Rhyme or Reason to Yuba Flows

[koffler]

Just wondering - maybe Ralph or Jon can weigh in as they seem to be in the loop up towards the Yuba. So today we had minimal rain, flows were bumped to 9k - flows out of Deer Creek are relatively minor IMO. Last week during the string of big storms the flows went up quickly but subsided equally as quick. I guess 2 questions:

1 - It's early in the season, what predicates the mass water release, is Englebright already full? I live across the street from Folsom Lake and it's pretty low and per that comment flows were already cut back to 2k or so as far as water being released into the American River. So why a different strategy water release wise for two semi-similar watersheds in the same general area?

2 - Per the comment above, is someone at the water agency guessing how much to release based on future anticipated rain? To put it another way, why not gather the rain/snow, store up to capacity, and then let the water out in a consistent manner once the max storage has been met? Seems as though consistency would be good for fisherman and more importantly good for fish.

Just talking out loud I suppose but curious.

Jason

[Darian]

The difference between the two systems is partially due to agreements for flood control, releases to the Delta on the American River. Also, not all of the forks of the lower Yuba run through Bullards Bar before entering Englebright Reservoir. Englebright doesn't have the capacity to hold back all of the water coming down river from releases from Bullards Bar and rain events like last weeks. According to a couple of photo's in prior threads, Englebright is spilling over the top. Water is, also, diverted at Daguerre diversion dam during growing season on the Yuba and that affects the flows on the lower Yuba but much of the flows are not as heavily regulated as those from Folsom Dam.

Folsom Dam captures all of the flows of all forks of the American River and is regulated by contractual agreements with downstream water contractors and the Sacramento Area Flood Control Agency (SAFCA). The latter agreement requires Folsom reservoir levels be maintained at 50% capacity over the course of each year.
So, aside from rain events, many releases from the dams on each river are for different purposes.

[Ralph]

Bullards Bar on the NF and Spaulding and Bowman on the SF are the primary flood control reservoirs for the Yuba. Currently they are holding back on releases. Englebrite Reservoir has no flood control capacity and is only used as an after bay to mitigate pulse releases from Bullards Bar. We got some good rain yesterday on saturated soil at the mid elevations of the SF watershed which quickly spiked flows.

[koffler]

Thanks for the responses. Definitely sheds some light on the situation. At the end of the day I'm no hydrologist - suppose similar questions remain if in fact Englebright is a spill way for lack of a better term and Bulllards Bar Reservior and others have the opportunity to store H2O upstream. At the end of the day the Yuba will be what it will be and just hope the powers that be have the fishery in mind - I may be Pauliana on this front. Again, thanks.

jv

[BigKahuna]

I ventured down to the Lower Yuba this morning, Sunday, 12/09 and took a series of photos. The "New Truck Road" on the south side is washed out but it looks like someone has taken a dozer and made a rough road around it. It's an all wheel drive or 4 wheel drive road. Its got plenty of rock base but a little soft, hence the all well drive recommendation. The river has about 12" of visibility and is a brownish tea color. I saw a drift boat on the river giving it a try. The river was posted on CDEC at 3600 cfs this morning.

You can check out the photos at www.flyfishingtraditions.blogspot.com (http://www.flyfishingtraditions.blogspot.com)

Clay