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The urgency of remedying the Boise River's excess phosphorous content

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On a crisp, clear fall afternoon, a team of scientists gathered along the banks of the Boise River near Barber Park, collecting samples of fish, insects and algae. One biologist fastened a weighty metallic device to her back. Moving into the water, surrounded by scientists wielding buckets and nets, she lowered two wire tentacles into the river, delivering an electric shock to the fish, rendering them motionless. The scientists scooped the water, raising stunned fish into barrels for examination, before discharging them back into the river.

The scientists, from the U.S. Geological Survey and the City of Boise, were collecting samples to test the quality of what is commonly known as the city's lifeline.

"We're monitoring for phosphorous and other nutrients to say whether or not they're meeting targets set by the [Environmental Protection Agency] and Department of Environmental Quality," said Alex Etheridge, a hydrologist with the USGS. "It's long-term trend monitoring. We look for change in flow, change in runoff periods, and how that affects the insects and the fish population."

"Excess phosphorous causes nuisance algae growth and excess plant growth, which alters the quality of the water," said Dorene MacCoy, a biologist with the USGS. "Algae takes up a lot of oxygen. This creates anoxic conditions in the water; when you go into more anoxic conditions, things become toxic."

The much-stricter EPA regulations are slated to take effect in 2012. Under these new guidelines, the City of Boise will be required to lower the phosphorous content in the Boise River from 5,550 micrograms per liter to 70 micrograms per liter. This could mean, at the very least, re-engineering the designs of the municipal water system. At worst, if nothing is remedied, fines of up to $37,000 per day could be slapped on municipalities. Either way, citizens will feel the impact of an increase in sewer bills.

There are a couple of different sources for this excess phosphorous.

"It comes from inputs from urban use such as wastewater treatment plants, runoff from people's lawns and fertilizers," said Etheridge. "Then further downstream there's a ton of agriculture use."

"The majority of phosphorous is coming off of farm fields and feedlots and getting into the Boise River that way," said Liz Paul, campaign coordinator with Idaho Rivers United. "The Clean Water Act exempts agriculture, so there's no regulatory stick for dealing with that."

Near Barber Park, the water quality is pristine. But, as it flows downriver, the quality worsens substantially.

"That it goes from a pretty pristine fishery, and within 20 miles it's degraded to the point where people don't want to swim in it, is cause for concern. It's a pretty short and dramatic change ... it effects not only the people that live around it, but the populations within the river," said MacCoy.

Etheridge, whose job is to return to the Boise River each year to gauge its integrity, insisted that the stretch near Barber Park "was probably the cleanest water in the state." She's hoping to "push" the pristine part of the river downstream.

Paul agreed.

"The Boise River is not impaired for phosphorous until you get a ways down it," she said. "What we're hoping for in the long run is a Boise River that is fishable and swimmable all the way to the mouth, that supports healthy aquatic communities of bugs, birds, plants, animals and fish."

According to Paul, the integrity of the Boise River is vital to the community.

"The cleaner the Boise River is, the more valuable it is for us in terms of recreation, property values and aesthetics," she said. "Every week, thousands of people fish in it, they float, they swim, their dogs swim in it, they ride their bikes along it, they look at the birds, they see all kinds of creatures.Why do people come here, why do businesses come here? A lot of it can go back to the value of the Boise River. That value is diminished as phosphorous levels and the sediment levels rise."

The quality of the Boise River also affects the quality of the community's drinking water, most of which comes from groundwater sources.

"There's an interaction between groundwater and surface water; those are not separate sources so there is interaction," said Tim Merrick, science information manager with the USGS. "The healthier the whole watershed is, the healthier we're going to be, the healthier the wildlife are going to be; it's a holistic system."

Cleaning up the excess phosphorous in the Boise River will take time, effort and money, but according to MacCoy, it's a worthy pursuit.

"It makes it more in balance," she said. "It helps the river reach an equilibrium. If we can get it to equilibrium where it's not super-saturated with phosphorous and nitrogen, I think we'll be OK."

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