Tuesday, February 14, 2012

Reusing Wastewater at Sweetwater Wetlands

A secluded corner in the Sweetwater Wetlands

 The Sweetwater Wetland is well known to Tucson’s birders. Located in the midst of an industrial area, between I-10 and the usually dry Santa Cruz River, Sweetwater is a man-made wetland constructed in 1996 to help treat secondary effluent and backwash from the reclaimed water treatment system at adjacent Roger Road Wastewater Treatment Plant. Not only does Sweetwater provide habitat for a wide variety of wildlife, it serves as an environmental education facility.

Away from the rest of the world    

Wide, level paths wind around ponds and streamside habitats, past informational signs and viewing platforms. Twelve-foot tall banks of rushes and cattails, cottonwood trees, and thickets of saltbrush give solitude to wild residents and human visitors alike. In the early morning the air is alive with the calls of birds. Flocks of ducks pattern the sky overhead. Birders with binoculars and cameras try to add rare species to their lists. More than 250 species have been reported at the wetlands, as well as amphibians, insects, and mammals such as bobcats.
A coot preening in the morning sunshine

Large recharging basins at one side of the complex not only attract thousands of waterfowl, they allow treated water to rapidly percolate down to the water table, where it can be recovered by wells and delivered for use in irrigating public spaces such as golf course , lawns, and roadside plantings.In 1940, the area’s water table was at 40’ below the surface. By 1998 it was below 100’. Reusing waste water is an idea whose time has come.
Shoveler ducks
Boat-tailed Grackle

Anna's Hummingbird

Sand Hill Cranes in Arizona

Courtesy Free Photos

When we traveled in Alaska, we sometimes saw sandhill cranes with their bright red foreheads feeding in fields on the hills above Homer and Kachemak Bay. Sandhill cranes are some of America’s largest birds. Adults can stand up to six feet tall. Occasionally we glimpsed a nesting pair in a marshy area near our home in Fairbanks, in interior Alaska. We didn’t know then that some of those same birds joined flocks of thousands to winter in Southeastern Arizona, the very place we’ve chosen to spend a month of our winter this year.

The annual Wings Over Willcox Birding and Nature Festival had ended by the time we heard of it, but the cranes stay until March. So we drove with daughter Lenora nearly one hundred miles toward Arizona’s Dragoon Mountains and the Sulphur Springs Valley to see them. Every morning they lift off from their roosting areas by the thousands to fly, silhouetted against the sunrise, to their feeding fields in a 60-square-mile protected area. Swaddled against chilly morning temperatures, birdwatchers from all over the world are overwhelmed by the whoosh of wings and the cacophony of calls as the spindly-legged, red-crowned birds fly overhead.

By the time we reached Willcox and drove another nine miles to where we’d been told we could find a viewing area, it was two PM. The birds had finished their morning foraging and returned to their resting sites. A sign at the parking lot said, “Crane Lake Viewing Area, 1.2 miles.”
Crossing Willcox Playa

Inhospitable habitat

After the long drive, another mile on foot didn’t seem too much to ask. We started along a sandy track scraped through thickets of trees and brush. A couple of people coming toward us said yes, the cranes were there. Lots of them. But we would have to stay at a distance to view them.

We trudged across an alkali playa, dry and flat as a table top except for hillocks of fine drifted silt and arroyos cut by storm water. Arizona is part of America’s basin-and-range zone, where ranges of mountains thrust skyward while intervening blocks of land dropped. In prehistoric times the valleys thus formed often filled with large, shallow lakes, gone now except for their dry beds, like this Willcox Playa. We were heading for a remnant of the ancient lake, where the cranes found protection while they rested.

Alkali dust soon coated our shoes. Mounds of tough grasses and occasional trees seemed uninhabited at mid-day, but along with the footprints of innumerable birdwatchers on the path we followed, we saw prints of coyotes, javelinas (pig-like creatures of the southwest), bobcats, rabbits, and even deer, patterning the dust or petrified in dried mud. There were hundreds of burrows belonging to who-knew-which hidden desert denizens, and scat left by coyotes and some other creature that obviously lived on seeds. Old bird nests in the trees testified that this was a place to see other birds beside cranes. 

Finally the flat ground rose to low hills. We’d reached the edge of the playa and from a man-made rise we could see Crane Lake glinting, still a quarter-mile off. We could go no closer. Time for the binoculars. What might have been a line of vegetation extending out into the shallow water became instead a line of hundreds of sand hill cranes, drowsing motionless during their mid-afternoon rest break.
Through my telephoto lens: hundreds of cranes at rest in Crane Lake

Aldo Leopold said about the sand hill crane in his book Sand County Almanac, “ When we hear his call, we hear no mere bird, we hear the trumpet of evolution.” Who knows how long these magnificent birds have been winging their way between north and south? It’s good that humans are now working together to keep their resting and feeding places safer. It was worth a two-hundred mile round trip to see them.

Thursday, February 2, 2012

God at Work in the Rocks

Rocks of the Texas Canyon formation

Rocks show spalling caused by freezing and thawing

Rocks. Mountain size, or miniaturized to a grain of sand, they’re everywhere. Especially here in the American Southwest, where there’s not much soil or plant life to hide them from view.

Recently, we pulled off Interstate 10 into Arizona’s Texas Canyon, in search of the private, non-profit Amerind Foundation museum. We found ourselves near an upthrust range of mountains intriguingly named the Dragoons. (A dragoon was a calvary soldier outfitted with the heavier armaments of a foot soldier.) It was to the vertical labyrinths of the Dragoon Mountains that the Apache warrior Cochise fled from the Confederate calvary that eventually defeated him.

But it was the nearer rocks that caught our attention. Stacked, balanced, and weirdly-sculptured, they looked like the abandoned playthings of some colossal child. What caused them to look like that?

In the museum, we found a brochure that gave the answer.

The formations in these photographs are part of a body of igneous rock called Texas Canyon quartz monzonite. It’s a granite, and it looks as it does because it was once magma (molten rock) that rose slowly without reaching the surface. It cooled beneath the earth’s crust, forming large crystals of the potassium-rich mineral, feldspar. Between the large crystals, other minerals crystalized: quartz, biotite, and plagioclase. Once the rocks that covered the blocks of quartz monzonite eroded away, they were exposed to natural weathering processes that rounded them at exposed surfaces and along the joints.

Tiny cracks formed between the larger crystals, allowing water and oxygen to invade and weaken the granite, prying the mineral grains apart. Sheets of rock spall off the outer surfaces of boulders along curved cracks or joints when water invades the spaces, then freezes. This helps round the blocks. As the rock around the boulders of quartz monzonite disintegrate, the pedestals, spires, and balanced boulders that form the Texas Canyon outcrop appear.

What a reminder of our creative God at work!

Only 40 miles to the east of Texas Canyon, a similar magma intrusion reached all the way to the earth’s surface. It caused a gigantic eruption that spread a thick deposit of lava and ash and left a tremendous crater. Today, in Chiricahua National Monument, one sees oddly-shaped columns and spires, the remnants of that almost 27 million year old ash blanket. The difference between one landscape and the other is all in how the rock reached the surface. 

Chiricahua National Monument, Photo courtesy of National Park Service

Texas Canyon quartz monzonite formations