Rain Gardening in the Comox Valley

Rain Gardening in the Comox Valley

​gilakas’la čɛčɛ haθɛč. We respectfully acknowledge that land on which we garden is the Unceded Traditional Territory of the K’ómoks First Nation, the traditional keepers of this land and our waters*.

So much of the flurry of garden tasks across the season involves water. Late winter seedlings started indoors need moisture to germinate and newly planted veggies in spring need water to burst into growth. Thirsty containers in our hot summer months depend on it, and even fall-planted trees need the gardener to provide a generous drink to let their roots settle in. In the late fall and winter months we are relieved of the task of watering. Therefore it is when rain is most abundant that, paradoxically, gardeners might think about water the least. But while we all know our gardens need water, not all gardeners know about the ways in which our waters need our gardens, especially in the winter months.

In an interview, Comox Valley Project Watershed Society (CVPWS) explained what impact Comox Valley gardeners can have on their watersheds. A watershed is an area of land that catches rainwater and snowmelt and channels that water into a common creek or stream, eventually leading to a larger body of water such as the ocean. Each and every one of our gardens is part of a watershed.

Creek in Seal Bay Nature Park

Caitlin Pierzchalski (executive director of CVPWS and restoration ecologist by training) and Jay Baker-French (biologist and program coordinator of CVPWS) explained that in urbanized areas a community’s roofs, sidewalks, roads, parking lots, and other impermeable surfaces do not allow water to soak into the earth. To protect from flooding, stormwater has to be captured and whisked away quickly and in huge amounts. For this reason, so much of the rain that falls on developed areas is captured by storm drains and sent gushing into streams and creeks, unfiltered. 

Glen Urquhart Creek

For aeons before our community was paved and developed, the ecosystem handled the rain water very differently. When rain falls on an undisturbed landscape, some of it is caught by trees and other vegetation. Some of this water evaporates back into the air, while the remainder falls to the earth. From there, it can evaporate or soak into the soil. Some of the water that soaks into soil will be taken up by plants and transpired back into the air. The water that isn’t taken up by plants trickles every so slowly underground through the little air pockets between soil particles into the groundwater. This is called infiltration. The earth below our feet (and below our gardens) acts as a great big filter for the water as it travels from the ground to streams and eventually into the ocean.

Fish Ladder in Brooklyn Creek in Comox

So although much of what occupies the thoughts of the gardener is the need for more water in the dry summer months, much of what we can offer our watersheds as gardeners is management of excess water in the rainy months. Though many gardeners have mere fractions of an acre of land to work with, we wield the power of permeable surfaces (i.e. your soil, where water can seep in) and claim the responsibility of impermeable surfaces (e.g. the roof, driveway, patio, where water runs off).

A dry creek bed wends through vibrant planting in this beautiful Comox Valley rain garden. A rain garden is designed with a depression in the earth that collects rain water. This supports infiltration and recharges the aquafer. Rain gardens are designed so that water soaks in – there is no standing water, so there are no worries about mosquitoes. A rain garden can be planted up with beautiful species that benefit from diverted stormwater, while also tolerating summer drought.

How can we make use of our permeable surfaces to support infiltration? Pierzchalski and Baker-French explained that one of the most impactful gardening choices would be to include a rain garden or bioswale. These landscape features can divert some of the stormwater from a property’s impermeable surfaces, like a roof, into a garden that is designed to slow down and hold that water so that it can infiltrate into the soil. “It can be a very aesthetic undertaking as well; it doesn’t have to be purely functional,” Pierzchalski assured. In addition to increasing infiltration of water and looking beautiful, rain gardens that use native plants species and layered planting scheme with a treed canopy and understory planting can create habitat and forage for wildlife.

A rain chain can help direct rainfall from impermeable surfaces to the rain garden.

The more rain gardens there are in an urban watershed, the better. Collectively, a community of rain gardens can have an impact on wildlife habitat, such as fish populations. Baker-French explained that coho and cutthroat trout rely on refuges where water flow is slow. Because water flows significantly more slowly through the ground, water that is diverted from paved surfaces to rain gardens can reduce big fluctuations in creeks’ water levels. This also helps to prevents erosion. Infiltration can also help to keep creek temperatures better regulated for fish. Rain gardens can recharge our aquifers and reduce pollutants before they reach our waterways. 

Brooklyn Creek in Comox

Diverting stormwater through rain gardens is a key way to modify our home landscapes to more closely emulate what was occurring naturally in the Comox Valley before European settlers began to develop what are now urban spaces. “As water moves through [the] landscape it picks up and holds the stories of the things that are happening in [that] landscape,” Pierzchalski described. So when our “wet coast” rain keeps you indoors and you put pencil to paper to make future garden plans, consider incorporating what is downstream of your garden in your designs. As more and more gardeners adopt these styles of gardening and landscaping in our urban community, the more our waters will tell a story of citizen watershed stewardship.

Resources:

• Wondering in which watershed are you gardening? Where does your garden’s water flow? Find out using Project Watershed’s “Interactive Estuary Map“
• Want to know more about how to make a rain garden? Caitlyn Pierzchalski recommends Rain Gardens for the Pacific Northwest: Design and Build Your Own by Keri DeTore and Zsofia Pasztor and Illustrated by Jill Nunemaker. Published by Skipstone in 2017. This is available through the Vancouver Island Regional Library.

*Gardening has the power to connect the gardener with the land they garden on. Many who garden here in the Comox Valley would call themselves settlers. I, the writer, am a settler, so will use the pronoun “we” in the following closing thought. As we deepen our relationships with this land (and these waters) through gardening, we can challenge ourselves to learn more about our own responsibility to keep land and water healthy, both in our backyards and downstream. 

Posted: 18 February 2024