Letters from the West

DEQ asks for comments on phosphorus cleanup plan for Boise River

The Idaho Department of Environmental Quality is seeking public comment on a proposed plan to improve water quality in the lower Boise River.

The lower Boise River has been identified as impaired by total phosphorus. Excess phosphorus can result in elevated algae growth and negatively impact ecological and recreational conditions.

The Lower Boise River TMDL is a plan that includes a complex scientific model, vetted by a wide group from farmers to environmentalists, which says phosphorus levels can be reduced to a fifth of today’s levels. City residents, anglers, boaters, farmers and industrialists have reached a consensus on how to clean up waterways that irrigate and drain tens of thousands of acres in the Boise River Valley.

Phosphorous is a nutrient common in human and animal waste and farm fertilizers. It feeds algae growth in bodies of water that can choke off fish and other essential aquatic life. Drains are canals or other channels that return irrigation water to the river. They often carry a load of fertilizer, sediment and other materials that contributes to overall river pollution.

Larger projects that remove phosphorus from the drains operated by the irrigation districts will be paid for by the cities along the river through a pollution-trading program that allows them to meet tough standards for wastewater treatment. Instead of paying more to remove small amounts of phosphorus from their own wastewater, the cities will pay for projects that reduce far greater pollution levels – but unregulated – at lower cost.

The document is available for review at DEQ’s Boise Regional Office and on DEQ’s website .

Submit written comments by 5 p.m. MDT, Monday, July 6, on DEQ’s website or or e-mail to: kati.carberry@deq.idaho.gov