Threats to Idaho's Wetlands Idaho has lost more than half of its wetlands, and they continue to be lost today. How does this happen? Road and highway fill and construction, Development, Irrigation and other water use. Converting grasslands to agriculture in the Palouse region. Hardrock mining, which can lower water tables, thus drying up wetlands that are fed by groundwater. Sand and gravel mining, and placer and dredge mining can destroy habitat along the bottoms and banks of rivers. Channelizing streams and rivers-such as the Portneuf River near Pocatello-increases water velocity, erosion, and flooding. Industrial-scale timber harvesting can damage riversides when road construction and the removal of tree from streamside areas and steep hillsides above streams cause runoff and sediment loads to increase.

How Are Wetlands Damaged?

Draining, dredging, building dikes, dumping pollutants, mining for sand and gravel, ditching, roading…These are just a few of the many direct ways that we damage or destroy wetlands. Add the indirect methods-the wakes of our motorboats, urban runoff, global climate change-and it's a wonder we have any wetlands left.

For hundreds of years, agriculture has been the chief destroyer of wetlands. If a field was too wet in the spring, farmers would dig a ditch to drain off the water. When the country and the world demanded more grain, the federal government paid people to drain more wetlands. And now, when family farmers struggle to make their mortgage each month, it's hard to ask them not to plow every square inch of ground.

Urban expansion gobbles up more large chunks of wetlands. Vast acres of marshes in the San Francisco Bay, Chesapeake Bay, New York Harbor and other coastal areas were dredged or filled in the twentieth century to make way for freeways, airports, industrial sites, business buildings, and thousands of homes. Those are the obvious losses. Most people barely notice the millions of small wetlands lost to bulldozers. These small wetlands, which often last only a few months each year, are vital purifiers of surface water, rechargers of groundwater, and providers of habitat for wildlife.

In the western United States, riparian areas along riverine wetlands face continued destruction from several sources. According to some researchers, hundreds of thousands of acres of riverine wetlands have been damaged by livestock grazing. Livestock not only consume the vegetation, but they also tend to remain in the same area for an extended period of time. Their movements to and from riversides can create gullies and otherwise undermine the banks. Our construction efforts, whether building roads and bridges or homes and businesses, also can impact streamside habitats by compacting the soil, ripping up vegetation, and accidentally carrying in seeds of non-native or noxious plants such as knapweed.

Wetland being drained. Photo: © USFWS 2004

We continue to lose wetlands today, but at least not as quickly as in the past.

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