As you know, Playa is one of the geomorphological forms that occurs in the lowest part of the catchment or surface plains and is usually affected by salt. but,
Wetlands maybe have water or sometimes be dry and may be salty or sweet, but in dry areas they are often salty. In many dry-lands, wetlands have become dried due to climate change or mismanagement of water and most of these wetlands are salty. Now: Can we say these areas are playa scientifically?
Dear Dr. Khosroshahi,
the criteria ofa playa such as an undrained desert basin with clay , silt and evaporitic mineralization in context with the playa lakes rendering it a ephemeral aquatic system and as such speaks in favor of your assumption. It is a general statement which other geomorphologists and hydrogeologists might narrow down and look at it at a more actue angle. There are many such inland lakes which previously were perennial an now turned into ephemeral ones. Their is a transition into salt pans, salars and salinas. All of these landforms are located between a dry and wet regime
Kind regards
H.G.Dill
Dear Professor Harald G. Dill
I'm so happy for your answer. I wanted to send this question to you specifically. Because we already had questions and answers about geological deserts and I used your guidance. Certainly wetlands, marshes, Swamp and Playa (in Iran we usually call it Kavir); each has its own definition. But in many areas of Iran there are wetlands (that have even been registered in the Ramsar International Convention) and are now dry, such as Gavkhuni, Bakhtegan, Maharloo and even part of Lake Urmia(They can be accessed via Google earth). All of these wetlands were fed by rivers that have already dried up due to dam upstream or water diversion for agriculture or droughts of the last two decades. Precipitation in these wetlands areas is low and fluctuates between 150-250 mm. These salty wetlands now look like a playa and have exactly the same physical conditions. For example In the central Great Salt Desert we have large salt polygons, and precisely in the dry Gavkhuni wetland there are this polygons of the same size. So after that we have to look at it like a Kavir or a playa.
I suppose there could be circumstances when lacustrine lakes, become shallow enough to vegetate with hydrophytic plants, and since they were lakes, probably have hydric soils. Salt marsh with species as Spartina found in shallow estuaries and brackish floodplains would meet wetland criteria of hydrophytic plants, hydric soils and hydrology. But barren bottom lakes that dry up fairly quickly in arid areas with high salt concentrations may not develop wetland character to classify out as wetlands before becoming what qualifies as playa. A lot may depend on your circumstances. Cowardin et al is a good classification reference with link https://www.fws.gov/wetlands/Documents/Classification-of-Wetlands-and-Deepwater-Habitats-of-the-United-States.pdf . I have not checked for playas if they fit into the classification. I would be careful assuming wetlands that loose their hydrology are destined to become playas, but it may fit for your circumstances.
Dear Professor Hansen Thank you very much for your scientific response, especially from the sources you have cited for wetland classification.
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