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HomeMy WebLinkAboutSW6191102_Wright-McPhail SHWT rpt_2/15/2020Southeastern Soil & Environmental Associates, Inc. P.O. Box 9321 Fayetteville, NC 28311 Phone/Fax (910) 822-4540 Email mike@southeastemsoil.com February 14, 2020 Mr. Jeff Wright Southeastern Construction of Rockfish 771 Bostic Road Raeford, NC 28376 Re: Hydraulic conductivity (permeability) analysis & seasonal water table determination (SHWT) for proposed stormwater control areas, McPhail Meadows Subdivision, off Pittman Grove Church Road, Hoke County, North Carolina Dear Mr. Wright, An evaluation of soil properties and hydraulic conductivity (Ksat) has been conducted at your request on portions of the aforementioned property (see attached map by Hilliard Engineering, PLLC). The purpose of the investigation was to determine seasonal soil water table depths (SHWT) based on soil profiles. In addition, Ksat was to be provided at a depth of approximately 2.0 feet below the ground surface (at least 2.0 feet above the SHWT elevation) for use with stormwater control calculations/design. Saturated hydraulic conductivity of the unsaturated zone was measured in a similar method as described in the Soil Science Society of America Journal, Vol. 53, no 5, Sept. - Oct. 1989, "A Constant Permeameter for Measuring Saturated Hydraulic Conductivity of the Vadose Zone" and Comparison of the Glover Solution with the Simultaneous Equations Approach for Measuring Hydraulic Conductivity." This consists of advancing a small diameter bore hole to a predetermined depth (typically 2 feet above SHWT). At this depth, a constant head (pressure) was established and maintained. Flow measurements were made at timed intervals after flow stabilized. Soils at the tested sites are most similar to the Wagram soil series (borings TS 2, TS 3 & 'TS 6 as identified on the enclosed map). Three borings were advanced to at least 6.0 feet below the soil surface. Seasonal High -Water Table (SHWT) as determined by evidence of colors of chroma 2 or less (and/or concentrations of high redox mottles) was encountered at depths ranging from 46 to 56 inches below the ground surface (see chart attached). SOIL/SITE EVALUATION • SOIL PHYSICAL ANALYSIS • LAND USE/SUBDlViSION PLANNING • WFTLANDS GROUNDWATER DRAINAGE/MOUNDING • SURFACFISUBSURFACE WASTE TREATMENT SYSTEMS, EVALUATION & DESiGN Three compact constant head permeameter (CCHP) tests were conducted at depths of at least 2.00 feet above the SHWT level. The measured Ksat rates ranged between 0.51 and 7.98 cm/hr (equivalent to 0.20 to 3.14 inches/hour). The attached map shows locations of the sample points as well as Ksat locations. It should be noted that the reported SHWT does not necessarily reflect the elevation of static groundwater (due to variations in groundwater recharge rates, annual rainfall, drought conditions, etc.). The data presented in this report are limited by a number of considerations. The primary consideration is that soil formations can be highly variable. The soils found on this site can be subject to inclusions of other soil types, perched water, artesian conditions and/or layers of undulating low permeability clay seams. These and other soil conditions can have an effect on the steady state of groundwater flow. To the extent possible, we have identified the soil types that will impact the flow of groundwater, and have provided a professional opinion as to the depth of SHWT. I trust this is the information you require at this time. Sincerely, A*Agz:-- Mike Eaker NC Licensed Soil Scientist ##1030 Southeastern Soil & Environmental Associates, Inc. P.O. Box 9321 Fayetteville, NC 28311 Phone/Fax (910) 822-4540 Email mike@southeastemsoii.com Measured Ksat Rates, McPhail Meadows, Pittman Grove Church Road, Hoke County, NC Ksat Ksat Location Depth in cm/hr in/hr TS 2 30 2.66 1.05 TS 3 29 0.51 0.20 TS 6 22 7.98 3.14 SOILJSITE EVALUATION • SOIL PHYSICAL ANALYSIS • LAND USE/SUBDIVISION PLANNING • WETLANDS GROUNDWATER DRAINAGE/MOUNDING • SURFACE/SUBSURFACE WASTE TREATMENT SYSTEMS, EVALUATION & DESIGN Southeastern Soil & Environmental Associates, Inc. P.O. Sox 9321 Fayetteville, NC 28311 Phone/Fax (910) 822-4540 Email mike 4southeastemsoil.com SHWT depths, McPhail Meadows Subdivision, Pittman Grove Church Road, Hoke County, NC BORING SHWT DEPTH (inches) Observed Water (inches} TS 2 56 36 TS 3 53 60 TS 6 46 53 Note: Observed water in boring TS 2 is above SHWT. This is a temporary condition related to recent rainfall and landscape position (not SHWT; no redoximorphic features observed above 56 inches below ground surface). SOIUSITE EVALUATION • SOIL PHYSICAL ANALYSIS • LAND USEISUBDIVISION PLANNING • WETLANDS GROUNDWATER DRAINAGE/MOUNDING • SURFACE/SUBSURFACE WASTE TREATMENT SYSTEMS, EVALUATION & DESIGN Southeastern Soil & Environmental Associates, Inc. P.O. Box 9321 Fayetteville, NG 28311 Phone/Fax (910) 822-4540 Email mike@southeasternsoil.com Soil Boring Log (TS 2), McPhail Meadows Subdivision, Pittman Grove Church Road, Hoke County, NC This reap unit consists of well drained soils that formed in loamy sediment on uplands. Slope ranged from I to 3 percent. A - 0 to 13 inches; very dark brown (I OYR 2/2) loamy sand; single grained; loose; very friable; common fine and medium roots; abrupt smooth boundary. E - 13 to 22 inches; yellowish brown (I OYR 5/6) sandy loam; weak fine granular structure; very friable; few fine and medium roots; clear smooth boundary. Bt - 22 to 56 inches; yellowish brown (1 OYR 5/6) sandy clay loam; moderate medium to weak fine subangular blocky structure; firm; gradual wavy boundary. BC - 56 to 66 inches; yellowish brown (IOYR 5/6) sandy loam; many medium prominent light gray (1OYR 7/1) mottles; weak fine subangular blocky structure; friable; gradual diffuse boundary. CI - 66 to 75 inches; light gray (I OYR 7/1) coarse loamy sand; many medium prominent brownish yellow (I OYR 6/6) mottles; massive structure; very friable. SHWT @ 56 inches (10YR 7/1) SOIUSITE EVALUATION • SOIL PHYSICAL ANALYSIS , LAND USE/SUBDIVISION PLANNING • WETLANDS GROUNDWATER DRAINAGE/MOUNDING • SURFACE/SUBSURFACE WASTE TREATMENT SYSTEMS, EVALUATION & DESIGN Southeastern Soil & Environmental Associates, Inc. P.O. Box 9321 Fayetteville, NC 28311 Phone/Fax (910) 822-4540 Email mike0southeasternsoil.com Soil Boring Log (TS 3), McPhail Meadows Subdivision, Pittman Grove Church Road, Hoke County, NC This map unit consists of well drained soils that formed in loamy sediment on uplands. Slope ranged from 1 to 3 percent. A - 0 to 6 inches; dark brown (1 OYR 3/3) loamy sand; single grained; loose; very friable; common fine and medium roots; abrupt smooth boundary. E - 6 to 25 inches; yellowish brown (2.5Y 6/6) loamy sand; weak fine granular structure; very friable; few fine and medium roots; clear smooth boundary. Btl - 25 to 36 inches; strong brown (7.5YR 5/8) sandy clay loam; moderate medium to weak fine subangular blocky structure; firm; gradual wavy boundary. Bt2 - 36 to 53 inches; strong brown (7.5YR 518) sandy clay loam; many medium prominent brownish yellow (10YR 6/6) mottles; weak fine subangular blocky structure; firm; gradual diffuse boundary. BC - 53 to 65 inches; mottled strong brown (7.5YR 5/8) and brownish yellow (1 OYR 6/6) sandy clay loam; many medium prominent light gray (I OYR 7/1) mottles; weak fine subangular blocky structure; firm; gradual diffuse boundary. C - 65 to 75 inches; mottled brownish yellow (I OYR 6/6), light gray (I OYR 7/1) and red (2.5YR 4/8) sandy clay loam; massive structure; firm. SHWT @ 53 inches (10YR 7/1) SOIL/SITE EVALUATION • SOIL PHYSICAL ANALYSIS o LAND LISE/SUBDIVISION PLANNING • WETLANDS GROUNDWATER DRAINAGE/MOUNDING • SURFACE/SLIBSURFACE WASTE TREATMENT SYSTEMS, EVALUATION & DESIGN Southeastern Soil & Environmental Associates, Inc. P.O. Box 9321 Fayetteville, NC 28311 Phone/Fax (910) 822-4540 Email mike@southeasternsoil.com Soil Boring Log (TS 6), McPhail Meadows Subdivision, Pittman Grove Church Road, Hoke County, NC This map unit consists of well drained soils that formed in loamy sediment on uplands. Slope ranged from 1 to 3 percent. A - 0 to 6 inches; dark brown (1 OYR 3/3) loamy sand; single grained; loose; very friable; common fine and medium roots; abrupt smooth boundary. E - 6 to 18 inches; yellowish brown (2.5Y 6/6) loamy sand; weak fine granular structure; very friable; few fine and medium roots; clear smooth boundary. BtI - 18 to 38 inches; yellowish brown (I OYR 5/8) sandy clay loam; moderate medium to weak fine subangular blocky structure; firm; gradual wavy boundary. Bt2 - 38 to 46 inches; brownish yellow (I OYR 6/6) sandy clay loam; many medium prominent strong brown (7.5YR 5/8) mottles; weak fine subangular blocky structure; firm; gradual diffuse boundary. BC - 46 to 60 inches; light yellowish brown (1 OYR 6/4) and light gray (I OYR 7/1) sandy clay loam; massive structure; firm; gradual diffuse boundary. C - 60 to 72 inches; mottled light yellowish brown (1 OYR 6/4), brownish yellow (1 OYR 6/6, light gray (10YR 7/1) and reel (2.5YR 4/8) sandy clay loam; massive structure; firm. SHWT @ 46 inches (I OYR 7/1) SOIUSITE EVALUATION ■ SOIL PHYSICAL ANALYSIS • LAND USEISUBDIVISION PLANNING • WETLANDS GROUNDWATER DRAINAGE/MOUNDING • SURFACE/SUBSURFACE WASTE TREATMENT SYSTEMS, EVALUATION & DESIGN r1 . ,y LOCATIONS ows —roc c R,, �, ,`,/