Quagga Mussels Found Below Glen Canyon Dam

Quagga mussels are now in the smooth water section of the Colorado River between Glen Canyon Dam and Lee’s Ferry.

These tiny clam-like creatures can grow to the size of a nickel and first showed up in the reservoir just downstream of the Grand Canyon, Lake Mead, in 2007. National Park officials fought for a decade to keep quagga out of Lake Powell, the reservoir above Glen Canyon Dam. They lost that battle in 2012.

Recently, National Park Service officials noted large numbers of the larva were passing through Glen Canyon Dam, and last week, quagga mussels were discovered by a Lee’s Ferry fishing guide attached to cobbles in the 15 mile section of Glen Canyon between Glen Canyon Dam and Lee’s Ferry. Below Lee’s Ferry the Colorado River flows through the 280 mile long Grand Canyon National Park.

Terry Gun, of Lee’s Ferry Anglers, is concerned. “We had heard these mussels would not inhabit the areas of the river with current, but the guides are finding the mussels in areas with flow, especially where the mussels are protected behind rocks.” According to Gunn, all boaters launching now at Lee’s Ferry have a possibility of having their rafts and hard hull boats contaminated with quagga. Two photos of quagga in Glen Canyon taken the week of October 27, 2014, may be seen here:



While the mussels can live for weeks out of the water, they do not survive in muddy water, especially at turbidity levels found in the Colorado River in Grand Canyon.

Concerns include quagga mussels colonizing hydroelectric plants such as the Hoover Dam and Glen Canyon Dam, the largest hydroelectric plants on the Colorado River. Quagga can clog water supply pipes used to cool generators, compressors, transformers and other equipment at these dams.

Research is ongoing to find a freshwater predator or bacteria that would be harmful to quagga. In the meantime, the mussel has arrived and the mussel’s impact to the Colorado River between Glen Canyon Dam and Lake Mead remains uncertain.