Yes. The following is from the State Parks website
MAY 1, 2006--Due to extreme amounts of floating debris, the vessel speed limit on Folsom Lake has again been reduced to 5 miles per hour. The winter storms have deposited large amounts of trees, logs and other floating debris into Folsom Lake causing navigational hazards. We recommend that all boaters use extreme caution while operating on the lake. Many logs are partially submerged and cannot be seen from the surface of the lake.
This temporary speed limit will be lifted once normal conditions return to the lake.
http://www.parks.ca.gov/?page_id=500