The right way to restore a streambank


Standing precariously on a gravelly chunk of riverbank, I reach over a thick sheaf of willow cuttings to grab the bucket being waved in front of me. And nearly drop it—it feels like cement hung from my hands. Pointy stems dig into my stomach; overhanging cottonwood branches brush my eyelids. With a mighty heave, I overturn the bucket and empty an avalanche of wet gravel and fine-grained topsoil over the baby willows.

“How many more?” my supervisor Christina calls over as I’m passed the bucket.

Hefting the bucket of dirt, I squint down at the trench in front of me. How much more topsoil needs to go in? How much fine dirt and organic matter, how much nitrogen and phosphorus, how much gravel and sand and clay can we pack into, around, these fragile willow stems without overtopping or building up a slowly settling foundation? Without silting into the river and drowning the fish in fine glacial dirt?

We’re filling in the last trench on a streambank restoration project on Scheffler Creek. Over the last several years, the narrow bank has been heavily used as a beach access trail and thus eroded down to muddy, devegetated slop at the water’s edge.

After hauling trees and dirt and rocks all day, this is the last gap between our built-up base on the eroded bank, and the raw edge three feet above. At this point, we’re literally putting the icing (topsoil, gravel, and alder and saltgrass plantings) on a layer cake of coir (coconut fiber log), gravel and topsoil “burritos” wrapped in burlap, and densely packed willow cuttings.

Resurrection Bay Conservation Alliance, a local conservation nonprofit, has pulled together the resources and volunteer manpower and pizza. The mission? rebuild the stream edge, reduce erosion, and improve Scheffler Creek both aesthetically and as habitat for salmon fry, which need clear, cold, silt-free water to thrive. I’m here as part of the exotic plants management team (EPMT) crew from Kenai Fjords National Park—it’s a change of pace, today; we’re planting instead of pulling, filling scars, healing the land in a very different way than our usual shoveling and uprooting.

It’s the details that matter in projects like this—how much dirt, how you tuck in carefully measured burlap, how you stake the massive coconut fiber logs that serve as a “toe” base. Questions keep coming up—how should we anchor the silt fence? How should we tuck in the base? What’s the right way to rebuild a stream?

“Is there an exact science to dirt and willow cuttings?” I ask, laughing. Willows are, I’m told, almost notoriously easy to root. Take a bare winter willow branch, cut a decent-sized length, leave it dormant in a snowbank or a refrigerated cooler until you spring, and then stick it in the ground. Ta-da, instant reveg.

Christina shrugs, smiles, raises her eyebrows. “As much soil contact as possible! Other than that…” We have to laugh at the absurdity of it all, at my elbows covered in mud, at our hip waders immersed in frigid stream water, at our ridiculously long bucket brigade, at our attempts to put nature in a box and fix it.

Is there an exact science to streambank restoration? Not really. If anything, it seems, restoration calls for rebellion against scientific method.

It’s a total paradigm shift. The traditional scientific method seeks pattern in chaos, breaking down random phenomena into timetables and categories and numbers. Easy quantification—biomass weights, transect percent cover, miles tracked and area treated—is the key to doing “good science” in ecology.

Restoration seems to asks the opposite. How can you take an easily quantifiable pattern of damage, or invasion, or abuse and allow nature to take back the wild randomness of growth?

Landowners, our visiting streambank expert from Alaska Fish and Game tells us, often want straight lines, clean-cut waterfront edges, grassy lawns that run straight down to the water (and channel fertilizer and runoff, too). But restoration often entails getting messy, and making messy; natural shorelines are never straight, but scraggly, brushy, uneven, filled with dead logs and heaped gravel that make great habitat for freshwater critters.

You follow a few simple rules—create as much soil contact as possible with cuttings, count on making a mess and use a silt fence to mitigate it, sandwich willow cuttings between gravel-soil-burlap burritos, check the tide tables to make sure your site won’t be overrun while you restore it—and make the rest up along the way.

And in the end, maybe there is no right way to rebuild a stream. We run out of time, and build up a trench with vertical willow plants staked along the edge, instead of a second berm of burlapped soil. On an 8-hour day, maybe we don’t have time to finish the job the way I’d want to. Maybe streambanks don’t adhere to schedules either, or scientific methods, or straight lines.