • Flow rates reported represent monthly average calculated from data obtained from automated monitoring system. Tab-03-01-BW-Rates 4. PLAN IMPLEMENTATION AND SCHEDULE Table 4-1 Estimated Timeline for Pumping Reduction Tasks Woodbury Site, Woodbury, MN Elapsed Time Since Week of Pumping Reduction (approximate)Implemented (weeks) Action/Task 02-May-16--Submit Pumping Reduction Plan to MPCA. 13-Jun-16--Meeting with MPCA to review the Pumping Reduction Plan. 1 22-Jun-16-- Perform 2Q2016 quarterly groundwater sampling event (including List 1 and barrier wells). 18-Jul-16--Submit revised Pumping Reduction Plan to MPCA that incorporates City of Cottage Grove and MPCA comments. 25-Jul-16--Collect PFC samples from barrier wells. 25-Jul-16--MPCA approval of revised Pumping Reduction Plan 01-Aug-16--Collect PFC samples from barrier wells and water levels from Site wells prior to start of pumping reduction. 01-Aug-16--Implement Pumping Reduction at Site. 2 08-Aug-161 Collect PFC samples from barrier wells and water levels from Site wells. Conference call with stakeholders. 15-Aug-162Collect PFC samples from barrier wells and water levels from Site wells. 22-Aug-163Collect PFC samples from barrier wells. 1 Perform 3Q2016 sampling event (including List 1, barrier wells, and additional wells: S03JS, S03PC, S04PC, 29-Aug-164 S05JS, S05PC, S05SP, S06JS, S06PC, MW-12, S08JS, S08PC, S09JS, MW-04 and MW-04L), and collect water levels from Site wells. The first monthly progress report will be submitted to MPCA and other stakeholders electronically. Monthly 05-Sep-165 2 conference call. 26-Sep-168Collect PFC samples from barrier and List 1 wells. Collect monthly water levels from Site wells. 2 03-Oct-169 Submit second monthly progress report to MPCA and other stakeholders electronically. Monthly conference call. 24-Oct-1612Collect PFC samples from barrier and List 1 wells. Collect monthly water levels from Site wells. 07-Nov-1614Submit third monthly progress report to MPCA and other stakeholders electronically. Monthly conference call. 1 14-Nov-1615 Perform annual groundwater sampling event (including List 1 and barrier wells). Collect monthly water levels. 05-Dec-1618Submit fourth monthly progress report to MPCA and other stakeholders electronically. Monthly conference call. 26-Dec-1621Collect PFC samples from barrier wells and monthly water levels from Site wells. 2 02-Jan-1722 Submit fifth monthly progress report to MPCA and other stakeholders electronically. Monthly conference call. 23-Jan-1725Collect PFC samples from barrier wells and monthly water levels from Site wells. 06-Feb-1727Submit sixth monthly progress report to MPCA and other stakeholders electronically. Monthly conference call. 13-Feb-1728Collect monthly water levels from Site wells. 1 Perform 1Q2017 quarterly groundwater sampling event(including List 1 and barrier wells) and collect 13-Mar-1732 monthly water levels from Site wells. 10-Apr-1736Collect monthly water levels from Site wells. 08-May-1740Collect monthly water levels from Site wells. Submit letter report to MPCA with findings of Phase 1 of the pumping reduction program and recommendations for 19-Jun-1746 Phase 2. Collect monthly water levels from Site wells. 03-Jul-1748Collect monthly water levels from Site wells. 1 17-Jul-1750 Perform 2Q2017 quarterly groundwater sampling event (including List 1 and barrier wells). 31-Jul-1752If warranted, implement Phase 2 of pumping reduction following MPCA approval. List 1 (key) wells: PZ01DR, PZ01JS, PZ02DR, PZ03DR, PZ04DR, S01PC/JS, S02DR/PC/JS, S10DR/JS, MWH and WR03. 1 - Groundwater samples will be collected from well locations specified in Final Woodbury Groundwater PFC Monitoring Plan (WESTON, Nov. 2013) 2 - Conference calls will be held in the later part of the week (i.e. Thursday or Friday) after groundwater elevation data has been evaluated during the early part of the week. 5. CONTINGENCY PLAN 5.1 GROUNDWATER ELEVATION DATA 5.2 PFC ANALYTICAL DATA 6. COMMUNICATION PLAN 7. REFERENCES KT3D_H2O: A Program for Kriging Water Level Data Using Hydrologic Drift terms. Twin Cities Metropolitan Area Regional Groundwater Flow Model. Version 3.0. Bedrock Geology – DRAFT. County Atlas Series Atlas C-39, Part A. Washington County, Plate 2 – Bedrock Geology. Evidence for hydraulic heterogeneity and anisotropy in the mostly carbonate Prairie du Chien Group, southeastern Minnesota, USA. Transactions, American Geophysical Union. Kriging Water Levels with a Regional- linear and Point-logarithmic Drift. 2013 Annual Groundwater Report. Perfluorochemical (PFC) Groundwater Assessment and Hydraulic Capture Zone Evaluation for the 3M Woodbury Site. June 2015 Semiannual Groundwater Report (January 2015-June 2015). Perfluorochemical (PFC) Groundwater Assessment and Hydraulic Capture Zone Evaluation for the 3M Woodbury Site. ATTACHMENT 1 HYDROGRAPHS ATTACHMENT 1A HYDROGRAPHS FOR WELLS EQUIPPED WITH PRESSURE TRANDUCERS ATTACHMENT 1B HYDROGRAPHS FOR WELLS MONITORED MANUALLY ATTACHMENT 1C MNDNR WELL HYDROGRAPHS ATTACHMENT 2 METRO-MODEL GROUNDWATER ELEVATION CONTOUR MAPS ATTACHMENT 3 BARRIER WELL B2 GROUNDWATER MAPS ATTACHMENT 3A DECEMBER 11, 2015 GROUNDWATER ELEVATION CONTOUR MAPS – BARRIER WELL B2 OPERATING ATTACHMENT 3B CHANGE IN WATER LEVEL – BARRIER WELL B2 OPERATING ATTACHMENT 4 BARRIER WELL B1 GROUNDWATER MAPS ATTACHMENT 4A DECEMBER 13, 2015 GROUNDWATER ELEVATION CONTOUR MAPS – BARRIER WELL B1 OPERATING ATTACHMENT 4B CHANGE IN WATER LEVEL – BARRIER WELL B1 OPERATING ATTACHMENT 5 BARRIER WELL B3 GROUNDWATER MAPS ATTACHMENT 5A DECEMBER 15, 2015 GROUNDWATER ELEVATION CONTOUR MAPS – BARRIER WELL B3 OPERATING ATTACHMENT 5B CHANGE IN WATER LEVEL – BARRIER WELL B3 OPERATING ATTACHMENT 6 BARRIER WELL B4 GROUNDWATER MAPS ATTACHMENT 6A DECEMBER 17, 2015 GROUNDWATER ELEVATION CONTOUR MAPS – BARRIER WELL B4 OPERATING ATTACHMENT 6B CHANGE IN WATER LEVEL – BARRIER WELL B4 OPERATING ATTACHMENT 7 METRO-MODEL PREDICTIVE SIMULATIONS ATTACHMENT 8 GROUNDWATER PFC ANALYTICAL DATA OCTOBER – NOVEMBER 2015 Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) (MPCA SPLIT) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) (MPCA SPLIT-DUP) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) (MPCA SPLIT) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Sentinel Wells (continued) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Barrier Wells Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Barrier Wells (continued) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Barrier Wells (continued) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Barrier Wells (continued) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Monitoring Wells Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Monitoring Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Monitoring Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Monitoring Wells (continued) (MPCA SPLIT) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Monitoring Wells (continued) Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Monitoring Wells (continued) Former Residential Well Summary of Groundwater PFC Analytical Data October 2010 - November 2015 Sampling Events Woodbury Site, Woodbury, MN PFBAPFPeAPFHxAPFHpAPFOAPFBSPFHSPFOS DATE (ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L)(ppb, ug/L) Well ID Combined Effluent Flow from Barrier Wells New Monitoring Wells NOTES: ATTACHMENT 9 TREND GRAPHS Sentinel Well S-01JS Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-01PC Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 06-S01-CHT Sentinel Well S-02DR Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-02JS Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-02PC Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 07-S02-CHT Sentinel Well S-03JS Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-03PC Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 08-S03-CHT WellS-04SP Groundwater Analytical Data(10/2010-11/2015) WellS-04PC Groundwater Analytical Data(10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 09-S04-CHT Sentinel Well S-05JS Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-05PC Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 10-S05-CHT Sentinel Well S-06JS Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-06PC Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 11-S06-CHT Sentinel Well S-07SP Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-07JS Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 12-S07-CHT Sentinel Well S-08PC Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-08JS Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 13-S08-CHT Sentinel Well S-10DR Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-10JS Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 15-S10-CHT Monitor Well MW-02 Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 16-MW02-CHT Monitoring Well MW-04 Groundwater Analytical Data (10/2010-11/2015) Monitoring Well MW-04L Groundwater Analytical Data (10/2010-11/2015) Sentinel Well S-09JS Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 14-S09-MW-4-4L-CHT Monitoring Well MW-06LR Groundwater Analytical Data (10/2010-11/2015) Monitoring Well MW-12 Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 17-MW6LR-MW12-CHT Monitoring Well MWB-PC Groundwater Analytical Data (10/2010-11/2015) * - Monitoring well installed in July 2012. Monitoring Well MWG-DR Groundwater Analytical Data (10/2010-11/2015) * - Monitoring well installed in July 2012. 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 22-MWGDR-MWBPC-CHT Barrier Well B-1 Groundwater Analytical Data (10/2010-11/2015) Barrier Well B-2 Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 18-B1_B2 Barrier Well B-3 Groundwater Analytical Data (10/2010-11/2015) Barrier Well B-4 Groundwater Analytical Data (10/2010-11/2015) 2015-11-Trend-Plots-WBMN-ALL_Charts(ISO-35)-Working 19-B3-B4