NOAA & The Oroville Dam
By Paul Homewood
NOAA have a good account of what has been going on with the Oroville Dam:
As mentioned previously in the Event Tracker, California is going through one of its wettest water years (October – September) on record. In particular, precipitation so far in 2017 is on a record pace for northern and central California. While the water has been a godsend in reducing and relieving drought conditions, it also has been too much of a good thing as flooding has resulted. One case in particular is the ongoing emergency at the Oroville Dam north of Sacramento. Tremendous amounts of precipitation have led to the Lake Oroville reservoir—the second largest reservoir in the state—to fill past capacity. The need to funnel water out of the reservoir and accompanying complications has led to flooding concerns and evacuations below the dam.
(top) Aerial view of the Oroville Dam on June 23, 2005. Photo Paul Hames, California Department of Water Resources. (bottom) Water gushing through a gully on river left of the primary spillway on February 11, 2017, following severe erosion on the paved portion of the ramp. Photo by William Croyle, California Department of Water Resources
The whole piece is worth a read as it is short and to the point. But the interesting bit is this graph:
Daily average inflow to Oroville Reservoir from January 1, 1995, through February 13, 2017. Recent inflows were the highest since 1997.
It shows that inflow to Oroville so far this year is far from unprecedented, with a much greater total in 1997.
And we can see from the state rainfall totals that January 2017 was nothing special:
But none of this stops NOAA from concluding:
Events like this are a reminder that in a warming world, in which heavy downpours are expected to increase (IPCC AR5) as greenhouse gases continue to rise, having resilient infrastructure will become even more important.
Oh well, we can’t win them all!