Delineating Playas in the Arid Southwest
A Literature Review
WILLIAM BROSTOFF, ROBERT LICHVAR, AND STEVEN SPRECHER
INTRODUCTION
their respective adjacent habitats. In the case of wet-
The Federal government regulates filling activities
lands, there are formal definitions and guidelines. Wet-
in certain parts of the landscape (including wetlands,
lands are identified on the basis of three parameters (or
tidal waters, lakes, rivers, streams, intermittent streams,
their respective indicators): soils, vegetation, and hy-
mudflats, sloughs, prairie potholes, wet meadows, nat-
drology, as specified in the Corps of Engineers Wet-
ural ponds, and playa lakes) under the provisions of
lands Delineation Manual (Environmental Laboratory
the Code of Federal Regulations (33 CFR 328.3 [a]) im-
1987). Wetland hydrology must, by definition ("frequen-
plementing Section 404 of the Clean Water Act (CWA).
cy and duration criteria"; Office of the Chief of Engi-
The Corps of Engineers (Corps) and others perform ju-
neers 1992, 1994), be met for 12 weeks of the year or
risdictional delineations of playas (and other landscape
5% of the growing season. For playas, the guidance is
features) to determine whether certain areas are subject
included in the definition of "Waters of the United
to Section 404 regulations.
States" (WoUS):
A playa is "[t]he flat-floored bottom of an undrained
"The term `waters of the United States' means (1)
desert basin that becomes at times a shallow lake which
all waters which are currently used, or were used
in the past, or may be susceptible to use in inter-
state or foreign commerce, including all waters
sum."* While identifying playas in a geologic context
which are subject to the ebb and flow of the tide;
is relatively unambiguous, delineating those areas of
(2) all interstate waters including interstate wet-
playas under the Corps' jurisdiction, particularly those
lands; (3) all other waters such as intrastate lakes,
of the arid southwestern United States (which differ
rivers, streams (including intermittent streams),
geomorphically and ecologically from other playa types
mudflats, sandflats, wetlands, sloughs, prairie
in the United States), has been found to be problematic
potholes, wet meadows, playa lakes or natural
(e.g., Doub and Colberg 1996, Lichvar and Sprecher
ponds, the use, degradation or destruction of
which could affect interstate or foreign com-
1996). This document considers the scientific back-
merce...; (4) all impoundments of waters otherwise
ground forming the basis for performing delineations
defined as waters of the United States under the
of such playas.
definition; (5) tributaries of waters identified in
Because the same personnel who routinely delineate
[items] (1)(4) [of this definition]; (6) the territorial
wetlands are sometimes involved in the delineation of
seas; (7) wetlands adjacent to waters (other than
playas, there has been an inclination to adopt wetland
waters that are themselves wetlands) identified
delineation protocols to playas. However, there are dif-
in [items] (1)(6) [of this definition]" (33 CFR
ferences in both the rules for and the characteristics
328.3[a]).
available for differentiating wetlands and playas from
All of these waters, except wetlands (which may co-
occur with non-wetland WoUS), are delineated to the
extent of Ordinary High Water (OHW) or high tide lev-
* Webster's Third New International Dictionary. Springfield,
els. The OHW is defined as
Massachusetts: Merriam Webster, 1964.
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