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HomeMy Public PortalAboutStantec_October 2017_Groundwater Analysis Stantec Consulting Services Inc. 400 Crown Colony Drive,Suite 200 Stantec Quincy,Massachusetts 02169-0982 FIL, E Cop October 23, 2017 File: 191750291 Attention: Steve Hurley, RA, LEED AP Janovsky/Hurley Architects, Inc. 37 Walnut Street Wellesley Hills, Massachusetts 0248 1-21 66 Dear Steve, Reference: Letter Report Concerning Effects of Foundation in Groundwater 33 Mount Auburn Street Watertown, Massachusetts Stantec Consulting Services, Inc. (Stantec) has prepared this letter report which evaluates the potential influences on groundwater due to a proposed building foundation at the referenced Site. We understand the Site is currently vacant. A commercial building was recently demolished to make way for the proposed construction. Stantec understands the proposed building includes a 2,000 square foot basement located in the northwest corner of the building. The remainder of the building would be on-slab construction. The depth of the basement is expected to be approximately 10.5 feet below grade. Depth to groundwater at the Site reportedly ranges between approximately 8 and 12 feet below grade (see Table 1). Based upon a portion of the proposed basement extending into the groundwater, the Watertown Building Department has requested an evaluation of the submerged portion of the basement and any effects it may have on abutting properties. Site and Area Seffina The Site is located in the center commercial district of Watertown (see Figure 1). It has frontage on the west side along Mount Auburn Street which is oriented in a northeast to southwest direction;and on the eastern side along Taylor Street (see Figure 2). According to the Watertown Assessors records, the area of the Site is 0.308 acres and it is zoned Central Business. The Site is abutted to the south by an automobile repair facility at 32 Arsenal Street and an office and residential condominium at 24 Arsenal Street. It is abutted to the west by a commercial building which has a 7-11 convenience store and a Verizon store, and further west by another commercial building which includes a hair salon,wireless communications business and a bank. Existina Reoorts Several reports have been prepared that detail the geologic and hydrologic conditions at the Site. Stantec reviewed these reports for pertinent information which is summarized below. Design with community In mind October 23, 2017 Attention: Steve Hurley Page 2 of 6 Reference: Letter Report Concerning Effects of Foundation in Groundwater Preliminary Site Assessment Report, Service Station Maintenance Corp (SSM), April 1990. SSM advanced 3 soil borings at the Site in 1990. The boring logs indicate very fill sand to 12 feet underlain by very fine sand to silt to 20 feet in one boring; and a fine to medium sandy fill to 15 feet underlain by fine to medium sand to 20 feet in the other two borings (see logs in Attachment A(. Based upon a wellhead survey of three monitoring wells installed at the Site in 1990, SSM conducted a water table mapping which indicated general groundwater flow direction through the Site towards the northwest. Stantec notes that the wells used were very close to each other and not very conducive to triangulation. Also, the wellhead elevations were all equated to the same benchmark datum instead of being relative to the datum. Therefore, the flow direction cited is not considered reliable. Environmental Site Assessment Update. Briaas Associates. Inc., October 2, 1992. Based upon topography, Briggs inferred regional groundwater flow direction to the south- southwest towards the Charles River. Briggs also conducted a water table mapping using the SSM wells. Briggs inferred groundwater flow direction within the overburden soils at the site to be to the south-southwest which agreed with their estimate for the regional flow direction. Phase I Initial Site Investigation Report, Tundra, July 1996 Tundra described soils at the Site during the completion of six test borings. Site soils to a depth of 15 feet below grade were observed to consist of 6 to 15 feet of sandy brown fill underlain by black to tan gravely sand. Groundwater was encountered at approximately nine to ten feet below grade. Based upon a water table mapping,Tundra inferred a groundwater flow direction generally toward the southwest,with a horizontal hydraulic gradient of approximately 0.02 feet/foot. Response Action Outcome Statement, Nautilus Environmental Services, Inc., August 3, 1998. Nautilus indicates a northwesterly groundwater flow direction on the Site Plan included with the report. However, they do not discuss how this direction was determined in the report. Therefore, the flow direction cited is not considered reliable. Design with community in mind October 23,2017 Attention: Steve Hurley Page 3 of 6 Reference: Letter Report Concerning Effects of foundation in Groundwater Phase II Comorehensive Site Investia_ation. C000erstown Environmental. LLC. November 2015. Cooperstown reviewed the information in the prior reports. Based on these investigations, they state the Site is underlain by a layer of fill to depths of up to 15 feet below ground surface. Native sands consisting of predominantly medium sand was observed beneath the fill to 20 feet. The soil description for the 20 to 25 foot interval changed to silt and sand indicating a change in the aquifer matrix material and the lower extent of the overburden aquifer at approximately 20 feet. They acknowledge that groundwater flow direction from prior studies appears to be a matter of some disagreement. Cooperstown conducted a wellhead survey which included additional wells they installed. Based on this analysis, they inferred groundwater flow direction towards the northwest. However, the report does not include survey data, and therefore,cannot be validated. Kurz Environmental. Inc.. Borina Loos.September 5, 2017. Stantec reviewed soil boring logs prepared for the Site by Kurz. The wells were installed on September 5, 2017 for an ongoing environmental assessment. Kurz installed 3 borings at the Site labelled KOW-1 through KOW-3 on Figure 3. They report soil conditions as fill to between 7 and 8 feet below grade underlain by tan to gray fine to medium sand, with intermittent lenses of coarse sand to 20 feet below grade and a trace of silt and gravel. Soils were generally wet at around 13 feet. Based upon groundwater elevations provided by Kurz, groundwater flow from measurements conduct in the September of 2017 appears to be towards the southwest. Soil boring logs for these investigations are included in Attachment A. Summary of Soil and Groundwater Information In summary, soils at the Site appear to consist of a fill layer underlain by native sands ranging from fine to coarse grained,with lens of gravel to approximately 20 feet below grade. The groundwater appears to be within both the lower extent of the fill and the native material. Based upon the historical record of groundwater gauging for monitoring wells at the Site, depth to groundwater ranges between 8.8 feet measured in 1990 to 11.76 feet in 2017. The shallow water table is often a Design with community in mind October 23, 2017 Attention: Steve Hurley Page 4 of 6 Reference: Letter Report Concerning Effects of Foundation in Groundwater subdued expression of surface topography. Shallow groundwater generally flows from areas of groundwater recharge, such as hills and broad uplands, to areas of groundwater discharge, such as wetlands, rivers, and lakes. Topographically, the Site is at the bottom of Mount Auburn Street, which slopes down towards Main Street which is at a slightly higher elevation than the Site. In reviewing the mapped topography (Figure 1),all surrounding properties to the north,east,and west appear to drain to this area before ultimately draining south to the Charles River. This area takes surficial flow from Whitney Hill located to the northwest and Meetinghouse Hill located to the north and an unnamed hill to the east. As such, water from these higher elevations may drain with groundwater or via the complicated network of subsurface utilities through the area of the Site, prior to eventually draining to the Charles River. Groundwater Flow Direction Based on the local surface topography and nearby surface water features, regional groundwater is expected to flow to the south or southwest towards the Charles River which is the assumed discharge point for groundwater. There are historical records of a former stream that existed west of Mount Auburn Street. The stream flowed from northeast to southwest and converged with the Charles River. Topographic contour lines along Spring Street seem to support this information. Former stream beds can often provide a preferential pathway for groundwater flow. Man-made features such as wells, roads, filled areas, buried utility lines and sewers, and drainage ditches may alter the natural shallow groundwater flow direction. The Watertown Department of Public Works states that stormwater drainage in Watertown is collected through catch basins, conveyed through drainage pipes, and then discharged into the Charles River. There are also reportedly sumps in many of the building basements in the vicinity of the Site which can also influence localized groundwater flow when they're being pumped. The approximate elevation at the Site is 25 feet above mean sea level. The Charles River, located approximately 500 feet from the Site,is only slightly higher than sea level at a few feet above. Tundra estimated a horizontal gradient for the water table of 0.02 feet/foot in 1996. Using the Kurz elevation data from 2017,the horizontal gradient for the water table is 0.003 feet/foot. The difference is likely attributed to the record of precipitation recharge events prior to the data collection. In the absence of obstructions, the water table would be expected to slope towards the south or southwest until it discharges into the Charles River. The amount of the slope and the rate at which groundwater flows through the soil is a function of the soil characteristics. These can be estimated by the hydraulic conductivity (K) which is an empirical value that can be measured in the field. Design with community in mind 5 October 23,2017 Attention: Steve Hurley Page 5 of 6 Reference: Letter Report Concerning Effects of Foundation in Groundwater None of the prior reports discussed a Site-specific K value, and permeability of soils in the area of the Site are not mapped by USGS. Available information for similar native soils as described at the Site suggest a range of K values from 10-2 to 10-3 cm/sec (Freeze &Cherry, 1979). For comparison, silty sands, tills, and clay soils have K values typically less than of 10-3 cm/sec, while gravelly soils have K values greater than 10-1 cm/sec. This suggests that the soils in the overburden aquifer are relatively transmissive. Groundwater contours can be developed based upon the surface of the water table and represent lines of equal head elevation above a datum. They typically run parallel to a discharge point such as the shoreline of a river of lake. Groundwater flow lines run perpendicular to the contour lines. Contours based upon the Kurz data are include on Figure 3. These contours indicate groundwater flow direction is towards the southwest. Effect of Foundations on Groundwater Flow Assuming that groundwater flow is in a steady state before construction and achieves another steady state after construction when foundations are added, the groundwater level and flow are modified to varying degrees. The foundation becomes a no flow boundary in that the groundwater that used to flow through soil is now impeded. It must either flow around or under the structure. This changes the dynamics of the flow regime. The degree to which the change is significant is dependent upon the soil type,amount of recharge,and the size (length and depth) and orientation of the structure. In general,the deeper the structure into the groundwater the greater the potential for a change to be noticeable. In aggregate circumstances where the number of foundations that intrude into the groundwater is high and the intrusion depths can be tens of feet, such as urban settings,the hydraulic head can be raised significantly. The theoretical assumption is that the extent to which the groundwater is influenced by a barrier, largely depends on the proportion to which the barrier cuts off the water bearing layers/aquifers. The proposed basement is only under a portion of the building with a reported footprint of 2,000 square feet (see Figure A1). The bottom of the basement will be approximately 10.5 feet from grade. Cooperstown encountered the lower limit of the overburden aquifer at approximately 20 feet below grade in MW-1 where a silt and sand layer was observed. If we consider the highest groundwater from historical data measured in wells at the Site of 8.8 feet below grade in 1990 (see Table 1), the saturated thickness of the aquifer at that time would be 11.2 feet. The bottom of the proposed basement at 10.5 feet below grade would extend 0.7 feet into the groundwater. Therefore, the proposed basement would encompass only approximately 6%of the aquifer [(0.7' / Design with community in mind October 23,2017 Attention: Steve Hurley Page 6 of 6 Reference: Letter Report Concerning Effects of Foundation In Groundwater 11.2') x 100 = 6.25%]. Recent groundwater data from 2015 and 2017 indicate the highest groundwater was 10.2 feet (saturated thickness = 9.8 feet) which would put the foundation into the groundwater by only 0.3 feet. This represents only 3% of the aquifer. These intrusion depths into groundwater are not significant. Yohannes Yihdego found in a study modelling the effect of hydraulic barriers on groundwater flow, that the reduction of flow does not appear to be significant until a 60%to 70% cut off of the saturated thickness'. Considering the relatively high transmissivities of native soils at the Site, the potential aquifer cut off by the proposed foundation are unlikely to alter the state of the groundwater dynamics. Groundwater impeded by the foundation wall will seek alternate flow paths around and /or under the structure, and this flow should be easily accommodated by the aquifer without significant mounding. In Stantec's opinion, the effect on the water level for surrounding buildings will be negligible. Note the closest building to the proposed foundation is the abutting commercial building to the west. This building is located downgradient of the basement with respects to groundwater flow and it also reportedly has a basement and operates a sump. We appreciate the opportunity to assist you with this matter. If you have any question, please contact us at your convenience. Regards, STANTEC CONSULTING SERVICES INC. Richard B. Learned, LSP Brian V. Moran, P.E., LSP Senior Environmental Project Manager Associate Phone: 508-591-4351 Phone: (508) 591-4389 Richard.Learned@stantec.com Brian.Moran@stantec.com da v:\1917\active\1917W291\0S_repod_deliv\deliverables\left rrepart_watert wn,docx I LBS College of Engineering, Kasaragod, Vol. 4, Special Issue 6, March 2017, Copyright to IARJSEf, Impact of Underground Structures on Flow of Groundwater-A Review. Design with community in mind ® Stantec FIGURES Figure 1 Site Locus Map Figure 2 Assessor's Map Figure 3 Groundwater Flow Plan Figure A 1 Janovsky/Hurley Architects, Inc. Basement Plan Design with community in mind OAF 11 ice► LIFE "lam ffm Olm � � , �.�� o Nye ,,/� Q3G',�'�a� `�✓��. �►�`mot• �` � , Mr ��� �• PIP �� �I�j %/III r�� •� �m� !A o �11pj� ///II►VA NO /` yl rA ma NOW �, �►�'� �1 Va tan 0 Y v�v - �, N _ N 0.0 N t Q W ul Z � � Q N t]N 03N3 br co Q cn © �g Q'�tr• j� w mCIA f4 _ m o �P z � ` to CO 5 o� �-N ZO 001, / ) 1001, Ile / 000, 1000, to N s 3 .040 p m �\ N ' / J d \ to � ' Z coot 0000 r► O sc k (10 J ! 3�{ to o"o fl N " I U � % I / I / ISM I F / j p / I U % o I / u j / W o U / q I K % w I ,1 \ 1 � of �_ zQ \ / j \ U� '\ W 1\ / / w .TA i yA 1\ / 00 / U p O m 2L O o �i Stantec TABLES Table 1 Depth to Water Measurements Design with community In mind Table 1 Depth to Water Measurements 33 Mount Auburn Street Watertown, Massachusetts (feet below grade) Well Well Sample Date ID Location 4/2/1990 5/29/1992 4/1/2015 1 10/13/2015 9/18/2017 SSM Briggs Cooperstown Kurz SSM-1 on-Site 9.64 9.88 10.34 11.65 SSM-2 on-Site 8.8 9.7 10.2 10.45 SSM-3 on-Site 9.27 10.78 11.35 11.45 KOW-1 on-Site 11.32 KOW-2 on-Site 11.76 KOW-3 on-Site 10.6 MW-1 off-Site 8.32 7.78 MW-2 off-Site 9.64 9.25 MW-3 unk 10.52 Notes SSM-Service Station Maintenance Corporation Briggs- Briggs Associates, Inc. Cooperstown -Cooperstown Environmental, LLC Kurz- Kurz Associates, Inc. Stantec ATTACHMENTS Attachment A Soil Boring Logs Design with community in mind BORING LOG Well No. SSA — Dlgsafe No Date Driller County Nor4l1l Use 1140Nr7'c -/'" Location Mnr.N' Ar,rOrrrn/ W4rOr- rvw Owner rvlllle/rri r Address r� ^r_ Drilling Methor+ 14111/1e1 <fP ,4,,0., Sampling Method 7 " r Hole Diameter Z/ /� Total Depth do CASING Typo c , 11> UO D v C Diameter a Length SCREEN Types G ! P��1 UD +'� Slot 4.0 �- Diameter -P Length Gravel Pack Si7P Casing Seal &W&W,-o- Static Water Level Geologic Formation r--1 t'. Gate Sox SOIL PROFILE IDENTIFICATION OF SOIL AND REMARKS — Ground Elevation \ / / Thickness of Surface Sea! Type of Surface Seal I , /•�mPn�'(' ( ( 2- /2 CoR,�S �•!�//G /=.. Goa Inside Diameter of PiNo ► / IIDiameter of Borehole --�+ I 12- Z o r CO hh�PS R^IG f Sa� fli' S C l 4 Bentonits Sealav / o� 1 DeOth to Too of Wellpoim I' ; Backtill Around Wellpoi Type of Well Point �►—,;.._. Z Inside Diameter of Wellpoint— s� Depth to Bottom of 1 Wellpoim Below Surface�.:►��:-:: I Bottom of Boring BORING LOG Well Na. 1 M - l7tgsats Mr, -�'��.+.j..+ �- � Gnu' 1� Cate Drilled � County �Ia Use Location `_s A _t,r.t /7 ht,:aJ '-7t J.41.4 - -_4*,oj ±A (Owner •k �rNrltd{ I�AJr?±rC tr+r Address i■� Cnlling Method lL//1:„ Sampling Methoe+ ■ Hcle Diameter ` Total Depth CASING = Type G'11m8tG! ;_'' •: Lit; gth SCREEN s:�'°.�y.d{af .r+ r�i.l f�. I7 f. ,'1 a�'Ltx� 'f Type Slot _ Diameter Le:tgt 1h _ t;rL'rel P3C1£ rJ`IF"'. Cfl5Et7g S$s'1.l ' ta*fiC Wator Level 1-4 GIiaoltJgic Formation aaLA Box 5CIL PROFILE IOEN71FICATION OF SOIL AND REMARKS �y y • ra'-_i� .'/-f�,' .f(',r.�}f)}' ;f P.�aJf?a i rnaenasa of Su:raca S®al ryLpa ci surrawe seat 17- I Lei J yr' -„F',( '✓J',fl"_'f+M'r' �.r na:ca Diameter d Poe C@ametw of Bereclo -�s+ 4 4 W -ta0 s+n[onrte Seal f,' �m L 1 ,T,•Duotlt iv 'cm or'a4uslmimt---� _;:°. - 3ac"11 Arrunc 'Msiboi YFa or Wall Pr. t la,.(t� t�iarrletar rt`Nallpa:n[��� t i9G.1n:l] fsortOPfl G^t L` _%acm of Banns F _ . COOPERSTOWN ENVIRONMENTAL, LLC SOIL BORING/MONITORING WELL FIELD LOG 'MW/uuSB,,NIle.: Dolling Lacalion: / ���[� IProtecVCiient: KYCArI IPmleot No.: ■{^�� �,� IM. St la/a�r[v►`�YW� ISdec.raina: / Contractor, /1 Nft -a Site Lacatmn IPID Baakgc(ppm)- Q�d crew b Data: 0 /�' if , 16, IPID Iomp lovl: J lll��,lll lima Slen: �1 yj �M Weather. e . ISurtace elevation(fl above at.point): Grill Methotl Fi triAti�s,! Tkn.End: 7 .on e.n Logged ey. {� ITOC Elevation(assays nor.point): SamPla M.Nod. -T'— J' Notes(Sutlaw Condition,SOli Sample Numbers,Soii Omms,etc) Sample Submission: y;Vi(lj mrver a.rev.ay samal.Nor Blow PID/FID Depth % M In D.vm counts (DDm) (rest) Soil Details Well Details 2 a 3 10 ART I _ nv,�zac o _ She. - 14 N oa4 _ 2 ti+tip .�fG'r' �..J S.•MC mdf ty - 24,,. -- - -- -- - 5 . ..28 - .- .. .. . 27 .. . 28 3031 A 32 33 38 36 37 38 I 39 40 4i 42 43 44 45 46 47 48 tnMiWllnn Wep Canslmclnn SeN Characknaalen IBormg Opopth: IWei 9la.(ID/D)): ty�^ "( IRsar Heghl: Conmele TranetlomeMavand wekoe the gppY Ceam Type:g.�PYL Looked: 111 Wali Casing - ): Pdmadly Sentl comments: wN 4,d1� Screen(O.gf slated) Pnmanly all �Y p er Send Pack(quetlz) Primarily Clay andante aedmek Cooperstoym Environmental,LLC Grout Heterogeneous Mixture 23 Main Stteel,Andover.MA 01810 COOPERSTOWN Depth to Groundwater iMatanal vain D Derstownenv.com environmental COOPERSTOWN ENVIRONMENTAL, LLC SOIL BORING/MONITORING WELL FIELD LOG MW/58N n IONIInp Local u � T - J�Pm1econnect 'Ptafecl Na.. MM , i+ 33 C,r—w-t�'^Sie Coma<f Cmuraciw C� � ISit.Luomioms.� I PID Backgr(ppm). �n crew: Dine: ,0 d /1r� I 33 ry{r° +)X. IPIDLamp(ev): Aso.(i �q Tlme Sian. g 1;11 „ Weeihoc �` 7d�� Surface Elevii(il above ref.it Dnil Meihod: C eo r T vPg jTim O e End: ;*1-1 Logged By Z F/ �TOG Elevation(ft above ref.point): Sample Meliu µ d S.�, ( ' Notes(Surface Candlil m,Soil Sample Numbers,Soil Drums,etc) Sample Submission /Oi/S H" onus nac.vaw Semple Ni Slow PIDIFID Dopih 4 ft. In Dal Counts (ppm) (feet) Soil Details Well Details 1 \ \\ 11 3 4 _. .. .. - . 5 8 —,e- _, .. - .... 9 12 Mq'GJ� C4' �� '•'WrN'K J"' / -' 4. —P/(F' .. -,. 15 I ` 14 .. . 15 17 19 20 21 22 23 24 25 -.-- - - - - 26 27 28 29 30 31 32 33 34 35 36 37 38 _ 39 40 41 -42 43 44 45 _ 46 47 48 -.._- _ma_eilerma Well caeaWagon Soil Cbaraand,salon BonngDepih (i�' wellaapDloo): w IRiearealghc ft- Commite Transitional Material IWail Depth: J�,�, ICesieg Type /Jy� jLakad: Wall Caseq " : Primarily SarM comments:��{,. pe r Scream(a 01 Monaco Pripanlysit Slj�ry} (t py� Sand Pack(quariz) �,�,.� Property Clay I antitank. asdrock Cooperstown Environmental,LLC crow Her........Mixture 23 Main Street,Andover,MA 01810 COOPERSTOWN Depthto Gr.urevothr Fin Material www.c000erstownenv.com e n v 'I r o n in e n t d I COOPERSTOWN ENVIRONMENTAL, LLC SOIL BORING I MONITORING WELL FIELD LOG MW ISB No Dnilmg Location' ProjmUclenl' ��� [Pmgadt Nc: I tf?L de tCe [SneC.rlat. Co0rac0" C� _ [Site Location: [Plosaagc(ppm) 0,n (Crew: Date' /001//1— 13 'ah4xx/(q INN Lamp(aV)• �, .6 ➢mo Stort: 3(t S� Weafbac �/V pG�y Surface Elavahon(Ilabov..LpomQ. 10nll Method' G uj 6nke Tlmo End: '/ � s, Logged By, (rF ITOC Elevation tit above ref.potn): [Sample Method �(�a _/ Natas(Surface Contlibon,See Sampla NYmbere,$ad Omms,atc) Sample Submission: ZOZOO" r O"ry ee Death I Blow Pppm) (feet) `R fl In Dapti, Counts (npm) ((Bet) SOIl0elags WBII Details _. - 1 . ..4. .. 61 S 6 9 Ir, I l 12 _r ;4. 15 Zj 16 L.. 21 22 . . . .. .. . .- _. ._ .. I 23 24 25 26 .. ._ ,_..._... . _ 27 29 2B 30 - 37 32 33 35 36 .....37..... 38 39 40 41 42 44 45 46 47 49 kVitorina Well Conalrellon SpACharactemouoa Bodog Doom' an (Wall D.,(0100): y" IMee,Helghl. Conant Transitional Material (Well Depth: 6' G Caamg Type: µeaed: Weil Casingl Pnmanly Sand Comments .` Screen i.slotted) prior ly Sill Sand Peak(quada) P:arlly Cley •,.•:.w 8.1.0le sedmck Cooperstown Environmental,LLC roin Helai-W.neouaMixture �23 Main Street,Andover,MA01810 COOPERSTOWNpj:,i{ Nall,to Groundvaler Fill Maleriel www.coo0erstownenv.com e n v i r o n men t a t TEST BORING LOG SHEET 1 Kurz Environmental, Inc DRILLER: BORING NO. KOW-1 Environmental Scientists P.O. Box 358 Sherborn, MA01770 SITE: 33 Mt. Auburn St. PROJECT NO. Watertown, MA DATE: 9/5/2017 Ground Elevation: GROUNDWATER OBSERVATIONS Date Started: 9/5/17 ( DATE I DEPTH CASING STABILIZATION Date Finished: 9/5/17 Driller: Soil Engineer/Geologist:LMK Depth Casing Sample Visual Identification Ft. bI/ft No. Fen/Rec Depth PID Result Strata of Soil and/or Rock Sample Brown to black coarse sand and gravel (FILL), some cobbles. Concrete fragments, ash noted. 1 3' 0.5 Brown to black medium to coarse sand and gravel 5 (FILL)to approx. 7 fbg, moist. 4' 0.3 10 Tan to gray fine to medium sand, intermittent lenses 4' of coarse sand to 20 fbg. Trace gravel, trace silt.Wet 1.1 at—13 feet. Sample (12—14) collected from groundwater interface for laboratory analysis. 15 5' 0.6 20 25 30 35 Notes: Monitoring well installed to approximately 20 fbg. Cohesionless: 0-4V.Loose, 4-101-oose, Trace 0to 10% CASING SAMPLE CORETYPE 10-30MDense, 30-SODense, 50+VDense. Little 30 to 20% ID SIZE(IN) Cohesive: 0-2VSoft, 2-4 Soft, 4-RMStiff Some 20 to 35% HAMMERWGT(LB) R-1Swff 1R-4nv Sti 9596 to Sn96 HAMMER FALL(IN) TEST BORING LOG SHEET 1 Kurz Environmental, Inc DRILLER: BORING NO. KOW-2 Environmental Scientists P.O. Box 358 Sherborn, MA01770 SITE: 33 Mt. Auburn St. PROJECT NO. Watertown, MA DATE: 9/5/2017 Ground Elevation: GROUNDWATER OBSERVATIONS Date Started: 9/5/17 DATE DEPTH CASING STABILIZATION Date Finished: 9/5/17 Driller: Soil Engineer/Geologist: LMK Depth Casing Sample Visual Identification Ft. bl/ft No. Pen/Rec Depth PID Result Strata of5oil and/or Rock Sample Brown to black coarse sand and gravel (FILL), some 1 cobbles. Concrete fragments noted. 2' 0.3 Brown to black medium to coarse sand and gravel, 5 trace silt (FILL)to approx.8 fbg, moist. 3' 0.2 10 Tan to gray fine to medium sand, intermittent lenses 4.5' of coarse sand to 20 fbg.Trace silt.Wet at—13 feet. 0.7 Sample (12—14) collected from groundwater interface for laboratory analysis. 15 4.5' 0.3 20 ii 25 30 35 Notes: Monitoring well installed to approximately 20 fbg. Cohesionless: 0-4 V.Loose, 4-10 Loose, Trace 0to 10% CASING SAMPLE CORE TYPE 30-30 M Dense, 30-50 Dense, 50+V Dense. Little 10 to 20% ID SIZE(IN) Cohesive: 0-2 VSoft, 2-4 Soft, 4-8 MStiff Some 20 to 35% HAMMERWGT(LB) R-tSGHff t5-Inv Cti I;%to Sn-A HAMMFRFALLIINI TEST BORING LOG SHEET 1 Kurz Environmental, Inc DRILLER: BORING NO. KOW-3 Environmental Scientists P.O. Box 358 Sherborn, MA 01770 SITE: 33 Mt. Auburn St. PROJECT NO. Watertown, MA DATE: 9/5/2017 Ground Elevation: GROUNDWATER OBSERVATIONS Date Started: 9/5/17 DATE DEPTH CASING I STABILIZATION Date Finished: 9/5/17 ) Driller: ' Soil Engineer/Geologist: LMK Depth Casing Sample Visual Identification Ft. bi/ft No. Pen/Re. Depth PID Result Strata of Soil and/or Rock Sample Tan to dark gray coarse sand and gravel (FILL), some cobbles. Concrete,ash, glass noted. 1 0.3 2.0' Tan to black medium to coarse sand and gravel,trace 5 silt(FILL) to approx. 8 fbg, moist. Minimal recovery. 1.0' 0.3 10 Tan to gray fine to medium sand, intermittent lenses 4.0' of coarse sand to 20 fbg. Trace silt,gravel. Wet at—13 0.4 feet. Sample(12—14) collected from groundwater interface for laboratory analysis. 15 5.0' 0.2 20 25 30 35 Notes: Monitoring well installed to approximately 20 fbg. Cohesionless: 0-4V.Loose, 4-101-oose, Trace 0to 10% CASING SAMPLE CORETYPE 10-30M Dense, 30-50 Dense, 50+V Dense. Little 10to20% ID SIZE(IN) Cohesive: 0-2VSoft, 2-4 Soft, 4-8 M Stiff Some 20to35% HAMMERWGT(LB) A-iSStiff 15-30V.Stiff. 30+Hard And 3S%tn 50% HAMMER FALL(IN