Stormwater Management Using Native Plantings

stormwater management
Front of Bioswale 7-30-2023

Stormwater Management is a growing challenge, particularly on Long Island. So much of the island is paved and built upon, and the woods and the marshes that used to soak up rainwater are shrinking day by day. Additionally, all our rivers and streams are dammed or culverted, slowing the flow of stormwater.

Stormwater Management: How We Mismanage It Today

Our suburban lawns, flat, hardened, are about as porous as a pool table, and we just keep clearing ground to build more. Along with that, people are putting curbstones along the front of their properties. They won’t have their front yards flooded. That’s a problem for those living downstream.

Finally, our storms are also becoming more violent and frequent, causing more flash flooding.

We badly needed a solution to this problem: Any good rain put a pond in my front yard. I could literally watch the water make its half mile journey from Main Street, increasing in flow as all the properties along the street added in their their rainwater until it made a left turn up my driveway.

Stormwater Management

Stormwater Management: A Personal Journey

My family first moved here in 1965. It was always wet down here near The Great South Bay, but now, 55 years later, everyone had their sump pump going, with the flow going all the way down the street to the bay.

In the photo above, from June 10th 2020, Spadefoot Design and Construction had already cleared out a lot of non-native and invasive plant material — There was privet (yes, it’s invasive) going all the way to the back along the driveway. Three large Norway Maples (most of our maple trees now are of this invasive type) came down, as well as a wall of yew (non-native) that ran along along the other side of the house.

It seems that non-native and invasive plants aren’t nearly as good at stormwater management as native plants are. Since they aren’t native, the whole biome is effected. Different microbes, different soils. How does drought or deluge effect them? Do they thrive anywhere near like our natives do? The science says we go native if we want effective stormwater management.

Step One In Stormwater Management: Remove What Does Not Belong

The first order of business was to create a bioswale that would redirect the water from the street through a phalanx of native plants so that it wouldn’t flow up the driveway or even down the street to the bay, but instead slowed, filtered and absorbed by the native plants.

The roots of native plants run deep. They are adapted for our “droughty” conditions — think bayberry and pitch pine, but also most of our native weeds.

Bioswale, Day One

The bioswale faced it’s first test just three days later on June 27th 2020:

The Bioswale’s First Test

Stormwater Management: An Opportunity To Plant Native Pollinators

Seaside Golden Rod. New York Ironweed. Joe Pye. Hayscented Fern. Little Blue Stem. A couple of Red Maples, some Arrowwood viburum, a Laurel or Black Gum. All these trees and plants together absorbed the floods when they came. We also dug several pits for the water to gather and sink into the ground on the far left and right.

Bioswale July 2nd 2020
Bioswale at Three Months
stormwater management
Bioswale 9-17-2020

As the native plants along the bioswale become established, they get progressively better at stormwater management.

Stormwater Management: Red Maples

Three Red or Swamp Maples Behind The Bioswale

Perhaps the greatest contributor to stormwater management along the bioswale are the three young Red Maples aka Swamp Maples thriving along the back of the bioswale at its termination. Funny thing about native plants: They love being where they should be!

Stormwater Management: Plant Thirsty Plants

The bioswale was not the only means by which Spadefoot Design and Construction employed in the name of stormwater management. In all, over 3000 native trees and plants were installed on less than half an acre. With all this native biomass “coming online,” the expectation was that this would help lower the water table around the house so that the sump pump was not a constant whirr.

This stand of 20 black willows was planted two years ago. We planted them close together so that the trees supported each other and didn’t overgrow standing alone. As soon as they hit the water table about 5 feet down, they exploded upward. The sump pump is now rarely heard from.

Black Willow Stand with Red Maple Left Foreground

Stormwater Management: The Rain Garden

Water tends to gather in various corners of the yard. Here at the confluence of some gutters in the back, we planted a rain garden.

Rain Garden June 26th 2022
Rain Garden 7-30-2023

Needless to say, the growth has been spectacular, especially with the elderberry. That translates into dryer ground.

Stormwater Management: Planting a Meadow

The driveway was forever flooding. We dug up the old blacktop.

What was blacktop for over a hundred years became a pollinator garden of some size within a year.

The Meadow, Besotted With Butterfly Milkweed September 2021

By Year Three (this year), our stormwater management strategy was working out quite well. Water no longer pooled there by contributed to some dramatic plant growth, with lots of “volunteers” joining in and planting themselves there:

stormwater management
The Meadow 7-30-2023

Stormwater Management: Yard Tours

In the course of things, my yard began to attract a lot of attention. In our flooded streets, people admired the bioswale and the plantings. Soon, we were organizing tours of the yard for garden clubs, schools, and local officials.

We even offer regular yard tours now. You can book them at this link. Here in addition is a link to our page on the tours, with descriptions of the nine planting zones that comprise it. Arguably, most of what was planted in the water was meant to keep the grounds dryer.

Conclusion: Native Plants Are An Important Tool In Stormwater Management

With each passing year, what was planted becomes more and more effective for stormwater management. The trees and bushes get bigger. The pollinators become far more numerous. The soil, broken up by countless roots, becomes less compacted, more porous. The stormwater is kept on the property rather than on the street. The toxins in the water don’t go to the bay but are filtered by the root systems. Nature is a great architect.

The plants thrive here and don’t need much care because they belong here. Besides everything else, they are truly beautiful.

The Bioswale, Looking North

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