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HomeMy WebLinkAbout16 NRCS ReportO\LOLSSON ASSOCIATES NRCS Soils Report OXY USA WTP LP Pond 13 E/W Centralized E&P Waste Management Facility OA Project No. 013-0655 760 Horizon Drive, Suite 102 TEL 970.263.7800 Grand Junction, CO 81506 FAX 970.263.7456 www.olssonassociates.com USDA United States Department of Agr culture o\ RCS 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 Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties Oxy Pond 13 E/W May 29, 2013 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 (http://soils.usda.gov/sqi/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (http://offices.sc.egov.usda.gov/locator/app? agency=nrcs) or your NRCS State Soil Scientist (http://soils.usda.gov/contact/ 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 for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (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. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 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 Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties 12 55—Parachute-Irigul complex, 5 to 30 percent slopes 12 56—Parachute-Irigul-Rhone association, 25 to 50 percent slopes 13 Soil Information for All Uses 16 Suitabilities and Limitations for Use 16 Building Site Development 16 Corrosion of Concrete 16 Corrosion of Steel 20 References 25 4 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 Custom Soil Resource Report 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 soil - landscape 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 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 39° 32' 59" 39° 32' 49" a 0 O Custom Soil Resource Report Soil Map CO 0 Map Scale: 1:2,150 if printed on A size (8.5" x 11") sheet. 0 25 50 100 Meters 150 0 100 200 400 Feet 600 108° 12' 52 39° 32' 59" O N m O O w a O O N 03 39° 32' 49" Custom Soil Resource Report MAP LEGEND 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 A. Other Special Line Features Gully Short Steep Slope Other Political Features 0 Cities Water Features Streams and Canals Transportation +++ Rails /wr Interstate Highways US Routes Major Roads y Local Roads MAP INFORMATION Map Scale: 1:2,150 if printed on A size (8.5" x 11") sheet. The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. 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: http://websoilsurvey.nrcs.usda.gov Coordinate System: UTM Zone 12N NAD83 This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 5, Feb 1, 2008 Date(s) aerial images were photographed: 8/29/2005 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. Custom Soil Resource Report Map Unit Legend Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties (C0682) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 55 Parachute-Irigul complex, 5 to 30 percent slopes 7.4 69.9% 56 Parachute-Irigul-Rhone association, 25 to 50 percent slopes 3.2 30.1% Totals for Area of Interest 10.61 100.0% 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 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. 10 Custom Soil Resource Report 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 Custom Soil Resource Report Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties 55—Parachute-Irigul complex, 5 to 30 percent slopes Map Unit Setting Elevation: 7,600 to 8,800 feet Mean annual precipitation: 18 to 22 inches Mean annual air temperature: 36 to 40 degrees F Frost -free period: 65 to 90 days Map Unit Composition Parachute and similar soils: 60 percent Irigul and similar soils: 30 percent Description of Parachute Setting Landform: Mountains Landform position (two-dimensional): Shoulder, summit Landform position (three-dimensional): Mountaintop Down-slope shape: Linear Across -slope shape: Convex Parent material: Residuum weathered from shale and siltstone and/or residuum weathered from sandstone and shale Properties and qualities Slope: 5 to 30 percent Depth to restrictive feature: 20 to 40 inches to paralithic bedrock Drainage class: Well 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: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Low (about 4.0 inches) Interpretive groups Farmland classification: Not prime farmland Land capability (nonirrigated): 6e Hydrologic Soil Group: B Ecological site: Mountain Loam (R048AY228C0) Typical profile 0 to 10 inches: Loam 10 to 25 inches: Very channery loam, extremely channery loam 25 to 29 inches: Unweathered bedrock Description of Irigul Setting Landform: Hills Landform position (two-dimensional): Backslope, shoulder, toeslope, summit, footslope Landform position (three-dimensional): Crest Down-slope shape: Convex Across -slope shape: Convex 12 Custom Soil Resource Report Parent material: Residuum weathered from sandstone and shale Properties and qualities Slope: 5 to 30 percent Depth to restrictive feature: 5 to 20 inches to lithic bedrock Drainage class: Well 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: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Very low (about 1.3 inches) Interpretive groups Farmland classification: Not prime farmland Land capability (nonirrigated): 7e Hydrologic Soil Group: D Ecological site: Loamy Slopes (R048AY303C0) Typical profile 0 to 6 inches: Channery loam 6 to 13 inches: Very channery loam 13 to 17 inches: Unweathered bedrock 56—Parachute-Irigul-Rhone association, 25 to 50 percent slopes Map Unit Setting Elevation: 7,600 to 8,800 feet Mean annual precipitation: 18 to 22 inches Mean annual air temperature: 36 to 40 degrees F Frost -free period: 65 to 80 days Map Unit Composition Parachute and similar soils: 35 percent Irigul and similar soils: 30 percent Rhone and similar soils: 20 percent Description of Parachute Setting Landform: Mountains Landform position (two-dimensional): Summit, shoulder Landform position (three-dimensional): Mountaintop Down-slope shape: Linear Across -slope shape: Convex Parent material: Colluvium derived from sandstone and shale and/or residuum weathered from siltstone Properties and qualities Slope: 25 to 50 percent Depth to restrictive feature: 20 to 40 inches to paralithic bedrock 13 Custom Soil Resource Report Drainage class: Well 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: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Low (about 4.0 inches) Interpretive groups Farmland classification: Not prime farmland Land capability (nonirrigated): 7e Hydrologic Soil Group: B Ecological site: Brushy Loam (R048AY238C0) Typical profile 0 to 10 inches: Loam 10 to 25 inches: Very channery loam, extremely channery loam 25 to 29 inches: Unweathered bedrock Description of Irigul Setting Landform: Hills Landform position (two-dimensional): Toeslope, summit, footslope, backslope, shoulder Landform position (three-dimensional): Crest Down-slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from sandstone and shale Properties and qualities Slope: 25 to 50 percent Depth to restrictive feature: 5 to 20 inches to lithic bedrock Drainage class: Well 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: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Very low (about 1.3 inches) Interpretive groups Farmland classification: Not prime farmland Land capability (nonirrigated): 7e Hydrologic Soil Group: D Ecological site: Loamy Slopes (R048AY303C0) Typical profile 0 to 6 inches: Channery loam 6 to 13 inches: Very channery loam 13 to 17 inches: Unweathered bedrock Description of Rhone Setting Landform: Hills, mountains Landform position (two-dimensional): Backslope, shoulder, summit, footslope Landform position (three-dimensional): Mountainflank, side slope 14 Custom Soil Resource Report Down-slope shape: Concave Across -slope shape: Concave Parent material: Colluvium derived from sandstone and shale and/or residuum weathered from sandstone and shale Properties and qualities Slope: 25 to 50 percent Depth to restrictive feature: 40 to 60 inches to paralithic bedrock Drainage class: Well 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: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water capacity: Moderate (about 7.5 inches) Interpretive groups Farmland classification: Not prime farmland Land capability (nonirrigated): 7e Hydrologic Soil Group: B Ecological site: Brushy Loam (R048AY238C0) Typical profile 0 to 10 inches: Loam 10 to 39 inches: Channery loam 39 to 55 inches: Very channery loam 55 to 59 inches: Unweathered bedrock Soil Information for All Uses Suitabilities and Limitations for Use The Suitabilities and Limitations for Use section includes various soil interpretations 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 interpretation. Building Site Development Building site development interpretations are designed to be used as tools for evaluating soil suitability and identifying soil limitations for various construction purposes. As part of the interpretation process, the rating applies to each soil in its described condition and does not consider present land use. Example interpretations can include corrosion of concrete and steel, shallow excavations, dwellings with and without basements, small commercial buildings, local roads and streets, and lawns and landscaping. Corrosion of Concrete "Risk of corrosion" pertains to potential soil -induced electrochemical or chemical action that corrodes or weakens concrete. 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 results in a severe hazard of corrosion. The concrete in installations that intersect soil boundaries or soil layers is more susceptible to corrosion than the concrete in installations that are entirely within one kind of soil or within one soil layer. The risk of corrosion is expressed as 'low," "moderate," or "high." 16 39° 32' 59" 39° 32' 49" O O 738900 738950 73700 739050 Custom Soil Resource Report Map—Corrosion of Concrete 739100 739150 73700 73V50 739.300 N O co in Tr "cr oa O o _V oe; co co co V m J5 m c7:.e W co co NI- i a O O coco co co O O N W - 1 738900 1 738950 739000 1 739050 Map Scale: 1:2,150 if printed on A size (8.5" x 11") sheet. 0 25 50 100 739100 Meters 150 0 100 200 400 Feet 600 1 739150 739200 739250 739300 N 0 39° 32' 59" O O N ▪ 39° 32' 49" Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest (AOI) Map Scale: 1:2,150 if printed on A size (8.5" x 11") sheet. Area of Interest (AOI) Soils Soil Map Units Soil Ratings 0 High n Moderate n Low Not rated or not available Political Features Cities Water Features Streams and Canals Transportation +++ Rails ,.. Interstate Highways US Routes Major Roads Local Roads The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. 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: http://websoilsurvey.nrcs.usda.gov Coordinate System: UTM Zone 12N NAD83 This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 5, Feb 1, 2008 Date(s) aerial images were photographed: 8/29/2005 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. Custom Soil Resource Report Table—Corrosion of Concrete Corrosion of Concrete— Summary by Map Unit — Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties (C0682) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 55 Parachute-Irigul complex, 5 to 30 percent slopes Low 7.4 69.9% 56 Parachute-Irigul-Rhone association, 25 to 50 percent slopes Low 3.2 10.6 30.1% Totals for Area of Interest 100.0% Rating Options—Corrosion of Concrete Aggregation Method: Dominant Condition Aggregation is the process by which a set of component attribute values is reduced to a single value that represents the map unit as a whole. A map unit is typically composed of one or more "components". A component is either some type of soil or some nonsoil entity, e.g., rock outcrop. For the attribute being aggregated, the first step of the aggregation process is to derive one attribute value for each of a map unit's components. From this set of component attributes, the next step of the aggregation process derives a single value that represents the map unit as a whole. Once a single value for each map unit is derived, a thematic map for soil map units can be rendered. Aggregation must be done because, on any soil map, map units are delineated but components are not. For each of a map unit's components, a corresponding percent composition is recorded. A percent composition of 60 indicates that the corresponding component typically makes up approximately 60% of the map unit. Percent composition is a critical factor in some, but not all, aggregation methods. The aggregation method "Dominant Condition" first groups like attribute values for the components in a map unit. For each group, percent composition is set to the sum of the percent composition of all components participating in that group. These groups now represent "conditions" rather than components. The attribute value associated with the group with the highest cumulative percent composition is returned. If more than one group shares the highest cumulative percent composition, the corresponding "tie-break" rule determines which value should be returned. The "tie-break" rule indicates whether the lower or higher group value should be returned in the case of a percent composition tie. The result returned by this aggregation method represents the dominant condition throughout the map unit only when no tie has occurred. Component Percent Cutoff: None Specified Components whose percent composition is below the cutoff value will not be considered. If no cutoff value is specified, all components in the database will be considered. The data for some contrasting soils of minor extent may not be in the database, and therefore are not considered. 19 Custom Soil Resource Report Tie-break Rule: Higher The tie-break rule indicates which value should be selected from a set of multiple candidate values, or which value should be selected in the event of a percent composition tie. Corrosion of Steel "Risk of corrosion" pertains to potential soil -induced electrochemical or chemical action that corrodes or weakens uncoated steel. 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. Special site examination and design may be needed if the combination of factors results in a severe hazard of corrosion. The steel in installations that intersect soil boundaries or soil layers is more susceptible to corrosion than the steel in installations that are entirely within one kind of soil or within one soil layer. The risk of corrosion is expressed as "low," "moderate," or "high." 20 Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest (AOI) Map Scale: 1:2,150 if printed on A size (8.5" x 11") sheet. Area of Interest (AOI) Soils Soil Map Units Soil Ratings 0 High n Moderate n Low Not rated or not available Political Features Cities Water Features Streams and Canals Transportation +++ Rails ,.. Interstate Highways US Routes Major Roads Local Roads The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. 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: http://websoilsurvey.nrcs.usda.gov Coordinate System: UTM Zone 12N NAD83 This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 5, Feb 1, 2008 Date(s) aerial images were photographed: 8/29/2005 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. Custom Soil Resource Report Table—Corrosion of Steel Corrosion of Steel— Summary by Map Unit — Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties (C0682) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 55 Parachute-Irigul complex, 5 to 30 percent slopes Moderate 7.4 69.9% 56 Parachute-Irigul-Rhone association, 25 to 50 percent slopes Moderate 3.2 10.6 30.1% Totals for Area of Interest 100.0% Rating Options—Corrosion of Steel Aggregation Method: Dominant Condition Aggregation is the process by which a set of component attribute values is reduced to a single value that represents the map unit as a whole. A map unit is typically composed of one or more "components". A component is either some type of soil or some nonsoil entity, e.g., rock outcrop. For the attribute being aggregated, the first step of the aggregation process is to derive one attribute value for each of a map unit's components. From this set of component attributes, the next step of the aggregation process derives a single value that represents the map unit as a whole. Once a single value for each map unit is derived, a thematic map for soil map units can be rendered. Aggregation must be done because, on any soil map, map units are delineated but components are not. For each of a map unit's components, a corresponding percent composition is recorded. A percent composition of 60 indicates that the corresponding component typically makes up approximately 60% of the map unit. Percent composition is a critical factor in some, but not all, aggregation methods. The aggregation method "Dominant Condition" first groups like attribute values for the components in a map unit. For each group, percent composition is set to the sum of the percent composition of all components participating in that group. These groups now represent "conditions" rather than components. The attribute value associated with the group with the highest cumulative percent composition is returned. If more than one group shares the highest cumulative percent composition, the corresponding "tie-break" rule determines which value should be returned. The "tie-break" rule indicates whether the lower or higher group value should be returned in the case of a percent composition tie. The result returned by this aggregation method represents the dominant condition throughout the map unit only when no tie has occurred. Component Percent Cutoff: None Specified Components whose percent composition is below the cutoff value will not be considered. If no cutoff value is specified, all components in the database will be considered. The data for some contrasting soils of minor extent may not be in the database, and therefore are not considered. 23 Custom Soil Resource Report Tie-break Rule: Higher The tie-break rule indicates which value should be selected from a set of multiple candidate values, or which value should be selected in the event of a percent composition tie. 24 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://soils.usda.gov/ Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http://soils.usda.gov/ Soil Survey Staff. 2006. Keys to soil taxonomy. 10th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http://soils.usda.gov/ Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://soils.usda.gov/ United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.glti.nrcs.usda.gov/ United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430 -VI. http://soils.usda.gov/ United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://soils.usda.gov/ 25 Custom Soil Resource Report United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. 26