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Accompanied by Team STREAM, Christopher Swain collected water quality data at 15 different locations along the Boise River: Source to Snake 102-mile journey - beginning in the Sawtooth Wilderness area at Redfish Lake, which Christopher swam across to access the trailhead to Spangle Lake — the source water for the Boise River. From Spangle Lake, he made his way down to Atlanta and the official start of the Boise River near Willow Creek and then ending at the confluence of the Snake River in Parma.

Here is a snapshot of the story this data brings to life!


The Boise River source water originates high in the Sawtooth Mountains at Spangle Lake. It courses its way out of the mountains down steep and rugged terrain to the town of Atlanta. The Boise River officially begins where the North Fork and Middle Fork of the Boise River converge, near Willow Creek. Atlanta is an old mining town and the river continued to be impacted today by that legacy and runoff that leads people without wells to boil their water in the early spring. The Boise River is affected by mining runoff into the Middle Fork Boise after it leaves the Sawtooth Wilderness, excess sediment from recreational camping roads that line the Boise National Forest, and storm-water runoff from streets in Ada County’s urban core. Pollutants like these greatly influence water quality and pose ecologic, economic, and public safety risks to the state of Idaho and its citizens.

One way to analyze this risk is to monitor water quality. The Water Quality Index (WQI) measures the scope, frequency, and amplitude of water quality exceedances and then combines the three measures into one score, between 0 and 100, that reflects how pollutants are influencing water quality at a certain time and place. The higher the score the better the quality of water.


WQI scores do not clearly capture whether or not a waterbody is drinkable, so to supplement our data we did some further research on drinking water standards and integrated those findings into the WQI analysis. The Global Drinking Water Quality Index Development and Sensitivity Analysis Report was released in 2007 and is a very popular source. However, given the many innovations in water quality testing and understanding since 2007, we have chosen to compare our WQI scores to the Canadian Drinking Water Standards. These standards are updated often and are more stringent – specifically, the drinking water guidelines connected to these standards were updated in 2010, 2012 and 2019.  (Spangle Lake does not have a WQI value because we did not have a BOD value for that location).

Our findings are clear.


The Boise River morphs from pristine conditions at its source in the Sawtooths to a depraved recipient of our waste, urban lives & rural food production as it dumps into the Snake.


Out of 15 test sites (14 without Spangle Lake), WQI results along the Boise River range from 85 (Good) to 65 (the lower bound of the Fair category). We were shocked to see zero portions of the Boise River scored as Excellent or Very Good.

57% of the Boise River tested into the Good WQI category and the other 43% of the Boise River tested into the Fair WQI category - with the worst location, Martin’s Landing, barley making the cut. This means zero portions of the Boise River is safely drinkable, and that although most portions of the river are safely swimmable and drinkable today, our waterway is deteriorating. Overall, there is a clear and consistent decrease in WQI scores from the Boise River’s source waters to its confluence with the Snake River that magnifies upon entering the urban environment at the Boise Watershed. Before entering the Snake River, some areas of the lower Boise River are uninhabitable for aquatic life and dangerous for recreationalists. Swain nearly swam into a barbed wire fence in the middle of the river, witnessed cattle urinating directly into the river, and passed countless irrigation canals dumping unfiltered, warm waste water into the waterway. The Boise River becomes so polluted over its 102-mile course that it turns from a beautiful turquoise, into a khaki brown.


Redfish Lake

Martin’s Landing


The good news is that it doesn’t have to be this way; the Boise River is our home - maintaining access to its full range of benefits is our right. Idaho can continue to thrive through relying on the Boise River without destroying it. Simple, cost-effective solutions to urban, agricultural, and industrial runoff exist, best practices for handling wastewater can actually save people money, and the returns from investing in clean water ripples through communities. Conservation is easy and rewarding. A swimmable, fishable Boise River provides unmatchable wellness benefits to our communities and is a vital asset in our growing outdoor recreation economy.

Although Team STREAM discussed seeing a visible difference in the river at Whittenberger Park, near rural Caldwell, WQI dropped from Good to Fair at the Boise Watershed test site; which goes to prove the importance of testing for water quality. Oftentimes, water that appears clean may still be hazardous. Consistently conducting water quality testing allows us to keep track of conditions that increase effective public and environmental safety planning and reveal future issues up and down stream. Additionally, with proper monitoring comes enhanced returns in mitigation, restoration and conservation efforts!

Individual water quality tests reveal more nuanced trends - more snapshots of data will be released soon!