Landscape Architecture Magazine Ι November 2020

Like a lot of landscape architects, Stephen McCarthy spends much of his time managing hydrology and restoring native ecologies. The sites he works on, in Milwaukee’s exurban fringe, are often landscapes of subtle differences: gentle rises and shallow streams, small agricultural plots hemmed in by hills and wetlands. At the Little Menomonee Prairie outside Mequon, Wisconsin, the city feels far away. It’s a native prairie of bluestem, Indiangrass, switchgrass, and yellow coneflower, inarticulate in the early March scrub. Red osier dogwood provides a few pops of color, voles scamper underfoot on the way down to the Little Menomonee Creek, and a red-tailed hawk shows up on cue as McCarthy and I pull into a tightly mowed area near the road that’s one of the only concessions to visitor access. A few months earlier in the fall, we might have seen wild salmon swimming upstream from Lake Michigan, McCarthy tells me. It’s a reminder that deep into the tilled and harvested expanses, water connects everything.

From the road, there’s a loose allée of still-spindly white swamp oaks that McCarthy planned and planted, which lead to the creek. “This is where, as a landscape architect, I don’t necessarily do things the way a landscape ecologist would,” he says. The trees “give some contour and flow to the prairie, and [lead you] in.” Further into the landscape are the teardrop-shaped wetland cell depressions McCarthy directed a team of contractors to sculpt, crisp white and frozen solid at the edges. “I wanted it to appear like a natural element in the landscape,” McCarthy says. As we approach, we notice there’s a provisional wooden bridge over the stream McCarthy had never seen before, spanning a root-armored creek bed, evidence that McCarthy’s subtle design cues have an audience. “My guess is it’s hunters. Good for them,” he says.

The 60-acre Little Menomonee Prairie parcel, which sits next to the original owner’s still-intact farmstead, was restored in 2012 at a cost of about $100,000. That’s a decent deal for a landscape restoration, but it’s an outrageous bargain for sewer and stormwater infrastructure, which has been the focus of McCarthy’s work for 20 years. McCarthy manages the Greenseams program at the Milwaukee Metropolitan Sewerage District (MMSD), which acquires tracts of land mostly beyond the city and restores and preserves them as native landscapes so that their marshy, hydric soils can soak up precipitation, sparing the city from flooding. McCarthy says he’s creating sewer infrastructure without a single pound of concrete engineering, and it’s apparent he’s applied a landscape designer’s pragmatism and deference to nature in giving water room to spread out. He also applies an aesthetic sense of landscape experience that most underground concrete pours don’t consider.

With Greenseams, a major American city’s sewer district has dedicated a significant portion of its portfolio toward managing flooding through ecosystem services and a landscape architecture lens. With more than 4,000 acres under its purview, MMSD has become one of the largest land preservation agencies in southeast Wisconsin. “Greenseams is green infrastructure for rural land,” says Kevin Shafer, the executive director of MMSD, and McCarthy’s boss. “I don’t think there’s another sewer utility in the country doing what we’re doing with this Greenseams program.”

McCarthy is an enthusiastic student of landscape architecture history and its intersections with regional conservation, and Jens Jensen, Alfred Caldwell, and Aldo Leopold (true to his Wisconsin roots) are his heroes. “You can’t study the native landscape like [Jensen] did or I’ve done and not have a connection to it that goes beyond just aesthetics,” he says. “There’s a spiritual aspect of the landscape.” Though McCarthy is very much a technocrat, he leaves room for hints of mystery. Divining rods are a part of his tool kit, and he uses them to locate drain tile irrigation tubes that spirit water off agricultural fields. When he uses construction site flag pins bent into an L shape, walking over underground utilities, water, or drain tile causes a mystical tug outward. I ask him if it’s some sort of magnetism.

“I can only describe it as the detection of an energy field,” he says.

The Greenseams program works in four Wisconsin counties (Ozaukee, Washington, Waukesha, and Milwaukee) across the Milwaukee River, Root River, Oak Creek, and Menomonee River watersheds, which flow west to east into Lake Michigan. The program has brought 124 properties under permanent protection and planted 114,000 trees. But McCarthy is largely a facilitator of natural processes, rather than a tabula rasa designer. “What we’re strictly doing is restoring these lands to natural sites,” he says. “They’re not reservoirs. It’s just the land itself that’s keeping water where it falls.”

To date it’s estimated the Greenseams program has kept 2.4 billion gallons of water out of the urban sewer system. That’s several times the capacity of Milwaukee’s previous major stormwater infrastructure investment, a deep tunnel project completed in phases beginning in the 1990s. MMSD bored a 28.5-mile-long, 32-foot-diameter tunnel 300 feet belowground, which can hold 521 million gallons of water until it can be treated. It cost more than $1 billion yet didn’t quite solve the problem. The city went from 50 to 60 combined sewer overflows (CSOs) each year to having just over two on average.

In 1997 and 1998, there were back-to-back 100-year floods, and there was another rash of strong storms a decade later. In 2018, MMSD experienced six overflows, tied with 1999 as the most in a calendar year since the CSO tunnel opened. “The amount of impervious surface [had] finally reached the point, coupled with these 100-year events, that Milwaukee suddenly saw expansive flooding in [a] way it had never seen before,” McCarthy says. To close this gap, MMSD and a consultant team came up with a series of proposals, including one to preserve wetlands and hydric soils upstream of the city, which became the Greenseams program.

To date, the Greenseams program has repaired and restored 935 acres, but its beginnings were sometimes awkward, if not antagonistic. In the early days of the program, Shafer recounts making his pitch at a village board meeting in the nearby suburb of Oak Creek. It didn’t go well. “They thought the government was going to come in and take their land away from them and their families, that they’ve lived on their whole lives and their parents had lived on,” he says. Lots of shouting and jeering ensued; the police were called and stood sentry at the back of the room. Shafer made it clear (to little avail): Greenseams only works with willing landowners. The police escorted him out of the meeting.

Considering how cost-effective Greenseams has been, they might have thanked him. The annual budget for the program today is only $1.2 million, and over its 20-year life, MMSD has spent $32 million, including $12 in grants given to partner organizations. And McCarthy is the program’s only full-time staffer, though he regularly works with a small team of other MMSD staff. For perspective, over the same time span, MMSD has spent about $500 million on hard engineering infrastructure, such as widening and deepening streams and rivers, as well as peeling back concrete embankments.

Even better, “There’s virtually zero dollars down the road needed to maintain [Greenseams sites] in the long term,” says Peter Ziegler, a project manager at EC3 Environmental Consulting Group, which works with McCarthy on Greenseams projects. Since 2018, the Greenseams program has included a series of prairie burns that keep the landscapes in ecological balance. “That’s the beauty of prairie,” says Rachel Samerdyke, a wildlife biologist with the U.S. Fish and Wildlife Service in Wisconsin, who also works on Greenseams projects. “You don’t have to bring in soil; you don’t have to put nutrients back into the soil. The prairie’s done that for you.”

This approach also means that when things go wrong they’re easier and cheaper to fix. At Greenseams’s Germantown Wilderness, in the swampy headwaters of the Menomonee River, McCarthy and a team of contractors broke apart drain tile tubes to let stormwater infiltrate the soil. But one section of tile collected enough water that it forced a blowout on a small rise, leading to rapid erosion. Instead of forcibly re-engineering the water, he let it take its place, excavating a wetland cell right there. “This isn’t a solution that an engineer would see,” McCarthy says. “I simply looked at the landscape and worked with the landscape to solve the problem, and we did it in an expeditious way that didn’t cost us more than $30,000 to excavate. Now we have a nice, seasonal wetland. That’s the single biggest intervention that we’ve made so far, and I can’t imagine us doing anything beyond that.”

Unlike the CSO tunnel, Greenseams landscapes can do more than one thing. In addition to providing stormwater management, they also recharge aquifers, improve water and air quality, and bring the quality-of-life improvements that come with added access to nature, wildlife habitats, and plant biomes.

It’s a long list, “versus $1 billion for a tunnel in the ground that is single-purpose, has ongoing costs associated with it, and we can’t afford to do it again,” McCarthy says. In conservative-leaning Wisconsin, McCarthy hammers home the economic value that ecosystem services offer. We have to “move beyond the habitat—beyond the fuzzy things and [get to] the pure economics of it,” he says. McCarthy is quick with dollar figures for everything, from the cost to burn one stretch of prairie ($3,000 at Little Menomonee Prairie) to the entire budget over the program’s history.

“I would much rather go out and spend a dollar on a Greenseams [project] that provides me with three dollars or four dollars of benefits when it comes to flood management, habitat, climate mitigation, recreational opportunities, [and] public health opportunities, than to spend a dollar on another tunnel extension,” Shafer says. “It’s a proactive approach to addressing an issue before it becomes an issue. A lot of times we’ll develop a floodplain, we’ll put an impervious cover on a watershed, and then we have to come back after the fact and retrofit that watershed to manage the flooding that we created ourselves.”

In terms of the dollars-and-cents equivalent of each of these ecosystem services, Greenseams has only loose estimates, which they peg at about $40 million per year. This estimate comes from a study that the nonprofit Conservation Fund (a critical Greenseams partner that stewards new properties with MMSD) completed for Chicago Wilderness, a regional alliance in Illinois that advocates for nature preservation.

With more detailed data on the value of these ecosystem services in Milwaukee, the Conservation Fund and MMSD would be able to better explain the benefits to people closest to these potential nature preserves. They could “look at our site and say, ‘[With] this property, we can assume that it’s going help reduce x amount of soil runoff,’ or ‘it’s going to help infiltrate x gallons of water,’” says David Grusznski, the program director of the Conservation Fund’s Milwaukee office. “And so, if they can start using that kind of information more, our program has more meaning to them than just flood management from a downstream perspective.”

McCarthy is the latest in a long tradition of progressive-minded advocates for sewer infrastructure in Milwaukee. The city’s three “sewer socialist” mayors governed Milwaukee between 1910 and 1960, and built their political coalition on a sturdy base of pro-union public works. The moniker “sewer socialist” was applied by outsiders who disdained the midwestern politicians for delivering high-quality public infrastructure over politics, but the locals embraced it. With a combination of grassroots organizing and reformist good-government intentions, Milwaukee’s socialist mayors established the department of public works, public housing, city parks, and numerous public health initiatives. Mayor Daniel Hoan (1916–1940) led the municipal takeover of the city’s water filtration infrastructure, and the city built its first treatment plant in 1934.

Greenseams works by purchasing land, as well as purchasing easement rights that prohibit development and guarantee public access. The budget for Greenseams properties is significantly supplemented by grants from Wisconsin’s Knowles-Nelson Stewardship Program and the USDA Natural Resources Conservation Service.The Conservation Fund is a vital intermediary between Greenseams and the eventual owners, which might be local land trusts, park districts, or municipalities. This chain of custody means the Conservation Fund can apply for conservation funding not available to government agencies.

Greenseams and the Conservation Fund hand over restored tracts to public and nonprofit agencies such as the Ozaukee Washington Land Trust (OWLT), where Tom Stolp is the executive director, for free. He says Greenseams “has really supercharged some of our acquisitions.” OWLT has completed about two dozen transactions with Greenseams, adding a total of 1,070 acres to its holdings. Stolp says there’s an accessibility and a permanence to natural landscapes that most other sewer infrastructure lacks. “If [you] visit a sewage treatment plant once, like when you’re in the fourth grade,” he says, “it’s interesting and it’s important work, but we’re creating infrastructure—green infrastructure—that’s going to serve our community for generations.”

Recently acquired in 2019, the North Branch Woods is 110 acres [SOURCE?] of wetland and agricultural fields along the north branch of the Milwaukee River that will be reseeded as prairie. In the early March thaw, it’s a landscape of ice and mud. You can comfortably take off your gloves, but the snow can also be a foot deep. A site that’s just come onto the Greenseams books, it has little evidence of human habitation outside of an agricultural access trail and a steel truss bridge flecked with lichen. Even the archaic barn on site, held up by steel braces, will be leveled. A flock of wild turkeys is the only action for acres.

“Largely, it’s not going to be visited by a lot of people,” McCarthy says. Like all Greenseams sites, it will be maintained for cross-country skiing, birding, and hunting, evidenced by the deer stand in a tree at the edge of a field. “There’s no parking lot. The only people that are going to come here [are] people who specifically want to come here to experience it for some kind of natural reason, to get out and hike [or] bird-watch.”

And that’s what brings McCarthy more than a little infectious joy. With a walking stick in hand as he treks up and down its gradual hills, he’s close to giddy. “Preserved in perpetuity. Ain’t going anywhere, ever. That’s the greatest thing. In perpetuity. That’s awesome.”

MMSD is not a public space agency. They don’t do amenities, trails, or programming. Trails can turn landscapes into de facto dog parks, which is bad for habitats, especially ground-nesting birds. Greenseams restores places for solitude and reflection in nature.

Which means that these landscapes are perfect for the social distancing dictates of the COVID-19 pandemic: expansive and aimless. The pandemic is causing other positive effects for Greenseams as well. McCarthy speculates that, as with the 2008 recession, COVID-19 will likely cause land values to drop and winnow the field of buyers to compete with MMSD. “I think we’re going to see more people turning to us now,” he says.

But often, McCarthy feels as if the parcels MMSD is looking at are undervalued. The benefits MMSD touts to villages and towns (stormwater capture, recreation, wildlife habitats) are seldom accounted for by development-driven real estate appraisals. “The prices that are being paid for wetlands and natural areas don’t even begin to address their real value,” he says. “The entire appraisal approach is archaic because of climate change, and we need to rethink the real value of natural areas. We should be paying more for them.”

It’ll likely be hard to assess how much more wetlands should be worth during an extended recession in the wake of COVID-19. But McCarthy sees the economic shock that settled over the world in March of 2020 as a cataclysmic warm-up. “What we’re dealing with now I think of as an opportunity to be prepared for something that’s far more tragic—climate change.” A warming planet means a wetter climate with more frequent torrential downpours and flooding in Wisconsin, and the task of retaining stormwater and preventing erosion will become even more critical.

“That isn’t even going to be the tip of the iceberg as to what’s going to happen when climate change hits us,” McCarthy says. “We’re spending this unbelievable amount of money in ways we never thought we would. With the protection of natural areas, it’s not whether we can afford to buy them and protect them, it’s a matter of what the cost will be if we don’t do it.

“I sit in a really unusual professional position where I’m watching how the district is handling things, and how the state is handling issues, and the federal government,” he says. “So I get to kind of become a divining rod, [for all] of these different energy forces [we’re] grappling with.”

With its 200-year-old archetypally gnarled oaks, Ryan Creek Prairie is one of Greenseams’s most picturesque properties. It’s very visible by program standards, placed along Highway 36, a main drag through the town of Franklin in Milwaukee County. As such, McCarthy used nonnative redtop (Agrostis gigantea) as a cover crop for the former agricultural tract. Once grown in, it’s a hazy, delicate gold, more attractive than wild rye, which tends to look weedy. After a burn last year, the redtop receded and natives took over.

The way Greenseams sites look from the road matters specifically because they aren’t heavily visited. “We kind of joke that for many people, the way they’ll experience our preserve is driving by. And that’s not a bad thing,” says Stolp of OWLT. “It took me a while to appreciate this, but there’s value for many people in the community just in knowing our protected places exist, and will exist; that it’s a place for wildlife to thrive, and a place that others in the community can go and enjoy. And so, you just get to go out and have this sense of wilderness and discovery. That’s kind of wonderful.”

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