Recent events that contaminated rivers that supply drinking water to communities in West Virginia and North Carolina should serve as a warning to all communities who, like Lawrence, depend on rivers for at least part of their municipal water supplies.

A federal grand jury investigation has been launched into the West Virginia chemical spill that left about 300,000 residents of Charleston, W.Va., unable to use that city’s water in January. The source of the chemical spill in West Virginia was a leaking storage tank that contained chemical foam used to wash coal.

In North Carolina, coal ash sludge poured out of a broken pipe into the Dan River for nearly a week in early February before the flow could be stopped. Several communities in North Carolina and neighboring Virginia draw drinking water from the Dan River, but despite tests showing higher levels of harmful chemicals such as arsenic in the river, officials have maintained that the water supply still is safe.

The coal ash that leaked into the Dan River was the material that remained after coal was burned to generate electricity at the retired power plant. That may get some additional attention from residents of Lawrence, which has a coal-fired power plant just upriver from its Kansas River water treatment facility.

There’s no particular reason to think the Kansas River, which represents about half of Lawrence’s water treatment capacity, faces a special threat, but the people who lived along the rivers in West Virginia and North Carolina probably thought the same thing. The fact is, the Kansas River, like many rivers across the country, is under constant pressure.

There are two other coal-fired power plants upstream from Lawrence on the river as well as dozens of wastewater treatment plants in the broader Kansas River watershed. Add to that surface runoff all along the route: runoff from communities and agricultural areas that carries everything from pet waste to herbicides and pesticides into the river. As population increases, various pollutants from runoff also increase.

How much can one river take?

Although we often take it for granted, water is our most precious resource, and will become even more precious in the future. We need to protect it.