Water Quality at Dixie Drain Facility: The Good, The Bad & The Ugly in the Boise River

Water Quality and Boise’s Pollution Problem

Boise, Idaho has a pollution problem affecting its water quality. Their sewer plants are contributing too much phosphorus to the Boise River. The EPA has called on the city to reduce the phosphorus from their sewer treatment plant by 98%. The City claims that filtering 93-94% of the phosphorus was very achievable but that last 4-5% was cost prohibitive.

So, they came up with a solution that was less expensive and filtered more phosphorus than required. But along the way, something was forgotten.

The River and The Slough

Flowing from the Sawtooth Wilderness Area, the Boise River runs more than one hundred miles through southern Idaho until it joins the Snake River at the Oregon border. The Boise River snakes through the City of Boise where the city’s sewage treatment plants pump treated water into the river. This treated water contains phosphorus which, when too concentrated, causes too much algal growth.

To address the phosphorus problem, the City proposed placing a water treatment facility along the banks of the Dixie Slough. The USDA calls Dixie Slough ‘a significant agricultural ditch’. At almost fifteen miles long, that seems to be an understatement. By some estimates, 40% of the phosphorus that the Boise River sends downstream to the Snake River comes from the Dixie Slough. The main source of phosphorus in the Dixie Slough is agriculture.

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The Good: Water Quality Improves at Dixie Drain & Money Is Saved

The Dixie Drain Water Treatment Facility at the confluence of Dixie Slough and Boise River filters upwards of ten tons of phosphorus and 8,000 tons of sediment every year. Furthermore, the City of Boise estimates it does this for $100 million less than improvements at the city’s sewage treatment plants.

The phosphorus reduction will have a great impact on the health of the Snake River, which receives the waters of the Boise River just downriver from the Dixie Slough. According to Boise City Engineer, John Tensen, “If we just strictly did what EPA required us to do, we’ll get 7 percent of the way to what EPA says needs to be done at the Boise confluence with the Snake River. If we do the Dixie Drain Project we’ll get 30 percent of the way.”

The project has won high praise for reducing phosphorus pollution and saving money, including from U.S. Representative Mike Simpson (R-ID). Simpson said: “The Dixie Drain project is an exemplary model of federal, state, and local cooperation. It sends a message that we can achieve desired regulatory results through flexible, innovative, and cost effective methods. I am so pleased that Idaho is leading the way in creating a framework that can be applied nationwide to help local communities deal with complex water issues.”


The Bad: Parts of the Boise River Are Left Behind

Unfortunately, the Dixie Drain is located some thirty miles downstream from the City of Boise. This leaves a long stretch of the river suffering from too much phosphorus pollution from the city’s sewer plants. One of the central tenants of pollution offset projects is that improvements need to be made upstream of the source, not downstream. This helps prevent situations where sections of waterways are left in a permanently degraded condition.

The Ugly: The River’s Watershed Is Forgotten

This entire project neglects to address the negative impact humans have on the overall watershed of the Boise River. There are no environmental improvements along the banks of the river. This is merely mechanical filtering of the water in the river.

No trees planted.

No wetlands restored.

No rewilding.

Investing in natural filtration by planting tress and restoring wetlands would achieve the same desired water quality improvements, and benefit water fowl and other wildlife.

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The Dixie Drain Facility has accomplished some laudable goals. Phosphorus in portions of the Boise River and Snake River are down and this decline was accomplished for a fraction of the predicted costs. However, long sections of the Boise River were neglected in this fix. And the solution completely forgot to examine the land management decisions of people in the Boise River’s watershed.

When we do not look at land management for solutions, we will lose part of the value of our ecological community. When rewilding is not part of the fix, a host of species that rely on our land management decisions gain nothing.

There may be places where projects like the Dixie Drain Facility are appropriate. And perhaps, the Boise River is an appropriate place for this type of project. Such projects, however, must be an exception. They should not as in the words of U.S. Senator Mike Crapo (R-ID) be a ‘national model.’

When water quality is below standard, the solutions for an improved water body must extend to areas beyond the borders of the blue polygon on the map. Nothing was done to reconnect the people of the Boise River watershed to the river. We must reconnect the water to the watershed and we must rewild the watershed. Otherwise, we risk creating a clean environment devoid of wildlife.



Photo Credit: Dixie Drain Facility. Meridian Press — Dixie Drain Phosphorus Removal Project Rendering
Article by Anna Staver astaver@idahopress.com © 2015 Idaho press-tribune,  Read the Meridian Press article here: http://bit.ly/2Foxulv