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Home My WebLink AboutSDP199900128 Study Final Site Plan and Comps. 1999-10-25 chol Nor USDA Natural Resources Conservation Service October 25, 1999 695 Berkmar Court -Ste 2 Charlottesville, VA 22901 TO: Stephen Waller Planning Department RE: Soils Report for: Whitewood Off Pk Grayrock North Shadwell Antiquaires RECEIVED OCT 2.7 1999 COMIIi1UNiT'fNDNGc EV�LONDPMENT 41114, iro ----164r4 .p, a�jye pfi, '':',.-::;:::':';f1:-' 2.6H- ':16%;':!*r' r'i': ftr et�"`$x rte ..� aY- � �A^,� '4.'•.,,,,,I° � (� • �� .'af,S"@ 43 � /(N lat .,f4,...,::::4: 3 ? ,...4-''''-:;.-:31,41:i.,5:„... �� l ' • ..-...::::41-4-;-,-, E 3, .lie*-4:-:-::-•..]•*‘.7.:4•2•':4'•;; ' ic,..':-1." \ ''''''''''' '' ''. '.e...--' -*1--...,-.0•if/ 'y� ""yAf•. o / �� . 4 '� 4„, ,..� ..! tt 3`cç :: 41 'rl at > A*1 ip AL '-'',7A, .1::, ' :c.,,,:.. ?:',4:. '1"J'F':.:',..'•. .,.','" ,. ' • 4$ \ Ilk - ...: "�. •,,,i,'-'. � i �CO '$�-' � .,,rte �� y � ,a,� Si . 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'' r 3n'' ,SV{ .re€,;, y, .A,{z1. .a <n .,,y .,V co :i.314)1‘ *.li: ' ' ' ' N,.. c° .,t,,-;,,,),!:„..,,rfe.:._,,,idik '....,,,...:;t.,,,t,-...„.:,,,,,,,„.").,;1431,:i•-•,*,--',.,-,t.r.,,,„„4 *,- i-a i 1 i cf, - ,/..-.=.-:',.;;1 •* ' 'N CD CA 1050,, \ ;• Z:-:2!--:,.1 a, ,,• tr4.-,..-....-,:,,,f•-:'';.4•:%-i;•."!',..,r,f, is-.., .- C.'''''-i....--...."?1;4 7/h '•. 4, ,t,�c` S , W y ,- Y7 � ' th -^ « , y3T,64 , '# twa "ms e, ' Y :.:t.::::„,A AT '63; 1- 'l''.-4.i.:1:!4:;,',;1:."j,,V.f'' 74 tritS, ii,,,,,u.„)..„ ,. „.,... .. ff o { , jpIlv T , , -:,..,;•-,,'", -"'"-`7,-'4' 4---'-', 'PLT, i vil(5:.t,":\ 1,) ._,. .:, ..!:„4,;;;;;.,:„...?,,,,tioe....:„.„1?ii.,:74.11,ii.4::::::. A 610 000 FEET rn W O W Cid NONTECHNICAL SOILS DESCRIPTION REPORT Shadwell Antiq Map Soil name and description Symbol 23C davidson clay loam, 7 to 15 percent slopes Davidson soils are deep and well drained. Permeability and available water capacity are moderate. Surface runoff and erosion hazard very with slope from moderate to severe. This soil has fair tilth. The subsoil has low shrink-swell potential. The root zone extends to a depth of 60 iches. The organic matter content is moderate, and the natural fertility is medium. This soil commonly is medium acid to strongly acid throughout, but reaction in the surface layer is variable because of local liming. Bedrock is generally at a depth of more than 5 feet. 58B myersville silt loam, 2 to 7 percent slopes Myersville soils are deep and well drained. Permeability and available water capacity are moderate. The hazard of erosion varies from moderate to very severe. The subsoil has low shrink-swell potential. The root zone extends to a depth of at least 40 inches. The orgamic matter content is low to moderate, and the natural fertility is medium. This soil commonly is very strongly acid to medium acid throughout, but reaction in the surface layer and upper part of the B horizon is variable becuase of local liming. Bedrock is generally at a depth of more than 5 feet. 51D manteo channery silt loam, 15 to 25 percent slopes Manteo soils are shallow, somewhat excessively drained soils. Permeability is moderately rapid and available water capacity is very low . The hazard of erosion is moderate to very severe. The natural fertility and the content of organic matter are low. The subsoil has low shrink-swell potential. The root zone extends to a depth of less than 20 inches. The surface layer and subsoil commonly are very strongly acid to extremely acid. 51B manteo channery silt loam, 2 to 7 percent slopes NONTECHNICAL SOILS DESCRIPTION REPORT Shadwell Antiq Map Soil name and description Symbol Manteo soils are shallow, somewhat excessively drained soils. Permeability is moderately rapid and available water capacity is very low . The hazard of erosion is moderate to very severe. THe natural fertility and the content of organic matter are low. The subsoil has low shrink-swell potential. The root zone extends to a depth of less than 20 inches. The surface layer and subsoil commonly are very strongly acid to extremely acid. Litiiii LOW U.S. DEPARTMENT OF AGRICULTURE PAGE 1 OF 4 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 PHYSICAL PROPERTIES OF SOILS Shadwell Antiq (Entries under "Erosion factors--T" apply to the entire profile. Entries under "Wind erodibility group" and "Wind erodability index" apply only to the surface layer) I I I I I I 1 'Erosion factors1Wind 'Wind Map symbol I Depth I Clay I Moist ' Permea- 1Availablel Shrink- 'Organic' lerodi-lerodi- and soil name I I I bulk ' bility 1 water swell I matter' I I Ibilitylbility 1 I density I 'capacity Ipotential l 1 K I Kf l T 'group (index I I I I I 1 In l Pct I g/cc I In/hr I In/in I I Pct I I I I I I I I I 1 I I I I I I I 23C: I I I I I I I I I I I I DAVIDSON l 0-4 20-3511.30-1.551 0.60-2.00 10.14-0.181Low 10.5-2.01 0.281 0.281 5 ' 6 l --- 4-10 127-4011.20-1.501 0.60-2.00 10.15-0.181L0w I --- 1 0.321 0.321 I I 10-63 140-7511.20-1.501 0.60-2.00 10.12-0.161Low I --- 10.241 0.241 I I 63-88 25-6011.20-1.501 0.60-2.00 10.12-0.181Low I --- 10.281 0.281 I I I I 1 1 I I 1 1 1 I I 58B: I I I 1 1 1 I I 1 I I I MYERSVILLE ' 0-7 I 5-2011.20-1.501 2.00-6.00 10.14-0.20ILow 11.0-3.01 0.371 0.371 4 I 6 ' --- ' 7-28 1 18-3511.20-1.501 0.60-2.00 10.14-0.181Low 10.0-0.51 0.321 0.321 I I 1 28-44 1 10-3211.20-1.501 0.60-2.00 10.08-0.161Low 10.0-0.51 0.321 0.371 I I 44-65 1 --- 1 ___ 1 0.00-0.06 I 1 1 1 _-_ I --- 1 I I 1 I I I I I I 1 I I 51D: I I I I I 1 1 I I I I I MANTEO 10-6 17-2711.25-1.551 2.00-6.00 10.10-0.161Low 10.5-2.01 0.281 0.371 1 1 8 1 --- 1 6-18 l 10-3511.35-1.651 2.00-6.00 10.07-0.141Low 10.0-0.51 0.281 0.431 I I 18-22 --- 1 --- 1 0.00-0.01 I I I I I I I I I 1 I I I l I I I I 51B: I I I I I I I I I I I I MANTEO I 0-6 ' 7-2711.25-1.551 2.00-6.00 10.10-0.161Low 10.5-2.01 0.281 0.371 1 ' 8 I --- 16-18 1 10-3511.35-1.651 2.00-6.00 10.07-0.141Low 10.0-0.51 0.281 0.431 I I 1 18-22 1 --- I --- 1 0.00-0.01 I I I I I I I I I_I U.S. DEPARTMENT OF AGRICULTURE PAGE 3 OF 3 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 WATER FEATURES Endnote --WATER FEATURES--Continued Information on the extent of flooding based on soil data is less specific than that provided by detailed engineering surveys that delineate flood-prone areas at specific flood frequency levels. High water table (seasonal) is the highest level of a saturated zone in the soil in most years. The depth to a seasonal high water table applies to undrained soils. The estimates are based mainly on the evidence of a saturated zone, namely grayish colors or mottles in the soil. Indicated in this report are the depth to the seasonal high water table; the kind of water table, that is, "Apparent", "Artesian", or "Perched"; and the months of the year that the water table commonly is high. A water table that is seasonally high for less than 1 month is not indicated in this report. An "Apparent" water table is a thick zone of free water in the soil. It is indicated by the level at which water stands in an uncased borehole after adequate time is allowed for adjustment in the surrounding soil. An "Artesian" water table exists under a hydrostatic beneath an impermeable layer. When the impermeable layer has been penetrated by a cased borehole, the water rises. The final level of the water in the cased borehole is characterized as an artesian water table. A "Perched" water table is water standing above an unsaturated zone. In places an upper, or "Perched", water table is separated from a lower one by a dry zone. Only saturated zones within a depth of about 6 feet are indicated. Ponding is standing water in a closed depression. The water is removed only by deep percolation, transpiration, evaporation, or a combination of these processes. This report gives the depth and duration of ponding and the time of year when ponding is most likely. Depth, duration, and probable dates of occurrence are estimated. Depth is expressed as the depth of ponded water in feet above the soil surface. Duration is expressed as "Very brief" if less than 2 days, "Brief" if 2 to 7 days, "Long" if 7 to 30 days, and "Very long" if more than 30 days. The information is based on the relation of each soil on the landscape to historic ponding and on local information about the extent and levels of ponding. CIS Liii, U.S. DEPARTMENT OF AGRICULTURE PAGE 1 OF 2 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 SOIL FEATURES Shadwell Antiq Bedrock I Cemented pan I Subsidence I I Risk of corrosion I I I I Potential Map symbol I I I I I I (frost action' Uncoated I and soil name I Depth (Hardness) Depth I Kind 'Initial' Total I I steel I Concrete I I I I I I I In I u In I I In I In I I I I I I I I I I I 23C: I I I I I I I I I DAVIDSON ' X60 --- I I I I I --- (High Moderate I I I I I I I I 58B: I I I I I I I I I MYERSVILLE 140-60 I Soft I --- I --- I --- ( --- (Moderate (Moderate (Moderate I I I I I I I I I 51D: I I I I I I I I I MANTEO ' 10-20 I Hard I --- I --- I --- I --- I --- (Low (High I I I I I I I 51B: I I I I I I I I I MANTEO 10-20 Hard ( I I --- I --- (Low 'High ( I I I I I I I U.S. DEPARTMENT OF AGRICULTURE PAGE 2 OF 2 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 SOIL FEATURES Endnote -- SOIL FEATURES This report gives estimates of various soil features. The estimates are used in land use planning that involves engineering considerations. Depth to bedrock is given if bedrock is within a depth of 5 feet. The depth is based on many soil borings and on observations during soil mapping. The rock is either "Soft" or "Hard". If the rock is "Soft" or fractured, excavations can be made with trenching machines, backhoes, or small rippers. If the rock is "Hard" or massive, blasting or special equipment generally is needed for excavation. Cemented pans are cemented or indurated subsurface layers within a depth of 5 feet. Such pans cause difficulty in excavation. Pans are classified as "Thin" or "Thick". A "Thin" pan is less than 3 inches thick if continuously indurated or less than 18 inches thick if discontinuous or fractured. Excavations can be made by trenching machines, backhoes, or small rippers. A "Thick" pan is more than 3 inches thick if continuously indurated or more than 18 inches thick if discontinuous or fractured. Such a pan is so thick or massive that blasting or special equipment is needed in excavation. Subsidence is the settlement of organic soils or of saturated mineral soils of very low density. Subsidence results from either desiccation and shrinkage or oxidation of organic material, or both, following drainage. Subsidence takes place gradually, usually over a period of several years. This report shows the expected initial subsidence, which usually is a result of drainage, and total subsidence, which usually is a result of oxidation. Not shown in the report is subsidence caused by an imposed surface load or by the withdrawal of ground water throughout an extensive area as a result of lowering the water table. Potential frost action is the likelihood of upward or lateral expansion of the soil caused by the formation of segregated ice lenses (frost heave) and the subsequent collapse of the soil and loss of strength on thawing. Frost action occurs when moisture moves into the freezing zone of the soil. Temperature, texture, density, permeability, content of organic matter, and depth to the water table are the most important factors considered in evaluating the potential for frost action. It is assumed that the soil is not insulated by vegetation or snow and is not artificially drained. Silty and highly structured clayey soils that have a high water table in winter are the most susceptible to frost action. Well drained, very gravelly, or very sandy soils are the least susceptible. Frost heave and low soil strength during thawing cause damage mainly to pavements and other rigid structures. Risk of corrosion pertains to potential soil-induced electrochemical or chemical action that dissolves or weakens uncoated steel or concrete. The rate of corrosion of uncoated steel is related to such factors as soil moisture, particle-size distribution, acidity, and electrical conductivity of the soil. The rate of corrosion of concrete is based mainly on the sulfate and sodium content, texture, moisture content, and acidity of the soil. Special site examination and design may be needed if the combination of factors creates a severe corrosion environment. The steel installations that intersect soil boundaries or soil layers is more susceptible to corrosion than steel in installations that are entirely within one kind of soil or within one soil layer. For uncoated steel, the risk of corrosion, expressed as "Low", "Moderate", or "High", is based on soil drainage class, total acidity, electrical resistivity near field capacity, and electrical conductivity of the saturation extract. For concrete, the risk of corrosion is also expressed as "Low", "Moderate", or "High". It is based on soil texture, acidity, and amount of sulfates in the saturation extract. ‘1111111/ LII04 U.S. DEPARTMENT OF AGRICULTURE PAGE 1 OF 3 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 SANITARY FACILITIES Shadwell Antiq (The information in this report indicates the dominant soil condition but does not eliminate the need for onsite investigation) I I I I I Map symbol I Septic tank I Sewage lagoon I Trench I Area Daily cover and soil name ' absorption ' areas ' sanitary I sanitary I for landfill ( fields I ' landfill ' landfill I I I I I I I I I I 23C: I I I I I DAVIDSON (Moderate: 'Severe: (Moderate: Moderate: (Fair: I percs slowly, I slope I slope, ' slope ( too clayey, slope I I too clayey I I hard to pack, ( slope I I I I I 58B: I I I I I MYERSVILLE (Moderate: (Moderate: 'Severe: 'Moderate: Fair: ( depth to rock, ' seepage, I depth to rock I depth to rock I depth to rock, ' percs slowly ( depth to rock, ( I I too clayey ' ( slope I I I I I I I I 51D: I I I I I MANTEO Severe: Severe: Severe: (Severe: (Poor: ( depth to rock, I seepage, ' depth to rock, ' slope, I depth to rock, ( slope I depth to rock, ' seepage, I seepage, I small stones, ( ' slope I slope I depth to rock slope I I I I I 51B: MANTEO Severe: Severe: Severe: (Severe: (Poor: ' depth to rock I seepage, I depth to rock, seepage, I depth to rock, I ( depth to rock ( seepage depth to rock I small stones I I I I U.S. DEPARTMENT OF AGRICULTURE PAGE 2 OF 3 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 SANITARY FACILITIES Endnote -- SANITARY FACILITIES This report shows the degree and kind of soil limitations that affect septic tank absorption fields, sewage lagoons, and sanitary landfills. The limitations are considered "Slight" if soil properties and site features generally are favorable for the indicated use and limitations are minor and easily overcome; "Moderate" if soil properties or site features are not favorable for the indicated use and special planning, design, or maintenance is needed to overcome or minimize the limitations; and "Severe" if soil properties or site features are so unfavorable or so difficult to overcome that special design, significant increases in construction costs, and possibly increased maintenance are required. This report also shows the suitability of the soils for use as daily cover for landfills. A rating of "Good" indicates that soil properties and site features are favorable for the use and good performance and low maintenance can be expected; "Fair" indicates that soil properties and site features are moderately favorable for the use and one or more soil properties or site features make the soil less desirable than the soils rated "Good"; and "Poor" indicates that one or more soil properties or site features are unfavorable for the use and overcoming the unfavorable properties requires special design, extra maintenance, or costly alteration. SEPTIC TANK ABSORPTION FIELDS are areas in which effluent from a septic tank is distributed into the soil through subsurface tiles or perforated pipe. Only that part of the soil between depths of 24 to 72 inches is evaluated. The ratings are base on soil properties, site features, and observed performance of the soils. Permeability, a high water table, depth to bedrock or to a cemented pan, and flooding affect absorption of the effluent. Large stones and bedrock or a cemented pan interfere with installation. Unsatisfactory performance of septic tank absorption fields, including excessively slow absorption of effluent, surfacing of effluent, and hillside seepage, can affect public health. Groundwater can be polluted if highly permeable sand and gravel or fractured bedrock is less than 4 feet below the base of the absorption field, if slope is excessive, or if the water table is near the surface. There must be unsaturated soil material beneath the absorption field to filter the effluent effectively. Many local ordinances require that this material be of a certain thickness. SEWAGE LAGOONS are shallow ponds constructed to hold sewage while aerobic bacteria decompose the solid and liquid wastes. Lagoons should have a nearly level floor surrounded by cut slopes or embankments of compacted soil. Lagoons generally are designed to hold the sewage within a depth of 2 to 5 feet. Nearly impervious soil material for the lagoon floor and sides is required to minimize seepage and contamination of ground water. This report gives ratings for the natural soil that makes up the lagoon floor. The surface layer and, generally, 1 or 2 feet of soil material below the surface layer are excavated to provide material for the embankments. The ratings are based on soil properties, site features, and observed performance of the soils. Considered in the ratings are slope, permeability, a high water table, depth to bedrock or to a cemented pan, flooding, large stones, and content of organic matter. Excessive seepage due to rapid permeability of the soil or a water table that is high enough to raise the level of sewage in the lagoon causes a lagoon to function unsatisfactorily. Pollution results if seepage is excessive or if floodwater overtops the lagoon. A high content of organic matter is detrimental to proper functioning of the lagoon because it inhibits aerobic activity. Slope, bedrock, and cemented pans can cause construction problems, and large stones can hinder compaction of the lagoon floor. SANITARY LANDFILLS are areas where solid waste is disposed of by burying it in soil. There are two types of landfill, trench and area. In a trench landfill, the waste is placed in a trench. It is spread, compacted, and covered daily with a thin layer of soil excavated at the site. In an area landfill, the waste is placed in successive layers on the surface of the soil. The waste is spread, compacted, and covered daily with a thin layer of soil form a source away from the site. Both types of landfill must be able to bear heavy vehicular traffic. Both types involve a risk of groundwater pollution. Ease of excavation and revegetation need to be considered. The ratings in this report are based Lid U.S. DEPARTMENT OF AGRICULTURE PAGE 3 OF 3 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 SANITARY FACILITIES Endnote -- SANITARY FACILITIES--Continued on soil properties, site features, and observed performance of the soils. Permeability, depth to bedrock or to a cemented pan, a high water table, slope, and flooding affect both types of landfill. Texture, stones and boulders, highly organic layers, soil reaction, and content of salts and sodium affect trench type landfills. Unless otherwise stated, the ratings apply only to that part of the soil within a depth of about 6 feet. For deeper trenches, a limitation rate "Slight" or "Moderate" may not be valid. Onsite investigation is needed. DAILY COVER FOR LANDFILL is the soil material that is used to cover compacted solid waste in an area type sanitary landfill. The soil material is obtained offsite, transported to the landfill, and spread over the waste. Soil texture, wetness, coarse fragments, and slope affect the ease of removing and spreading the material during wet and dry periods. Loamy or silty soils that are free of large stones or excess gravel are the best cover for a landfill. Clayey soils may be sticky or cloddy and are difficult to spread; sandy soils are subject to soil blowing. After soil material has been removed, the soil material remaining in the borrow area must be thick enough over bedrock, a cemented pan, or the water table to permit revegetation. The soil material used as final cover for a landfill should be suitable for plants. The surface layer generally has the best workability, more organic matter than the rest of the profile, and the best potential for plants. Material from the surface layer should be stockpiled for use as the final cover. U.S. DEPARTMENT OF AGRICULTURE PAGE 2 OF 4 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 PHYSICAL PROPERTIES OF SOILS Endnote -- PHYSICAL PROPERTIES OF SOILS This report shows estimates of some characteristics and features that affect soil behavior. These estimates are given for the major layers of each soil in the survey area. The estimates are based on field observations and on test data for these and similar soils. CLAY as a soil separate consists of mineral soil particles that are less than 0.002 millimeter in diameter. In this report, the estimated clay content of each major soil layer is given as a percentage, by weight, of the soil material that is less than 2 millimeters in diameter. The amount and kind of clay greatly affect the fertility and physical condition of the soil. They determine the ability of the soil to adsorb cations and to retain moisture. They influence shrink-swell potential, permeability, plasticity, the ease of soil dispersion, and other soil properties. The amount and kind of clay in a soil also affect tillage and earthmoving operations. MOIST BULK DENSITY is the weight of soil (ovendry) per unit volume. Volume is measured when the soil is at field moisture capacity, the moisture content at 1/3 bar moisture tension. Weight is determined after drying the soil at 105 degrees C. In this report, the estimated moist bulk density of each major soil horizon is expressed in grams per cubic centimeter of soil material that is less than 2 millimeters in diameter. Bulk density data are used to compute shrink-swell potential, available water capacity, total pore space, and other soil properties. The moist bulk density of a soil indicates the pore space available for water and roots. A bulk density of more than 1.6 can restrict water storage and root penetration. Moist bulk density is influenced by texture, kind of clay, content of organic matter, and soil structure. PERMEABILITY refers to the ability of a soil to transmit water or air. The estimates indicate the rate of downward movement of water when the soil is saturated. They are based on soil characteristics observed in the field, particularly structure, porosity, and texture. Permeability is considered in the design of soil drainage systems, septic tank absorption fields, and construction where the rate of water movement under saturated conditions affects behavior. AVAILABLE WATER CAPACITY refers to the quantity of water that the soil is capable of storing for use by plants. The capacity for water storage is given in inches of water per inch of soil for each major soil layer. The capacity varies, depending on soil properties that affect the retention of water and the depth of the root zone. The most important properties are the content of organic matter, soil texture, bulk density, and soil structure. Available water capacity is an important factor in the choice of plants or crops to be grown and in the design and management of irrigation systems. Available water capacity is not an estimate of the quantity of water actually available to plants at any given time. SHRINK-SWELL POTENTIAL is the potential for volume change in a soil with a loss or gain of moisture. Volume change occurs mainly because of the interaction of clay minerals with water and varies with the amount and type of clay minerals in the soil. The size of the load on the soil and the magnitude of the change in soil moisture content influence the amount of swelling of soils in place. Laboratory measurements of swelling of undisturbed clods were made for many soils. For others, swelling was estimated on the basis of the kind and amount of clay minerals in the soil and on measurements of similar soils. If the shrink-swell potential is rated moderate to very high, shrinking and swelling can cause damage to buildings, roads, and other structures. Special design is often needed. Shrink-swell potential classes are based on the change in length of an unconfined clod as moisture content is increased from air-dry to field capacity. The change is based on the soil fraction less than 2 millimeters in diameter. The classes are "Low," a change of less than 3 percent; "Moderate," 3 to 6 percent; and "High," more than 6 percent. "Very high," greater than 9 percent, is sometimes used. U.S. DEPARTMENT OF AGRICULTURE PAGE 3 OF 4 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 PHYSICAL PROPERTIES OF SOILS Endnote -- PHYSICAL PROPERTIES OF SOILS--Continued ORGANIC MATTER is the plant and animal residue in the soil at various stages of decomposition. In report J, the estimated content of organic matter is expressed as a percentage, by weight, of the soil material that is less than 2 millimeters in diameter. The content of organic matter in a soil can be maintained or increased by returning crop residue to the soil. Organic matter affects the available water capacity, infiltration rate, and tilth. It is a source of nitrogen and other nutrients for crops. EROSION FACTOR K indicates the susceptibility of the whole soil (including rocks and rock fragments) to sheet and rill erosion by water. Factor K is one of six factors used in the Universal Soil Loss Equation (USLE) to predict the average annual rate of soil loss by sheet and rill erosion in tons per acre per year. The estimates are based primarily on percentage of silt, sand, and organic matter (up to 4 percent) and on soil structure and permeability. Values of K range from 0.05 to 0.69. The higher the value, the more susceptible the soil is to sheet and rill erosion by water. EROSION FACTOR Kf is like EROSION FACTOR K but it is for the fine-earth fraction of the soil. Rocks and rock fragments are not considered. EROSION FACTOR T is an estimate of the maximum average annual rate of soil erosion by wind or water that can occur without affecting crop productivity over a sustained period. The rate is in tons per acre per year. WIND ERODIBILITY GROUPS are made up of soils that have similar properties affecting their resistance to wind erosion in cultivated areas. The groups indicate the susceptibility of soil to wind erosion. Soils are grouped according to the following distinctions: 1. Coarse sands, sands, fine sands, and very fine sands. These soils are generally not suitable for crops. They are extremely erodible, and vegetation is difficult to establish. 2. Loamy coarse sands, loamy sands, loamy fine sands, loamy very fine sands, and sapric soil material. These soils are very highly erodible. Crops can be grown if intensive measures to control wind erosion are used. 3. Coarse sandy loams, sandy loams, fine sandy loams, and very fine sandy loams. These soils are highly erodible. Crops can be grown if intensive measures to control wind erosion are used. 4L. Calcareous loams, silt loams, clay loams, and silty clay loams. These soils are erodible. Crops can be grown if intensive measures to control wind erosion are used. 4. Clays, silty clays, noncalcareous clay loams, and silty clay loams that are more than 35 percent clay. These soils are moderately erodible. Crops can be grown if measures to control wind erosion are used. U.S. DEPARTMENT OF AGRICULTURE PAGE 4 OF 4 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 PHYSICAL PROPERTIES OF SOILS Endnote -- PHYSICAL PROPERTIES OF SOILS--Continued 5. Noncalcareous loams and silt loams that are less than 20 percent clay and sandy clay loams, sandy clays, and heroic soil material. These soils are slightly erodible. Crops can be grown if measures to control wind erosion are used. 6. Noncalcareous loams and silt loams that are more than 20 percent clay and noncalcareous clay loams that are less than 35 percent clay. These soils are very slightly erodible. Crops can be grown if ordinary measures to control wind erosion are used. 7. Silts, noncalcareous silty clay loams that are less than 35 percent clay, and fibric soil material. These soils are very slightly erodible. Crops can be grown if ordinary measures to control wind erosion are used. 8. Soils that are not subject to wind erosion because of coarse fragments on the surface or because of surface wetness. The WIND ERODIBILITY INDEX is used in the wind erosion equation (WEQ) . The index number indicates the amount of soil lost in tons per acre per year. The range of wind erodibility index numbers is 0 to 300. ‘11110104 U.S. DEPARTMENT OF AGRICULTURE PAGE 1 OF 2 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 HYDRIC SOILS LIST NON-HYDRIC MAPUNITS Shadwell Antiq The "Hydric Soils Criteria" columns indicate the conditions that caused the mapunit component to be classified as "Hydric" or "Non-Hydric". These criteria are defined in "Hydric Soils of the United States" (USDA Miscellaneous Publications No. 1491, June, 1991. The "FSA Criteria" columns contain information needed for the Food Security Act determinations required by Section 512.11(h) (4) of the National Food Security Manual (August, 1991) . See the "Criteria for Hydric Soils" endnote to to determine the meaning of these columns. Spot symbols are footnoted at the end of the report. I I I I I FSA Criteria and I I I I Hydric Soils Criteria I Information I Map Symbol IComponent(C)/I I I I I Mapunit Name Ilnclusion(I) I Hydric I Local I Hydric I Meets I Meets I Meets I Natural I I I I I Landform I Criteria ISaturation1FloodinglPonding ICondition' Needs I I I Code I Criteria ICriterialCriterial of Soil 10n-Site I I I I I I I I I I I I I I I I I I I I I 23C: I I I I I I I I I I davidson clay loam, 7 I I I I I I I I I I to 15 percent slopes-- DAVIDSON (C)-I NO I I I I I I I I I I I I I I I I I I 58B: I I I I I I I I I myersville silt loam, I l I I I I I I I 2 to 7 percent slopes-IMYERSVILLE I I I I I I I I (C) I NO I I I I I I I I I I I I I I I I I I 51D: I I I I I I I I I I manteo channery silt I I I I I I I I I I loam, 15 to 25 I I I I I I I I I percent slopes IMANTEO (C)---I NO I I I I I I I I I I I I I I I I I I 51B: I I I I I I I I I manteo channery silt I I I I I I I I I I loam, 2 to 7 percent I I I I I I I I I I slopes IMANTEO (C)---I NO I I I I I I I I I I I I I I I I I I U.S. DEPARTMENT OF AGRICULTURE PAGE 2 OF 2 NATURAL RESOURCES CONSERVATION SERVICE HYDRIC SOILS CRITERIA CODES AND DEFINITIONS Endnote -- HYDRIC SOILS LIST The column 'Natural Condition of the Soil' indicates the following information: 'Wooded' indicates the soil supports woody vegetation under natural condition; 'Farmable' indicates the soil can be farmed under natural conditions without removing woody vegetation or other manipulation; and 'Neither' indicates neither of the above conditions are met. 1. All Histosols, except Folists, or 2. Soils in Aquic suborders, great groups, or subgroups, Albolls suborder, Aquisalids, Pachic subgroups, or Cumulic subgroups that are: a. somewhat poorly drained with a water table equal to 0.0 foot (ft.) from the surface during the growing season, or b. poorly drained or very poorly drained and have either: (1) water table equal to 0.0 ft. during the growing season if textures are coarse sand, sand, or fine sand in all layers within 20 inches (in.), or for other soils, or (2) water table at less than or equal to 0.5 ft. from the surface during the growing season if permeability is equal to or greater than 6.0 in/hour (h.) in. all layers within 20 in., or (3) water table at less than or equal to 1.0 ft. from the surface during the growing season, if permeability is less than 6.0 in./h. in any layer within 20 in., or 3. Soils that are frequently ponded for long or very long duration during the growing season, or 4. Soils that are frequently flooded for long or very long duration during the growing season. U.S. DEPARTMENT OF AGRICULTURE PAGE 1 OF 3 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 WATER FEATURES Shadwell Antiq I I Flooding I High water table and ponding I I Map symbol IHydro-I I I I Water I I ( ' Maximum and soil name 'logic I Frequency ' Duration I Months I table I Kind of I Months I Ponding I ponding Igroup I I I depth 'water table' ' duration ' depth I I I I I I I I I I I I I I Ft I I I Ft I I I I I I I I I 23C: I I I I I I I I I DAVIDSON I B 'None I --- I --- I >6.0 I --- I --` I --- I --- I I I I I 58B: I I I I I I I I I MYERSVILLE ' B 'None I I -- ( >6.0 ' --- I --- ' --- ' --- I I I I I I I I 510: I I I I I I I I MANTEO I C/D 'None I --- I --- ' >6.0 ( --- I --- I "-- I I I I I I I I I 51B: I I I I I I I I I MANTEO I C/D 'None I --- I >6.0 --- I --- I --- --- I I U.S. DEPARTMENT OF AGRICULTURE PAGE 2 OF 3 NATURAL RESOURCES CONSERVATION SERVICE 10/26/99 WATER FEATURES Endnote -- WATER FEATURES This report gives estimates of various soil water features. The estimates are used in land use planning that involves engineering considerations. Hydrologic soil groups are used to estimate runoff from precipitation. Soils not protected by vegetation are assigned to one of four groups. They are grouped according to the infiltration of water when the soils are thoroughly wet and receive precipitation from long-duration storms. The four hydrologic soil groups are: Group " A". Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group "B". Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group "C". Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group "D". Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a permanent high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to two hydrologic groups in this report, the first letter is for drained areas and the second is for undrained areas. Flooding, the temporary inundation of an area, is caused by overflowing streams, by runoff from adjacent slopes, or by tides. Water standing for short periods after rainfall or snowmelt is not considered flooding, nor is water in swamps and marshes. This report gives the frequency and duration of flooding and the time of year when flooding is most likely. Frequency, duration, and probable dates of occurrence are estimated. Frequency is expressed as "None", "Rare", "Occasional", and "Frequent". "None" means that flooding is not probable; "Rare" that it is unlikely but possible under unusual weather conditions; "Occasional" that it occurs, on the average, once or less in 2 years; and "Frequent" that it occurs, on the average, more than once in 2 years. Duration is expressed as "Very brief" if less than 2 days, "Brief" if 2 to 7 days, "Long" if 7 to 30 days, and "Very long" if more than 30 days. The information is based on evidence in the soil profile, namely thin strata of gravel, sand, silt, or clay deposited by floodwater; irregular decrease in organic matter content with increasing depth; and absence of distinctive horizons that form in soils that are not subject to flooding. Also considered are local information about the extent and levels of flooding and the relation of each soil on the landscape to historic floods.