San Pedro pond, a big draw for bird-watchers, goes dry

Sediment inflow cited, but drought, pumping could also be factors
2013-07-03T00:00:00Z 2014-07-15T17:48:37Z San Pedro pond, a big draw for bird-watchers, goes dryTony Davis Arizona Daily Star Arizona Daily Star
July 03, 2013 12:00 am  • 

The scenes at Green Kingfisher Pond include turkey vultures and great blue herons strolling on parched soil, laced with cracks.

The pond, a popular bird-watching spot along the San Pedro River in Cochise County, dried up in mid-June for the first time in its existence.

It's not the only major Southern Arizona pond and bird haven to suffer of late. At the main pond at Roy P. Drachman-Agua Caliente Regional Park northeast of Tucson, 40 percent of the surface area now is exposed mud flats due to drought.

But at Green Kingfisher Pond, authorities blame sediment as the biggest single cause of its drying. Yet they won't rule out drought, heat and groundwater pumping as contributing factors.

Over the years, the pond, which was dug out by man, has slowly and steadily filled with sediment carried by flood flows via a small channel from the neighboring river, said Bureau of Land Management officials Ben Lomeli and Heather Swanson. Today, the pond, one to two acres in size, is a foot deep, down from up to 6 feet deep in the past, said Swanson, a BLM natural resource specialist.

It can't be sustained as a pond because sediment cuts it off from the underlying water table, which feeds the pond, said hydrologist Lomeli. His agency manages the pond as part of the San Pedro Riparian National Conservation Area.

It's expected to eventually return to its natural state as a large patch of sacaton grassland, Swanson said this week, adding that she regards that as a good thing because it would be natural.

But for bird-watchers, which the Sierra Vista area draws in droves, the pond's drying is a big loss. More than 130 individual bird species have been seen there, says the popular birding site ebird, run by Cornell University's Laboratory of Ornithology. They include the kingfisher pond's namesake, a rare Southern Arizona bird that is common in northern Mexico.

"I was in shock. It freaked me out," said Bob Herrmann, a Sierra Vista nature photographer, of the dry pond, after photographing it annually since 2007.

For birders, the pond is a showpiece, added Robert Weissler, executive director of the nonprofit Friends of the San Pedro River. It lies a short hike east from the San Pedro House, a popular starting point along Arizona 90 east of Sierra Vista for San Pedro birders.

The pond has drawn numerous other water bird species such as herons, egrets, snipes, rails, ducks and ibises. It also has played host to the tropical kingbird, a yellow-breasted, common Mexican species that strays only into Southern Arizona and South Texas in this country.

"If there was a single place that people would gravitate when they went birding along the San Pedro … it was Kingfisher Pond," Weissler said.

Still, Swanson said she recently banded 21 bird species even at the dry pond, which is encircled with cottonwood and willow trees and marsh vegetation.

The pond was for decades a gravel pit, until the federal government obtained 40 miles of the San Pedro in 1988 and created a conservation area there. Sand and gravel operators who had pumped out groundwater to dig the pit were kicked out. The pit then filled with water.

Now, one reason BLM's Lomeli believes sedimentation is the biggest factor in the pond's drying is that a second pond known as Black Phoebe Pond, lying south of Green Kingfisher Pond, still carries water. Named after the black phoebe, another San Pedro-area bird, the second pond also was once a gravel pit. But it has no channel to the San Pedro and receives no floodwaters or sediment.

For environmentalist Tricia Gerodette in Sierra Vista, the kingfisher pond's drying is still a dramatic visual symbol of threats to the neighboring river, which today runs wet and dry in various segments.

But it's not publicly known if the water table near the river is falling, which could be a sign that groundwater pumping is affecting that area including the pond. That's because the bureau won't release data from its monitoring wells along the river, since it is in Superior Court over San Pedro issues involving a proposed 7,000-home development nearby.

"I suspect it will be awhile" before the well data is released, BLM's Lomeli said. "This thing will be in court for quite a while."

On StarNet: Find more science, technology and health stories at azstarnet.com/news/science

Contact reporter Tony Davis at tdavis@azstarnet.com or 806-7746.

Copyright 2014 Arizona Daily Star. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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