How Our 8 Colorado Rivers Rank in Water Quality from Best to Worst

Many factors play into river health; water quality is one of them. Here's how our eight rivers in Colorado rank. Are you surprised by anything?

# 1 The Yampa • Excellent

The Yampa is known for its stunning beauty and wild nature. It is also a model of a healthy river system. There is hardly any pollution, no major mines or dams impact the quality or flow of the river, and the temperature remains relatively stable year over year. Thanks to Friends of the Yampa for protecting this incredible river!

#2 North Platte River • Good

Water quality on the North Platte is pretty good which means the fish at this renowned fishing hot spot are happy in their ecosystem. The main issues in water quality stem from oil pollution and gas activity. In recent years there have been lower levels of dissolved oxygen which are critical for fish to survive. To prevent this, we need to make strides towards maintaining water quality and flow for the long term.

#3 Rio Grande • Good

The Rio Grande is the 5th longest river in the U.S. and is a critical resource for agriculture. Despite its high demand for agricultural use, the water quality of the river is pretty good. This is because locals have implemented innovative water conservation programs that help farms operate more efficiently and reduce their demand for water use. Those decreases in water consumption have been huge in maintaining the water quality of the river. Old Mines have the potential to pollute the river heavily, but there are already organizations working on a solution!

#4 North Fork Gunnison • Needs Work

The river quality of the North Fork needs some work. The water quality of the river is most impacted by a high concentration of dissolved salts, metals, and other inorganic materials from industrial and agricultural activity. The biggest threat to the river's water quality is the gas and oil industry who have sights set on the surrounding area, which would put the North Fork at risk of pollution. Keep your eyes out for petitions to sign that protect the North Fork Valley from irresponsible oil and gas development. Without a supply of clean water, this picturesque landscape and surrounding community are in trouble.

#5 The Arkansas River • Poor

The Arkansas River struggles with water quality. According to the Colorado Division of Reclamation, Mining and Safety, Hardrock mines have leaked toxic mining waste into the Arkansas River for decades. Mining waste pollutes the Ark with iron and other metals, along with excessive nitrogen and phosphorus - causing proliferation of algae which suffocate ecosystems and impair drinking water.

#6 Colorado River • Water Quality: Poor

The Colorado River is the lifeline of the southwest, with over 40 million people across eight states relying on it as their primary water source. The Colorado River is one of the most threatened rivers in the U.S. due to several factors, one being the poor quality of the river itself. As our population increases, so does the demand for water supply and the amount of waste that ends up in the river. Today, agricultural runoff is the top contributor to the decline in the Colorado River's water quality. There is a bigger problem at large, but from a consumer standpoint, we need to work to reduce water consumption and increase daily habits that conserve and protect the Colorado River.

#7 The Dolores • Water Quality: Bad

While the Dolores is not heavily polluted by trash or waste runoff, the water quality in the river is very poor. The root of the issue: a 60% decrease in flows over the past ten years. Decreased flows have reduced the amount of dissolved oxygen in the water and led to rising water temperatures, threatening the livelihood of cold-water fish. The river is also polluted by uranium tailings and runoff from old mines at the headwaters.

#8 South Platte • Bad, Almost Failing

The South Platte continues to struggle with water quality issues, including nutrients (nitrogen and phosphorus), temperature increase, mining pollution, overuse, and more. The stretch that runs through Confluence Park in Denver is even more of a concern as it is heavily polluted by human waste and commercial dumping. We are working with Denver Parks and Recreation on a restoration project that improves the South Platte's water quality. We also host regular cleanup events to minimize trash that ends up in the river.