Preliminary Layout Drawings

Transcription

1 Preliminary Layout Drawings

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5 Geotechnical Evaluation Memorandum

6 Memorandum To: From: Ryan S. Kingsbury Stephen L. Whiteside, P.E. Tyler C. Dunn Michael P. Smith Date: November 9, 2011 Subject: Preliminary Evaluation of Raw Water Impoundment Georgia Ports Authority, Savannah, Georgia Purpose and Scope The purpose of this memorandum is to present the preliminary evaluation of the proposed raw water impoundment based on geotechnical, civil, and site constraints. Specifically, the scope of work included the following: Review available existing site information; Evaluate the civil, geotechnical, and site constraints; Evaluate the bottom elevation of the impoundment; Perform wave run up analysis; Evaluate embankment settlement; Evaluate potential reuse of onsite soils; Locate/evaluate potential borrow sources; and Prepare a memorandum summarizing the results of the evaluations. Elevation Datum Elevations noted herein are in feet and reference to the North American Vertical Datum of 1988 (NAVD 88). Background CDM (August 2011) performed a study to evaluate the potential impacts of the Georgia Ports Authority (GPA) Savannah Harbor Expansion Project (SHEP) on treated water quality at the City of Savannah Industrial & Domestic water treatment plant (I&D WTP). The SHEP authorized a deep draft navigation project up to a depth of 48 feet below Mean Lower Low Water (MLLW) level subject to further evaluation and concurrence by the regulatory agencies.

7 Ryan S. Kingsbury November 9, 2011 Page 2 The City of Savannah I&D WTP provides drinking water to approximately 10,500 domestic customers as well as a number of industries, and draws water from an intake on Abercorn Creek, which joins the Savannah River approximately one mile upstream of the I 95 bridge. Although the intake is well upstream of the proposed harbor deepening project, the deepening would increase the amount (percentage) of seawater that reaches the intake under conditions of high tide and low freshwater flow in the creek. As result, the water quality will be impacted, likely making it difficult for the I&D WTP to continue comply with drinking water regulations. Therefore, CDM recommended that an HDPE lined raw water impoundment (RWI) with a usable volume of 77.5 million gallons (MG) be constructed in order to stabilize and reduce the chloride concentration pumped to the plant, or that a supplemental intake further upstream be constructed. CDM recommended the total volume of the impoundment be approximately 20% greater than the 77.5 MG usable volume to allow for sediment accumulation, for a total volume of approximately 97 MG. Existing and Proposed Site Conditions Existing Site Conditions The proposed site for the RWI is located within Parcel 3 of the Savannah River International Trade Park (SRITP) located off Route 21 in Savannah, Georgia, as shown on Figure 1. The site is located within a developing industrial park owned by GPA that is primarily undeveloped and covered by both planted pine trees and naturally grown hardwood trees. The site is bounded to the north by an adjacent property and Black Creek, to the west by the CSX railroad, to the south by Little Hearst Branch Creek and Parcel 2, and to the east by an access road and Parcel 4. The site grades are approximately El. 6 in the north along Black Creek and gradually slope up to approximately El. 19 to El. 26 in the middle of the site. The site then gradually slopes down to approximately El. 13 in the south along Little Hearst Branch Creek. Proposed Construction The proposed 97 MG RWI will be approximately 681 ft by 681 ft in plan dimension at the bottom. The impoundment embankments will be constructed with 3 horizontal to 1 vertical (3H:1V) interior and exterior slopes and a 20 foot wide crest. The impoundment will have a normal pool water depth of 23 feet above the impoundment bottom and a minimum operating water depth of feet. Four (4) 36 inch diameter pipelines will extend from the existing raw water pipeline on the opposite side of the CSX railroad to the impoundment. An evaluation of the crossings is beyond the scope of this study. A detailed study will need to be performed to evaluate the feasibility of conventional versus trenchless construction methods and to provide recommendations for the design and construction of the crossings.

8 Ryan S. Kingsbury November 9, 2011 Page 3 Civil Evaluation A civil evaluation was conducted for the proposed RWI. The civil evaluation consisted of siting the impoundment to reduce cut and fill and determine the bottom of the impoundment. Impoundment Bottom The base flood elevation for the 100 year flood event within the area of the RWI is equal to El. 12, according to the FEMA Flood Insurance Rate Map. A design groundwater level equal to the 100 year flood level, El. 12, should be used for the impoundment and its appurtenant structures. To reduce the potential for the development of uplift (buoyancy) forces on the bottom of the liner, we recommend the bottom of the impoundment be approximately at the design groundwater elevation. Sloping the impoundment bottom down from El. 13 to El. 11 for collection is acceptable. Site Constraints Various site constraints control the location of the impoundment, such as the topography, wetlands, railroad tracks, and irregular parcel shape. In addition, GPA has requested CDM to site the RWI so as to maintain usable acreage in Parcel 3 for potential lease. CDM evaluated potential locations for the RWI to reduce the amount of cut and fill assuming the bottom of the impoundment is at El. 12. Based on the site constraints, the RWI was located on the western extent of Parcel 3 adjacent to the railroad tracks, as shown on Figure 2. The proposed layout reduces the anticipated cut and fill, reduces embankment height, and maintains usable acreage on Parcel 3. Geotechnical Evaluation Embankment Design The RWI layout and cross section are shown on Figures 2 and 3, respectively. The impoundment embankments are approximately 22 feet high with a crest width of 20 feet and an interior and exterior slope of 3H:1V. The freeboard is 6 feet above maximum operating pool level (EL. 35). The embankment cross section includes a chimney and blanket drain that will be constructed with ASTM C 33 sand. A toe drain will be constructed at the outboard end of the blanket drain as shown on Figure 3. Wave Run up Analyses Wave run up analyses were performed for the interior slopes of the impoundment to assure the embankment is not overtopped during a design storm event. The analyses were performed in accordance with USACE engineering manual EM and EM To estimate the wave run up at each interior slope, five key input parameters were required; average water depth, maximum wind speed, wave fetch distance, slope roughness, and slope angle.

9 Ryan S. Kingsbury November 9, 2011 Page 4 The average initial water depth for wave run up analysis was based upon maximum operating pool conditions at EL. 35 for an average depth of 23 feet. The two design storm events analyzed in the wave run up included: A 3 second wind gust of 50 mph and a rain storm event of the equal to the Probable Maximum Precipitation (46 inches) over a 24 hour period. A design 3 second wind gust of 188 mph for Category 5 hurricane winds and a rain storm event equal to 25 percent of the Probable Maximum Precipitation (11.5 inches) over a 24 hour period. The wave fetch distance is limited by the embankment of the impoundment and is estimated as the radial average of path lengths centered on the longest path to the opposite embankment. The internal slopes of the embankment will be lined with a 60 mil HDPE liner as shown on Figure 3. All internal slopes were assumed to be 3H:1V, smooth, and impermeable. The wave run up calculations indicate the total height of the run up will be approximately 5 feet above the maximum operating pool for all cases analyzed. Therefore, the 6 feet of available freeboard should be sufficient to prevent overtopping even during rainfall from the design storm event. Settlement Evaluation No previous geotechnical studies have been performed at the site to date. A preliminary geotechnical study was performed for Parcels 1, 2, 5, and 7 at the SRITP by WPC (2005). Based on the WPC report, highly variable soil conditions were encountered across the referenced site at the exploration locations. In general, the subsurface soils encountered in the explorations consisted of interbedded loose to medium sands, clayey sands and firm to stiff sandy clays in the upper 7 to 10 feet underlain by loose to medium dense sands to a depth of 17 to 20 feet. Below the sands, soft clays with interbedded sand layers were encountered to depths of 35 to 38 feet followed by dense to very dense sands until the explorations were terminated. It should be noted that the subsurface explorations conducted at the adjacent parcels are up to more than a 1 mile away and up to 20 feet lower than the existing ground surface at the RWI site, therefore subsurface conditions are anticipated to vary from those encountered at the adjacent parcels. A conceptual level settlement evaluation was performed for the RWI embankments assuming subsurface conditions are likely similar to those encountered at the other parcels. Based on the settlement evaluation, up to 3 inches of settlement is anticipated for the RWI embankments. Approximately half of the RWI embankment settlement is anticipated to occur during construction of the embankment.

10 Ryan S. Kingsbury November 9, 2011 Page 5 Source of Embankment Fill Suitability of Onsite Material for Reuse A conceptual level evaluation of the potential reuse of onsite soils as embankment fill was performed. Soil survey maps and information from the United States Department of Agriculture (USDA) were obtained for the subject site, Attachment A. The USDA soil survey indicates soils in the area belong to the Ocilla complex and the Pelham Loamy Sand. Based on the survey, the top 2 feet in the area is anticipated to consist of Silty Sand (SM) and Poorly Graded Sand with Silt (SP SM). Based on the present vegetation on site, the material will have various amounts of organic content and roots in the top 2 feet. This material is considered unsuitable for reuse as embankment fill and should be stripped prior to constructing the embankments. The soil survey indicates the material transitions to a slightly plastic to medium plasticity Sandy Clay (CL) or Clayey Sand (SC) below the top 2 feet. This material is considered suitable for constructing the embankment fill. The depth of the soil survey is limited to approximately 6 feet below ground surface, and no data are available. Until further studies are conducted, we recommend a third of the material encountered be considered unsuitable for planning purposes and additional material will need to be imported from a borrow source. Suitability of the material should be confirmed by a combination of test borings and test pits and laboratory testing. Potential Borrow Sources Parcel 5 GPA has indicated a stormwater detention pond may be constructed on Parcel 5, and therefore, it may be a potential borrow source. Parcel 5 of the industrial park is currently undeveloped. A conceptual level evaluation of soils suitability was performed based on the USDA soil survey and WPC test pits. As part of the WPC geotechnical study two test pits, TP 3 and TP 4, were performed on Parcel 5. A summary of the soils encountered in the test pits is presented below. Poorly Graded Sand (SP) was encountered to depths ranging from 0.5 to 4 feet below ground surface. The top 6 inches also contained roots and organics. This layer of soil is considered unsuitable for embankment construction. Below the SP material, slightly plastic to medium plasticity Sandy Clay (CL) or Clayey Sand (SC) was encountered in the test pits to depths ranging from 6 to 10 feet below ground surface. This material is considered suitable for embankment construction. Below the CL/SC material a Poorly Graded Sand (SP) was encountered to the bottom of the test pits. This material is not considered suitable for embankment construction.

11 Ryan S. Kingsbury November 9, 2011 Page 6 Based on the soil survey map, the soils at Parcel 5 belong to the Ocilla complex, Ogeechee loamy fine sand, and Cape Fear Soils. The soil survey map for Parcel 5 generally agrees with the soils encountered in the test pits. The material belonging to the Ocilla complex and Ogeechee loamy fine sand is anticipated to generally have the same composition as the material at the site. Similar to the site, the top layer of Silty Sand (SM) and Poorly Graded Sand with Silt (SP SM) is not considered suitable for embankment construction. The lower material generally comprised of Sandy Clay (CL) or Clayey Sand (SC) is anticipated to be suitable for construction. The material belonging Cape fear soils generally consist of slightly plastic to high plasticity silt (ML/MH) and/or clay (CL/CH). Material with a Liquid Limit greater than 45 and a Plasticity Index greater than 15 is not considered suitable for embankment construction. Some separation and processing of the material encountered would likely be required to obtain a suitable mix of granular and fine grained material to produce a Sandy Clay (CL) or Clayey Sand (SC). Other Sources There are several active borrow pits operating in the Savannah, GA area. CDM contacted multiple borrow pit operators to search for suitable embankment fill. Based on discussions with borrow pit operators, prices for material generally comprised of Sandy Clay (CL) or Clayey Sand (SC) ranged from approximately $3/cubic yard picked up at the borrow pit to approximately $10 to $11/cubic yard delivered to the site. Closure This memorandum has been prepared exclusively for the Georgia Ports Authority Raw Water Impoundment in Savannah, Georgia based on our understanding of the project at this time and described in this memorandum. The results of the evaluations presented in this memorandum are based on information available at the time of the study and on experience and engineering judgment. This memorandum has been prepared in accordance with generally accepted engineering practices. No other warranty, express or implied, is made. In the event that changes in the design or location of the structures occur, the evaluations and conclusions contained herein should not be considered valid unless verified in writing by CDM. Attachments: Figure 1 Locus Map Figure 2 Preliminary Raw Water Impoundment Site Layout Figure 3 Preliminary Raw Water Impoundment Section and Details Attachment A USDA Soil Resource Report

12 26 Ft. 13 Ft. Figure 1 Locus Map Raw Water Impoundment Savannah, Georgia 19 Ft. 6 Ft. 6 Ft. Legend 13 Ft. 19 Ft. Railroad Contour Surface Water 26 Ft. 26 Ft. 26 Ft. 26 Ft. 26 Ft. Approximate Parcel Boundary NOTES: 1. Parcel boundary is approximate and not surveyed* 2. Parcel PIN: Acreage: Contour data obtained from USGS DLGs (1996) 5. Elevations are in feet and reference to NAVD 88 Feet ,000 1 inch = 1,000 feet South Carolina Georgia 13 Ft.

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15 Attachment A USDA Soil Resource Report

16 United States Department of Agriculture Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Bryan and Chatham Counties, Georgia Georgia Ports Authority - Raw Water Reservoir October 18, 2011

17 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments ( and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center ( agency=nrcs) or your NRCS State Soil Scientist ( state_offices/). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Soil Data Mart Web site or the NRCS Web Soil Survey. The Soil Data Mart is the data storage site for the official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means 2

18 for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C or call (800) (voice) or (202) (TDD). USDA is an equal opportunity provider and employer. 3

19 Contents Preface...2 How Soil Surveys Are Made...5 Soil Map...7 Soil Map...8 Legend...9 Map Unit Legend...10 Map Unit Descriptions...10 Bryan and Chatham Counties, Georgia...12 As Albany fine sand...12 Cc Cape Fear soils...13 Cx Craven loamy fine sand...13 Ocilla complex...14 c Ocilla-Urban land complex...15 Ok Ogeechee loamy fine sand...17 Ol Olustee fine sand...18 Pl Pelham loamy sand...19 Pn Pooler fine sandy loam...20 Tmh Tidal marsh, fresh...20 W Water...21 Waf Wahee sandy loam...21 Soil Information for All Uses...23 Soil Properties and Qualities...23 Soil Qualities and Features...23 Unified Soil Classification (Surface)...23 Soil Reports...29 Soil Physical Properties...29 Engineering Properties...29 Physical Soil Properties...38 References

20 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the survey area, they compared the 5

21 individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soillandscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. 6

22 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 7

23 Pn Custom Soil Resource Report Soil Map 32 12' 39'' 32 9' 6'' ' 1'' 81 12' 1'' State Hwy 21 State Hwy 21 Black Creek Little Hearst Branch ± Pl Pl Ok Ok As Pl Ok Pn Pl W Ok Waf Cc Ol Pl Ok Cx Pn Ok Ok W Ok Waf Pl Cx Pn Pl Cx Pl Ok Waf Ok Pn Cx Ok Pl Cc Pl Ok Pl Tmh Cc Cx Map Scale: 1:31,400 if printed on A size (8.5" x 11") sheet. As 5 Tmh Cc Pn Ok W Pn Little Hearst BR Creek Meters ,200 1,800 Feet 0 1,000 2,000 4,000 6,000 Tmh Cx Tmh Ol Pn Cc Ok Pn Tmh Tmh Pn Tmh Pn Ok Ok Pl Cx Front River Tmh Tmh Tmh W W W W c Tmh Tmh W Tmh Tmh Front River Front River ' 55'' 81 8' 55'' ' 40'' 32 9' 6''

24 MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Units Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Gully Short Steep Slope Other Political Features Cities Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Map Scale: 1:31,400 if printed on A size (8.5" 11") sheet. The soil surveys that comprise your AOI were mapped at 1:20,000. Please rely on the bar scale on each map sheet for accurate map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: UTM Zone 17N NAD83 This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Bryan and Chatham Counties, Georgia Survey Area Data: Version 7, Mar 28, 2011 Date(s) aerial images were photographed: 7/19/2007 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

25 Map Unit Legend Bryan and Chatham Counties, Georgia (GA613) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI As Albany fine sand % Cc Cape Fear soils 1, % Cx Craven loamy fine sand % Ocilla complex % c Ocilla-Urban land complex % Ok Ogeechee loamy fine sand % Ol Olustee fine sand % Pl Pelham loamy sand % Pn Pooler fine sandy loam % Tmh Tidal marsh, fresh % W Water % Waf Wahee sandy loam % Totals for Area of Interest 4, % Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the 10

26 contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha- Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 11

27 Bryan and Chatham Counties, Georgia As Albany fine sand Map Unit Setting Elevation: 20 to 450 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Albany and similar soils: 95 percent Minor components: 5 percent Description of Albany Setting Landform: Flats Landform position (three-dimensional): Rise Down-slope shape: Linear Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: About 12 to 30 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Very low (about 2.7 inches) Interpretive groups Land capability (nonirrigated): 3w Typical profile 0 to 48 inches: Fine sand 48 to 56 inches: Sandy loam 56 to 88 inches: Sandy clay loam Minor Components Pelham Percent of map unit: 5 percent Landform: Depressions, flats Landform position (three-dimensional): Dip Down-slope shape: Concave, linear Across-slope shape: Concave, linear 12

28 Cc Cape Fear soils Map Unit Setting Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Cape fear and similar soils: 100 percent Description of Cape Fear Setting Landform: Drainageways, depressions Down-slope shape: Linear, concave Across-slope shape: Concave Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Very poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: About 0 to 12 inches Frequency of flooding: Rare Frequency of ponding: None Available water capacity: High (about 9.6 inches) Interpretive groups Land capability (nonirrigated): 6w Typical profile 0 to 16 inches: Loam 16 to 52 inches: Clay 52 to 62 inches: Loamy fine sand Cx Craven loamy fine sand Map Unit Setting Elevation: 20 to 450 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days 13

29 Map Unit Composition Craven and similar soils: 95 percent Minor components: 5 percent Description of Craven Setting Landform: Interfluves Down-slope shape: Convex Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Moderately well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.57 in/hr) Depth to water table: About 18 to 42 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Moderate (about 7.3 inches) Interpretive groups Land capability (nonirrigated): 2w Typical profile 0 to 13 inches: Loamy fine sand 13 to 48 inches: Sandy clay 48 to 58 inches: Sandy clay loam 58 to 80 inches: Sandy clay loam Minor Components Pelham Percent of map unit: 5 percent Landform: Depressions, flats Landform position (three-dimensional): Dip Down-slope shape: Concave, linear Across-slope shape: Concave, linear Ocilla complex Map Unit Setting Elevation: 10 to 450 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days 14

30 Map Unit Composition Ocilla and similar soils: 95 percent Minor components: 5 percent Description of Ocilla Setting Landform: Interfluves Down-slope shape: Convex Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: About 12 to 30 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Low (about 5.5 inches) Interpretive groups Land capability (nonirrigated): 3w Typical profile 0 to 28 inches: Loamy fine sand 28 to 59 inches: Sandy clay loam 59 to 67 inches: Sandy clay loam Minor Components Ellabelle Percent of map unit: 3 percent Landform: Depressions, drainageways Down-slope shape: Concave, linear Across-slope shape: Concave Pelham Percent of map unit: 2 percent Landform: Depressions, flats Landform position (three-dimensional): Dip Down-slope shape: Concave, linear Across-slope shape: Concave, linear c Ocilla-Urban land complex Map Unit Setting Elevation: 10 to 450 feet Mean annual precipitation: 44 to 52 inches 15

31 Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Ocilla and similar soils: 60 percent Urban land: 30 percent Ogeechee and similar soils: 5 percent Minor components: 5 percent Description of Ocilla Setting Landform: Interfluves Down-slope shape: Convex Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: About 12 to 30 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Low (about 5.5 inches) Interpretive groups Land capability (nonirrigated): 3w Typical profile 0 to 28 inches: Loamy fine sand 28 to 59 inches: Sandy clay loam 59 to 67 inches: Sandy clay loam Description of Ogeechee Setting Landform: Depressions, drainageways, flats Down-slope shape: Concave, linear Across-slope shape: Concave, linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 0 to 12 inches Frequency of flooding: Frequent Frequency of ponding: None Available water capacity: Moderate (about 6.4 inches) Interpretive groups Land capability (nonirrigated): 4w 16

32 Typical profile 0 to 8 inches: Loamy fine sand 8 to 23 inches: Sandy clay loam 23 to 42 inches: Sandy clay 42 to 60 inches: Sandy clay loam Minor Components Pelham Percent of map unit: 5 percent Landform: Depressions, flats Landform position (three-dimensional): Dip Down-slope shape: Concave, linear Across-slope shape: Concave, linear Ok Ogeechee loamy fine sand Map Unit Setting Elevation: 10 to 50 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Ogeechee and similar soils: 100 percent Description of Ogeechee Setting Landform: Flats, depressions, drainageways Down-slope shape: Linear, concave Across-slope shape: Linear, concave Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 0 to 12 inches Frequency of flooding: Frequent Frequency of ponding: None Available water capacity: Moderate (about 6.4 inches) Interpretive groups Land capability (nonirrigated): 4w Typical profile 0 to 8 inches: Loamy fine sand 17

33 8 to 23 inches: Sandy clay loam 23 to 42 inches: Sandy clay 42 to 60 inches: Sandy clay loam Ol Olustee fine sand Map Unit Setting Elevation: 10 to 450 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Olustee and similar soils: 95 percent Minor components: 5 percent Description of Olustee Setting Landform: Flats Landform position (three-dimensional): Talf Down-slope shape: Linear Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 18 to 30 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Low (about 5.8 inches) Interpretive groups Land capability (nonirrigated): 3w Typical profile 0 to 7 inches: Fine sand 7 to 15 inches: Sand 15 to 38 inches: Sand 38 to 80 inches: Sandy clay loam Minor Components Ellabelle Percent of map unit: 3 percent Landform: Depressions, drainageways Down-slope shape: Concave, linear Across-slope shape: Concave 18

34 Pelham Percent of map unit: 2 percent Landform: Depressions, flats Landform position (three-dimensional): Dip Down-slope shape: Concave, linear Across-slope shape: Concave, linear Pl Pelham loamy sand Map Unit Setting Elevation: 20 to 450 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Pelham and similar soils: 100 percent Description of Pelham Setting Landform: Depressions, drainageways, flats Landform position (three-dimensional): Dip Down-slope shape: Concave, linear Across-slope shape: Concave, linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: About 0 to 12 inches Frequency of flooding: Occasional Frequency of ponding: None Available water capacity: Low (about 5.9 inches) Interpretive groups Land capability (nonirrigated): 5w Typical profile 0 to 27 inches: Loamy sand 27 to 56 inches: Sandy clay loam 56 to 68 inches: Sandy clay loam 19

35 Pn Pooler fine sandy loam Map Unit Setting Elevation: 20 to 100 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days Map Unit Composition Pooler and similar soils: 100 percent Description of Pooler Setting Landform: Depressions, flats Down-slope shape: Concave, linear Across-slope shape: Concave, linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: About 0 to 12 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Moderate (about 8.7 inches) Interpretive groups Land capability (nonirrigated): 6w Typical profile 0 to 6 inches: Fine sandy loam 6 to 12 inches: Sandy clay loam 12 to 52 inches: Clay 52 to 72 inches: Sandy clay loam Tmh Tidal marsh, fresh Map Unit Setting Elevation: 0 to 10 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days 20

36 Map Unit Composition Tidal marsh, fresh: 100 percent Description of Tidal Marsh, Fresh Setting Landform: Tidal marshes Down-slope shape: Linear Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 1 percent Drainage class: Very poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: About 0 inches Frequency of flooding: Frequent Frequency of ponding: Frequent Maximum salinity: Nonsaline (0.0 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum: 20.0 Available water capacity: High (about 11.4 inches) Interpretive groups Land capability (nonirrigated): 7w Typical profile 0 to 8 inches: Silty clay loam 8 to 60 inches: Silty clay W Water Map Unit Setting Mean annual precipitation: 52 to 68 inches Mean annual air temperature: 54 to 59 degrees F Frost-free period: 160 to 210 days Map Unit Composition Water: 100 percent Waf Wahee sandy loam Map Unit Setting Elevation: 20 to 450 feet Mean annual precipitation: 44 to 52 inches Mean annual air temperature: 64 to 70 degrees F Frost-free period: 230 to 290 days 21

37 Map Unit Composition Wahee and similar soils: 95 percent Minor components: 5 percent Description of Wahee Setting Landform: Interfluves Down-slope shape: Convex Across-slope shape: Linear Parent material: Marine deposits Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: About 6 to 18 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: High (about 9.2 inches) Interpretive groups Land capability (nonirrigated): 2w Typical profile 0 to 11 inches: Sandy loam 11 to 56 inches: Clay 56 to 65 inches: Sandy clay loam Minor Components Pooler Percent of map unit: 5 percent Landform: Depressions, flats Landform position (three-dimensional): Talf Down-slope shape: Concave, linear Across-slope shape: Concave, linear 22

38 Soil Information for All Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil. Unified Soil Classification (Surface) The Unified soil classification system classifies mineral and organic mineral soils for engineering purposes on the basis of particle-size characteristics, liquid limit, and plasticity index. It identifies three major soil divisions: (i) coarse-grained soils having less than 50 percent, by weight, particles smaller than mm in diameter; (ii) finegrained soils having 50 percent or more, by weight, particles smaller than mm in diameter; and (iii) highly organic soils that demonstrate certain organic characteristics. These divisions are further subdivided into a total of 15 basic soil groups. The major soil divisions and basic soil groups are determined on the basis of estimated or measured values for grain-size distribution and Atterberg limits. ASTM D 2487 shows the criteria chart used for classifying soil in the Unified system and the 15 basic soil groups of the system and the plasticity chart for the Unified system. The various groupings of this classification correlate in a general way with the engineering behavior of soils. This correlation provides a useful first step in any field or laboratory investigation for engineering purposes. It can serve to make some general interpretations relating to probable performance of the soil for engineering uses. 23

39 For each soil horizon in the database one or more Unified soil classifications may be listed. One is marked as the representative or most commonly occurring. The representative classification is shown here for the surface layer of the soil. 24

40 Pn Custom Soil Resource Report Map Unified Soil Classification (Surface) 32 12' 39'' 32 9' 6'' ' 1'' 81 12' 1'' State Hwy 21 State Hwy Black Creek Pl Little Hearst Branch Pl Ok Ok As Pl Ok Pn Pl W Ok Waf Cc Ol Pl Ok Cx Pn Ok Ok W Ok Waf Pl Cx Pn Pl Cx Pl Ok Waf Ok Pn Cx Ok Pl Cc Pl Ok Pl Tmh Cc Cx Map Scale: 1:31,400 if printed on A size (8.5" x 11") sheet. As Tmh Cc Pn Ok W Pn Little Hearst BR Creek Meters ,200 1,800 Feet 0 1,000 2,000 4,000 6,000 Tmh Cx Tmh Ol Pn Cc Ok Pn Tmh Tmh Pn Tmh Pn Ok Ok Pl Cx Front River Tmh Tmh Tmh W W W W c Tmh Tmh W Tmh Tmh Front River Front River ' 55'' 81 8' 55'' ' 40'' 32 9' 6''