18 November 2007

Protection of Playa Wetlands Enhance Ogallala Aquifer

James Ed. Ducey

Efforts to conserve and manage playa wetlands of the southern High Plains provides important sites for recharge of the Ogallala aquifer, according to conservation officials.

More than 60,000 shallow, and seasonal playa wetlands spread across the landscape of the southern High Plains, according to officials of the Playa Lakes Joint Venture. The wetlands occur in eastern New Mexico, western Texas, the Oklahoma panhandle, southeast Colorado, southwest Kansas, and to a more limited extent, western Nebraska.

“Playas are the primary source of recharge for the Ogallala,” according to group officials, and “contribute between 85 and 95% of the total water returned to the aquifer” in the southern portion of the region, according to researchers. “This amounts to about 1 to 3 inches per year, depending on their location and depth” to groundwater. The wetlands are also “important wetland habitat for wildlife in the region, supporting millions of ducks, shorebirds and other migratory and resident birds and other wildlife year-round.”

“Whether they are wet or dry depends on the local weather,” according to joint venture findings. “Playas can be wet year-round, or stay dry for months and sometimes years on end. This natural, wet/dry cycle of playas that helps them recharge the Ogallala aquifer. Playa basins are lined with clay soils, so when they dry out, deep cracks form in the basin and along the perimeter of the playa. When water comes into the playa from rainfall or other runoff event, it runs through these cracks and edges and into the underlying water table.”

“Once the connection is made that playas recharge the Ogallala, almost any farmer or rancher will express an interest in protecting it,” said Mike Carter, coordinator for the joint venture. “In fact, in a recent survey of playa landowners, we found that more than 70% are willing to conserve their playas.”

One of the most effective means of conserving these wetlands is to “maintain or restore the native prairie grasses around” the basin, the group has determined. “Grass buffers filter out sediments and contaminants before they get into the playa.”

Landowners involved in wetland management projects typically are enthusiastic if the change is also beneficial to their operation and bottomline, Carter said. “Sometimes, producers do it just for habitat or birds but this is a less common case. Frankly, we would rather they do it for their bottomline and for that opportunity to be pervasive in programs.”

“Buffer strips protect the wetland but there are many species such as the Long-billed Curlew, meadowlarks, sparrows that also use the buffer,” Carter said. “Conservation dollars are so limited that we have to look for 2 for 1 opportunities like buffers that protect wetlands and provide habitat.”

The success of a project for wild birds is measured “against the ability of the change to increase carrying capacity of a habitat for the desired species or group of species.”

Examples of current projects include Drummond Flats and the Jamestown Wildlife Area.

“More than 70 percent“ of playa wetlands ”have been altered from their natural state due to pitting, filling, cropping and road construction, among other threats,” according to findings of the PLJV group. “The biggest threat is sedimentation” which occurs “when rain or irrigation water carries loose soils into the playa, gradually filling it. Playas filled with sediment can no longer hold as much water for the same amount of time, significantly reducing their value for recharge and wildlife. Researchers estimate more than half of all playas are filled with sediment and are effectively ‘fossilized’ and have lost most wetland functions.”

The PLJV, which has a pivotal role in protecting the playa wetland resources in the high plains, is comprised of federal and state wildlife agencies, conservation groups, private industry and landowners. Its mission is to “conserve playas, other wetlands and associated landscapes … for the benefit of birds, other wildlife and people.” Its general headquarters are in Lafayette, CO.

Incentive programs that can assist in wetland management include the Wetland Reserve Program and Wetlands Restoration Non Floodplain Initiative provided through the Farm Bill, and administered by the Natural Resources Conservation Service. Also, the Farmable Wetlands Initiative is available through the Conservation Reserve Program. The Fish and Wildlife Service, and state and private agencies can also provide funding to conserve wetlands.

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