After more than 10 years, multiple projects, consultations and evaluations, RESPEC is thrilled to join the Natrona County Conservation District and the Wyoming Department of Environmental Quality in announcing that the Environmental Protection Agency has removed more than 36 miles of the North Platte River from the 303(d) list of impaired waterbodies thanks  to a locally led watershed restoration effort and implementation of improved irrigation practices.

From the EPA, “In 1998, the Wyoming Department of Environmental Quality (WDEQ) added a 36.8-mile segment of the river to the Clean Water Act section 303(d) list due to aquatic life, coldwater fisheries, and wildlife designated uses being impaired by selenium. Voluntary restoration efforts led by Natrona County Conservation District in cooperation with local irrigators along with the NCCD’s partners including but not limited to the Casper Alcova Irrigation District, the City of Casper, Natrona County, the Natural Resource Conservation Service, Wyoming Association of Conservation Districts, the WDEQ, and the Wyoming Water Development Commission have reduced selenium loading to the river from irrigated cropland activities. The segment of the North Platte River now meets the selenium water quality criterion, and WDEQ has removed it from the impaired waters list in the 2016/2018 305(b)/303(d) Integrated Report.”

What is selenium, and why was is it a concern for the North Platte River?

Selenium is a naturally-occurring element, widespread in Wyoming and the Western United States due to volcanic tuff, coal deposits, and marine shale. However, in high concentrations, selenium can be destructive to the surrounding environments and ecosystems. According to the Natrona County Conservation District,  selenium “which we usually receive in our normal diet, higher intake concentrations can cause health problems in humans, wildlife, aquatic life, and agriculture products.”

How did RESPEC help?

In partnership with the Natrona County Conservation District and the Wyoming Department of Environmental Quality, RESPEC completed the TMDL project to better identify the problem and reason for an excess of selenium in the North Platte River and surrounding areas, and worked with the Natrona County Conservation District to  implement a plan to improve irrigation practices and reduce selenium loading to the river. RESPEC will continue to work with the Natrona County Conservation District to implement irrigation projects that reduce selenium on tributary streams that enter the delisted segments of the North Platte River.

Projects completed over the last 10 years, and projects still ongoing include:

  • Selenium TMDL for the Wyoming Department of Environmental Quality (WDEQ) 2010-2012
  • Middle North Platte Watershed Study, Level 1 for the Wyoming Water Development Commission (WWDC) from 2012-2014
  • North Platte River Watershed Implementation Project – Segments 1, 2 & 3 for the Natrona County Conservation District (NCCD) from 2012-2022