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Thursday, December 27, 2012

Lower Yuba River - Tailwater or Freestone?

There are times of the year that the Lower Yuba has the characteristics of a tailwater with bottom released flows from Englebright Dam. During these times the river can be spring creek like with crystal clear water and wary trout where fishing with stealth is a must. This is the time of year that the flows stabilize from somewhere between 850 and 1600 cfs. This happens at two specific times of year. The first in mid to late summer once the agricultural flows are dropped down and second during the winter and early spring when the powers that be determine that they need to hold water back for summer agricultural need. These two periods are when the river fishes as a true tailwater.

Once winter hits the river can turn into a raging river with water pouring over the top of Englebright dam with flows in the neighborhood of 30,000, to even 80,000 cfs. The river seems more like a brawling Alaskan Coastal river during these times. Just like a free flowing freestone river.

Lets break the flow regimes of the Lower Yuba River through the year and compare. Tailwater or Freestone characteristics?

January through April - More like a Freestone

The Lower Yuba River in the period between January and April can be all over the place. It can drop down to fishable levels of 900 cfs to 2000 cfs with decent clarity, 2 to 8 feet or it can be a raging torrent. This is the time of year for Baetis and Pale Morning Duns mayflies, March Browns, and the Skwala Stones.

In these months the river flows go up and down depending on the size and duration of the storms. As the bigger storms come in the flows change uncontrollably. This is the result of the three branches of the Yuba River all flowing into Englebright Reservoir and the inability of that impound to handle flows over 5600 cfs +/-. Englebright Reservoir is a bottom release dam that has the capacity of releasing about 5600 cfs.  When flows are 5600 cfs or lower the water is released from the bottom of the reservoir. Once the flows exceed the 5600 +/- it flows unregulated over the top. This can turn the Lower Yuba into a  raging unfishable freestone stream, flooding out of its normal channels and cutting corners, moving thousands of tons of gravel, rocks and boulders and changing the characteristics of the river. Let me try to explain how.

When conditions are such that there is snow up high in the Sierras and a warmer storm comes in with rain at higher elevations, the snow pack starts melting and running off. This results in huge amounts of water running down every creek, and tributary which eventually ends up in Englebright Reservoir. This is when there can be flows like 30,000, and up to 120,000 cfs. This happened just two weeks ago in December of 2012 when a big wet storm came in and the river peaked at 36,000 cfs.  When the Lower Yuba gets these type of flows multiple times during the course of one winter it can affect the bug life in the fishery for years to come.

How do these high flows affect the river? The Lower Yuba is a channelized river as a result of these high flows over the years. The bugs live in this portion of the river. When big flows run over the top of Englebright the rocks, boulders and gravel get pushed around and the river gets "rolled". The bugs live in this part of the river and the next thing they know is that their homes are getting destroyed. The bug population is decimated. I'm no entomologist but evidence from watching and fishing the river over the years has enforced my hypothesis. .

Part of this eveidence is the fact that the caddis hatches above the Parks Bar Bridge has been almost nonexistent  in the past number of years. The Skwala populations are also down above the bridge. Last year when the Skwalas were showing, we had meager success above the Parks Bar Bridge while guide friends were having big days throwing Skwalas below the bridge. In 2012, the further you's head down below the Parks Bar Bridge the more bugs and hatches you'd encounter. This has been the trend. The fish also tend to go where the bugs are.

So in summary, flows in January through the end of April can be all over the place, it can fish like a tailwater when the flows drop and stabilize at lower levels of 2,000 cfs or less or it can become unfishable during high winter storms. The fishable range is from 800 cfs to 2,000 cfs when walk and wading of up to 6000 cfs when fishing from a boat. With that said you really need 2 feet of visibility to make it worth your while. The water during these months will typically be off-colored and the river will fish more like a freestone than a tailwater.

Big edge to Freestone Characteristics.

April  through Early June - More like a Tailwater with a touch of Freestone

Once you hit May the storm season is about over. Flows stabilize and the flows will depend upon predicted weather and its affect on storing agricultural water. If the powers that be feel that they need to store water the flows can stabilize at lower levels typically in the 1600 cfs range. The water can clear up and there can be good visibility. When this happens the river fishes more like a tailwater fishery. The PMD's, Stoneflies and Caddis start coming into play.

If the longer range weather forecast is for additional storms and the snowpack is high the powers that be may start releasing water in anticipation of the late spring early summer runoff. If they start releasing water the flow come up and the river can fish more like a freestone.

This makes these months sort of a crap shoot. Each year can be different. What hold true is that flows typically are somewhere between 1600 cfs and 5,000 and are bottom released from Englebright. The river tends to run more off-colored and can muddy up from Deer Creek with seasonal small storms.

Edge to Tailwater Characteristics.

Late June through Mid July

Once the early summer hits, flows are ramped up to deliver water to the valley for growers, rice, fruit etc. The flows can bump up to 4000 to 5500 cfs +;-. This typically continues through mid summer. During this period water is bottom released from Englebright and is often off-colored. More green than blue. This is the result of the muck that is at the bottom of Englebright. The water in the lake is always a off colored gumbo. Any larger volumes of released water cloud the water. This can produce great results using deep nymphing techniques as the trout can see your flies but they can't see you. The fish are pushed to the edges and soft eddy water. They also tend to pod up. The off colored water provides stealth. The fishing gets really good once clarity hits the 6 foot mark. I've had some of my best days during these conditions. Throwing hoppers to the bank can be excellent. Banging the banks.

The river fishes like some of the tailwaters in Montana that release water for irrigation.

Edge to Tailwater Fishery

Late July until winter storms arrive, typically December - Definitely a Tailwater

Once the agricultural needs subside the flows drop to the 900 cfs to 1200 cfs levels at mid to late summer and are typically maintained through the rest of the summer and early fall. This period is when the river turns into a spring creek with unlimited clarity and the trout being the most wary. It is also the time when salmon start appearing and digging their redds, The trout will start eating eggs as early as August and will continue to eat them the rest of the year.

The tailwater characteristics continue up to the point that the first series of big storms come in. Then it can be like the winter storms that blow out the river.

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Have any Questions or Comments? Let me know, Clay.