Appendix B. Technical Memoranda and Reports

Transcription

1 Cotton Belt Corridor Regional Rail Project Draft Environmental Impact Statement Appendix B Technical Memoranda and Reports Technical memoranda and reports were prepared as independent documents to support the preparation of the Draft Environmental Impact Statement (DEIS) for the Cotton Belt Corridor Regional Rail Project. Information from these documents was incorporated into the DEIS to provide information on existing conditions, and in some cases assess potential impacts to the resources. Information contained in the DEIS is the most current and supersedes information in the technical memoranda and reports

2 Cotton Belt Corridor Regional Rail Project Draft Environmental Impact Statement B-9 Geology and Soils Existing Conditions Technical Memorandum

3 Memo Date: Friday, June 23, 2017 Project: Task Order 32- Cotton Belt Corridor PE/DEIS To: John Hoppie, Project Manager, DART Capital Planning From: Tom Shelton, GPC6 Program Manager Subject: DART GPC VI; Contract Number: C ; Cotton Belt Corridor Geology and Soils Existing Conditions Technical Memorandum; HDR PN: Introduction: This memorandum addresses geology and soils found within the Cotton Belt Regional Rail Corridor Project (Cotton Belt Project) study area. The proposed Cotton Belt Project would provide connectivity between the Dallas/Fort Worth International Airport (DFW Airport) and the communities of Grapevine, Coppell, Carrollton, Addison and Dallas, ultimately connecting to the existing Dallas Area Rapid Transit (DART) Red Line Light Rail Transit (LRT) corridor in Plano and Richardson, Texas. The project study area (study area) used for the assessment of potential geological or soil impacts includes a one-quarter-mile corridor positioned on the project centerline of the Cotton Belt Corridor right-of-way (Cotton Belt Corridor). Existing literature and maps in addition to Geographic Information Systems (GIS) resources were then used to evaluate the geology and soils of the study area. Non-digital maps examined include the Geologic Atlas of Texas Dallas Sheet (UT-BEG, 1987), and U.S. Department of Agriculture Natural Resource Conservation Service (NRCS) Soil Surveys for Dallas County (NRCS, 1980), Collin County (NRCS, 1969) and Tarrant County (NRCS, 1981). DESCRIPTION OF EXISTING CONDITIONS This section describes the existing conditions with respect to geology and soils within the study area. Geology Four geologic rock units underlie the project area the Eagle Ford Formation, alluvium, fluviatile terrace deposits, and Austin Chalk. These are discussed below and depicted on Figure 2-1. Figure 2-2 shows an additional east-west, sub-surface, cross-section of the geology of Dallas County. The Eagle Ford Formation, comprised of shale, siltstone, and limestone of late Cretaceous origin, underlies approximately the western one-quarter of the project area, and is also found in the central portion of the project area (UT-BEG, 1987). This formation has an average thickness of Geology and Soils 1

4 Geology and Soils 3

5 Geology and Soils 4

6 475 feet (The Dallas Geological Society, 1965). The Eagle Ford Formation includes primarily blue shale with an occasional thin bed of sandstone, which contains lime concretions of various sizes both as layers and isolated individuals. Although fossils are rarely found in the Eagle Ford Formation, fish bones and teeth are occasionally discovered in this layer (Shuler, 1918). Alluvium consists of sand, silt, clay and gravel of variable thickness and recent origin. This geologic feature is generally associated with major streams. Within the project area, alluvium is found in the vicinity of the Elm Fork of the Trinity River and its tributaries (UT-BEG, 1987). Alluvial deposits result in rich soils, and sand and gravel deposits which contribute to the areas economic value (Shuler, 1918). Fossils are commonly found in these deposits (Shuler, 1918). Fluviatile terrace deposits include sand, gravel, silt, clay, or mud of recent origin. Generally associated with remnants of ancient floodplains, this rock unit and is found on terraces. A small area containing these deposits is found in the central portion of the project area, in association with alluvium (UT-BEG, 1987). Sand deposits in terrace areas have economic value, and fossils are commonly found in them (Shuler, 1987). Austin Chalk, of late Cretaceous origin, is comprised of chalk (microgranular calcite), with some interbedded calcareous clay and hard lime mudstone. It underlies approximately the eastern onehalf of the project area (UT-BEG, 1987). Austin Chalk often overlies the Eagle Ford Formation (The Dallas Geological Society, 1965). This formation is an average of 500 feet thick, and includes alternating beds of chalk, shaly limestone, and marls. These beds have a blue color when saturated with underground water, but are cream or white after exposed to weathering. (Shuler, 1918). The formation includes approximately 85 percent limestone (calcium carbonate), with lesser amounts of silica, zinc oxide, aluminia, and magnesia; iron pyrite concretions are common in the lower layers (Shuler, 1918). Small-scale faulting is a characteristic feature of Austin Chalk; during faulting, the chalk breaks into irregular blocks by fissure planes along which slight movements have taken place (Shuler, 1918). Soils Seven soil associations are found within the project study area. Figure 2-3 displays the soil within the study area. These include (from west to east): Houston Black-Navo-Heiden association gently sloping, deep, clayey and loamy soils of uplands. Includes moderately well drained and well drained soils with slopes of 1 to 5 percent (NRCS 1981); Houston Black-Heiden association deep, nearly level to strongly sloping, clayey soils of uplands. Generally used for pasture or cropland (NRCS, 1980); Wilson-Rader-Axtell association deep, nearly level to gently sloping, loamy soils of uplands. Medium potential for pasture and very slow permeability (NRCS, 1980); Trinity-Frio association deep, nearly level, clayey soils of floodplains that are poorly drained (NRCS, 1980); Eddy-Stephen-Austin association very shallow, shallow, and moderately deep, gently sloping to moderately steep, loamy and clayey soils of uplands. Available water capacity is very low and runoff is medium (NRCS, 1980); Austin-Houston Black association moderately deep and deep, nearly level to sloping, clayey soils of uplands. Permeability is moderately slow, and available water capacity is low (NRCS, 1980); and Geology and Soils 5

7 Houston Black-Austin associations gently sloping to sloping, clayey soils of uplands that are over deep marl and chalk. Most areas are cultivated (NRCS, 1969). A total of 56 different soil map units are found within the study area. Descriptions of each soil map unit are included below (grouped by main soil series type, as appropriate) and depicted on Figure 2-3 along with soils determined to be prime farmland or farmland of statewide importance. Altoga These soils are sloping to strongly sloping and occur on uplands and stream terraces. They are found in Collin and Dallas Counties and are not classified as prime farmland (NRCS 1969; NRCS, 1980; NCRS, 2017). Altoga silty clay, 5 to 8 percent slopes, eroded This soil series occurs on uplands and stream terraces and erosion hazard is severe. This soil is found in Collin County and is not classified as prime farmland (NRCS, 1969; NRCS, 2017). Altoga silty clay, 5 to 12 percent slopes, eroded This soil series consists of deep, well drained, clayey soils found on escarpments of stream terraces. This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Arents These soils are comprised of discarded overburden from gravel and sand mining operations. They are found in Dallas County and are not classified as prime farmland (NRCS 1980; NCRS, 2017). Arents, loamy, gently undulating These areas have been smoothed following discard of mined material and pits have been filled with soil (NRCS, 1980; NCRS, 2017). Arents, loamy, hilly These areas have not been smoothed, and overburden has been left in mounds and ridges (NRCS, 1980; NCRS, 2017). Austin silty clay This soil type consists of deep, calcareous, clayey soils that are gently sloping to sloping (NRCS, 1969; NRCS, 1980). Austin silty clay, 1 to 3 percent slopes This soil series is found in Collin County and Dallas County and is classified as farmland of statewide importance (NRCS, 1969; NRCS, 1980; NCRS, 2017). Austin silty clay, 2 to 5 percent slopes, eroded This soil series is found in Collin County and is not classified as prime farmland (NRCS, 1969; NCRS, 2017). Austin silty clay, 5 to 8 percent slopes, moderately eroded This soil series is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Austin-Urban land complex This complex is made up of nearly level and gently sloping, welldrained soils and areas of Urban land on uplands. These soils are found in Dallas County and are not classified as prime farmland (NRCS, 1980; NCRS, 2017). Austin-Urban land complex, 0 to 2 percent slopes Austin soil makes up approximately 50 percent of the complex, urban (developed) land makes up about 40 percent, and the rest is comprised of minor soils (NRCS, 1980; NCRS, 2017). Bastsil-Urban land complex This complex is made up of nearly level to gently sloping, welldrained soils and areas of urban land. These soils are found in Dallas County and are not classified as prime farmland (NRCS, 1980; NRCS, 2017). Geology and Soils 6

8 Geology and Soils 7

9 Bastsil-Urban land complex, 0 to 2 percent slopes Bastsil soil makes up approximately 40 percent of the complex, urban (developed) land makes up about 35 percent, and the rest is comprised of minor soils (NRCS, 1980; NCRS, 2017). Burleson clay This soil type includes deep, nearly level to moderately sloping clays that have a crusty surface when dry. They are found on uplands and old alluvial terraces along major streams (NRCS, 1981; NRCS, 1980; NRCS, 2017). Burleson clay, 0 to 1 percent slopes This soil series is found in Dallas and Tarrant Counties and is classified as prime farmland (NRCS, 1980; NRCS, 1981; NCRS, 2017). Burleson clay, 1 to 3 percent slopes This soil series is found in Dallas County and is classified as prime farmland (NRCS, 1980; NCRS, 2017). Crockett fine sandy loam This soil type is made up of deep, moderately well drained, nearly level to gently sloping loamy soils on uplands (NRCS, 1980, NRCS, 2017). Crockett fine sandy loam, 1 to 3 percent slopes Deep, gently sloping, moderately well drained soil on uplands. These soils are found in Dallas County and are classified as farmland of statewide importance (NRCS, 1980, NCRS, 2017). Crockett fine sandy loam, 2 to 5 percent slopes, eroded Deep, gently sloping, moderately well drained soil found on uplands. These soils are found in Dallas County and are not classified as prime farmland (NRCS, 1980; NCRS, 2017). Dalco clay, 1 to 3 percent slopes This is a moderately deep, gently sloping, moderately well drained soil of uplands (NRCS, 1980). This soil is found in Dallas County and is classified as prime farmland (NRCS, 1980; NRCS, 2017). Dalco-Urban land complex, 0 to 3 percent slopes This complex includes moderately deep, moderately well drained, nearly level and gently sloping soils and areas of urban land. Dalco soil comprises approximately 50 percent of the complex, urban land comprises 30 percent, and minor soils make up the rest. This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Dutek loamy fine sand, 1 to 5 percent slopes This soil series is deep, gently sloping, and well drained. It is found on old stream terraces on uplands. This soil is found in Dallas and Tarrant counties and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Eddy clay loam, 3 to 8 percent slopes This soil series consists of very shallow to shallow, well drained, gently sloping to sloping soil overlying the Austin Chalk formation. This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Eddy Series The Eddy series consists of soils that are shallow to very shallow, well drained, moderately permeable soils that formed in residuum from chalky limestone. These soils are on gently sloping to moderately steep uplands (NRCS, 1969; NRCS, 2017). Eddy-Stephen complex, 1 to 5 percent slopes This complex consists of gently sloping, well drained, very shallow and shallow soils over the Austin Chalk formation (NRCS, 1980). Eddy soils make up approximately 60 percent of the complex, Stephen soil makes up about 30 percent, and minor soils make up the rest. This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Geology and Soils 8

10 Eddy-Urban land complex This complex includes gently sloping, shallow and very shallow, well drained soils and areas of urban land. These soils are found in Dallas County and are not classified as prime farmland (NRCS, 1980; NCRS, 2017). Eddy-Urban land complex, 1 to 4 percent slopes This complex is made up of approximately 55 percent Eddy soil, 25 percent urban land, and 20 percent minor soils (NRCS, 1980; NCRS, 2017). Eddy-Urban land complex, 4 to 8 percent slopes This complex is made up of approximately 50 percent Eddy soil, 30 percent urban land, and 20 percent minor soils (NRCS, 1980; NCRS, 2017). Ferris-Heiden complex This complex includes deep, well drained, gently rolling and rolling soils on hillsides (NRCS, 1980; NRCS, 1981; NCRS, 2017). Ferris-Heiden complex, 2 to 5 percent slopes -- Found on convex ridges and side slopes, these soils are deep, gently sloping and clayey. Found in Tarrant County, these soils are considered to be prime farmland soils (NRCS, 1981; NRCS, 2017) Ferris-Heiden complex, 5 to 12 percent slopes This complex is comprised up approximately 60 percent Ferris soil, 20 percent Heiden soil, and 20 percent minor soils (NRCS, 1980). It is found in Dallas and Tarrant counties and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Ferris-Urban land complex, 5 to 12 percent slopes This complex is made up of deep, well drained, sloping and strongly sloping soil and area of urban land (NRCS, 1980). Ferris soil comprises approximately 60 percent, urban land comprises approximately 25 percent, and the remainder is minor soils. This soil is found in Dallas and Tarrant counties and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Frio silty clay These soils are deep, well drained, nearly level soils found on floodplains. They soils are found in Dallas County (NRCS, 1980). Frio silty clay, 0 to 1 percent slopes, occasionally flooded This soil is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Frio silty clay, 0 to 1 percent slopes, frequently flooded This soil is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Frio-Urban land complex This complex includes deep, nearly level, well drained soils and areas of urban land on floodplains of small streams (NRCS, 1980). Frio soil makes up approximately 70 percent of the complex, urban land makes up approximately 15 percent, and the rest is minor soils. This soil is found in Dallas and Tarrant counties and is not classified as prime farmland (NRCS, 1980; NRCS, 2017). Heiden clay These soils are deep, well drained, gently sloping soils on uplands (NRCS, 1980). Heiden clay, 1 to 3 percent slopes This soil series is found in Tarrant County and is classified as prime farmland (NRCS, 1981; NCRS, 2017). Heiden clay, 2 to 5 percent slopes, eroded This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Heiden clay, 3 to 5 percent slopes, eroded This soil is found in Collin County and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Houston Black clay This soil type includes deep, calcareous, clayey soils found on uplands or old alluvial terraces. These soils form cracks to a depth of more than 30 inches when dry (NRCS, 1969; NRCS, 1980; NRCS, 1981). Houston Black clay, 0 to 1 percent slopes This soil series is found in Collin County and Dallas counties and is classified as prime farmland (NRCS, 1969; NRCS, 1980; NCRS, 2017). Geology and Soils 9

11 Houston Black clay, 1 to 3 percent slopes This soil series is found in Collin and Dallas Counties and is classified as prime farmland (NRCS, 1969; NRCS, 1980; NRCS, 1981; NRCS, 2017). Houston Black clay, 2 to 4 percent slopes, eroded This soil series is found in Collin County and is not classified as prime farmland (NRCS, 1969; NRCS, 2017). Houston Black-Urban land complex This complex includes deep, moderately well drained, nearly level and gently sloping soils and areas of urban land. This soil type is not classified as prime farmland (NCRS, 2017). Houston Black-Urban land complex, 0 to 4 percent slopes In Dallas County, this complex is made up of approximately 40 percent Houston Black soil, 35 percent urban land, and 25 percent minor soils (NRCS, 1980, NRCS, 2017). Houston Black-Urban land complex, 1 to 4 percent slopes These soils are found on uplands and is moderately well drained. In Tarrant County, the complex is comprised of percent Houston Black soils, percent urban land, and less than 25 percent other, similar soils (NRCS, 1981, NRCS, 2017). Justin loam, 1 to 3 percent slopes This soil is a deep, gently sloping soil found on convex ridges on uplands. Found in Tarrant County, this soil is considered to be a prime farmland soil (NRCS, 1981, NRCS, 2017). Leson clay, 1 to 3 percent slopes This soil is found on uplands and is deep and gently sloping. Found in Tarrant County, they are considered to be prime farmland soils (NRCS, 1981, NRCS, 2017). Lewisville silty clay These soils consist of deep, well drained, calcareous clays that are gently to moderately sloping. They are found on stream terraces and areas that slope to streams (NRCS 1969; NRCS, 1980). Lewisville silty clay, 1 to 3 percent slopes This soil is found in Collin and Dallas Counties (NRCS, 1969; NRCS, 1980). It is classified as prime farmland (NRCS, 2017). Lewisville silty clay, 3 to 5 percent slopes, eroded This soil is found in Collin and Dallas counties and is not classified as prime farmland (NRCS, 1969; NRCS, 2017). Lewisville silty clay, 5 to 8 percent slopes This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1969; NRCS, 2017). Lewisville-Urban land complex This complex is made up of deep, well drained, nearly level and gently sloping soils and areas of urban land (NRCS, 1980). These soils are not classified as prime farmland (NRCS, 1980; NCRS, 2017). Lewisville-Urban land complex, 0 to 4 percent slopes This complex is found in Dallas County, and is comprised of approximately 55 percent Lewisville soil, 30 percent urban land, and 15 percent minor soils (NRCS, 1980). Lewisville-Urban land complex 4 to 8 percent slopes Located in Dallas County, Lewisville soil makes up approximately 60 percent of this complex, urban land makes up 30 percent, and 10 percent is minor soils (NRCS, 1980). Maybank soils Deep, nearly level, somewhat poorly drained soil found in slight depressions on uplands (NRCS, 1980). Geology and Soils 10

12 Mabank fine sandy loam, 0 to 1 percent slopes These soils are found in Dallas County and are classified as farmland of statewide importance (NRCS, 1980; NRCS, 2017). Mabank fine sandy loam, 1 to 3 percent slopes These soils are found in Dallas County and are classified as farmland of statewide importance (NRCS, 1980; NRCS, 2017). Navo clay loam, 1 to 3 percent slopes A deep, gently sloping, loamy soil on side slopes and low ridges along drainageways. This soil is found in Tarrant County and is designated as farmland of statewide importance (NRCS, 1981, NRCS, 2017). Seagoville clay, occasionally flooded This soil series is deep, moderately well drained, and nearly level (NRCS, 1980). It is found on floodplains. This soil is found in Dallas County and is classified as prime farmland (NRCS, 1980; NCRS, 2017). Silawa fine sandy loam, 3 to 8 percent slopes This soil is deep, well drained, gently sloping to sloping, and is found on uplands (NRCS, 1980). This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Stephen-Eddy complex, 2 to 5 percent slopes A very shallow or shallow soil that is well drained and located on uplands. Found in Dallas County, not considered prime farmland (NRCS, 1980, NRCS 2017). Stephen-Urban land complex, 1 to 4 percent slopes This complex includes shallow, well drained, gently sloping soils and areas of urban land over the Austin Chalk formation. Stephen soil comprises approximately 60 percent of the complex, urban land makes up 30 percent, and minor soils make up the rest. This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Sunev clay loam, 3 to 8 percent slopes A deep, well drained, gently sloping soil found on uplands. This soil is found in Dallas County and is not considered to be prime farmland (NRCS, 1980, NRCS, 2017). Trinity clay This soil type includes deep, somewhat poorly drained, calcareous, clayey soils on floodplains of major streams and their tributaries. When dry, these soils can crack to a depth of up to 20 inches (NRCS, 1969; NRCS, 1980). Trinity clay, occasionally flooded This soil is found in Collin and Dallas Counties (NRCS, 1969; NRCS, 1980). In Collin County, it is associated with Pittman Creek. In Dallas County, it is found in association with the Elm Fork of the Trinity River. This soil is not classified as prime farmland (NCRS, 2017). Trinity clay, frequently flooded This soil series is found in Dallas and Tarrant Counties (NRCS, 1980). This soil is not classified as prime farmland soil (NRCS, 2017). Trinity-Urban land complex This complex is made up of deep, nearly level, somewhat poorly drained soils and areas of urban land on floodplains. It is comprised of approximately 60 percent Trinity soil, 20 percent urban land, and 20 percent minor soil. This soil is found in Dallas County and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). Wilson clay loam This is a deep, somewhat poorly drained soil on uplands (NRCS, 1980). Wilson clay loam, 0 to 1 percent slopes This soil is nearly level. It is found in Dallas County and is classified as a farmland of statewide importance (NRCS, 1980; NCRS, 2017). Geology and Soils 11

13 Wilson clay loam, 0 to 2 percent slopes This is a nearly level to gently sloping, loamy soil. It is found on upland ridges and in slightly depressed areas above drainageways. This soil is found in Tarrant County (NRCS, 1981). This soil is classified as farmland of statewide importance (NRCS, 2017). Wilson clay loam, 1 to 3 percent slopes This is a gently undulating soil. It is found in Dallas County and is classified as a farmland of statewide importance (NRCS, 1980; NCRS, 2017). Wilson-Urban land complex, 0 to 2 percent slopes This complex includes nearly level to gently sloping, deep, somewhat poorly drained soils and areas of urban land. Wilson soils make up approximately 60 percent of the complex, urban land makes up 30 percent, and the rest is minor soils. This soil is found in Dallas County, and is not classified as prime farmland (NRCS, 1980; NCRS, 2017). DISCUSSION OF POTENTIAL IMPACTS This section addresses potential impacts to geology and soils. Geology No substantial impacts are anticipated to the geology within the project area. Soils The Farmland Protection Policy Act (FPPA), as detailed in Subtitle I of Title XV of the Agricultural and Food Act of 1981, provides protection to the following: 1) prime farmland; 2) unique farmland; and 3) farmland of local or statewide importance. FPPA defines prime farmland as land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber, and oilseed crops, and is also available for these uses (not urban built-up land or water). It has the soil quality, growing season, and moisture supply needed to economically produce sustained high yields of crops when treated and managed, including water management (irrigation), according to acceptable farming methods. Unique farmland is farmland that is used for production of specific high value food, feed, and fiber crops. Farmland of local or statewide importance is determined by the appropriate state or local government agency or agencies. The project study area contains eleven soil types designated as prime farmland soils, comprising approximately 1,918.9 acres, or 40 percent of the project study area. See Figure 2-3. In addition, eight soils encompassing approximately acres or 9 percent of the project study area are considered to be farmland of statewide importance. However, the project study area is primarily committed to urban use. The FPPA exempts from consideration those lands committed to urban use (within city limits or zoning boundaries). Thus, NRCS, FPPA coordination would not be required for project development activities within the study area. Potential soil erosion and sedimentation during construction will be addressed in a Stormwater Pollution Prevention Plan (SWPPP), to be prepared prior to beginning construction activities. The SWPPP will detail best management practices (BMPs) to be incorporated into the project design related to erosion control, sedimentation control, and post-construction total suspended solids (TSS) removal. Table 3-1 lists individual soil type characteristics, including shrink-swell potential, risk of erosion, risk of corrosion, and constraints related to construction/excavation. Detailed geotechnical borings would be completed prior to the final design stage in order to identify and avoid through design any potential structural stability issues. Geology and Soils 12

14 General Soil Type Altoga Arents Table 3-1. Soil Characteristics Related to Construction Shrink- Swell Potential None Risk of Erosion Risk of Corrosion Uncoated Steel Concrete Severe High Low Low, except on slopes Austin High Moderate High Low Bastsil Burleson Crockett High- high Moderate Slight Construction/ Excavation Constraints Shrink-swell, low strength, erosivity, corrosivity High Low Slope, floods, corrosivity High Low Low Low Dalco Very high Moderate High Low Eddy Low Severe High Low Shrink-swell, low strength, unstable material, corrosivity, erosivity Corrosivity, erosivity Shrink-swell, unstable material, corrosivity, cutbanks cave, low strength, erosivity Shrink-swell, low strength, corrosivity Shrink-swell, low strength, corrosivity, cutbanks cave, erosivity Shallow depth to rock, slope, corrosivity, erosivity Ferris Very high Severe High Low Frio Moderate Slight High Low Heiden Houston Black Justin Very high Very high Slightmoderate Lowmoderate Moderatehigh Lowmoderate Lowmoderate Slightmoderate Moderatehigh Moderatehigh Moderatesevere High High Low Low Moderate Moderate Low Shrink-swell, slope, corrosivity, cutbanks cave, erosivity Floods, low strength, corrosivity Shrink-swell, low strength, corrosivity, cutbanks cave, erosivity Shrink-swell, low strength, corrosivity, cutbanks cave, very plastic material Shrink-swell, changes in moisture and permeability Geology and Soils 13

15 Table 3-1. Soil Characteristics Related to Construction General Soil Type Shrink- Swell Potential Risk of Erosion Risk of Corrosion Uncoated Steel Concrete Leson High Moderate High Low Lewisville High Moderatesevere High Low Construction/ Excavation Constraints Shrink-swell, changes in moisture and slow permeability Shrink-swell, low strength, corrosivity, erosivity Mabank Low-high Slightmoderate Moderatehigh Moderate Shrink-swell, low strength, corrosivity, wetness Navo Moderatehigh Severe High Low Shrink-swell, corrosivity, erosivity Seagoville High-low Slight High-low Low Floods, shrink-swell, cutbanks cave Silawa Low-very low Moderate (wind)- severe (water) Lowmoderate Moderate Corrosivity, erosivity Stephen Moderate Severemoderate High Low Chalky limestone at a depth of 8-20 inches, corrosivity, erosivity Sunev Low Severe Moderate Low Corrosivity, erosivity Trinity Very high Slight High Low Low strength, wetness, floods, shrink-swell, cutbanks cave, corrosivity Wilson Low-high Slightmoderate High Low Low strength, wetness, shrink-swell, corrosivity Sources: NRCS, NRCS, NRCS, Geology and Soils 14

16 Literature/Sources Cited Dallas Geological Society The Geology of Dallas County: Symposium on Surface and Subsurface Geology, Gravity, Physiography, Underground Water Supply, Economic Geology and Engineering Geology of Dallas County. Dallas, Texas. The Geologic Atlas of Texas (GAT) was created United States Geological Survey (USGS), in cooperation with the Texas Water Development Board (TWDB). Natural Resources Conservation Service (NRCS) Soil Survey of Collin County, Texas. United States Department of Agriculture. NRCS Soil Survey of Dallas County, Texas. United States Department of Agriculture. NRCS Soil Survey of Tarrant County, Texas. United States Department of Agriculture. NRCS Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at Accessed (03/29/2017). Shuler, E.W The Geology of Dallas County. University of Texas Bulletin No. 1818: March 25, Bureau of Economic Geology and Technology, Division of Economic Geology. University of Texas Bureau of Economic Geology (UT-BEG) Geologic Atlas of Texas: Dallas Sheet. Geology and Soils 15