Payette Lake Water Quality

Status: Completed
Principal Investigator: Molly Wood
Study Update


Payette Lake, Idaho
Photo by Molly Wood, USGS
Big Payette Lake is a 21.6 square kilometer natural lake situated in the upper drainage of the Payette River, which drains into the Snake River in southwest Idaho. The City of McCall is located near the outlet at the lake's southern end. The population increases seasonally because McCall is a popular recreation area in both summer and winter. The area's resident population has increased substantially over the last decade as evidenced by the residential and commercial development around the shoreline and heavy recreational use of the lake.

The recent increases in development pressure, coupled with evidence of water-quality degradation and cultural eutrophication, prompted local residents to request a comprehensive water-quality study of the lake. The Idaho State Legislature responded by passing the Big Payette Lake Water Quality Act in 1993. The Act mandated the formation of a water-quality council which was tasked with developing a water-quality study of the lake and its watershed.

In the mid 1990s, the council requested that the USGS assist with portions of the water-quality study. Over the course of water years 1997 through 2003, the Idaho Department of Environmental Quality (IDEQ) and the USGS cooperatively funded water-quality monitoring of the lake. In 2004, the IDEQ conducted sampling on the lake. Since 2005, the IDEQ has funded the USGS to complete water-quality monitoring of the lake.


The objective of this study is to monitor the water-quality in Payette Lake.