ROOTED IN CLAY
Conservationist’s dream of restoring habitat along the San Pedro River washed away with floodwaters and dried up due to drought
Peter Else once hoped to create a nature reserve in his own backyard, next to the San Pedro River in southern Arizona. ● During the summer rains of 2017, the flooding river turned much of his 40-acre property into a lake, leaving a thick layer of clay blanketing the ground. ● When the water dried up weeks later, the clay layer was 3 to 5 feet deep in places and nearly buried barbed wire fences to the tops of their metal stakes.
Abrupt changes in the ecosystem followed, coming suddenly and dramatically over the past year. Mired in the thick clay, mesquite and cottonwood trees died. Invasive tamarisk trees sprang up in thickets, forming a nonnative forest that spread aggressively.
For Else, watching this metamorphosis has been crushing.
For years, he has been a leading voice advocating for the protection of the San Pedro River and the oasis it nourishes in southeastern Arizona, a green corridor of riparian forests where cottonwoods, willows and mesquites provide a teeming haven for wildlife.
He wanted to restore a degraded piece of the riverine ecosystem in his backyard near the town of Mammoth, a property that slopes down to the floodplain, where vegetation sprouts in a wide strip of land along the meandering
riverbed.
Else started working on this habitat restoration project more than a decade ago. He removed some tamarisk trees, which at the time were much sparser, and replaced them with native Goodding’s willows. He gradually put up fencing to prevent a neighbor’s roaming cattle from trampling the saplings.
Else dreamed of making his property another gem in a string of conservation lands along the lower San Pedro, a personal contribution to ensuring a healthy watershed and the survival of one of Arizona’s last remaining intact river ecosystems, one threatened by climate change, drought and groundwater pumping.
Much of the year, this stretch of the river retreats underground, leaving its channel dry. When rainstorms come, they send roiling torrents of brown water flowing through.
But in late July 2017, the floodwaters poured onto his land unlike ever before. And the water swiftly rose. As the muck has hardened and the hardy tamarisks have flourished, Else has been forced to dramatically alter his plans.
He has come to accept that his restoration project is no longer achievable, at least not in the way he had hoped.
“It’s sad that I was unable to follow through on it. Now my property has become more of an ecological liability than an asset,” Else said.
Instead, he has started working with a neighbor who lives on the other side of the river to apply for grants that would enable them to gradually remove the thicket of tamarisks, which poses a fire hazard for surrounding homes.
Else, who is 72, said he also hopes to find other types of plants that can survive in the mass of clay.
“But as far as a restoration plan, it won’t happen in my lifetime,” he said.
Else said the rapid change that swept across his land showed how a decision by Pinal County officials to build a dike near the river altered its natural flow and left lasting damage. He filed a claim against the county for the damage, but the county government denied responsibility.
He said the heavy load of sediment that ended up on his property showed why it’s important to have stringent clean-water protections in the Southwest and what can happen when watersheds along desert rivers aren’t adequately protected.
Thick clay and a tamarisk invasion
In his backyard, Else set off down a trail wearing work gloves and a widebrimmed hat. He has walked this path, and its steep slope to the floodplain, for three decades.
He bought the first of his land in 1990 while working in Tucson at the University of Arizona. Else had experience farming and his original plan was to start a truck garden. With his son, Oliver, who was then a teenager, Else revived an old field and started growing crops including basil, cilantro, sweet corn, squash and okra, selling the produce in Tucson.
When Else retired in 2005, he built his house on the property and began focusing on conservation work, looking for ways he could help protect the San Pedro River. He felt strongly that the San Pedro should be protected and not allowed to go the way of other rivers, like the Gila and Santa Cruz, that have been dammed, diverted and pumped dry. He had seen how groundwater pumping and declining aquifer levels had killed off native trees along the Santa Cruz and Rillito rivers in Tucson, and he didn’t want to see the same fate befall the San Pedro.
By the mid-2000s, Else had become a conservation activist. He and 10 other people in the area got together in 2012 and established the Lower San Pedro Watershed Alliance. Else became chair.
He was inspired by other wildlands that had been set aside for conservation along the river, such as 7B Ranch, where a hiking trail winds through a thriving mesquite bosque, and Three Links Farm near Cascabel, where the river flows beneath a canopy of towering cottonwoods.
He had learned that tens of thousands of acres in the watershed were set aside over the years for environment mitigation purposes to compensate for the destruction of wildlife habitat through development elsewhere in Arizona. That included mitigation lands protected in exchange for habitat losses with the construction of the Central Arizona Project Canal and the raising of Roosevelt Dam, among other projects.
While development continued to boom in Arizona’s so-called Sun Corridor, Else saw that his home was part of a parallel San Pedro River corridor, “the default corridor for mitigating the impacts” on the environment.
Else wanted his land, which had previously been used for farming and cattle grazing, to become another healthy piece of the ecosystem along the river. So he started developing a restoration plan, and he got to work with a backhoe, removing tamarisks and digging holes to plant Goodding’s willow trees.
He was careful not to take out tamarisks
during the nesting season of southwestern willow flycatchers because nesting pairs of the endangered birds had previously turned up on his land. The U.S. Fish and Wildlife Service encouraged him to set up a watering station for wildlife, so he did.
Next to the shallow trough, Else installed a wildlife camera, which began capturing images of animals like foxes, javelinas, bobcats, skunks and dozens of species of birds.
“I was very excited about the progress we were making,” he said. “I wanted to be a part of it. I wanted my land to play a role in a movement to save this last remaining desert river ecosystem.”
He was inspired by the idea that he could perhaps leave a permanent legacy by laying the groundwork for a wildlife conservation area that would become a link between other intact habitats.
As Else walked into the floodplain, stands of cottonwood trees in the distance glowed with golden yellow leaves. From afar, the vegetation in the river valley seemed intact.
But at the bottom of the hill, the trail reached a field of clay, sunbaked and deeply cracked, which was left by the 2017 flood. The clay had engulfed the trunks of mesquite trees, and the leafless branches cast shadows on the cracked soil.
Before the flood, Else said, these mesquites were thriving. He and his partner, Suzanne Kelly, had harvested mesquite pods and milled them to make flour, which they had enjoyed using to make pancakes.
“All the mesquites are dead in this area,” Else said. “The same for the cottonwoods. We had big, gorgeous cottonwoods. They suffered the same fate.”
When so much clay piles up, he said, the new impermeable layer apparently smothers the trees by starving their roots of oxygen.
Else stopped at a white shed housing his original well. The floodwaters had overtopped the well and stained its walls with a brown line.
Unable to use the water after the flood, Else put in a new well. He later tried to recoup the old well by adding 4 feet of new casing on top and raising its electrical outlet and control valves.
“Where I’m standing right now, there’s 3 feet of clay under my feet,” he said.
Else continued, passing the top of a metal fencepost that protruded from the ground where the muck had nearly buried a 4-foot, 8-inch barbed wire fence.
After the flood, he said, the water level here had reached nearly 7 feet deep.
At the time, he had noticed some brown debris floating on the surface of the floodwaters. He later realized they were tamarisk seeds. When the chocolate-colored water dried up and dissipated after six weeks, the seeds settled on the clay and germinated.
Beside his garden, Else squatted down and touched a tiny plant sprouting from the clay soil — another tamarisk seedling.
“These are all tamarisks,” he said, motioning ahead on the path to the dense foliage. “It came up looking like a field of wheat. It just came up as a solid stand.”
Last summer, during one of the hottest and driest years on record, he watched as the tamarisk forest grew rapidly and spread.
“It grew over four feet during the last summer, just on the moisture that had been stored in the clay,” he said. “There was just an unbelievable influx of tamarisk that took place as a result of this flooding — human-caused flooding.”
A dispute over flood damage
Leading the way into the thicket, Else stepped over a piece of barbed wire that ran ankle-level across the soil like a tripwire.
He had cut a path through the tamarisks with pruning shears, and some parts of the trail became tunnel-like beneath the bushy branches. A smattering of native seep willow shrubs sprouted in the clay, but the non-native tamarisks dominated.
The San Pedro River has long had some tamarisks mixed in with native vegetation. But Else said the thick layer of clay laid down during the flood created the conditions for the invasive trees to take over.
After the flood, Else requested and obtained various public documents, including
emails between Pinal County officials, that detail conversations about previous flooding on a neighbor’s property and the eventual construction of a berm by county workers.
The documents reveal that a downstream neighbor was cited by the Pinal County Flood Control District for a “wash obstruction violation.” The property owner later addressed the citation and the case was closed. Else said the neighbor had tried to put up barriers to keep floodwaters out.
The released emails showed that the neighbor had shared photos and video of previous flooding in early 2017 and had thanked a county official for planning work clearing debris along a road “to get some relief from flooding waters.”
Else said the land in the floodplain had undergone subtle shifts over the years as cattle roamed, carving paths with their hooves. He said he believes those cattle trails cut deeply enough into the soil that when the river flowed during rains, the water would follow the trails, worsening the flooding for the neighbor.
In a later email in March 2017, thensupervisor Pete Rios shared a photo of recent flooding in the area and asked Louis Andersen, then the public works director, if he thought it would be a good idea to put a “gentle” berm along the roadway to help with the next rainy season.
Andersen replied: “Yes — won’t hurt.” Andersen said he and others would look at this the following week. County workers soon built the berm. Else had just returned from a trip to Oregon when the floodwaters started pouring onto his land. He emailed thenCounty Manager Greg Stanley on July 24 saying neighbors told him the county was responsible for constructing the new berm along a dirt road downstream from his property.
“This berm caused a substantial obstruction to the flow of the river, acting as a dam,” Else wrote. “Starting last week, a large lake formed upstream of the berm.”
The berm averaged 8 feet in height and was over 500 feet long, Else said. He filed a claim with the county that August, alleging the dike led to the flooding on his property and caused damage.
Deputy County Attorney Kevin Costello responded in a letter, saying “studies performed by the County demonstrate that the berm referenced in your claim did not cause nor contribute to the flooding of your property.”
Else argued the county’s studies were wrong. But officials stood by their conclusion and denied his claim.
James Daniels, the county’s communications director, reiterated that officials met with Else and reviewed his claim but determined that the county’s action “neither caused nor contributed to any damage” to his property.
“Pinal County considers this matter concluded,” Daniels said in an email.
Several months after the berm was built, federal officials got involved. The U.S. Army Corps of Engineers asked the county to remove the dike, and in October 2017 county officials agreed. Workers returned with machinery to take it down.
By that time, the water had completely dried up on Else’s land but the thick clay remained.
He began observing how the change in soil triggered changes in the vegetation.
Years ago, he studied soil science as an undergraduate at the University of California, Berkeley, and he described his land pre-flood as having a “beautiful” sandy loam that allowed water to infiltrate into the ground.
With that soil buried under solid clay, Else said, the ground went from permeable to impermeable. He said the clay sealed off the ground, preventing water from soaking down to the underlying aquifer.
While the tamarisks flourished, native trees struggled. Nearly all his mesquite trees died.
At the edge of the floodplain, he marked the line between dead and living trees with pieces of pink tape. More than 100 dead trees were removed this past winter.
Else has talked with officials from the state Department of Forestry and Fire Management about what to do next.
“Now I realize that my original plan is no longer practical,” Else said. “The conclusion we came to is that I’m not going to see restoration of native forest species here during my lifetime and we should focus on hazardous fuel reduction at this point.”
That means controlling the tamarisk invasion as much as possible and creating defensible space between his home and the new forest, which he fears would burn intensely in a wildfire.
Source of watershed’s ‘unnatural’ sediment load
The San Pedro River stretches 140 miles from its headwaters in Mexico to its end in Winkelman, where it joins the Gila River.
Much of the river’s flow is fed by groundwater that emerges in springs and seeps. Over decades, as more wells have been drilled across the river valley, pumping has lowered the water table and many segments of the river have suffered long-term declines.
Some stretches that once flowed have been transformed into dry sand most of the time, running only when rainstorms bring a surge of runoff.
The San Pedro collects water from rains and melting snow across a vast watershed. For millennia, natural erosion has sculpted the valley and sent sediment-laden water flowing into the river.
The “unnatural part” of the sediment now reaching the river, Else said, comes from all sorts of human activities — past and present — that have disturbed soil in the watershed, including cattle grazing, development, mining and off-road vehicles speeding across the land.
Years of drought intensified by the warming climate have contributed to these problems by drying up vegetation, and wildfires have left pieces of the landscape charred and vulnerable.
When the soil is disturbed and left without enough vegetation to hold the land in place during heavy rains, more erosion results.
Even before the flood damage, Else had noticed that if he waded into the river after rains, his legs would come out coated in mud. But he said the thick clay layer revealed the “extraordinary” sediment load that now courses through the river.
Else estimated that during rains perhaps a third of the flowing river is sediment suspended in the water.
“This really reflects on the health of the watershed as a whole,” Else said.
Last fall, he started hacking through the tamarisks with a machete and then turned to use pruning loppers. He spent two days cutting a path, much of the time working on his knees.
Tice Supplee, director of bird conservation for Audubon Arizona, toured the property and described what happened to it as “catastrophic.”
“He now has feet of clay soil that has completely changed the character of the site, has killed the mesquite bosque that was there,” Supplee said. “Peter lost in the big picture. I don’t know if the river has lost in the big picture. Because it’s dynamic, and so the river channel moves.”
She said she thinks Else’s experience shows the complexity of maintaining healthy ecosystems along the San Pedro and other rivers in the Southwest.
“The tamarisk issue had not been a big issue on the San Pedro, and I think it’s increasing with drought,” Supplee said. “We’re in an extended drought phase that may never go away with the changing climate, which means that these stands of tamarisk are going to become more successful in more rivers and tributaries.”
Else said watching the sudden ecological downturn has been traumatic. And the degradation of 25 acres of his property, he said, shows “why it’s so important that we protect all the ephemeral waterways that feed this river.”
Over the past year, the Trump administration’s rollbacks of environmental rules dramatically downscaled protections for many streams and wetlands. The new clean-water rule eliminated regulation of most ephemeral streams and washes, which flow intermittently when it rains but otherwise sit dry much of the time.
In Arizona and other southwestern states, many streams that were previously regulated by the federal government were removed from protection under the Clean Water Act.
Gov. Doug Ducey’s administration supported the change and convened a series of meetings to develop a “local control” approach to regulating Arizona’s waters. A bill establishing this state regulatory program is now working its way through the Legislature, with support from representatives of the mining industry, agriculture and developers, among others.
Conservationists have opposed the legislation, saying it doesn’t go nearly far enough in protecting streams.
In written comments in December, Else said Arizona should require dredge-and-fill permits for construction work in ephemeral streams and not simply rely on creating what officials call “best management practices.”
He said the damage to his property shows how the heavy sediment load in the San Pedro River causes problems, and he warned that these problems will worsen where ephemeral streams are left unprotected.
The proposed legislation, House Bill 2691, was passed by the House in early March and awaits a final vote in the Senate. Else and 16 other leaders of conservation groups sent a letter opposing the bill, saying “it does not protect Arizona’s waters at a time when we should be doing more, not less, to protect them.”
Else’s Lower San Pedro Watershed Alliance is also one of several conservation groups suing to challenge the federal government’s decision to grant a dredge-and-fill permit for a housing development that would bring 28,000 homes and golf courses to the river valley near Benson. They argue groundwater pumping for the planned development threatens the river.
Else said the San Pedro faces a host of threats that are interconnected and some of these threats converge on his land, where the degraded ecosystem shows what can be lost. He said the transformation since the flood underlines “the importance of looking holistically at the watershed.”
Because soil erosion can have such devastating consequences downstream, Else said, protecting the watershed’s slopes and ephemeral streams is vital.
He said he hopes President Joe Biden’s administration will restore the water rules that were rolled back under Trump, but he expects that could take two or three years, “and in the meantime, a lot of damage can be done.”
Else said through his ordeal, he has learned just how important the Clean Water Act’s protections are for maintaining healthy rivers.
“The Clean Water Act was developed because there were some very smart ecologists who understood that if you start messing with a natural river ecosystem, with dredging and filling and diking and berming and those sorts of things, there are going to be consequences,” he said. “Regulations are there for a purpose. And when you ignore those regulations, you can have ecological catastrophes like the one you just saw.”
Ian James covers water, climate change and the environment for The Arizona Republic. Send him story tips, comments and questions at ian.james@ arizonarepublic.com and follow him on Twitter at @ByIanJames.
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