Blanca wetlands provide prime habitat

Blanca Wetlands via the National Park Service
Blanca Wetlands via the National Park Service

From The Pueblo Chieftain (Matt Hildner):

The most important resource at the Blanca Wetlands greets visitors the moment they get out of their cars. Mouths, ears, eyes and loose pant legs are all inviting targets for the bugs, which, more importantly, play a critical role in making the 10,000-acre wetlands a magnet for migrating shore birds and songbirds.

“That’s really our job, I think, out here, is to grow bugs,” Sue Swift-Miller, a wildlife biologist for the U.S. Bureau of Land Management, said.

Swift-Miller and fellow wildlife biologist Jill Lucero help oversee the wetlands, which sits 8 miles northeast of town, and manage the complex interplay of water management with the timing of bug hatches and bird migrations.

The bird species that come in the largest number include the Wilson’s Phalarope, Baird’s Sandpiper and the American Avocet.

But the wetlands and their bugs also attract species such as the western snowy plover, American white pelican, and the white-faced ibis. Those species and 10 others that visit the wetlands are designated as sensitive species by the agency, meaning they or their habitat are either in decline or projected to do so.

Overall, more than 163 mammals use the wetlands.

That the birds and the bugs are here in such numbers is the result of the BLM’s decision in the 1960s to restore the wetlands by drilling 43 wells into the confined aquifer, the deeper of the San Luis Valley’s two major groundwater bodies. The water, which averages out to roughly 5,000 acre-feet annually, is then funneled into a series of basins that range from fresh water ponds that support both cold- and warm-water fisheries to shallower basins that have a higher salt content than the ocean.

After years of study, Swift-Miller said it’s become evident that bugs need specific water-quality parameters, depending on the species. BLM officials can, with the help of hundreds of miles of canals and culverts, funnel fresh water to certain basins to dilute the salinity or withhold to emphasize it.

The intermittent use of water is particularly important in habitat areas known as playas, which are generally saline basins with clay dominated soils that historically went through wetting and drying cycles in the valley.

While drought and diversions for agriculture have cut wetting cycles, the BLM has found a jump in insects such as fairy and brine shrimp when it’s added water to the playas.

Macro Invertebrates via Little Pend Oreille Wildlife Refuge Water Quality Research
Macro Invertebrates via Little Pend Oreille Wildlife Refuge Water Quality Research

“We’re getting macroinvertibrates that have been in cyst stage for years,” Lucero said. “Nobody’s seen them for 50 years and suddenly they’re coming out as we wet an area.”

But choosing when to apply water is just as critical.

“If you’ve got bugs available when the birds aren’t here, you really haven’t done yourself any good,” Swift-Miller said.

The agency’s use of groundwater will soon be coming under a new set of state regulations, as is the case with all groundwater users in the valley. Those regulations, which remain in draft form, are expected to require groundwater users to obtain surface water to offset the injury their pumping causes to surface-water users.

But the BLM’s augmentation efforts began even before the draft regulations thanks to 20 illegal wells the agency drilled in the late 1970s.

While the agency will still have to get more augmentation water, Swift­Miller said it’s possible the agency will get enough to avoid shutting down any wells at the wetlands.

“I think we’re in pretty good shape for that,” she said.

Before the agency and other area water users began pumping groundwater, the Blanca Wetlands was the endpoint in a string of marshes, playas and lakes that extended to the north end of the valley. A map from 1869 shows the Blanca Wetlands as part of a large lake. Aerial photos from the 1940s in the agency’s possession show a string of connected wetlands that run to where the current San Luis Lake State Park sits, at the southwestern edge of the Great Sand Dunes National Park.

Earlier this year, the BLM approved a proposal that would allow it to buy property from willing landowners in an effort to expand the Blanca Wetlands and improve habitat connectivity. The search for willing sellers would focus on the area that extends north and northeast from the Blanca to the west side of the state park.

Another focus area for expansion sits further north on the western edge of Baca National Wildlife Refuge and runs east to Mishak Lakes.

While expansion funding would need to navigate the gridlock that has dominated congressional budget proceedings, the proposal did make it into the White House’s budget proposal for the 2015 fiscal year, which begins Wednesday.

More Rio Grande River Basin coverage here.

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