Table 1. Summary of selected specific reports on possible OHW and/or wetland indicators on playas and
some annotated references.
Focus of paper and
Summary of findings as
Reference
possible indicator type
Geographic location
potential indicator
Blodgett and
Hydrology
Rogers Playa,
Lakebed flooding from a 2.54-cm rainfall in 1983 drained
Williams 1990
California
into fissures and sink-like depressions within 24 hours.
Clarke 1979
Surface type
Coyote and Mesquite
Both were intermittently inundated. Coyote Dry Lake
Dry Lakes, California
demonstrated desiccation fractures and polygons that
"healed" after rewetting or infilling. Following heavy
rainfall, flooding, and drying in 1976, fissures up to 5 m
deep, 2 m wide, and 500 m long appeared at Mesquite Lake.
Roots of Distichlis spicata were concentrated at 10
Dahlgren et al.
Soil, hydrology,
Owens Lake Playa,
1997
vegetation
California
40 cm and not deeper than 70 cm; groundwater depth
was 95 cm. Anoxic conditions (as indicated by black
soil layers) were present to within 60 cm. Some D. spicata
roots and rhizomes with an oxidized rhizosphere were
found penetrating ~10 cm into the anoxic soil zone.
Dinehart and
Hydrology
Rogers Playa,
A storm of 2.3 cm in Feb 1996 caused a 30.5- to 91.4-cm-
McPherson 1998
California
deep flooding that evaporated over a one-month period.
Hunt et al. 1966
Surface type
Death Valley,
Inundation/drying is the major cause of patterned ground.
(and references
California
However, the extent and development is proportional to salt
cited)
content of soil. Polygons, generally four- to six-sided, are
reported up to 10.7 m in diameter.
Hunt et al. 1966
Surficial charac-
Death Valley,
Lowest places (where water collects): Salt crust
(and references
teristics, patterned California
2.530.5 cm thick, complex pattern of polygons (slabs
cited)
ground
30.561 cm in diameter, blisterlike forms 15.230.5 cm wide,
arching over 2.55 cm high, and superimposed nets formed
of irregular low hummocks. Mud below the salt may remain
wet between successive flooding.
Frequently flooded: Efflorescence of salts 12 mm thick. Pat-
terns vary depending on salt content and length of inundation.
Intermediate flooding frequency: Persistent desiccation cracks
(polygons), more salt accumulation than frequently flooded
areas or lowest places.
Infrequent flooding: Netlike patterns.
Lichvar et al.
Soil
Dugway Proving
Soils of hard and soft playas were indistinguishable except
1995
Ground, Utah
for bulk density and the more friable consistency in the upper
30 cm of the soft playas.
Allenrolfea occidentalis grows along the margins of playas,
Lines 1979
Vegetation
Bonneville Salt Flats
and Pilot Valley
on playas on phreatophyte mounds, and in channels in the
Playa, Utah
playa up to 1.6 km beyond its "normal" distribution. It is normally
limited to areas that contain brines less than 100,000 mg/L
chloride; their distribution in channels is thought to be due to
freshwater intrusion and subsequent brine dilution during rain,
ameliorating effects of high salinity.
Lines 1979
Vegetation
Bonneville Salt Flats
Phreatophyte mounds are more common on the soft- than
and Pilot Valley
hard-surface type.
Playa, Utah
Lines 1979
Classification
Bonneville Salt Flats
The soft, puffy surface is most commonly found near the
and Pilot Valley
edges of playas where there is no flooding by surface waters
Playa, Utah
except in distributary channels. These become wet at the
surface only after rain or snow. The smooth, hard type most
commonly occurs between the puffy type and the sulfate
zone.
Lines 1979
Surface indicators Bonneville Salt Flats
As the surface dries, small desiccation polygons 5.115.2 cm
and Pilot Valley
across form. If there is no rain over a period of 23 weeks
Playa, Utah
during the summer, a white salt forms on the surface. These
desiccation polygons and salt coating disappear with only a
small amount of precipitation.
Lines 1979
Surface indicators Bonneville Salt Flats
A thin salt crust developed by evaporation of surface brine
and Pilot Valley
that flooded parts of each playa during Oct 1975May 1976.
Playa, Utah
Motts 1972
Surface type
Panamint Playa,
A single flood event (1966) converted the soft type into hard;
California
by the following winter, the surface had large areas of the soft
type again.
14
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