HEALTH RISKS of USING GRAY SOIL COLORS to DETERMINE ONSITE - - PowerPoint PPT Presentation

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HEALTH RISKS of USING GRAY SOIL COLORS to DETERMINE ONSITE - - PowerPoint PPT Presentation

Jul 28, 2023 233 likes •455 views

HEALTH RISKS of USING GRAY SOIL COLORS to DETERMINE ONSITE SUITABILITY Jay F. Conta - Virginia Tech Interpretive Soil Scientist Department of Crop & Soil Environmental Sciences WATER TABLE RESEARCH SITE MATERIALS

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HEALTH RISKS of USING GRAY SOIL COLORS to DETERMINE ONSITE SUITABILITY

Jay F. Conta - Virginia Tech Interpretive Soil Scientist Department of Crop & Soil Environmental Sciences

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WATER TABLE RESEARCH SITE

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MATERIALS AND METHODS

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SOILS STUDIED

Emporia sandy loam: Fine-loamy, siliceous, subactive, Thermic, Typic Hapludult Two research sites in Henrico County, Virginia Both sites in residential subdivisions

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Henrico County Precipitation Comparison

Nov - Dec 99: 42% of long-term average Jan - May 00: near normal (29 yr average) Oct - Dec 00: 41% of long-term average Jan - May 01: 75% of long-term average

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Depth Below Surface (inches)

Hydrograph at Ryall Road Site November 1999- June 2000

Well #1

Strong Brown Concentrations Str Brown & Very Pl Brown Features Gray Depletions NOV/ DEC / JAN / FEB / MAR / APR / MAY / JUN

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Ryall Road: Nov 18, 1999 - May 11, 2000

During this 176 day period where there was water in the

  • bservation well:

0 - 16 None 5 3 16.1- 29 St Brown 112 64 29.1- 41 St Brown & 176 100 Very Pl Brown Depth ( in.) Redox Feature # Days % Cumulative Days

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Depth Below Surface (inches)

Hydrograph at Ryall Road Site December 2000- May 2001

Well #1 Strong Brown Concentrations Strong Brown & Very Pl Brown Features Gray Depletions DEC / JAN / FEB / MAR / APR / MAY

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Ryall Road: Dec 17, 2000- May 2, 2001

During this 137 day period where there was water in the

  • bservation well:

Depth ( in.) Redox Feature # Days % Cumulative Days 0 - 16 None 8 6 16.1- 29 St Brown 68 50 29.1- 40.3 St Brown & 122 89 Very Pl Brown 40.4 - Dry Hole 11 100

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This residence utilized a Puraflo onsite system, with the gravel pad at a depth of 18- 24 inches. This system was designed and installed in compliance with the Sewage Regulations and the manufacturer’s recommendations. Based on this research, the seasonal water table was into the peat moss containers, the gravel pad or the 12 inch standoff zone ( beneath the pad ) at least 1/2 to 2/3 of the time during a winter- spring period.

Summary of Ryall Road Site

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Summary of Ryall Road Site

The Puraflo system directly discharged into the shallow seasonal water table for extended periods

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The Emporia soil clearly met the Oxyaquic criteria. Even during a drought, horizons with strong brown redoximorphic features were saturated for 1/2 to 2/3 of the time during the winter- spring periods.

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Even during a drought, horizons with strong brown & very pale brown redoximorphic features were saturated for 90- 100 % of the time during the winter- spring periods. The presence of redox features clearly relates to the duration of soil wetness. The seasonal water table will be significantly closer to the ground surface than the depth to gray depletions, for extended periods of time.

Summary of Ryall Road Site

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RESEARCH CONTRIBUTORS