Superfund reclamation – specifically, revegetation – isn’t your standard landscaping. Don’t expect to see a county worker mowing and manicuring the grass like you see being done at the park or on a golf course. Also, don’t expect to see the reclaimed areas in Butte being irrigated.
Yes, there are some reclaimed and redeveloped Superfund areas in Butte irrigated and mowed. Examples include Copper Mountain Park, the butterfly gardens at the Lexington Stamp Mill (corner of Arizona and Broadway Streets) and the Original and Belmont mine yards. But the majority of reclaimed areas in Butte are neither mowed, manicured or watered.
One reason: the purpose of revegetation on a Superfund site is different. Grass at the park or flowers in the garden are meant to be lush and colorful so that we may lay on them or look at them in enjoyment. The plants growing on a Superfund site are not there to look pretty.
They’re there to hold the soil in place in order to cover up harmful mine waste beneath. If the soil on these reclaimed caps erode away, the acidic mine wastes beneath could be exposed and wash away into our streams, damaging the environment. Job No. 1 for the plants selected is erosion control.
Job No. 2 for reclamation plant species is to provide a low or no maintenance cap. That means no regular mowing, fertilizing or watering, which means the species selected must be able to survive and reproduce in Butte’s climate and soil conditions.
Why is “low maintenance” important?
Think about how much time, water and resources it would take for work crews to irrigate, mow, weed, fertilize, etc. all 600-plus acres of reclaimed Superfund sites, all summer long, which are scattered all across the city. For starters, that’s not very practical.
Secondly, if the plants on top of our Superfund caps needed irrigation to grow, that would mean a lot of water used. It would also mean a lot of water percolating through the soil caps and into the mine waste beneath, which would make that water contaminated. Butte already has enough contaminated groundwater and surface water to deal with, so taking good water and turning it into bad is not wise. Luckily, it’s not necessary either.
The seed mixes for our Superfund sites are selected to provide a diverse plant community of grasses and forbs (broad-leaf plants that aren’t grasses, trees/shrubs or wetland species), and in some cases, trees and shrubs. Some of the species are “nitrogen fixers.” Nitrogen fixers are plants that utilize bacteria in their roots to pull nitrogen – a key nutrient for plants – out of the air and put it into the soil.
This task is very important, since the soils around Butte are low in nutrients and native plants growing in them need all the help they can get. Three nitrogen-fixing species commonly used in our Superfund seed mixes are alfalfa, red clover and my favorite, bird’s foot trefoil (see photo).
Not all of the plants seeded are native, but they’re all species that can survive in the dry, cold, high-altitude conditions we call home without much help from us. “Not much help,” means that once the seeds are put in the ground with some fertilizer and maybe a little mulch and/or compost, they’re on their own.
Once planted and established, the sites are evaluated periodically to ensure the caps are growing properly and not eroding away (see my previous column on the Butte Reclamation Evaluation System). Weed control is necessary to keep out noxious species and some sites that are right on top of residences are mowed to prevent fires. Other than these minimal actions, the plants on Butte’s Superfund caps receive no more TLC than the plants you see growing on a hillside outside of town or the vacant field or lot down the street.
I’ll introduce more plant species used in our reclamation in a future column or two…or three. Until then, remember that the plants growing on Butte’ Superfund sites have a job to do. Try to get to know them and recognize that while they might not be soft and green, or pretty and pink, they’re important just the same – maybe even more so!
PHOTO CUTLINE: Bird’s foot trefoil (Lotus corniculatus) is a Butte reclamation species included in certain seed mixes for its nitrogen-fixing abilities and its penchant to colonize site edges and roadside ditch areas. It grows low to the ground and has a striking, yellow-orange blossom when in bloom.