Slowing the Flow

The arroyo near her house had flooded, so Mori Hensley knew it was time: She climbed in the car with her mom and dog and drove into town to see the new Brother’s Lane Rain Garden on East Alameda in action.

The City of Santa Fe’s Public Works Department and the watershed association announced the completion of the Brother’s Lane Rain Garden and Camino Escondido Stilling Basins on July 6, and they’ve been tested during recent monsoon rains.

Hensley saw stormwater running off from east of Paseo de Peralta and rushing down the side of the road. Usually, that water races through the gutters, occasionally diverting into storm drains and running into the Santa Fe River, carrying with it all the trash, cigarette butts, petrochemicals, tire residue and other contaminants it’s picked up along the way.

“It’s like taking a fire hose to the soil,” says Hensley, who is the executive director of the Santa Fe Watershed Association. “It’s basically ripping the soil away along with any plant roots or microbes holding the soil together—so after the storm has passed, the landscape and the channel are left drier than before.”

This day, though, it looked a little different: The big puddle that normally accumulates at the corner of East Alameda and Old Santa Fe Trail during a storm was smaller than usual.

The scene might have gone unnoticed by most Santa Feans, but Hensley—project manager for the new rain garden—saw it as a win.

Funded by a River Stewardship grant from the state Environment Department for about $160,000, the project is a collaboration between the Santa Fe Watershed Association, the City of Santa Fe, The RainCatcher Inc., and Watershed West. It’s the latest project in the Alameda Rain Garden Program, a city initiative designed to take stormwater from the streets, slow it down and improve its quality by passing it through “bioinfiltration basins” and other structures before releasing it back into the river. For Hensley and others who worked on the garden, such projects indicate an inflection point in the way Santa Fe thinks about stormwater.

“Our paradigm of dealing with stormwater has been that it’s a menace,” Hensley says, and Santa Fe, like most cities, is designed to get it off the landscape as quickly as possible before it floods buildings and damages infrastructure.

But she says that needs to change. Stormwater can be a tool to improve Santa Fe’s resilience in the face of climate change, instead of becoming a greater threat as storms become more severe and unpredictable.

That’s the idea behind rain gardens. Rather than water running off streets, parking lots and other impervious surfaces into storm drains, rain gardens guide stormwater into “stilling basins” where it can pool and infiltrate into the soil.

In the Brother’s Lane Rain Garden, designed by Reese Baker, owner of sustainable landscaping company The RainCatcher, a special mixture of soil in the basins that helps water infiltrate more quickly—24 hours at most, Hensley says.

There’s a series of basins, each of which serves a purifying function.

Water flows from the street into the first stilling basin, which catches trash and debris and can be easily cleaned out. During a rainstorm, the water in the first basin is almost black. In the next basin, there are native grasses with extensive root systems that stabilize the soil, adding carbon and helping to trap chemicals and break them down.

“A lot of petrochemicals are carbon-based, so they still have value to some of these species,” Hensley explains.

Then, the stormwater encounters elm branches that have been inoculated with oyster mushroom spores. The mushrooms help to further break down chemicals.

The rain garden serves another ecosystem benefit: aquifer recharge. By slowing stormwater down, instead of stripping soil moisture, rain garden structures lend soil the ability to hold moisture, allowing water to infiltrate—”hopefully into our shallow aquifers where they can be kind of a savings account for our city water,” Hensley says.

She notes that the city has a practice of “resting wells,” relying primarily on surface water to save groundwater for when other resources aren’t as available.

“I look at stormwater management as not only a way to deal with a potential hazard, but also as a way to improve quality of life for our community and our ecosystems,” says Zoe Isaacson, acting river and watershed manager for the city. “Back in the day, we thought we were in the land of plenty, so we pumped our groundwater as much as we needed and we didn’t recognize that we were depleting our aquifers and not recognizing the surface water for its value.”

The Camino Escondido Stilling Basins focus on curbing erosion, explains Melissa McDonald, Parks and Open Space Division director.

They cleaned out a place that was “basically just an old dump site,” creating structures so that as water comes from the streets—Camino Escondido, Canyon Road and others—it flows through a pipe to a series of energy dissipators that slow water down like eddies in a stream, capturing sediment and debris in the basins and then releasing the water into the river.

McDonald says the city is working with the watershed association to test the water quality at the entrance to the basin and then in the river to track any improvement.

So far, they’ve only gotten a baseline, which McDonald says “told us what we’ve kind of known”—that the site has an issue with contamination from dog waste and car pollutants.

“It’s not flagged as an area of concern,” she says, “but it’s something that we wanna watch because as our city grows and there’s more traffic and people walk more dogs, we need to keep our water quality up for our downstream users and for our wastewater treatment plant.”

Finding ways to slow stormwater is also a safety concern. Flash floods happen when water can’t seep into the earth quickly enough, and they can be fatal. Just last week, the Santa Fe Police Department identified a man who’d been found dead in an arroyo after heavy rainfall on June 25 as 37-year-old Wilfredo Flores-Diaz.

“Nothing is a silver bullet,” says Hensley, but she sees rain gardens and similar low-tech green infrastructure projects as an essential tool for Santa Fe to become “a more ecologically healthy and resilient place.”