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Conservation Corner PDF Print E-mail

Playas are valuable wet or dry

By Janet Lagler
Natural Resources Conservation Service

What is a playa? “Playa,” and its synonym “playa lake,” are vague terms like “swamp” or “marsh” used to describe some type of wetland. Wetlands are often called the “kidneys of the landscape” since they filter out harmful materials.
Wetlands improve water quality by keeping nutrients, sediments, etc. from entering lakes, streams, and reservoirs. Wetlands often function like natural tubs or sponges, storing water and slowly releasing it.
Wetlands conservation is one of the most important sensitive natural resource issues in our country today.
Destruction of wetlands can lead to serious consequences, such an increased flooding, extinction of species, and decline in water quality. We can avoid these consequences by maintaining the wetlands.
One might think that a dry playa doesn’t have much to offer for nature or people. It is a perfectly excusable assumption that a wetland is at its best when it is, well, wet. The truth is that playas require periods of drying out to produce food for wildlife and recharge the Ogallala Aquifer.         Here are some reasons why:
• Dry playas are refuges for life–Scoop some soil from a dry playa basin and put it in a glass jar. Add water. In a few weeks, tiny life forms–water fleas, fairy shrimp, and tadpole shrimp.        The soil collected could have been dry for months or years. But it is full of life nevertheless.
Some of wetland birds’ favorite foods–smartweed, toads and other treats–depend on the wet/dry cycle of playas for their survival.
If a playa were wet all the time, some of these species would not grow at all, while others would be eaten up by predators. Toads can lie dormant in dry playa basins for several years, basically taking refuge until the next storm hits the playa.
The length of time a playa is wet or dry is extremely important to maintaining its productivity.
Sedimentation—the number one threat to playas—can cause playas to dry out too quickly. Sedimentation occurs when rain or other runoff event carries loose soils into playa basins.     
Sedimentation reduces the amount of water a playa can hold, and spreads it out to a larger surface area which increases water loss by evaporation. More than 50 percent of all playas have been effectively “fossilized” by sedimentation and have lost most wetland functions.
• Seasonal wetlands support more ducks–Because of the seasonal flush of plants and inverts, playas and other temporary wetlands actually produce more food for birds and other wildlife than do permanent wetlands.
• Dry playas set the stage for aquifer recharge–Recharge to the Ogallala Aquifer would be significantly compromised if playas never dried out. Current research on recharge indicates that most infiltration through playas happens when the wetland is first inundated with water.
Once full of water, the clay layer expands, cracks close, and the basin forms a seal to hold water and recharge slows.             Playas are the primary source of recharge for the Ogallala, contributing up to 95 percent of the overall return of water to the aquifer.      
Follow these dos and don’ts: Don’t–drain, dredge, fill or alter without prior approval of NRCS. Don’t–farm wetlands differently than adjacent field. Do–keep grass buffers around wetlands.
Contact NRCS for further information at 352-4776 ext. 3.