For a description of the annual growth cycles of algae and widgeon grass, download A Year In The Life Of Lake Merritt
Update
Note that despite the massive growth of widgeon grass in June during the 1980’s – 2003, only very limited growth occurred in 2004 and 2005.
Widgeon grass growth resumed in 2006, but hardly any was seen in 2007, 2008 and 2009.
Although the reason for this shift is not known, it may be related to the limited rainfall and runoff in 2007-9. If so, growth may resume in 2010, which has had more precipitation.
The City harvester boat is currently not in use, having been damaged in an accident. Algae and widgeon grass are now removed using harvester boats under a contract with Aquatic Environments.