Soils, Groundwater Recharge, and On-site Testing

1. Soils, Groundwater Recharge, and On-site Testing Presented by: Mr. Brian Oram, PG, PASEOWilkes UniversityGeoEnvironmental Sciences and Environmental Engineering DepartmentWilkes - Barre, PA 18766570-408-4619 http://www.water-research.net

2. Presentation Dedicated ToMr. John Pagoda, Jr Anthracite Mining History Expert Geologist and Soil Scientist in Training

3. Soils Defined • Natural Body that Occurs on the Land Surface that are Characterizedby One or More of the Following: • Consists of Distinct Horizons or Layers • The ability to support rooted plants in a naturalenvironment • 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 (Chris Watkins, 2002)

4. Soils Are A Three Phase System • A Natural 3 - Dimensional Body at the Earth Surface • Capable of Supporting Plants • Properties are the Result of Parent Material, Climate, Living Matter, Landscape Positionand Time. Soil Composed of 4 Components (mineral matter, organic matter, air, and water) Air and Water – 35 to 55 %Solid Material – 45 to 65 %

5. Five Soil Formation Factors • Organisms • Climate • Time • Topography and Landscape Setting • Parent Material R Point: Soils are Created in Geological Time, but can be destroyed in a very short time – Keys are Proper Site Design and Management

6. Describing SoilsDo Not Rely on Published Soils Mapping • Soil Texture • Structure • Consistency • Soil Color • Coarse Fragment Content • Redoximorphic Features • other Diagnostic Properties

7. Soil TextureGet Your Hands Dirty 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: 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”when wet and they are hard to squeeze.

8. Soil Textural Classification Source: Brady, Nyle. 1990. The Nature and Properties of Soils

9. Soil Textural TriangleUSDA System

10. Soil Structures

11. Water Movement and Structure

12. Field Photos Me Confirmation Testing Side-by-SideTesting Vertical PermeabilityTesting

13. Nearly 50% of Soil is Space or Space Filled with Water • Water – 25+ % • Air – 25 + % • Pore Space Makes Up 35 to 55 % of the total Soil Volume • This Space is called Pore Space

14. Types of Pores Macropores (> 1,000 microns)-Large Mesopores (10 to 1,000 microns)-Medium Micropores (< 10 microns)- Small Source: http://www2.ville.montreal.qc.ca

15. How can a silt loam have more macropores than sand? Source: Brady, Nyle, C. “ The Nature and Properties of Soils” (1990).

16. Better Structural Development More Macropores Source: Brady, Nyle, C. “ The Nature and Properties of Soils” (1990).

17. Key Points on Soil Pores Under gravity, water drains from macropores, where as, water is retained in mesopores and micropores, via matrix forces. Coarse-textured horizons (e.g., sandy loam) tend to have a greater proportion of macropores than micropores- but they may not have more macropores than finer textured soils. Soils with water stable aggregates tend to have a higher percentage of macropores than micropores. Proportion of micropores tends to increase with soil depth, resulting in greater retention of water and slower flow of water .

18. Water Stable Aggregates I Aggregates on left are more water stable, i.e., aggregate stays together and do not separate into the its components, i.e., three soil separates. Water Stable Aggregates

19. Water Stable Aggregates – IIThe Classic Photo Source: Brady, Nyle, C. “ The Nature and Properties of Soils” (1990)Great Desk Reference Text !!!!

20. 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

21. Soil HorizonsO- 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 • Organic Matter Critical in Maintaining Water Stable Peds O Horizon Dark in Color Because of Humus Material - 1,000,000 bacteria per cm3

22. Soil HorizonsA Horizons: “ Topsoil” • Mineral Horizon NearSurface • Eluviation Process Moves Humic and Minerals from O Horizon into A horizon • Ap - Plowed A Horizon • Ab - Buried Horizon • Soil dark in color, coarser in texture, and high porosity A Horizon

23. Soil Horizons: E HorizonsAlbic Horizon (Latin - White) • Mineral Horizon NearSurface • 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

24. Soil Horizons: B HorizonsZone 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

25. 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

26. C- HorizonsDistinguished 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

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

28. Soil Structure and Horizon Source: http://www.vanaturally.com/soil.html

29. Soil Physical Properties • Particle Density (pd)- Approximately 2.65 g/cm^3mass solid particles /volume soilds • Dry Bulk Density (bd) Mass oven dry soils / bulk volume of soil (soils) Mass wet soil/ bulk volume of soil (engineers) • Water Content by weight (Og)Mass of Water/ Mass of dry Soil • Water content by volume (Ov)Volume of Water/ Volume of Soil • Porosity (n)=(1- (Bulk Density /Particle Density)) • Degree Saturation – Volume Wet/ Volume Total • Depth of Water (dw) = Ov* soil depth (d)

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

31. 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 are 4 Hydrologic Soil Groups (A, B, C, D). Drainage Class and Soil Group were developed foragricultural applications.

32. Hydrologic Group A • 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 A- Well Drained

33. Hydrologic Group B 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 Layers over 50 to 100 cm or 20 to 40 inches. Group B With Fragipan

34. Hydrologic Group C 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. Redoximorphic Water

35. Group D • 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). Gleyed Horizon Group D - Poorly DrainedHighest Runoff Potential

36. Hydrologic Soil Terms • Infiltration - The downward entry of water into the immediate surface of soil or other materials. • Infiltration Flux (or Rate)- The volume of water that 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. It is a volume flux of water flowinginto the profile per unit of soil surface area (expressed as velocity). • Infiltration Capacity (fc)- The amount of water per unit area of time that water can enter a soil under a given set of conditions at steady state. • Cumulative infiltration:Total volume of water infiltrated per unit area of soil surface during a specified time period. Horton Equation, Philip Equation, Green- Ampt Equation

37. Flux Density or Permeability Flux Density (q): The volume of water passing through the soil per unit cross-sectional area per unit of time. It has units of length per unit time such as mm/sec, mm/hour, or inches/ day (q = -K(ΔH/L )) Actually the term is volume/area/time= q = Q/At Hydraulic Conductivity (K)quantitative measure of a saturated soil's ability to transmit water when subjected to a hydraulic gradient. It can be thought of as the ease with which pores of a saturated soil permit water movement . Side by Side (Pagoda, J, 2004)

38. Percolation Rate Percolation -Downward Movement of Water through the soil by gravity. (minutes per inch) at a hydraulic gradient of 1 or less. Used and Developed for Sizing Small Flow On-lot Wastewater Disposal Systems. Onlot Disposal Regulations (Act 537) has preliminary Loading equations, but for large systems regulations typically require permeability testing. Also none as the Perc Test, SoakAway Test (UK) Not Directly Correlated to or a Component of Unsaturated or Saturated Flow Equations

39. Comparison Infiltration to Percolation Testing Percolation Testing Over Estimated Infiltration Rate by 40% to over 1000% * Source: On-site Soils Testing Data, (Oram, B., 2003)

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

41. Infiltration Rate Function of Slope & Texture Source: Rainbird Corporation, derived from USDA Data (Oram,2004)

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

43. Infiltration (Compaction/ Moisture Level) Site Compaction – Can Significantly Reduce Surface Infiltration Rate

44. Rain Drop Impact Bare Soil Destroys Soil AggregatesDisperses Soil SeparatesSeals Pore SpaceAids in Loss of Organic Material Creates a Surface Crust Source: (D. PAYNE, unpublished)http://www.geographie.uni-muenchen.de

45. Infiltration Rate (Time Dependent) Steady Gravity Induced Rate Infiltration with Time Initially High Because of a Combination of Capillary and Gravity Forces f = fc +(fo-fc) e^-ktfc does not equal K Final Infiltration Capacity(Equilibrium)- InfiltrationApproaches q - Flux Density

46. Infiltration Rate Decreases with Time 1) Changes in Surface and Subsurface Conditions2) Change in Matrix Potential and Increase in Soil Water Content and Decrease in Hydraulic Gradient3) Overtime - Matrix Potential Decreases and Gravity ForcesDominate - Causing a Reduction in the Infiltration Rate 4) Reaches a steady-state conditionfc – final infiltration rate

47. Infiltration Rate Function of Horizon A, B, Btx, Bt, C, RC/R Testing - Areas Fractured Rock Source: On-site Infiltration Testing - Mr. Brian Oram, PG (2003)

48. Double Ring Infiltrometer

49. Single Rings Infiltrometers Cylinder - 30 cm in Diameter- Smaller Rings Available.Drive 5 cm or more into Soil Surface or Horizon.Water is Ponded Above the Surface- Typically < 6 inches. Record Volume of Water Added with Time to Maintain a Constant Head. Measures a Combination of Horizontal and Vertical Flow

50. ASTM 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 HeadRings Driven - 5 cm to 6 inches in the Soil and if necessary sealed Very Difficult to Install and Seal – ASTM Double Rings in NEPA