The Grand Lake Adaptive Management (GLAM) Season wrapped up on Sept. 11 with good news for Grand Lake: both clarity goal qualifiers were met. The season’s 2.5 meter minimum Secchi depth was maintained, and the season average Secchi depth reached the 3.8 meter target.
GLAM is a collaborative framework operated in partnership with Grand County, the Town of Grand Lake, the Colorado River District, the Northwest Colorado Council of Governments, the Bureau of Reclamation and Northern Water. The partners work together to adaptively manage Grand Lake clarity through operations of the Three Lakes System, aiming to meet or exceed 3.8 meter average clarity, and the 2.5 meter minimum in Grand Lake between July 1 and Sept. 11. Clarity is monitored by the Grand County Water Information Network (GCWIN) three times a week throughout the season.
A Hot, Dry Year
Conditions in 2026 were challenging. Hot, dry weather and a dismal runoff into the Three Lakes System led to an early start to Farr Pump Plant pumping and the highest July-through-September pumped volume since 2012.
Season Results
Clarity was at its lowest on July 3 at 2.5 meters, right at the minimum goal. For the remainder of the season, clarity generally ranged between 3 and 4 meters. During the last 30 days of the clarity season, measurements improved by more than 3 meters to a striking maximum of 6.2 meters on the last day of the season. This is one of the highest observations since 2011. That late improvement lifted the season average to exactly 3.8 meters, meeting the average goal as well. While 2026 data are still under review, possible drivers of this improvement include late season decreases in algal biovolumes and decreases in suspended particulate concentrations. See the interactive graphic for clarity results.
Looking Ahead
The 2026 season comes just ahead of the new CLEAR Agreement, which builds on the GLAM framework and takes effect in January 2027.
