Transcript Powerpoint - Colorado FFA

Section: Plant & Soil Science
Unit: Soil Management
Lesson Title: Homesite evaluations
1
SURFACE TEXTURE
• A certain feel based on their make-up sand, silt, and
clay,
• Classified as fine, medium, and coarse.
TEXTURE CLASSES
FINE
clay (C), sandy clay (SC), clay loam (CL), silty
clay (SiC), silty clay loam (SiCL)
MEDIUM
sandy clay loam (SCL), loam (L), silt loam (SiL),
silt (Si)
COARSE
sand (S), loamy sand (LS), sandy loam (SL)
2
PERMEABILITY
•The speed of internal soil drainage. What areas do you
think internal drainage affects?
PERMEABILITY CLASSES
VERY SLOW
Sandy clay, silty clay, and clay subsoils
are plastic and sticky when wet and very hard when
dry
SLOW
Clay loam, sandy clay loam and silty clay loam
subsoils, often with subangular blocky or massive
structure
MODERATE
Sandy loam, loam, silt loam and silt subsoils with
weak prismatic to blocky structure
RAPID
Sand and loamy sand subsoils
3
SOIL DEPTH
• The vertical depth of surface soil plus
subsoil plus any material to a level that
would restrict root penetration or inhibit
excavation.
• A factor for basements and determining
the style of the house.
• Soil depth can be very shallow, shallow,
moderately deep, deep, or very deep.
4
SLOPE
• Refers to the inclination of the soil surface,
and has a direct influence on site
drainage.
• Slopes are broken down into;
Gentle, moderate, Strong, Steep, and
Very Steep.
5
EROSION
•Loss of topsoil, airborne soil particles
•Soil piling up in areas not wanted, and
severe rills and gullies create problems
for septic systems, landscaping and
other uses.
•Must be given a soil erosion rating of;
slight, moderate, severe, very severe.
6
Soil Erosion con’t
SOIL EROSION CLASSES
NONE-SLIGHT There is little or no evidence of soil movement. Plants and
rocks show little to no evidence of pedestalling. Gullies are absent.
MODERATE
Litter is deposited against rocks and plant crowns. Small
rock and plant pedestals are present. Rills ½ to 6 inches deep are present
at > 10 foot intervals. Gullies are present and eroding along < 10% of their
length.
SEVERE
Soil is deposited against rocks and plant crowns. Most rocks
and plants are pedestalled and plant roots may be exposed. Rills 3 to 6
inches deep may be present at <5 foot intervals. Gullies are numerous,
well-developed eroding along > 50 % of their length, and are > 100 feet
apart.
VERY SEVERE Frequent, uncrossable gullies are present. Blow-outs may be
numerous and deep. Wind deposits may be present.
7
Surface runoff
•Surface run-off is a problem when water runs off of the
surface before it goes into the soil.
•Most worried about water running off from above and into
our home.
SLOW
SURFACE RUNOFF CLASSES
Occurs on 0-3% slopes and coarse textured
soils.
MODERATE
May occur on 3-5% slopes where soils are
not coarse textured.
RAPID
Usually occurs on >5% slopes where soils
are not coarse textured.
8
Shrink-swell
•Clay percentage determines amount of shrink and swell
•Smectite clay will trap water molecules causing them to swell to many
times their original size, shrinking back to their original size when the water
is removed.
•The horizon having the most clay should be considered when determining
shrink-swell limitations.
SHRINK-SWELL CLASSES AND LIMITATIONS
None-slight
sand, loamy sand and sandy
loam soils
Moderate
loam, silt loam, silt, clay loam,
sandy clay loam and silty clay loam soils
Severe
sandy clay, silty clay and clay soils
9
Water Table
• Refers to how far it is to available water.
• A shallow water table will cause many problems
for a home site.
• Look at the time of the year when the water table
is the closest to the surface.
• Water table depth can be broken into the
following areas: slight, moderate, and severe.
10
Flooding
• As home areas become urbanized and the area
becomes “sealed” with asphalt or concrete,
surface runoff increases dramatically.
• If the site is close to a floodplain, the flood
hazard may also increase.
• Landscape position and proximity to streams
are flood hazard indicators.
•
Our ratings are; None, Rare, and Frequent.
11
Surface Texture
Building
Landscaping
Foundations
Fine
Severe
Severe
Medium
None-Slight
None-Slight
Coarse
Moderate
Moderate
Septic
Systems
Sewage
Lagoons
12
Permeability
Building
Foundations
Landscaping
Septic
Systems
Sewage
Lagoons
Very Slow
Severe
Very Severe
None to
Slight
Slow
Moderate
Severe
None to
Slight
Moderate
None to
Slight
Moderate
Moderate
Rapid
Moderate
Very Severe
Severe
13
Soil Depth
Depth
(inches)
Building
Foundation Landscaping
Septic
Systems
Sewage
Lagoons
Very
Shallow
<10
Very
Severe
Very Severe
Very
Severe
Very
Severe
Shallow
10-20
Severe
Severe
Very
Severe
Very
Severe
Moderately
Deep
20-40
Moderate
Moderate
Severe
Severe
Deep
40-72
None-Slight
None-Slight
Moderate
Moderate
Very Deep
>72
None-Slight
None-Slight
NoneSlight
NoneSlight
14
Slope
Slope (%)
Building
Foundation
Landscaping
Septic
Systems
Sewage
Lagoons
Nearly
Level
0-3
None-Slight
None-Slight
NoneSlight
NoneSlight
Moderate
3-5
None-Slight
None-Slight
NoneSlight
Moderate
Strong
5-8
None-Slight
None-Slight
NoneSlight
Moderate
Steep
8-15
Moderate
Moderate
Moderate
Severe
Very
Steep
>15
Severe
Severe
Severe
Severe
15
Erosion
Building
Landscaping
Foundations
Septic
Systems
Sewage
Lagoons
None-Slight
None-Slight
None-Slight
None-Slight
None-Slight
Moderate
None-Slight
None-Slight
None-Slight
None-Slight
Severe
Moderate
Moderate
Moderate
Moderate
Very Severe
Severe
Severe
Severe
Severe
16
Surface Run-off
Building
Landscaping
Foundations
Septic
Systems
Slow
Severe
None-Slight
Severe
Moderate
None-Slight
None-Slight
None-Slight
Rapid
None-Slight
Severe
None-Slight
Sewage
Lagoons
17
Shrink-swell
Building
Landscaping
Foundations
Septic
Systems
Sewage
Lagoons
Low
None-Slight
None-Slight
None-Slight
Moderate
Moderate
Moderate
Moderate
High
Severe
Severe
Severe
18
Water Table
Building
Landscaping
Foundations
Septic
Systems
Sewage
Lagoons
Slight
>30”
>24”
>72”
>60”
Moderate
18-30”
12-24”
48-72”
40-60”
Severe
<18”
<12”
<48”
<40”
19
Flooding
Building
Landscaping
Foundations
Septic
Systems
Sewage
Lagoons
None
None-Slight
None-Slight
None-Slight
None-Slight
Occasional
Severe
None-Slight
Moderate
None-Slight
Frequent
Severe
Severe
Severe
Severe
20