Restoring Your Playa

A typical playa restoration project will include hiring a contractor to remove sediment or perform other restoration activities, planting a native grass mix into existing crop residues or a planted cover crop, and controlling weeds while the grass becomes established. In theory, restoration practices could be completed in the spring, a cover crop seeded in the summer, and the grass mix planted the following spring; however the timeline for these activities varies due to contractor availability and variable weather conditions.

Establish a Native Prairie Vegetation Buffer

Playa buffers — areas of permanent vegetation surrounding a playa — protect the playa by preventing sediment, which may carry contaminants from surrounding farm fields, from reaching the basin and should be a part of every restoration project when the playa is in cropland. Buffers provide habitat for many species of wildlife, while improving the quality of the water entering the playa basin and, in turn, the water that reaches the aquifer.

The buffer width is dependent on many factors, some biological and others more practical in nature. Studies have shown that buffer widths of at least 130 feet can effectively trap the majority of sediment and contaminants from reaching the playa; however, that is dependent on the plant species chosen. Since the majority of playas are found within crop fields, considerations for buffer size and shape are often determined by the most efficient method of farming the rest of the field.

The seed mix should be determined based on management goals. Diverse mixes with native grasses, forbs, and legumes increase biodiversity for wildlife and provide diverse forage for livestock. Restoring historic plant communities offers the best chance of success. Predominant native grass species that are suitable for playa buffers and adapted to the high plains include blue grama, buffalograss, sideoats grama, and little bluestem, while numerous species of forbs and legumes native to the region can be included in the seeding mix.

Sedimentation is usually caused by issues within the surrounding watershed. To keep sediment out of a playa, determine where and how sediment is deposited in the basin and what can be done to prevent sediment accumulation in the future.

Remove Accumulated Sediment

Once the sources causing sedimentation have been identified and addressed with buffers and other conservation activities, planning for sediment removal can begin. Other than excavation, wind is the only other way sediment is removed from a playa; but wind alone cannot remove all the excess sediment that is often found in modified playas and those without a grass buffer. Sediment accumulation in playas is usually not evenly distributed across the playa basin, with sediment depth related to where it came from and how it was deposited.

When addressing sediment issues, the soil type within the watershed should also be considered, especially in surrounding fields that do not have adequate vegetative cover throughout the year. Since medium textured soils are more easily eroded than fine soils, playas in areas with medium textured soils often have nearly twice the excess sediment of those in areas with fine soils. Also, sediment carried by water flowing in through a channel may travel farther into the playa than sediment transported by normal overland flow. Sediment removed from the playa should be spread out in areas that won’t create new sources of sedimentation. Spoil areas within the buffer area will need to be vegetated.

Fill Drainage Features

Pits and ditches concentrate water into a small area and keep the playa from going through its normal wet and dry cycle. While a pit may trap and hold water for a longer period of time, it comes at the cost of keeping the rest of the playa functional since it cannot go through the critical wet-dry cycle, which reduces habitat for wildlife and affects groundwater recharge.

Filling pits allows rainwater and runoff to reach all the large cracks in a dry playa — which is essential for recharge to occur — rather than collecting in the pit. A pit may also break through or remove part of the clay soil, which will circumvent the cleaning function of the playa. In most cases, the spoil pile from the original excavation is present and should be used to refill the pit. Although the pit may not be completely filled or level when using the soil from the spoil pile, it will smooth out once the playa has been filled with water several times.

Channels are often cut into playas to facilitate draining the water within the playa. Removing these channels can be a matter of simply filling them in with appropriate materials and stabilizing the site of disturbance with vegetative cover.

Restore Water Flow

Redirecting water diverted from the playa is a critical but often overlooked part of playa restoration. Terraces, diversions, roads, clogged culverts, and other modifications to the area surrounding a playa have likely changed the water flow and may be preventing water from reaching the playa basin and reducing playa function. To fully restore playa function and recharge potential, include the surrounding area in your planning process. Sometimes, these modifications or diversions are located on a neighbor’s property and may require a collaborative effort to address.