by Anna Mockler

Free Press contributor

Wetlands in King County are being lost on two fronts: many development activities take a bite, and many replacement wetlands don't work. Small areas of wetland loss, especially "low-value" wetlands, are permitted even under King County's regulations, which are stricter than the state's. However, the county has acted under the belief that where wetlands are destroyed by development, the replacement wetlands, or mitigation wetlands, are keeping the county's wetland acreage at status quo.

This is not true if the mitigations don't work, and recent inspections have shown that they don't.

What is wetland mitigation? When wetlands, streams, or their buffers are damaged or lost due to human activity, King County requires mitigation: repair or replacement of the functions and values formerly performed by those sensitive areas.

For example, streambank vegetation provides shade for fish and other aquatic creatures, roosting and nesting perches for birds, and wildlife forage. Roots hold the bank together, and protect it from erosion. Plants improve water quality by trapping sediment and taking up nutrients that would otherwise harm the stream. If streambank vegetation is cleared, an entire world disappears. Mitigation begins the process of healing and replacing that world.

We can't replace a mature ecosystem overnight. What we can do is accelerate the recovery process by planting seedlings that will be mature in 10, 50, or 100 years, and by protecting them during the first few difficult years from competition by non-natives like Himalayan blackberry, Scots broom, and English ivy.

It is a very complicated and difficult thing to do. Compare it to putting together a small community from scratch. We can install homes (trees, shrubs, ponds, large woody debris, etc.), roads (greenways, buffers, streams, etc.), and services (organic soil, good forage, in-stream logs, etc.) that are likely to bring the inhabitants together in ways that will form a community. But we can't control the natural world any more than we can force neighbors to be friends. All we can do is the best we know how, based on our experience.

When we install roads, we have over 3,000 years of experience to draw on. When we install sewer systems, we have over 300 years of experience to guide us. When we install mitigations, we have less than 30 years of history to help us. Years of rigorous science have drawn many solid theories, but mitigation is still chancy.

Almost Nothing Works
Here's how the process works: King County's Sensitive Areas Ordinance (SAO) demands you show how leaving that wetland intact denies you all reasonable use of your property. If it does, the county requires you mitigate for any wetland you fill, drain, or damage.

King County had lost over 90 percent of its wetlands when the SAO took effect. Wetland mitigation was designed to stop that loss, in compliance with the federal regulation of "No Net Loss", and if possible to reverse it.

Yet in a recent survey of the county's older mitigation sites (more than three years old, the minimum required to make a determination), 83 percent were unsuccessful. The 17 percent of wetlands deemed successful, were only successful in that they were built as designed. But many designs, attractive on paper, show up on the ground as mere assemblages of pretty shrubs that seldom control erosion, improve water quality, or offer wildlife habitat, some of the functions and values the destroyed wetlands performed. Of the 17 percent of mitigations that passed inspection, perhaps 1/4, or 4.25 percent of the total, really replace lost wetlands.

What are the causes of mitigation failure? Slope, soil, sun, specifications, and stewardship. Natural wetlands have slopes gentler than 10 percent; most mitigations are installed on slopes with 30-50 percent slope - most plants have a hard time staying upright on such steep slopes. Most natural wetlands have soil that is highly organic (lots of plant matter); mitigations are generally installed on clayey subsoil that heavy machinery has compacted, which means that in a year or two their roots run up against that soil like it was a clay pot. Even if the soil's not compacted, few plants will flourish without organic matter, which is why we fertilize and compost our gardens. Many mitigation plans specify plant species that require shade, while mitigation sites are generally cleared areas in the middle of developments, exposed to full sun - the plants crisp right out.

Another design problem is the tendency of mitigation plans to favor looking pretty over working well. A natural wetland is messy. It's full of fallen logs, debris, mud, fluctuating water levels, and sulfuric odor. Many plants native to King County wetlands are seen as weeds, like cottonwoods, alders, willows. A natural wetland has trees, at least on its borders, that provide shade. Developers or homeowners fear that big trees near their houses will grow up into hazard trees. Designers tend to exclude trees and chaos in favor of flowering shrubs and attractive arrangements.

Some of these mistakes result from ignorance. Ten years ago, when the county first started mitigating, they didn't realize how shade-dependent many species are. Clear-cuts were used as a model, but the fact that many species in clear-cuts sprout from well-established root systems wasn't taken into account. No one thought about adding compost because native plants aren't fertilized - now we realize they use root mycorrhizae that transform minerals into nutrients. Mostly, no one realized that a mitigation is a construct, not an imitation.

But most mistakes result from greed. If you have to carve low-lying wetland out of your upland site, which is a pretty typical mitigation, you'll lose less buildable land if you have steep slopes. If you know no one is being paid to inspect these sites, why throw money away maintaining them?

Secrets of Swamp Success
Maintaining mitigations - stewardship - may well be the root cause of failure. No one is assigned to care for these mitigations, to notice that they are failing to thrive, and the blackberries set root and creep right over them. The 4.25 percent of the wetlands inspected that actually replace lost wetlands were all carefully looked after. The best mitigation site inspected in King County was the result of good stewardship. The owners started with a stream cleared right to the ground, compacted and dry. They put in what the county told them to, which is where most mitigations stop. But these people were determined, and fond of their stream. When something failed, they carefully researched neighboring wetlands and replaced the failure with the same kind of plants that were working nearby. They went out twice a year and cut down the blackberries. They picked up the litter that was smothering plants. They waited for alders to sprout and provide shade, and then put in shade-dependent plants. That's the kind of stewardship required to make a wetland mitigation succeed.

Yet the new SAO may relax the rules for wetland mitigation even further. Why has the county acted as though wetland mitigation were as simple as installing a sidewalk?

For one thing, wetland mitigation mostly occurs in the context of building activities, which are regulated by those knowledgeable about building. Fair enough, that is who you want inspecting construction. But these people aren't trained in sensitive areas preservation or mitigation.

Until this year, no one was assigned to inspect mitigations. Thus the building department could keep believing they were a success. Mitigations won't be maintained if no one inspects them and requires maintenance. For someone to inspect, staff positions have to be included in the budget. Staff positions are routinely deleted from the budget in favor of positions that will uphold government's obligation to provide housing. Thus the success of so few wetlands.

In effect, the county's been telling its citizens that as long as they go through the process - present a mitigation plan and install it - there is no need for them to be stewards of that mitigation.

When what you want to believe corresponds to the information you're getting, you're likely to keep on believing it. We've comforted ourselves long enough with believing that modern technology alone can create a wetland where none bloomed before, but permit the repetition: 81 percent of the mitigations are failures by the loosest standards, and 95 percent fail to mimic the natural systems they replace.

Anna Mockler is a wetlands scientist.

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Contents this page were published in the May/June, 1998 edition of the Washington Free Press.
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