Precipitation
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2007 0.0 5.7 0.4 1.7 0.6 0.5 0.4 0.0 0.3 1.3 0.8 4.1
2008 4.5 3.6 0.2 0.3 0.0 0.0 0.0 0.0 0.0 1.8 2.5 2.7
2009 2.2 6.6 2.1 0.4 1.9 0.2 0.0 0.0 0.6 1.7 1.4 3.8
2010 8.0 3.1 2.3 4.5 1.4 0.0 0.0 0.0 0.0 2.6 2.6 7.2
2011 1.8 4.1 6.9 0.6 2.7 1.1 0.1 0.0 0.0 2.1 1.6 0.3
2012 4.4 1.1 5.8 2.2 0.0 0.1 0.0 0.0 0.0 1.4 4.4 7.2
2013 0.7 0.5 2.0 0.8 0.3 0.6 0.0 0.0 0.8 0.1 1.5 0.3
2014 0.4 6.1 5.2 0.3 0.3 0.0 0.0 0.2 0.7 1.2 2.6 8.9
2015 0.1 2.5 0.4 1.5 0.0 0.0 0.0 0.1 0.1 0.2 2.7 2.9
2016 7.2 0.7 6.8 1.1 0.4 0.1 0.0 0.0 0.0 3.2 2.2 5.5
2017 7.5 8.6 2.9 3.0
precip inches rounded to tenths
https://www.wunderground.com/history/airport/KOVE
Avg Elev Lake Oroville
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2007 850 858 866 871 866 852 818 782 748 730 713 699
2008 703 716 737 753 757 748 718 693 680 675 667 661
2009 661 679 758 787 804 799 760 724 712 708 695 674
2010 675 704 732 769 813 838 833 803 770 754 749 767
2011 811 830 854 869 888 897 899 892 876 860 853 838
2012 827 830 840 875 898 891 860 819 789 770 762 812
2013 834 848 857 868 859 842 813 777 751 741 724 711
2014 703 711 739 765 764 745 714 688 677 668 651 686
2015 719 744 760 763 748 729 702 679 673 670 658 656
2016 690 754 829 881 890 875 836 787 753 738 733 755
2017 834 861 851
lake elevation rounded to feet
https://cdec.water.ca.gov/cgi-progs/queryMM
Station ID ORO Sensor Number 6 Date 04/17 Span 144
Ray76’s data shows there was a 3 month period ending in August 2011 when the lake level stayed above 891’, within 10’ of topping out. This contrasts with 2017, when the lake was above 891’ for just 4 days, and has averaged closer to 850’.
Hence, there was more elevation head on the dam for a longer period in 2011 than so far in 2017. Yet the green area (apparently, as assessed by locals) is larger now than in 2011. Had this green area had stayed “green” through August 2011, correlating with the high lake levels on the opposite side of the dam, someone would have noticed and taken pictures, as you don’t get green grass in California in the summer without irrigation.
This indicates that either the internal piping through the dam has gotten much worse recently, passing a higher flow rate now under less head; or this green area is not a function of lake level, but more of a function of the extent and duration of precipitation.