Water conservation

Chloride Pollution Top Concern for Minnesota’s Degraded Water | Wild news


It is proposed that over 70 water bodies in Scott and Carver counties be placed on Minnesota’s latest degraded water list.

It is proposed to add Bevens Creek in Carver County, which empties into the Minnesota River, next year due to the presence of chlorpyrifos, a neurotoxic pesticide.

The creek, proposed to become Carver County’s 39th list, is one of 305 statewide water bodies proposed to be added in 2022.

In Scott County, it is proposed that 34 water bodies remain listed, but no local water is proposed to be added next year.

Monitoring efforts

The state’s list of degraded waters is updated every two years by the Minnesota Pollution Control Agency, in accordance with the federal Clean Water Act.

Minnesota’s list is proposed to exceed 2,900 degraded water bodies by 2022.

In the Southwest Metro, some water bodies – including the Minnesota River, Picha Creek, and Fish Lake – have been listed for about two decades.

However, in Scott County the most degraded waters were added to the list in 2018, including Credit River, Lower Prior Lake, O’Dowd Lake, Spring Lake, Sand Creek, Raven Creek, Robert Creek and a dozen streams.

Scott County Senior Water Planner Melissa Bokman works with the Scott Watershed Management Organization.

Bokman explained that the wave of new listings in 2018 is linked to a large state-led study that increased the amount of water monitoring infrastructure in Scott County.

The Watershed Restoration and Protection Strategy, or WRAPS, study is only conducted in Scott County about once a decade, she said.

At the local level, water monitoring is often carried out by volunteers in partnership with the Metropolitan Council’s Citizen-Assisted Monitoring program, called CAMP.

Cedar, McMahon, and O’Dowd are among the local lakes that are monitored by sample collection by local residents who live near the shore.

For the degraded waters of Minnesota, there are a wide variety of pollutants or stressors in the water.

Sediment, for example, harms aquatic organisms by clouding the water and preventing sunlight from reaching aquatic plants.

Mercury, found in fish throughout Scott County, is air pollution that comes from smoke stacks and other industrial sources.

Polychlorinated biphenyls, or PCBS, are a class of toxic chemicals – once widely used in products – that were found in fish from the Minnesota River.

Excess sediment and nutrients are common deficiencies, but Bokman said bacteria and chloride lists are becoming more common.

Reduce salt

Shelby Roberts, education and outreach specialist with the Scott Soil and Water Conservation District, said one teaspoon of salt is enough to permanently pollute five gallons of fresh water in any water system , including a lake, river or stream.

Salt is heavy and sticky, Roberts explained, so it can adhere to sediment in freshwater, causing disruptions in dissolved oxygen levels as it sinks to the bottom of the body of water.

An upcoming webinar hosted by Scott SWCD aims to help local home and business owners prevent chloride pollution by effectively using salt during the winter months.

For winter maintenance contractors, grants are available through Scott SWCD to provide salt reduction equipment.