Boise River earns B-grade in first community-led report card

The Boise River received a grade of B to B-minus in its first community-led report card, according to Idaho Rivers United, which released the assessment Thursday after volunteers conducted 103 water quality tests between June and November 2025.

The report card establishes a baseline for tracking the health of one of the Treasure Valley's most popular natural resources and comes as the Boise-based nonprofit launches its Boise River Stewards Program, a volunteer-driven effort focused on river cleanups, water-quality monitoring and community education.

What the tests measured

Volunteers tested the river at three locations: Barber Park, the Parkcenter Boat Ramp, and the Americana Bridge. The report card evaluated eight indicators, including average river temperature, pH level, dissolved oxygen levels, turbidity, biochemical dissolved oxygen levels, prevalence of nitrates and phosphates, total coliform bacteria, and trash removal.

The river earned top marks for turbidity, pH levels, average temperature, and trash removed from the waterway, according to KIVI-TV. Water temperatures ranged from 6°C to 20°C, typical for the Boise River and supportive of most cold-water species. The pH level fell near neutral, between 6.0 and 8.0, supporting a wide variety of fish and other aquatic organisms.

"The Boise River is doing pretty well," Idaho Rivers United Communications Director Dave Womack said in an interview with Idaho Capital Sun. "We are doing well under the Clean Water Act standards, which is safe for swimming, safe for human contact and safe for fishing."

Womack said the river meets federal standards for human contact. "It follows the Clean Water Act requirements. People can swim in it, people can fish, you can touch the water," he told KTVB.

The report identified several areas that merit additional testing and monitoring. Dissolved oxygen levels may be less than ideal for aquatic species, according to Idaho Rivers United officials. The organization acknowledged limitations with testing equipment, noting that some dissolved oxygen readings came back as 0 mg/L, which is nearly impossible for rivers.

After excluding those readings, the revised average dissolved oxygen concentration was 4.5 mg/L, near the lower limit of fish tolerance and unsuitable for prolonged exposure. The ideal range is 8+ mg/L for excellent conditions, while levels below 5 mg/L start stressing aquatic organisms.

Elevated nitrogen levels, most likely from fertilizers used in the Boise River basin, also appeared in the results. Nitrate levels hovered near the threshold of natural background levels but remained well below drinking water limits. Phosphate levels tested high, though the test kits used did not have the ability to read small concentrations or provide precise measurements, making those results inconclusive.

Coliform bacteria is present, but officials could not identify the type or concentration. Around 75% of tests returned positive for coliform, but the tests employed simply return a result of positive or negative with no indication of concentration level. Further testing is necessary to identify the kind of bacteria and quantify the number of colonies found, according to KIVI-TV.

Conditions for salmonid spawning and coldwater aquatic life are suboptimal due to temperatures, low flows and habitat alteration, the report card noted. "The temperature on average is pretty good, but it's not great for salmonid spawning – fish spawning conditions for cold water species," Womack told Idaho Capital Sun.

Historical context

The Boise River is healthier in every respect compared to previous decades, when the river was polluted and used as a dumping site before the Clean Water Act was passed in 1972, Idaho Rivers United officials said in the report.

The U.S. Geological Survey has worked with the Idaho Department of Environmental Quality and the Lower Boise Watershed Council to monitor water quality in the Boise River since the 1970s. For decades, the lower Boise River downstream of Lucky Peak Reservoir has been highly enriched with phosphorus, creating a cycle of excessive plant growth, decreased oxygen for fish, and algal blooms.

Volunteer effort and trash removal

The report card comes as Idaho Rivers United highlights the work of its Boise River Stewardship volunteer program. Through the program, volunteers donated 486 hours of volunteer time, conducted 15 Boise River cleanups, and removed 971 pounds of trash from the river in addition to conducting the 103 water quality samples.

Overall, Idaho Rivers United reported removing 3,850 pounds of trash from the river last year. During the organization's annual spring cleanup in April, 233 volunteers removed more than 1,400 pounds of trash from areas along the river, according to KTVB.

Boise resident Madeleine Shapiro has been volunteering as a Boise River Steward for four years, since she heard about Idaho Rivers United's volunteer programs while attending a local beer festival. Shapiro said it is a perfect volunteer opportunity because she is able to volunteer on weekend mornings and help clean up the same sections of the Boise River that she enjoys fly fishing in.

"I come from Texas, where all of the rivers are kind of murky and green and warm," Shapiro told Idaho Capital Sun. "When I moved here I had never seen a live trout before, and I really wanted to learn how to fly fish, and so I was out there (on the Boise River) every single day trying to figure it out. And I just watched the area that I was in just kind of get overrun with garbage as it got warmer and warmer and as more people began to recreate."

Womack said access to the river is one of the reasons he enjoys living in Boise. "Being able to spend time floating the river several times a summer, sitting by it. I bike along it to work every single day," he told KTVB. But with the region's rapid growth has come an increase in trash along the Greenbelt and river corridor.

Idaho Rivers United plans to continue water testing and issue updated reports each year. "This is the first year that we've done water quality tests, and this is intended to be our baseline so that we can do a sort of vertical comparison as we go forward on an annual basis," Womack told Idaho Capital Sun.

"We're going to make sure that this is an ongoing resource in order to provide information to decision makers, to the public and to anyone who will be impacted by the water quality," he said.

River enthusiasts who wish to get involved in supporting a healthy Boise River can volunteer with Idaho Rivers United by joining its Boise River Stewards program.