Environmental Engineering Reference
In-Depth Information
4.12.2 Quick Identification of Soils That Lack Field
Indicators of Hydric Soils
The following key was created to identify soils that will definitely not meet a Field
Indicator. This key does not identify soils that are not hydric soils. However, the
identification of soils that cannot meet a Field Indicator saves field time by
eliminating the more tedious process of identifying a Field Indicator.
A quick way to identify these soils is to dig a hole to 6 in. (15 cm) and address the
following questions:
1. Do organic soil materials or mucky modified layers exist?
2. Do chromas
2 exist?
3. Are there any distinct or prominent redox concentrations as soft masses or pore
linings?
4. Is it a sandy soil with stripped zones?
5. Is there a hydrogen sulfide odor?
6. Are you in red parent material, a depression, on a floodplain, or within 200 m
(656 ft.) of an estuarine marsh and 1 m (3.3 ft.) of mean high water?
If answer is no to all five questions, the soil will not meet an indicator. This does
not mean the soil is not hydric. If the soil meets the definition of a hydric soil but
fails this test it only means it will not meet a Field Indicator.
4.12.3 Problematic Soil Situations
There are many problematic soil situations that currently lack an appropriate Field
Indicator. Chapter 5 of the Corps Regional Supplements suggests methods to assist
in the identification of a hydric soil in these problematic situations. Also, at the end
of Chapter 3 of each Regional Supplement is a list of test indicators that may help in
problematic soil situations. Test indicators are Field Indicators that show potential
but have not been approved by the NTCHS.
If no hydric soil indicator is present, the additional site information below may
be useful in documenting whether the soil is indeed non-hydric or if it might
represent a “problem” hydric soil that meets the hydric soil definition despite the
absence of indicators. Addressing the following questions can aid in the identifica-
tion of problematic soil situations.
1.
Hydrology
- Is standing water observed on the site or is water observed in the
soil pit? What is the depth of the water table in the area? Is there indirect
evidence of ponding or flooding? Is the site adjacent to a downcut or channelized
stream? Is the hydrology impacted by ditches or subsurface drainage lines?
2.
Slope
- Is the site level or nearly level so that surface water does not run off
readily, or is it steeper where surface water would run off from the soil?
