Grand Lake clarity takes center stage as Bureau of Reclamation prepares for NEPA study
December 20, 2016
For several decades the issue of water clarity in Grand Lake has simmered on the back burner as other pressing concerns, such as diversion levels and stream impacts, have taken the forefront of water discussions in the Colorado River headwaters area.
But Grand Lake's water clarity will soon be a focal point of ongoing water discussion in the high country. In late Nov. the US Department of the Interior Bureau of Reclamation (BOR) sent notification to Grand County informing them of BOR plans to conduct an Environmental Assessment (EA) for water clarity in Grand Lake under the auspices of the National Environmental Policy Act (NEPA) on a project called the Grand Lake Clarity Project (GLCP).
The notification sent by the BOR to Grand County requests Grand County's participation in the GLCP as a cooperating agency. On Dec. 6 Grand County responded to the BOR accepting the invitation to participate. A letter from the Grand County Board of County Commissioners (BOCC) to the BOR states, "The County has both special expertise in Grand Lake Clarity matters as well as jurisdiction over municipal and industrial water projects within the County."
The letter sent by the BOR to the BOCC outlines what the BOR is proposing to do as part of the EA. The BOR intends to conduct the GLCP to, "identify and evaluate alternatives… that could ultimately assist in meeting narrative clarity standards for Grand Lake". The letter goes on to outline the narrative clarity standards approved by the Colorado Water Quality Control Commission in June 2016: an average clarity depth of three-and-eight-tenths meters and a minimum clarity depth of two-and-a-half-meters.
Determining the clarity depth for bodies of water like Grand Lake is surprising simple in terms of operation. The process uses a device called a Secchi disk, named for Angelo Secchi the man who invented it. The Secchi disk is a round disk roughly 12 inches in diameter. The surface of the disk is often divided into four equal quarters with two of the corners painted black and two the corners painted white, vaguely resembling a checkerboard pattern; though sometimes Secchi discs are completely white.
The Secchi disk is attached to a pole or length of string and is slowly lowered into whichever body of water is being tested for clarity depth. When the disk is no longer visible the clarity depth of the water body is recorded.
According to the letter sent to the BOCC by the BOR the NEPA work on the GLCP is scheduled to begin in early 2017. The BOR will serve as the lead agency for the NEPA study on Grand Lake.
In their letter to the BOCC the BOR outlines their responsibilities for the project while providing few specifics. The letter states the BOR is responsible for, "determining the purpose and need, selecting alternatives for analysis, identifying effects of alternatives, selected preferred alternative, issuing finding of no significant impact or record of decision, filing, developing schedules, and making staff commitments to keep the NEPA process on track and within the time schedule."