1. Soils, Infiltration, and On-site Testing
Presented by:
Mr. Brian Oram, PG, PASEO Wilkes University GeoEnvironmental Sciences and Environmental Engineering Department Wilkes - Barre, PA

2. Soils Defined
Natural Body that Occurs on the Land Surface that are Characterized by One or More of the Following:
Consists of Distinct Horizons or Layers
The ability to support rooted plants in a natural environment
Upper Limit is Air or Shallow Water
Lower Limit is Bedrock or Limit of Biological Activity
Classification based on a typical depth of 2 m or approximately 6.0 feet

3. Another Definition of Soils
A Natural 3 - Dimensional Body at the Earth Surface
Capable of Supporting Plants
Properties are the Result of Parent Material, Climate, Living Matter, Landscape Position and Time.
Soil Composed of 4 Components (mineral matter, organic matter, air, and water)

4. Five Soil Formation Factors
Organisms
Climate
Time
Topography and Landscape Setting
Parent Material R

5. Soil Food Web - Organisms
Micro & Macroscopic
Decomposition of Organic Matter
Animals Living in Soil
Vegetation Types
Human Activity
Redoximorphic Feature Formation
Image Source: The University of Minnesota, 2003

6. Climatic Elements (Energy & Precipitation)
Annual and Seasonal Rainfall
Temperature Range
Biologic Production and Activity
Weathering (Wind, Water, and Ice)
Translocation of Material

7. Climate and Soil Development
Image Source: University of Wisconsin, 2002

8. Geologic Time
Time

9. Landscape and Relief (Soil Texture)
A- Sandy Texture and Loamy Sand B- Sandy Textures
C- Clay Loam, Loam, Silt Loam
Image Source: University of Wisconsin, 2002

10. Landscape and Relief (Drainage)
Water Movement Soil Drainage Landscape Configuration
(Convex, Concave) Elevation Water Movement
Image Source: NJ NRCS, 2002

11. Parent Material Bedrock Geological Materials Minerals and Rocks
Glacial Materials
Loess (wind blown)
Alluvial Deposits
Marine Deposits
Organic Deposits
Influences
Minerals Present
Colors
Chemical Reactions
Water Movement
Soil Development
Glacial Material
Bedrock

12. Describing Soils Soil Texture Structure Consistency Soil Color
Coarse Fragment Content
Redoximorphic Features
other Diagnostic Properties

13. Soil Texture The way a soil "feels" is called the soil texture.
Soil texture depends on the amount of each size of particle in the soil.
The three soil separates are sand, silt, and clay
Sand are the largest particles and they feel "gritty."
Silt are medium sized, and they feel soft, silky or "floury."
Clay are the smallest sized particles, and they feel "sticky" and they are hard to squeeze.

14. Soil Textural Triangle

15. Soil Structures

16. Water Movement and Structure

17. Soil Consistency
Soil Consistency the feel of the soil, reflecting relative resistance to pressure: eg friable, firm, hard, loose, plastic. The term soil consistency is used to describe the resistance of a soil at various moisture contents to mechanical stresses or manipulations. It is commonly measured by feeling and manipulating the soil by hand.

18. Consistency Terms

19. Soil Color Munsell Notations
In the Munsell system of notation,
color characteristics are designated by
three axes: Hue (the name of the color)
Value (the darkness or lightness of the color)
Chroma (the intensity, or strength of the color)
For example, 10YR4/3
Hue (10YR), Value (4), Chroma (3)
Color: brown
In PA - The primary hues are typically 10YR and 7.5YR.

20. Soil Color-Munsell Notation
Red- indicates the presence of Fe-oxides (iron oxides). Grey- indicates the presence of elevated water tables and reduced Fe (iron). Black-indicates the presence of organic matter, Mn-oxides (manganese), or FeS (iron sulfides). Organic matter suggest the soil is nutrient rich and fertile. Iron sulfides occur in wetlands and associated with rotten egg odor.
White- indicates the presence of carbonate or soluble salts.

21. Soil Horizons Layer of Soil Parallel to Surface
Properties a function of climate, landscape setting, parent material, biological activity, and other soil forming processes.
Horizons (A, E, B, C, R, etc)
Image Source: University of Texas, 2002

22. Soil Horizons O- Organic Horizons
Organic Layers of Decaying Plant and Animal Tissue
Aids Soil Structural Development
Helps to Retain Moisture
Enriches Soil with Nutrients
Infiltration Capacity function of Organic Decomposition
O Horizon
Dark in Color Because of Humus Material - 1,000,000 bacteria per cm3

23. Soil Horizons A Horizons: “ Topsoil”
Mineral Horizon Near Surface
Accumulation of Organic Material
Eluviation Process Moves Humic and Minerals form O Horizon into A horizon
Ap - Plowed A Horizon
Ab - Buried Horizon
Soil dark in color, coarser in texture, and high porosity
A Horizon

24. Soil Horizons: E Horizons Albic Horizon (Latin - White)
Mineral Horizon Near Surface
Movement of Silicate Clay, Iron, and Aluminum from the A Horizon through Eluviation
Horizon does not mean a water table is present, but the horizon can be associated with high water table , use Symbol Eg (gleyed modifier)
Underlain by a B (illuvial) horizon
E Horizon

25. Soil Horizons: B Horizons Zone of Maximum Accumulation
Mineral Horizon
Illuviation is Occurring - Movement into the Horizon
B Horizon Receives Organic and Inorganic Materials from Upper Horizons.
Color Influence by Organic, Iron, Aluminum, and Carbonates
Bw - Weakly Colored or Structured
Bhs- Accumulation of illuvial organic material and sesquioxides
Bs- Accumulation of sesquioxides
Bt- Translocation of silicate clay
Bx- Fragipan Horizon, brittle
Bhs Horizon
Bs Horizon
Bw Horizon

26. Soil Horizons: Bx and Bt Horizons
Horizons Indicate Reduced Infiltration Capacity and Permeability
Bx: B horizon with fragipan, a compact, slowly permeable subsurface horizon that is brittle when moist and hard when dry. Prismatic soil structure, mineral coatings and high bulk density
Area of Highest Permeability along Prism Contact
Bt: Clay accumulation is indicated by finer soil textures and by clay coating peds and lining pores

27. C- Horizons Distinguished by Color, Structure, and Deposition
Mineral Horizon or Layer, excluding Rock
Little or No Soil-Forming
May be Similar to Overlying Formation
May be Called Parent Material
Layer can be Gleyed
Developed in Place or Deposited

28. R- Horizons Hard, Consolidated Bedrock
Typically Underlies a C Horizon, but could be directly below an A or B Horizon.
R Horizon

29. Soil Structure and Horizon

30. Source of Soils Data
Soil Surveys in GIS Format
Soil Survey Maps

31. Soil Hydrologic Cycle
Source: Vepraskas, M.J, et. Al. “ Wetland Soils”, 2001.

32. Soil Drainage Class and Soil Group
Soil Drainage Class - Refers to Frequency and Duration of Periods of Saturation or Partial Saturation During Soil Formation. There are 7 Natural Soil Drainage Classes.
Hydrologic Soil Group-Refers to Soils Runoff Producing Characteristics as used in the NRCS Curve Number Method. There area 4 Hydrologic Soil Groups (A, B, C, D).

33. Group A and B Group A- Well Drained
Group A is sand, loamy sand or sandy loam types of soils. It has low runoff potential and high infiltration rates even when thoroughly wetted Deep, well to excessively drained sands or gravels and have a high rate of water transmission. Root Limiting / Impermeable layers over 100 cm or 40 inches *****************
Group B is silt loam or loam. It has a moderate infiltration rate when thoroughly wetted Moderately deep to deep, moderately well to well drained soils with moderately fine to moderately coarse textures. Root Limiting / Impermeable e layers over 50 to 100 cm or 20 to 40 inches
Group A- Well Drained

34. Group C and D Group D - Poorly Drained Highest Runoff Potential
Group C soils are sandy clay loam. They have low infiltration rates when thoroughly wetted and consist chiefly of soils with a layer that impedes downward movement of water and soils with moderately fine to fine structure. Perched water table 100 to 150 cm or 40 to 60 inches; root limiting 20 to 40 inches *****************
Group D soils are clay loam, silty clay loam, sandy clay, silty clay or clay. They have very low infiltration rates when thoroughly wetted and consist chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near the surface and shallow soils over nearly impervious material ( < 20 inches).
Group D - Poorly Drained Highest Runoff Potential

35. Definitions
Infiltration - The downward entry of water into the immediate surface of soil or other materials.
Infiltration Capacity- The maximum rate at which water can infiltrate into a soil under a given set of conditions.
Infiltration Rate- The rate at which water penetrates the surface of the soil and expressed in cm/hr, mm/hr, or inches/hr. The rate of infiltration is limited by the capacity of the soil and rate at which
water is applied to the surface. This is a volume flux of water flowing into the profile per unit of soil surface area (expressed as velocity).
Percolation -Vertical and Lateral Movement of water through the soil by gravity.

36. Infiltration Rate and Capacity
Soil Factors that Control Infiltration Rate: - Vegetative Cover, Root Development and Organic Content
- Moisture Content
- Soil Texture and Structure - Porosity and Permeability
- Soil Bulk Density and Compaction
- Slope, Landscape Position, Topography

37. Infiltration Rate (Time Dependent)
Decreasing Infiltration
Steady Gravity Induced Rate
Infiltration with Time Rate is Initially High Because of a Combination of Capillary and Gravity Forces
Final Infiltration Capacity (Equilibrium)- Infiltration Approaches Saturated Permeability

38. Infiltration Rate (Moisture)
Infiltration Decreases with Time 1) Changes in Surface and Subsurface Conditions 2) Change in Matrix Potential 3) Overtime - Matrix Potential Decreases and Gravity Forces Dominate - Causing a Reduction in the Infiltration Rate

39. Measuring Infiltration Rate
Flooding (ring) Infiltrometers
Single ring
Double ring
Flooded Infiltrometers
Tension Infiltrometers
Rainfall-Runoff Plot Infiltrometers

40. Measuring Infiltration Rate

41. Single Rings Infiltrometers
Cylinder - 30 cm in Diameter Drive 5 cm or more into Soil Surface or Horizon Water is Ponded Above the Surface
Record Volume of Water Added with Time to Maintain a Constant Head
Measures a Combination of Horizontal and Vertical Flow

42. Double Rings Infiltrometers
Outer Rings are 6 to 24 inches in Diameter (ASTM - 12 to 24 inches) Mariotte Bottles Can be Used to Maintain Constant Head Rings Driven - 5 cm to 6 inches in the Soil and if necessary sealed

43. Other Infiltrometers Ponded Infiltrometers
Tension Infiltrometer Unsaturated Flow Of Water

44. Infiltration Rate by Soil Group/ Texture
Source: Texas Council of Governments, 2003.

45. Infiltration Rate Function of Slope & Texture
Source: Rainbird Corporation, derived from USDA Data

46. Infiltration Rate Function of Vegetation
Source: Gray, D., “Principles of Hydrology”, 1973.

47. Comparison Infiltration to Percolation Testing
Percolation Testing Over Estimated Infiltration Rate by 40 to over 400%

49. Infiltration (Compaction/ Moisture Level)

50. Case 1 :Myers Proposed Development Worcester Township, Pennsylvania
Abbottstown Silt Loam, Deep to Moderately Deep, Somewhat Poorly Drained
Some Areas Shallow Depth to Firm Bedrock
Signs of Erosion
Low Surface and Near Surface Infiltration Rates Associated with Surface Smearing, Btx, Bx Horizons
BC/ C /R Horizons Higher Infiltration Rate.
Readington Silt Loam
Deep Moderately Well Drained
Low Infiltration Surface, Bd, and Btx
High Infiltration in C and R Horizons

51. Infiltration Rate Function of Horizon A, B, Btx, Bt, C, R C/R Testing - Areas Fractured Rock
Source: On-site Infiltration Testing - Mr. Brian Oram (Wilkes University)

52. Evaluation Infiltration
Step 1: Desktop Assessment - GIS
Review Published Data Related to Soils, Geology, Hydrology
Step 2: Characterize the Hydrological Setting Where are the Discharge and Recharge Zones? What forms of Natural Infiltration or Depression Storage Occurs?
Step 3: On-Site Assessment
Deep Soil Testing Throughout Site Based on Soils and Geological Data
Double Ring Infiltration Testing
How will water move through the site ?
Step 4: Engineering Review and Evaluation
Step 5: Additional Infiltration or On-site Testing
Step 6: Final Design

53. Soils, Infiltration, and On-site Testing
Presented by:
Mr. Brian Oram, PG, PASEO Wilkes University GeoEnvironmental Sciences and Environmental Engineering Department Wilkes - Barre, PA 18766

54. Horton Equation (1939)
Infiltration is a Function of Time as defined by:
f(t) = fc + (fo – fc)e^-kt f(t) = infiltration rate for any time “t” from beginning of infiltration
fc = infiltration capacity fo = initial infiltration rate at (t=0)
e = 2.71 =base of natural log
k is a measure of the rate of decrease in infiltration rate (constant that depends on soil type)
Large Watershed Application - Replaced by Philip and Green-Ampt Horton Method Used in EPA Storm Water Management Model

55. Green-Ampt Equation Soil pores are saturated behind wetting front;
Green-Ampt model was the first physically-based model/equation describing the infiltration of water into soil. The model yields cumulative infiltration and the infiltration rate as an implicit function of time. The volume of infiltration was a function of:
Soil pores are saturated behind wetting front;
Wetting front moves in response to capillary forces; and
Darcy’s flow governs that headloss in the saturated zone.
Approx. Equation: f = (A/F)+B; f = infiltration rate, F - accumulative infiltration, and A and B are fitted parameters
The Green-Ampt Model has been modified to calculate water infiltration into non-uniform soils by several researchers . In 1989, GALAYER was developed for heterogenous soils
Models Available at:

56. Philip Equation (1960)
where: F = total depth of infiltrated water in mm. t = time in seconds K = hydraulic conductivity in mm/sec m = the average moisture content of the soil to the depth of the wetting front m­­0 = initial soil moisture content - based on API calculation or input Pot = capillary potential at the wetting front in mm Pot = 250 log (K) + 100
D1 = depth of water on the soil surface
Takes into account the “Ponding Head”
Models Available at:

57. Soils, Infiltration, and On-site Testing
Presented by:
Mr. Brian Oram, PG, PASEO Wilkes University GeoEnvironmental Sciences and Environmental Engineering Department Wilkes - Barre, PA 18766