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Home My WebLink AboutSW3231104_Soils/Geotechnical Report_20240730 May 3, 2023 SUMMIT Mr. Joseph Pace ENGINEERING • LABORATORY•TESTING Roman Catholic Diocese of Charlotte A Universal Engineering Sciences Company 1123 South Church Street Charlotte, NC 28203 Email: JAPace@rcdoc.com Subject: Estimated Seasonal High Water Table (ESHWT) Determinations Holy Spirit Catholic Church 537 NC-16 Business Denver, North Carolina SUMMIT Project No. 3944.G0579 Dear Mr. Pace: SUMMIT Engineering, Laboratory and Testing, Inc. (SUMMIT) is pleased to submit this letter summarizing our observations of the soil test borings as related to Estimated Seasonal High Water Table Elevation (ESHWT) determinations in the proposed stormwater BMP ponds to be constructed for the proposed project listed above. This report contains a brief description of the project information provided to us, general site and subsurface conditions revealed during this exploration. PURPOSE OF EXPLORATION The primary purpose of this exploration was to obtain information regarding the subsurface conditions in the proposed stormwater BMP ponds, assess the engineering characteristics of the subsurface materials, and determination of the estimated seasonal high water table mark (if evident). 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com Summary of ESHWT Determinations SUMMIT Project No. 3944.G0579 Holy Spirit Catholic Church May 3, 2023 This report contains the following items: • Site Vicinity Map and Boring Location Plan, • Summary of Test Boring Observations, visual soil classifications and descriptions, • A general review of the subsurface soils and estimated seasonal high water table depth from existing ground surface (if evident), • Groundwater level measurements. EXPLORATION PROCEDURES SUMMIT visited the site on April 26th, 2023 and performed two (2) soil test borings (identified as SW-10 and SW-11) in the proposed stormwater BMP ponds. The approximate locations of the borings are shown on Figure 2 — "Boring Location Plan" provided in Appendix 2. The client (Roman Catholic Diocese of Charlotte) provided SUMMIT a plan sheet titled "Phase I Site Plan" prepared by William Heyer Architect, dated March 9, 2023 that indicated the approximate locations of the proposed stormwater BMP ponds. The borings were located by professionals from our office using the provided plan, recreation-grade handheld GPS, existing topography, and aerial maps as reference. Since the boring locations were not surveyed, the location of the borings should be considered approximate. We recommend the actual boring location be surveyed to determine the actual boring location and existing ground elevation. The soil test borings were performed using an ATV-mounted CME 550X drill rig. Borings SW-10 and SW-11 were extended to approximate depths of 10 feet below the existing ground surface. Hollow-stem, continuous flight auger drilling techniques were used to advance the boring into the ground. Standard Penetration Tests (SPT) were performed within the mechanical boring continuously to the termination depth in general accordance with ASTM D 1586. When properly evaluated, the SPT results can be used as an index for estimating soil strength and density. In conjunction with the penetration testing, representative soil samples were obtained from the test location and returned to our laboratory for visual classification and potential laboratory testing. The soil samples collected were visually examined and classified in general accordance with ASTM D-2488. The Munsell Soil Color Charts (2009 Revision) were used to identify the hue, value, and chroma of soil samples. Water level measurements were attempted at the 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com Summary of ESHWT Determinations SUMMIT Project No. 3944.G0579 Holy Spirit Catholic Church May 3, 2023 termination of drilling. The classification symbols are depicted on the "Boring Log" provided in Appendix 2. GENERALIZED SUBSURFACE STRATIGRAPHY General subsurface conditions observed during our geotechnical exploration are described herein. For more detailed soil descriptions and stratifications at the test location, the respective "Boring Log" provided in Appendix 2 should be reviewed. The horizontal stratification lines designating the interface between various strata represents approximate boundaries. Transitions between different strata in the field may be gradual in both the horizontal and vertical directions. Beginning from the ground surface, a layer of topsoil (surficial organic soils) was observed in Boring SW-11 with a thickness of approximately 3 inches. Fill (disturbed) soils were encountered beneath the topsoil or at ground surface that consisted of Elastic Silts (MH). Beneath the fill soils, residual (undisturbed) soils were encountered that consisted of elastic silts (MH) and sandy silts (ML). Partially Weathered Rock (PWR) and auger refusal materials were not encountered in the borings. GROUNDWATER LEVEL MEASUREMENTS At the time of drilling, groundwater was not observed in the borings. After waiting more than 24 hours, water was not observed in the borings. It should also be noted that groundwater levels tend to fluctuate with seasonal and climatic variations, as well as with some types of construction operations. Therefore, water may be encountered during construction at depths not indicated in the borings performed for this exploration. ESTIMATED SEASONAL HIGH WATER TABLE ESHWT is defined as the shallowest depth to a wet soil layer as a result of"true" or "permanent" groundwater at any time during the year. The ESHWT is typically identified with a change in the color of the soil layer due to water staining (typically, gray redoximorphic depletions and 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com Summary of ESHWT Determinations SUMMIT Project No. 3944.G0579 Holy Spirit Catholic Church May 3, 2023 mottling). Spots or blotches of different color or shades of color interspersed with a dominant color in soil, commonly referred to as mottling. Mottling is a historic indication for the presence of groundwater caused by intermittent periods of saturation and drying, and may be indicative of poor aeration and impeded drainage. Mottling is a "general indication of groundwater" flow through this layer, but it is not known whether the groundwater flow was recent. CONCLUSIONS Based on our observations, ESHWT indicators were evident in soils sampled in Borings SW-10, and were not evident in soils sampled in Boring SW-11. Please note that even though ESHWT indicators were not evident in Borings SW-and SW-, perched water conditions can develop above a low permeable material such as partially weathered rock (PWR). Perched water conditions differ from the "true" or"permanent"water table.A perched water table is water standing above an unsaturated zone and is often influenced by soil conditions, and occurrence of less permeable soils. Where the ESHWT is defined as the shallowest depth to a wet soil layer as a result of"true" or "permanent" groundwater at any time during the year. The BMP designer should take into consideration that perched water conditions may exist above the low permeable PWR stratum. The following table summarizes the results of the borings and our observations. Summary Table of the Boring Results and Our Observations Approx. GW Depth Approx. Auger Boring ESHWT GW Depth After PWR Refusal Test Depth Depth ATD 24 Hours Depth Depth Location (Feet)1 (Feet)1 (Feet)1 (Feet)1 (Feet)1 (Feet)1 SW-10 10 8 NE NE NE NE SW-11 10 NE NE NE NE NE 1 Depths from existing ground surface. NE — Not Encountered in boring The analyses submitted in this report were based, in part, on data obtained from this exploration. If the above-described project conditions are incorrect or changed after the issuing of this report, 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com Summary of ESHWT Determinations SUMMIT Project No. 3944.G0579 Holy Spirit Catholic Church May 3,2023 or subsurface conditions encountered during construction are different from those reported, SUMMIT should be notified and these recommendations should be re-evaluated based on the changed conditions to make appropriate revisions. We have prepared this report according to generally accepted geotechnical engineering practices. No warranty, express or implied, is made as to the professional advice included in this report. CLOSING SUMMIT appreciates the opportunity to provide our professional services for you on this project. If you have any questions concerning the information in this proposal or if we may be of further service, please contact us at 704.504.1717. Sincerely, SUMMIT ENGINEERING, LABORATORY&TESTING, INC. \\\��•\ \\\ CAR° /// � ��,,��. cjik /N9 SEAL 052284 - = • SUMMIT • .„x°,a a cue _m . Engineering,Laboratory : oz < ' .F 3/2023 �. . � �•• &Testing,Inc. ; h /VGINE �, i • No.F 1454 • / ` ilk. OF AV��O`\• 6,u C'o w2Q- L. Brian Cantrell, P.E. Christian Payne Geotechnical Dept. Manager Assistant Project Manager LIST OF APPENDICES Appendix 1 Figure No. 1—Site Vicinity Map Figure No. 2— Boring Location Plan Appendix 2 Boring Logs 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com Summary of ESHWT Determinations SUMMIT Project No. 3944.G0579 Holy Spirit Catholic Church May 3, 2023 SUMMIT ENGINEERING • LABORATORY • TESTING A Universal Engineering Sciences Company APPENDIX 1 Figures 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com icoat Company ai Lake Norman I Professional... Puppy Planet 0 16 cL 0tj NaG Water Oaks Or Water Oaks Or Miller Pipeline 9 0 45 Townsend M Townsend wnsend Dr Dr Carolina Boat and railer Boa dealer Eagle Wood 4? SITE IPHoly S.irit Cathol c Church 9 West Harbor Insurance Services One Church Minis ies 9 9westLak 9 Loftis Mini Storage Holy Spirit Catholic Churchijah Figure 1 537 NC-16 Business Site Location Plan Denver, North Carolina SUMMIT A UN. W rny'VnYp Woven 4owpnn/ 3575 Centre Circle SUMMIT Project No.: 3944.G0579 Fort Mill,South Carolina 29715 SCALE: NTS (803)504-1717 /; ' I/. -_---� -_- APPROXIMATE PROPERTY UNE y� �yy ` _' --- if / — SRE}. I 9 / 40 40 10 40 44 4k*-4` ]y1'` 41 w 14 i•! 9P # 44 41 44 40 10 1� 41 40 ,,,r BLDG r.y1 r '.., II ��I EXIST IXI' ,RFIC:=POND % ;/ >\ �/ , C 6/ ; Q II — BLDG I_ II i i" J I ,II i _ r EXIST STORM I i i / , r y' PIPES SHOWN I 4 ./ I II-- 5 7 ill: AREA PLAN u - / /. ' r 0 El El 1 II 1 I NTS /r L_— o---JI PARKING ANALYSIS /rr II I 6. I to 1 V_CHURCH CAPACITY(PER CODE CALC) 685 i rr /• 20 —— 3 SPACES BASED ON DEVELOPMENT STANDARDS 229 /r . -`" /r I e R 3 IN LARGEST ASSEMBLY HALL) / / 19 EXISTING 'DSED SPACES 291 / /r( II .PAC _ ; USIVE OF EXISTING SPACE) r ' r II USIVE OF ACCESSIBLE SPACES) . II J ,� EXIST STORM ` II 3 ACCESSIBLE SPACES(216) S '` 't P PES S • It9 'OSED ACCESSIBLE SPACES 18 ——— 0 — — EXIST V .. .. .• eLnG LAWN II o is 6i V i+-7* �,. U ———� • 41111?- Lliko 0 / \ I I ® \ � ' `� PROPOSED - /, , (\f_-�\ �Y CHURCH `>< / *19 -(rrI / II 4S // U Eel �+4 2 # 10 10 ,0 / / \ / EXISTING 6O ® PARISH BLDG ? \..... s / ENTRY PLAZA Q # ED I 15 /--,o \ n II k., \ 2 /9 II ,, II J , //////////2/////////// o611 �\ 111.7—pm I ED SW-11 ��=- et o r 1 --- ia • ` M�� 1. I I. � ---r�--ter-.. W 1• _�s� -=--r- °-"' — - PHASE I SITE PLAN 0 II�� II SCALE:1"=0'0" AM HEYER ARCHITECT HOLY SPIRIT CATHOLIC CHURCH /L ENT. F.com OHiiiiiiL 0 AR w OM 37 N HIGHWAY 16,DENVER,NC 28037 Figure 2 Holy Spirit Catholic Church /1.11 Boring Location Plan 537 NC-16 Business SUMMITDenver, North Carolina .,m.4-I.MAN.r-TC'}Tti[ Approx. Soil Test Boring Location ctl.a16IE•tf46'9 kIA9NCo.P.rV 3575 Centre Circle SUMMIT Project No.: 3944.G0579 Fort Mill,South Carolina 29715 SCALE: NTS (803)504-1717 Summary of ESHWT Determinations SUMMIT Project No. 3944.G0579 Holy Spirit Catholic Church May 3, 2023 SUMMIT ENGINEERING • LABORATORY • TESTING A Universal Engineering Sciences Company APPENDIX 2 Boring Logs 3575 Centre Circle Drive, Fort Mill, SC 29715 summit-companies.com SUMMIT ENGINEERING KEY TO SYMBOLS /MIK 3575 CENTRE CIRCLE FORT MILL,SC 29715 SUMMIT 704-504-1717 .,.maiEti...E,soon..,Company CPAYNE@SUMMIT-COMPANIES.COM CLIENT Roman Catholic Diocese of Charlotte PROJECT NAME Holy Spirit Catholic Church PROJECT NUMBER 3944.G0579 PROJECT LOCATION Denver, North Carolina LITHOLOGIC SYMBOLS SAMPLER SYMBOLS (Unified Soil Classification System) Standard Penetration Test ■ ASPHALT: Asphalt BLANK I FILL: Fill (made ground) tin GW: USCS Well-graded Gravel liffi MH: USCS Elastic Silt MLS: USCS Sandy Silt TOPSOIL: Topsoil WELL CONSTRUCTION SYMBOLS ABBREVIATIONS LL -LIQUID LIMIT(%) TV -TORVANE PI -PLASTIC INDEX(%) PID -PHOTOIONIZATION DETECTOR W -MOISTURE CONTENT(%) UC -UNCONFINED COMPRESSION DD -DRY DENSITY(PCF) ppm -PARTS PER MILLION NP -NON PLASTIC v, Water Level at Time -200 -PERCENT PASSING NO. 200 SIEVE Drilling, or as Shown PP -POCKET PENETROMETER(TSF) Water Level at End of 1 Drilling, or as Shown w Water Level After 24 Hours, or as Shown // SUMMIT ENGINEERING BORING NUMBER SW-10 lik 3575 CENTRE CIRCLE FORT MILL,SC 29715 PAGE 1 OF 1 SUMMIT 704-504,1 7 1 7 <�M,.olEr,E,..Hnq �Co m CPAYNE@SUMMIT-COMPANIES.COM CLIENT Roman Catholic Diocese of Charlotte PROJECT NAME Holy Spirit Catholic Church PROJECT NUMBER 3944.G0579 PROJECT LOCATION Denver, North Carolina DATE STARTED 4/26/23 COMPLETED 4/26/23 GROUND ELEVATION HOLE SIZE 6 inches DRILLING CONTRACTOR SUMMIT GROUND WATER/CAVE-IN: DRILLING METHOD Hollow Stem Auger AT TIME OF DRILLING ---GW NE ATD LOGGED BY J Parrish CHECKED BY C.Payne AT END OF DRILLING ---GW NE>24 hrs NOTES See Figure 2"Boring Location Plan"for Approx. Boring Location AFTER DRILLING --- w o A SPT N VALUE A 0 U >-ct } cow 0 20 40 60 80 100 _ I—w EC^ Hn It Q ,..,1- O MATERIAL DESCRIPTION J 2 >of �O n Q I M " J o O. m O> 0 20 40 60 80 100 (3 2z () oz w < ❑FINES CONTENT(%)❑ co 0 20 40 60 80 100 :.: (MH)FILL: -$5 Firm Red(10R,4/6)Sandy Elastic SILT _ - �_�♦_ SPT 4-2-3-5 I I 1 (5) Firm Red(10R,4/6)Sandy Elastic SILT (ML)Stiff Moist Red(10R,5/8)Slightly Clayey Sandy SILT SPT 2-4-8-11 2 (12) (ML)Firm Red(10R,5/8)Slightly Clayey Sandy SILT s.o SPT 2-3-5-5 3 (8) (ML)Firm Red(10R,5/8)Slightly Clayey Sandy SILT with Manganese Stains SPT 3-4-4-5 4 (8) (ML)Firm Red(10R,5/8)and white(7.5YR,9.5/1)Slightly Clayey Sandy SILT with Manganese Stains SPT 2-2-3-4 5 (5) 10.0 Bottom of Boring at 10 feet bgs, Boring Terminated 15.0 20.0 // SUMMIT ENGINEERING BORING NUMBER SW-11 lik 3575 CENTRE CIRCLE FORT MILL,SC 29715 PAGE 1 OF 1 SUMMIT 704-504-1717 <�M,.olEr,E,..Hnq ScioneasCompany CPAYNE@SUMMIT-COMPANIES.COM CLIENT Roman Catholic Diocese of Charlotte PROJECT NAME Holy Spirit Catholic Church PROJECT NUMBER 3944.G0579 PROJECT LOCATION Denver, North Carolina DATE STARTED 4/26/23 COMPLETED 4/26/23 GROUND ELEVATION HOLE SIZE 6 inches DRILLING CONTRACTOR SUMMIT GROUND WATER/CAVE-IN: DRILLING METHOD Hollow Stem Auger AT TIME OF DRILLING ---GW NE ATD LOGGED BY J Parrish CHECKED BY C.Payne AT END OF DRILLING ---GW NE>24 hrs NOTES See Figure 2"Boring Location Plan"for Approx. Boring Location AFTER DRILLING --- w o A SPT N VALUE A 0 U } ci w 0 20 40 60 80 100 I-w �^ H� L"O MATERIAL DESCRIPTION J 2 >of �O n Q J a O. m O> 0 20 40 60 80 100 (3 2z () oz w < ❑FINES CONTENT(%)❑ 0 20 40 60 80 100 �;\ Approx.3"of Topsoil 7 - (MH)�i�i�i �.�.�. FILL: SPT 2-2-2-2 Soft Red(10R,4/6)Sandy Elastic SILT / 1 (4) (MH)RESIDUUM:: Soft Red(10R,4/6)Sandy Elastic SILT (MH)FILL: Stiff Red(10R,4/6)Sandy Elastic SILT SPT 2-4-5-6 2 (9) (MH)FILL: s.o Very Stiff Red(10R,4/6)Sandy Elastic SILT with Rock SPT 2-12-12-14 Fragments 3 (24) (ML)RESIDUUM: Soft Moist Red(10r,5/8)Slightly Clayey Sandy SILT SPT 2-2-2-3 4 (4) • (ML)Firm Moist Red(10r,5/8)and White(7.5Y,9.5/1)Slightly Clayey Sandy SILT SPT 1-2-3-3 5 (5) 1 0.0 Bottom of Boring at 10 feet bgs, Boring Terminated 15.0 20.0