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Idaho Water Science Center

New Tools to Address Boise River's Phosphorus Problem

Diversion dam near Lucky Peak.

Water-quality impairment in the lower Boise River is associated with excess phosphorus. In cooperation with the Department of Environmental Quality, we have provided numerical models to assist resource managers with their understanding of how the river would respond to phosphorus reduction strategies.

Algae and periphyton growth examples.

In rivers, excess phosphorus can promote vegetation growth including algae (left) and periphyton (right). Both can reduce water quality and impair aquatic habitat.

USGS staff collecting a water-quality sample.

To develop the model, USGS personnel collected water-quality samples at many sites in the Boise River watershed on three different occasions. This approach gave us an in-depth snapshot of the river's health at key times of the year.

Simplified phosphorus cycle.

Phosphorus enters the river from point and nonpoint sources. Along the Boise River, output from point sources is regulated. Nonpoint sources are not. Our model takes both sources into consideration.

Graph of phosphorus-reduction strategies.

Resource managers will use our model to evaluate phosphorus-reduction strategies for point and nonpoint sources. The target is 0.07 mg/L where the Boise and Snake Rivers converge.

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Current Streamflow. Click to go to WaterWatch.
Map symbol explanation

What's Up Upstream?

At home or on the go, you can access real-time information about Idaho's water resources provided by the USGS.

USGS WaterWatch (shown at right) provides a statewide snapshot of streamflow conditions compared to historical data for this date.

USGS WaterAlert lets you set conditions you want to know about (flow, level, temperature) to receive text or e-mail alerts when those conditions are met.

USGS WaterNow lets you query a USGS monitoring station and receive a return text with current conditions at that station.

Check out this fact sheet about these and other web-based tools from the USGS.


Our Latest Publications

Evaluation of Quality-Control Data Collected by the U.S. Geological Survey for Routine Water-Quality Activities...

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In cooperation with the U.S. Department of Energy, our scientists collect water-quality samples from the eastern Snake River Plain aquifer to monitor the quality of groundwater at the Idaho National Laboratory. As part of this monitoring work, scientists also collect quality-control samples to ensure data robustness by documenting the variability and contamination bias of the water-quality data.

In this report, hydrologist Gordon Rattray analyzed quality-control data collected from 2002 to 2008 and found that contamination bias of the water-quality samples and cross-contamination of perched groundwater samples was insignificant.



Groundwater Level and Nitrate Concentration Trends on Mountain Home Air Force Base, Southwestern Idaho

This presentation given to the U.S. Air Force summarizes water-level and nitrate concentration data collected at Mountain Home Air Force Base primarily between 2001 and 2013.

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Trends in those data show that groundwater levels declined at an average rate of about 1.08 feet per year.

For nitrate concentrations, 3 of the 17 wells monitored (18 percent) show an increasing trend, 3 wells (18 percent) show a decreasing trend, and 11 wells (64 percent) show no trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).