Wetlands are an important part of urban ecosystems, acting like a powerful natural filter and sponge that helps slow the rush of rainwater sweeping chemicals and debris into waterways, Puget Sound, and ultimately the ocean. Wetlands help regulate the quantity of water moving through a watershed by retaining water during wet periods, letting it get absorbed naturally into the groundwater, and releasing it during dry periods.
However, these critical and ecologically important areas are threatened in the Puget Sound region: freshwater wetlands including swamps, marshes, and bogs have been filled or drained to provide farmland, housing areas, and other urban development. Some urbanized areas in Puget Sound have experienced losses of essential wetlands from as much as seventy percent and more, according to the Washington State Department of Ecology, and in some areas, the wetlands are just gone.
In other areas, wetlands have been significantly degraded; if they haven’t been filled in, they are not functioning the way they should. Many of these wetland areas have been harmed by the impacts of polluted water pouring into them during storm events, carrying excessive amounts of fertilizers, oils, and other toxins we use in our daily lives. The major cause of continuing loss and degradation of wetlands is urban expansion, forestry and agricultural practices, and invasion of exotic plants and animals.
The health of our wetlands affects us directly: years ago, flooding didn’t occur at the levels that it does now, according to the Washington State Department of Ecology. Generally, our current flooding events are due to the amount of impervious or water-impenetrable surfaces that are everywhere; concrete, hard-packed ground, and even buildings themselves are impervious surfaces.
The solutions are multiple and can be achieved through sustainable building techniques and thoughtful development. Sustainable building is not anti-development; rather, it is about choosing different ways of doing that same development without causing negative or unintended consequences.
In addition to integrating more pervious spaces onsite where we live, allowing water to infiltrate naturally where it falls, we need to leave natural corridors, not only for wildlife, but also for stormwater. Ultimately, we need to have places for rain water to go.
What You Can Do
1. Protect wetland areas from development and allow them to thrive; preserve buffer zones and allow native plants within the wetland to grow and attract wildlife.
2. Maintain the natural hydrology of a wetland. This is the key to protecting them, notes the Washington State Department of Ecology. “Channelizing, dredging, diking, impounding, and draining are the most common activities that disrupt or destroy the hydrologic balance of wetland systems. The result often is increased flooding, filling, and pollutant levels,” the department says on their website. They note that while these activities are often undertaken to reverse the effects from the loss of essential wetlands, ironically they lead to increased flooding.
3. Build using Low Impact Development (LID) strategies, a series of integrated site strategies designed to keep stormwater from leaving the site. LID can be applied to new development, redevelopment, or as retrofits to existing development. There are multiple strategies that can be used, although not all LID strategies need to be incorporated into every project. The idea is to construct a natural way of collecting stormwater and allowing it to infiltrate onsite. Some strategies include rain gardens (see “Rain Gardens – Beautiful & Beneficial for Everybody” on page 20), bioretention areas, green roofs, previous pavement options, amending soil, and rain water harvesting.
4. Preserve and protect all critical areas during construction. Install and maintain erosion control.
For more information:
Washington State Dept. of Ecology:
Low Impact Development:
Washington Stormwater Center:
By Sheldon and Cate O’dahl
(Note: this article was originally published in the Sustainable Living Guide 2015, in Seattle Natural Awakenings, April 2015)