In the first installment of this two-part series on playa lakes, North Plains GCD Program Coordinator, Odell Ward, introduced the idea of playas as ephemeral water bodies, meaning they are not always full of water. Ward explained many of the characteristics of these often-misunderstood low places in the topography. In the final part of the series Ward writes about the role playas play in the ecosystem.
These temporary wetlands are located almost entirely on privately owned lands, resulting in inconsistent management strategies from one playa to another. Playas form at the lowest point in an enclosed watershed, meaning there is no outlet like a stream or creek to allow the water to drain off. The landcover surrounding a playa dramatically influences the health of a playa. Grasses around the playas work to filter sediments and slow runoff that prevents otherwise suspended sediments from clogging playa bottoms. Slowing flow into the playa from surrounding areas prevents channeling in the playa perimeter reducing or preventing erosion.
Playa lakes are essential to the region in several ways including an aesthetic value. Fall ponding in playas is important to migratory waterfowl and other water birds as they provide resources and rest stops for the migrating birds. During dry cycles, playas provide cover and habitat for native non-migrating animal species as well.
Don Kahl is a Migratory Game Bird Specialist for Texas Parks & Wildlife Department and the coordinator of the Texas Playa Conservation Initiative. Don takes interested groups on walking tours of a playa at the Ogallala Commons Playa Classroom in Nazareth.
The greatest threat to playa lakes is the constant encroachment of urban development and mechanized agriculture. As cities expand and incorporate more lands into their boundaries, playas are filled, cross cut with roads and highways, and otherwise destroyed. In many urban areas where houses and shopping centers are constructed, playas are filled in and leveled to reduce flooding.
In many areas, farmers plow and plant playas during the dry cycles to increase acreage. Farming playas breaks up the clay-rich soils that accumulate in the bottom on the playa over thousands of years. Farming removes the grassy areas around the perimeter of the playa resulting in increased soil erosion. The combination of the increased sedimentation from erosion and the breaking up of the clay layer prevents cracks from forming in the bottom of the playas that ultimately reduce or restrict water infiltration altogether.
Playa lakes in their natural states can benefit urban centers in many ways if left intact. Proper buffers of native vegetation surrounding the playas can catch sediments and slow runoff, allowing salts and some chemical pollutants to precipitate out before entering playas. Playas near urban settings can add an aesthetic value to the landscape by attracting multiple species of mammals and birds to the water, food and cover they provide. The plants and animals in turn attract people. In addition, playas in urban settings can increase property values by reducing flooding potential, reduce the need for wastewater treatment and holding ponds, and can filter out contaminants.