FFA Soils Presentation Summer 2015 Urban Contest - Slope Urban - - PowerPoint PPT Presentation

FFA Soils Presentation

Summer 2015

Urban Contest - Slope

Urban Contest - Landform

Urban Contest – Flood Hazard/Soil Stability

Slippage/Subsidence

The vast majority of soil conditions in Ohio are typically stable. However, some areas of the state have soil features that create stability issues resulting in landslides, and subsidence. In fact, per capita wise, the Cincinnati area is often called the slip prone capital of the US.

• Slippage typically occurs on slopes that are greater than 12

percent, where impervious strata (bedrock) underlie clay or fine textured materials.

• Subsidence is settling of organic soils, soils containing

semifluid layers or materials that are dissolved in solution.

Urban Contest – Texture, Surface

Soil Texture

• Relative proportion of

sand, silt and clay in a soil sample

• Does not include
• rganic matter

Soil Separates

• Most soils have a combination of soil

particles sizes

• Sand
• Silt
• Clay

Texture ( Particle Size Distribution )

• Important for determining

suitability for various uses

• Considered a basic property

because it doesn’t change

Soil Texture Classification Systems

• USDA Soil Texture Classification System
• Unified Soil Classification System
• AASHTO (American Association of State Highway and Transportation

Officials )

Particle Sizes

• Clay: less than 0.002 mm
• Silt: 0.002-0.05 mm
• Sand: 0.05-2 mm
• 0.05 – 0.1 mm very fine
• 0.1 – 0.25 mm fine
• 0.25 – 0.5 mm medium
• 0.5 – 1 mm coarse
• 1 – 2 mm very coarse
• Gravels: 2-75 mm
• Cobbles:75-250 mm
• Stones: 250-600 mm
• Boulders: >600 mm

. Sand

Silt

Clay

Sand Silt Clay Beachball Frisbee Dime

Texture Determination

• Laboratory Methods
• Pipette method
• Hydrometer method
• Field
• “Feel” of soil when

moistened and worked

• Graininess, coherence,

smoothness, stickiness

• Ribboning behavior

Sand + Silt + Clay = 100%

Texture = CLAY LOAM 34 % Sand 33 % Silt 33 % Clay

FFA Land Judging Texture

• Old Contest
• 3 textures
• Sand (sand, loamy sand)
• Clay (sandy clay, clay, silty

clay)

• Loam (silt, silt loam, loam,

sandy loam, sandy clay loam, clay loam, silty clay loam)

• New Contest
• 5 textures
• Coarse (sand, loamy sand)
• Moderately Coarse

(sandy loam)

• Medium (loam, silt loam,

silt)

• Moderately Fine (sandy

clay loam, clay loam, silty clay loam)

• Fine (sandy clay, clay, silty

clay)

Triangle Comparison

Urban Contest – Texture, Subsoil

Urban Contest – Texture, Substratum

Urban Contest – Structure, Subsoil

Urban Contest – Structure, Subsoil

• Soil Structure is the result of soil particles that bind

together to form aggregated soil peds. Structure is a very important characteristic of the soil because it can allow or disallow good air and water movement, and allow for good root penetration.

Structure Types

Granular

Blocky

Platy

Single Grained

Massive

Urban Contest – Drainage Class

Redoximorphic Features

• Redoximorphic features are red, yellow and gray

colored depletions and concentrations that are indicative of a saturated zone within the soil

• profile. Redox depletions are gray in color

(chromas of < 2) where elements solubilized by anaerobic or reducing conditions have been

• removed. The redox depletions are the indicator
• f where the water table is located. Redox

concentrations are the red or red-yellow concentrations of iron oxides. Redox features are described by their presence, abundance, and contrast.

Redoximorphic Features

Redoximorphic Features

Concentrations and Depletions

Urban Contest – Drainage Class

Urban Contest – Drainage Class

Urban Contest – Depth to Restrictive Soil Features

Urban Contest – Depth to Restrictive Soil Features

• Any layer that limits water and roots altogether, or into

vertical seams and plains of weakness.

• NOT Bedrock!
• Dense Glacial Till
• Fragipans
• Dense Lacustrine Deposits.

* The above are only examples of layers that could be considered

• restrictive. Other layers not listed could still limit water and roots, and

would still be considered a restrictive feature.

Urban Contest – Depth to Bedrock

Bedrock

• Some bedrock is soft in place and can be excavated. Typically

after the material is uncovered, it will harden.

• Siltstone, sandstone and shale are examples of soft bedrock.
• For this contest, both soft and hard bedrock will be considered

bedrock.

Urban Contest – Part II

Urban – BMPs – Buildings with Basements

BMP

• Moderate to extensive landshaping is required; a protective

soil cover should be used to reduce erosion during construction. Condition to call for BMP

• Slopes between 6 and 35 percent

Urban – BMPs – Buildings with Basements

BMP

• Choose an alternate site. - *when this is selected , no other

selection should be marked Condition to call for BMP

• Areas subject to flooding, slippage, subsidence, seasonal

high water table less than 8 inches on nearly level concave slope, or slopes greater than 35 percent

Urban – BMPs – Buildings with Basements

BMP

• Basement walls should be reinforced and porous material

used for backfill to reduce damage from shrinking and swelling. Condition to call for BMP

• Fine texture present in the subsoil or substratum

Urban – BMPs – Buildings with Basements

BMP

• Footer drains, elevated site, exterior waterproofing coatings
• n the basement walls, and granular porous material for

backfill should be used to prevent wet basements. Condition to call for BMP

• Seasonal high water table present within 40 inches

Urban – BMPs – Buildings with Basements

BMP

• Basement excavation should include 3/1 side slopes to

decrease the likelihood of soil sloughing and undercutting.

• Condition to call for BMP
• Single grained soil structure in the subsoil

Urban – BMPs – Buildings with Basements

BMP

• Moderate to extensive excavation of bedrock is required, or

redesign the building to accommodate the site. Condition to call for BMP

• Bedrock within 60 inches

Urban – BMPs – Buildings with Basements

BMP

• Good site; limitations are easy to overcome.

Condition to call for BMP

• No moderate or severe limitations

Urban – BMPs – Sewage Treatment Systems

BMP

• Manufacturer’s prohibitions and instructions should be

followed when installing components on steep slopes. An alternative method of distribution should be used. Condition to call for BMP

• Slopes greater than 18 percent

Urban – BMPs – Sewage Treatment Systems

BMP

• Choose an alternate site.

Condition to call for BMP

• Areas subject to flooding, slippage or subsidence

Urban – BMPs – Sewage Treatment Systems

BMP

• Use an alternative system or design component such as drip

distribution, spray irrigation, or an approved pretreatment device to ensure uniform dispersal and water quality standards. Condition to call for BMP

• Any of the following present: Slopes 6 to 12 %, coarse or

fine texture in any layer, single grained, platy or massive soil structure, moderately deep to restrictive features or bedrock.

Urban – BMPs – Sewage Treatment Systems

BMP

• Design and implement an engineered drainage system to

effectively lower the seasonal water table. Condition to call for BMP

• Seasonal high water table within a depth of 16 inches,

with no other moderate or severe limitations.

Urban – BMPs – Sewage Treatment Systems

BMP

• Elevate the infiltrative surface of soil absorption components

above the ground surface to increase the vertical separation distance through the use of approved sand fill material. Condition to call for BMP

• Less than 20 inches to restrictive soil features or bedrock

Urban – BMPs – Sewage Treatment Systems

BMP

• Conventional leaching trenches will work well on this site.

Condition to call for BMP

• No moderate or severe limitations

Urban – BMPs – Driveways and Local Roads

BMP

• Contruct driveways and local roads across the slope to reduce

the angle of incline. Place drainage ditch on the upslope side. Condition to call for BMP

• Slopes greater than 6 percent

Urban – BMPs – Driveways and Local Roads

BMP

• Elevate driveways and local roads above the anticipated high

water level Condition to call for BMP

• Flood plains

Urban – BMPs – Driveways and Local Roads

BMP

• Costly measures are needed to reduce the hazard of slippage
• r subsidence.

Condition to call for BMP

• Soils subject to slippage or subsidence

Urban – BMPs – Driveways and Local Roads

BMP

• Replace the surface soil and/or subsoil with suitable base

material to prevent damage due to low soil strength. Condition to call for BMP

• Any of the following present: medium textured soil in any

layer, or moderately fine textured soil in the surface, single grained and granular structure in the subsoil.

Urban – BMPs – Driveways and Local Roads

BMP

• Surface and/or subsurface drainage is needed to reduce

wetness and increase soil strength. Condition to call for BMP

• Seasonal high water table within a depth of 16 inches

Urban – BMPs – Driveways and Local Roads

BMP

• Costly measures are needed for excavating, filling, and grading

roadbeds and driveways. Condition to call for BMP

• Bedrock within a depth of 40 inches

Urban – BMPs – Driveways and Local Roads

BMP

• Good site; limitations are easy to overcome.

Condition to call for BMP

• No moderate or severe limitations

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Avoid unnecessary cutting of the soil during construction.

Provide mulch on new lawns and around trees and shrubs to prevent erosion. Condition to call for BMP

• Slopes greater than 6 percent

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Choose an alternate site. *when this is selected , no other

selection should be marked Condition to call for BMP

• Areas subject to slippage or subsidence

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Use and manage this site within its limitations

Condition to call for BMP

• Soils subject to flooding

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Mix an adequate layer of medium topsoil in the existing soil

surface layer. Condition to call for BMP

• Fine, moderately fine, or coarse surface texture

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Use plants adapted to adverse subsoil conditions or use an 8

inch cover of medium topsoil to increase the favorable soil depth. Condition to call for BMP

• Any of the following present: fine, moderately fine, or

coarse subsoil or substratum texture; platy or massive subsoil structure.

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Provide surface and/or subsurface drainage. Use plants

tolerant of wetness. Condition to call for BMP

• Seasonal high water table within a depth of 16 inches

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Select shallow rooted trees and shrubs. Use a medium cover
• f soil material to increase soil depth to at least 30 inches

Condition to call for BMP

• Bedrock or restrictive soil feature within a depth of 30

inches

Urban – BMPs – Lawns Gardens and Landscapes

BMP

• Good site; limitations are easy to overcome.

Condition to call for BMP

• No moderate or severe limitations