Piedmont Hydric Soils

MAPSS Hydric Soils Workshop Notes, Eastern Mountains and Piedmont Regional Supplement, November 15-16, 2010

Day One, 11/15/10

The v.2.0 (final) Piedmont Manual will be in force on October 13, 2011.

A re-write of the 1987 Wetland Delineation Manual (v.2.0) will be out by December 31, 2010 and contain three-pages of “normal circumstances.”

Always address “landscape position” on data sheets and in reports (page 7 in Manual).

A new National List of Plant Species That Occur in Wetlands: Northeast (Region 1) is pending, which will include many more non-native, horticultural plants.  2000 of the 5000 Region 1 plants are non-native.  The new plant list will remove the plus and minus modifiers.  Remember that OBL, FACW, FAC and FACU are “probabilities” that they occur in a wetland and/or upland.

Adding photos is an important consideration at each data station.  Compose the photo to be a good representation of the wetland or upland in question.

Many JD field reviews by Frank at the Corps show that delineators do not know plant identification very well.  Gave path rush as an example, many plants mis-identified.

Plot location is important, consider micro-topography, shrink the plot size if you need to.  Make the plot dimensions fit entirely within the wetland so that you are not reading upland plants out along the margins of the plot.  The plot does not have to be a 30-foot radius, it can be a square, rectangle or whatever it take to get a true read of the micro-topography and “character” of the wetland being recorded.

We no longer consider soil horizons (i.e. O, A, E) when documenting hydric soils.  Instead we are to evaluate depth, thickness and “layers” within the first 16-inches (i.e. 1 chroma or 2 chroma with redox/depleting matrix).  Someone needs to produce one-inch marks on our soil probes so that we do not need to carry a yard-stick in the field.

Fresh tidal can develop F3 (depleted matrix) within 5-years.  But remember . . . hydric soils remain forever, hence the need for the three-parameter approach.

We no longer have County soil scientists.  Instead, we have “regional” soil scientists.  My Howard County soil scientist is now a Northern Mountains and Piedmont MLRA 147 and 148 of LRR S, based out of a regional office in Frederick County.

Should buy a new Munsell soil color book every other year (2-year color life) because chips age and become invalid.

Growing season (biological activity) starts when two or more herbaceous plants are growing in the plot (reference page 72 in Manual).  We have 29 species of sphagnum peat moss in the Maryland coastal plain, some wetter, some drier, but all a minimum of FAC, then going to OBL.

Chapter 5 of the manual addresses “difficult situations” such as mosaics (page 127), with my mental example being Entrix, where we have extensive amounts of wetlands, with patches and islands of uplands.  Many/most delineators do not necessarily call out small patches of uplands within wetlands along floodplains (i.e. first alluvial bench nearest a perennial stream, where that stream draws down the water table).  We can always go back and delineate a specific area in “comprehensive” detail for a bridge, road crossing if it becomes necessary.  Otherwise we may have an exhaustive, difficult delineation if we attempt to call out all of the small upland pockets.

Day 2, 11/16/10

We should make a half-sized reduced copy of the Piedmont Manual so that we have a field copy of the Hydric Soil Indicators.  We need to have a “cheat sheet” as we determine which indicator is applicable for our data station (attached).  We will need to talk-through our soil call in the field using the book for a few dozen delineations until we are all comfortable with Technical Descriptions and User Notes for each described indicator.

An NRCS soil map is allowed to have up to a 25% allowance for incorrect information per each soil classification description and boundary!  Use the map as a broad guide.

The Indicator F3 (Depleted Matrix) makes up 90% of all calls in the Piedmont!  The three most common piedmont indicators are F3, then A11 (depleted below dark surface) and finally F6 (redox dark surface).  Our class emphasized indicator F19 (piedmont floodplain soils) and problematic TF2 (red parent materials).

The morning was spent looking at four open soil pits at Gillis Falls, Carroll County with all four pits mapped as Codorus (Ch) soil, which contain hydric inclusions.  The site was a riparian woodland stream valley with an active floodplain expanding into an old-field.

My first pit (Martin Rabenhorst) was adjacent to the creek and was an F19 (piedmont floodplain soils) in transition.  The site had post-colonial, three-feet of 200 to 300-year old soil over the original A-horizon topsoil.  The materials are therefore young.


My second pit (Lenore Vasalis) was an upland pit, cut long to show the transition to wetland soil.  The wetland soils began on an obvious micro-topography slope/bench.  The upland soils were 3 chroma (10YR 4/3) and did not have 20% concentrations (magnesium concretions and iron staining).  The wetland soils at the lowest end of the pit met the 20% or greater concentrations and the soil moved toward 10YR 4/2, meeting F3 (depleting matrix) criteria.


My third pit was a no-brainer wetland (F3).  Lots of soft rush and Arthraxon, at edge of forest in active floodplain, but in a bench of the slope.  More water comes from the slope, concentrating along the bench and not from overflow from the creek.  Mottled to the surface indicating highly variable/fluctuating water table.  The site was classified as F3.


My fourth pit was upland, well up on the slope, with materials in the pit indicative of the ridge tops (shale).  Used the Key to Soils That Lack Field Indicators, which says dig a hole 6-inches – Do organic soil material or mucky layer exist?  Does chroma 2 or less occur?  Are there any distinct or prominent redox concentrations as soft masses or pore linings occur?  If no to all three, then it’s an upland soil.


The afternoon site was three red-parent material soil pits located at Taneytown Memorial Park, mapped as Bowmansville (BoA) soils, classified as hydric and occurring adjacent to a wooded perennial stream, otherwise surrounded by agricultural fields in corn and winter wheat in rotation.

The first afternoon pit was an Indicator TF2 Red Parent Material hydric soil.  The color was a hue of 7.5 YR or redder, a chroma of 4 or less, and had a layer of 4-inches thick and most importantly 2% or more redox depletions and/or redox concentrations occurring as soft masses and/or pore linings, then finally having this wetland “layer” occurring within 12-inches of the soil surface.


The second pit, a tad upslope did not meet TF2 because more than 2% redox did not begin until deeper than 16-inches.


The third, add-on pit in a swale was such new alluvium that it did not meet hydric soil criteria.  IRIS tubes however would suggest a reducing condition.  The soil was technically not hydric, although most any delineator would have flagged it as wetlands.


The following photo is of the manufacturer for Alpha Alpha Dipyridyl (AAD) strips.  If a wet red parent soil sample is applied/rubbed onto the paper strip and it turns orange-red, it would suggest that the soil is in a reducing condition and although masked, may be a legitimate hydric soil.  They cost $1.00 per strip.  It may be better to try and look for the 2% plus reducing conditions.


The next future MAPSS class will be on green glauconite and gley soils to be held in New Jersey or possibly in Prince George’s County sometime when raining in 2011.

PDF Attachment:  Mark’s Hydric Soils Indicators Cheat Sheet  Hydric Soil Indicators