You can check Lake Levels at two different web sites. The Army Corps of Engineers web site has a great deal of historical information, but generally runs 48 hours behind.
The Department of Water Resources
web site shows real time water levels and flows for the current day.
The pump intake at Lake Mendocino is at approximately 695' above mean sea level. In December
2002 we pumped down to 705', or 24,500 acre feet. We aren't exactly sure how far down we can still pump but estimate it at somewhere around 700'/23,000 acre feet. We're hoping we never find out.