One of the Boise River’s biggest problems is invisible. It’s phosphorus.
Water polluted with the nutrient phosphorus can be perfectly clear with no foul odor or taste, but this invisible pollutant causes very visible problems – excessive growth of slimy, slippery algae. Algae is not only unappealing to people, at night algae pull dissolved oxygen from the river stressing and sometimes suffocating fish.
Phosphorus-laden water from roads, yards, wastewater treatment plants, septic systems, farms, dairies and fish hatcheries flows into the Boise River.
I serve on a stakeholder committee working with Idaho Department of Environmental Quality on a plan to reduce phosphorus pollution. The plan establishes how much pollution can enter the river before it becomes a problem. That amount is called the Total Maximum Daily Load (TMDL), and the plan is commonly referred to as the TMDL. The TMDL will require all of the polluters to cut back, but negotiations continue over how much each polluter is responsible to reduce.
You can watch this IRU video of DEQ’s Troy Smith to learn more about phosphorus pollution and the TMDL.