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Home My WebLink Aboutsoils reportSOILS REPORT AL OEN & ASSOCIATES, INC. SOIL & ENVIRONMENTAL SCIENTISTS P.O. Box 400, 266 Old Coats Road Lillington, NC 27546 -0400 Phone (910) 893 -8743 / Fax (910) 893 -3594 www.halowensoil.com 21 August 2012 Mr. Frank Weaver Allied Investors, Inc. Post Office Box 53786 Fayetteville, NC 28305 Reference: Soil Scientist Investigation For Stormwater Management The Summit — Section Four Dear Mr. Weaver, A site investigation has been conducted for the above referenced property, located on Boulder Drive and Copper Loop in The Summit residential subdivision, off of Alpine Drive (SR 1141), Barbecue Township, Harnett County, North Carolina. The purpose of this investigation was to provide a general characterization of the soils in the area proposed for a stormwater bioretention facility, including a determination of the depth to evidence of a seasonal high water table and estimation of the permeability of the various soil layers. In -situ hydraulic conductivity testing was also conducted. All soil determinations were made in accordance with the "North Carolina Stormwater Best Management Practice Manual" and Administrative Code Section: 15A NCAC 2H .1000. The materials at the site were described in accordance with the USDA Field Book for Describing and Sampling Soils. This report represents my professional opinion as a Licensed Soil Scientist. SOIL PROFILE DESCRIPTIONS Three soil profile descriptions were collected at the site at the locations indicated in Figure 1. Hand powered soil auger borings were utilized to make observations. The soil infiltration/permeability rates for the various soil horizons are estimations based on professional interpretation and not in -situ measurements. In -situ testing was conducted and is described in the following section "Hydraulic Conductivity Testing ". The following narrative describes the findings at the site and provides some insights and recommendations. A full description of each observation can be found attached to this report. Profile 1 was dug to a depth of 120 inches below ground surface. Soil morphological characteristics indicating a seasonal high water table (SHWT) were not observed within a depth of 120 inches. Infiltration rates (permeability) range from 2 to 6 in/hr in the sandy loam layer below 110 inches to as high as 6 to 10 in /hr in the loamy sand textured soils observed between the surface and 110 inches below surface. This site appears well suited for the proposed activity. Soil Science Investigations • Wetland Delineations, Permitting, and Consulting HAL OWEN & ASSOCIATES, INC. Figure 1. Locations of Soil Profile Descriptions and Hydraulic Conductivity Tests (>( Profile '1 C --- '°^_ 1B'CYL 3�.'w -„ i'r5�'nc E` .6C -VS6t Profile 2 rt � n! :e ' C �f 4 1 I Soil Science Investigations e Wetland Delineations, Permitting, and Consulting HAL OWEN & ASSOCIATES, INC. Profile 2 was dug to a depth of 120 inches below ground surface. Soil morphological characteristics indicating a seasonal high water table (SHWT) were not observed within a depth of 120 inches. Infiltration rates (permeability) range from 2 to 6 in/hr in the sandy loam layer between 70 and 120 inches to as high as 6 to 10 in/hr in the loamy sand textured soils observed between the surface and 70 inches below surface. This site appears well suited for the proposed activity. Profile 3 was dug to a depth of 90 inches below ground surface. Soil morphological characteristics indicating a seasonal high water table (SHWT) were not observed within a depth of 90 inches. Infiltration rates (permeability) range from 2 to 6 in/hr in the sandy loam layer between 70 and 120 inches to as high as 6 to 10 in/hr in the loamy sand textured soils observed between the surface and 70 inches below surface. This site appears well suited for the proposed activity. HYDRAULIC CONDUCTIVITY TESTING Hydraulic conductivity testing was conducted using a Compact Constant Head Permeameter (CCHP), specifically an Amoozemeter, by using the shallow well pump -in technique as detailed in the user's manual. Hydraulic conductivity results can vary, even within similar soils, depending on the temperature and composition of the water used, climatic conditions, proximity of the test layer to the water table, and other factors. Therefore, the results from one boring may not be indicative of the entire area. Hydraulic conductivity tests were performed within the soil layers located approximately 7 feet below surface. At Soil Profile 1, attempts to establish a constant head of water in the bore hole failed due to the high permeability of the soils; therefore, steady state was not reached and the hydraulic conductivity of the soil could not be calculated. At Soil Profiles 2 and 3, a constant head of water was established within each 3 cm radius bore hole, and readings were made of the rate of water flow from the meter until it appeared that steady state had been reached. The Glover Solution was used to calculate the hydraulic conductivity; where Ksat = A * Q, A = {sinh -1 (H/r) - [(r/H)2 + 1]1'2 + r/Hj /(21IH2), Q is the steady -state rate of water flow from the CCHP into the bore hole, H is the depth of water in the bore hole, and r is the radius of the bore hole. For detailed information about each test, please refer to the Ksat field datasheets that are attached. During the first test at Soil Profile 1, readings were made of the rate of water flow from the meter even though a constant head of water had not been established in the bore hole. After 45 minutes, water was flowing from the meter at a rate of 449280 cm3 /day (4.9 gal/hr) and the depth of water in the bore hole was less than 7 cm. A minimum depth of water of 15 cm is needed to calculate the hydraulic conductivity of the soil using the Glover Solution. Given the rate of water flow from the meter and the physical limitations of testing, it does not appear feasible to calculate the hydraulic conductivity of the soils in this area using an Amoozemeter. However, it is clear that the hydraulic conductivity at this site will exceed 365.76 cm /d (6.0 in /hr). Soil Science Investigations e Wetland Delineations, Permitting, and Consulting HAL OWEN & ASSOCIATES, INC. At Soil Profile 2, a three cm radius bore hole was advanced to a depth of 78 inches (198 cm). A constant head of water (H) was established in the bore hole with a depth of 15.5 cm, and the steady -state rate of water flowing from the meter (Q) was about 309960 cm3 /day. The saturated hydraulic conductivity (Ksat) of the soil layer is calculated as 312.13 cm /day (5.12 in /day) At Soil Profile 3, a three cm radius bore hole was advanced to a depth of 78 inches (198 cm). A constant head of water (H) was established in the bore hole with a depth of 18.5 cm, and the steady -state rate of water flowing from the meter (Q) was about 680400 cm3 /day. The saturated hydraulic conductivity (Ksat) of the soil layer is calculated as 527.99 cm /day (8.66 in /day). CONCLUSION Both sites appear very well suited to support dry detention basins. The soils exhibit a high rate of hydraulic conductivity and therefore can be expected to provide a high rate of infiltration into the soils below the basin. I appreciate the opportunity to provide this service and trust that you will feel free to call on me again in the future. If you have any questions or need additional information, please contact me at your convenience. P-r-_V" Sincerely, Hal Owen Licensed Soil Scientist Soil Science Investigations e Wetland Delineations, Permitting, and Consulting HAL OWEN & ASSOCIATES, INC. SOIL PROFILE DESCRIPTIONS FOR STORMWATER MANAGEMENT DEVICES CLIENT: Frank Weaver PROJECT NAME: The Summit PROPOSED FACILITY: Detention Basin LOCATION OF SI COUNTY: Harnett PROPERTY SIZE: EVALUATED BY: Hal Owen NC Licensed Soil Scientist EVALUATION METHOD: Auger Boring ®, Pit ❑ DATE EVALUATED: 12 October 2010 PROMI,F,: 1 HORIZON DEIPTH MATRIX MOTTLES TEXTURE STRUCTURE CONSIS- PERMEABIL NOTES TENCE ITY IN/HR A 0 -3 LS 2 M GR VFR 6.0-10.0 El 3 -52 Yellowish LS 2 M GR VFR 6.0-10.0 Brown c 2 Light E2 52 -64 Yellowish Yellowish LS I MGR VFR 6.0-10.0 Brown Brown, and c 2 reddish brown E3 64 -96 Light Yellowish f 1 Yellowish LS 1 MGR VFR 6.0-10.0 Brown Brown Yellowish E4 96 -110 Light Yellowish Brown, Reddish LS 2 M GR VFR 6.010.0 variegated Brown, Very Brown Pale Yellow c 2 Light Bw 110 -120 Yellowish Yellowish SL 2 M GR FR 6.0 Brown Brown AWT >120 inches SHWT >120 INCHES SLWT SLOPE DRAINAGE SOIL SERIES VEGETATION long leaf pines and turkey oaks Soil Science Investigations • Wetland Delineations, Permitting, and Consulting HAL OWEN & ASSOCIATES, INC. SOIL PROFILE DESCRIPTIONS FOR STORMWATER MANAGEMENT DEVICES CLIENT: Frank Weaver PROJECT NAME: The Summit PROPOSED FACILITY: Detention Basin LOCATION OF COUNTY: Harnett PROPERTY SIZE: EVALUATED BY: Hal Owen NC Licensed Soil Scientist EVALUATION METHOD: Auger Boring ®, Pit ❑ DATE EVALUATED: 14 August 2012 PR OFII ,F.: 2 HORIZON DEPTH (IN) MATRIX MOTTLES TEXTURE STRUCTURE CONSIS- TENCE PERMEABIL ITY (IN/HR NOTES A 0 -3 10YR 4/1 LS 2 M GR VFR 6.0-10.0 El 3 -55 10YR 5/6 LS 2 M GR VFR 6.0-10.0 lower part stripped Bt 55 -90 25YR 4/6 10YR 6/8 SL 1 M SBK FR 4.0-6.0 AWT >90 inches >90 inches SHWT >90 inches SLWT 3% IEE� SLOPE SOIL SERIES 3% DRAINAGE long leaf pines and turkey oaks SOIL SERIES VEGETATION long leaf pines and turkey oaks PROFILE: 3 HORIZON DEPTH IN MATRIX MOTTLES TEXTURE STRUCTURE CONSIS- TENCE PERMEABIL ITY IN/HR NOTES A 0 -3 10YR 4/1 LS 2 M GR VFR 6.0-10.0 E1 3 -78 10YR 5/6 LS 2 M GR VFR 6.0-10.0 lower part stripped Bt 78 -90 1 2.5YR 4/6 10YR 6/8 SL 1 M SBK FR 4.0-6.0 AWT >90 inches SHWT >90 inches SLWT SLOPE 3% DRAINAGE SOIL SERIES VEGETATION long leaf pines and turkey oaks Soil Science Investigations • Wetland Delineations, Permitting, and Consulting HAL OWEN & ASSOCIATES, INC. LEGEND OF ABBREVIATIONS FOR SOIL PROFILE DESCRIPTIONS TEXTURE S - Sand LS - Loamy Sand SL - Sandy Loam L - Loam SCL - Sandy Clay Loam CL - Clay Loam SiL - Silt Loam Si - Silt SiCL- Silt Clay Loam SC - Sandy Clay C - Clay SiC - Silty Clay O - Organic MOIST CONSISTENCE L - Loose VFR - Very Friable FR - Friable FI - Firm VFI - Very Firm EFI - Extremely Firm AWT — Apparent Water Table SHWT — Seasonal High Water Table SLWT — Seasonal Low Water Table MOTTLES f — few 1 - fine F - Faint c — common 2 - medium D - Distinct m — many 3 - coarse P - Prominent STRUCTURE 0 - structureless 1 - weak 2 - moderate 3 - strong VF -very fine G - Single Grain F - fine M - Massive M - medium CR - Crumb C - coarse GR - Granular VC - very coarse SBK - Subangular Blocky ABK - Angular Blocky PL - Platy PR - Prismatic Soil Science Investigations . Wetland Delineations, Permitting, and Consulting