By Terry Gunn
Normal high flows began on Dec. 1 and are scheduled to continue through January. These high flows are very good for the river . . . and ultimately all of us. They feed the fish by moving large food items around. The flows are 10,000 to 18,000-cfs and will be lower on weekends. Lower flows should prevail for the spring. It is possible that the flows might be adjusted upward if there is an above normal snowpack in the Rockies.
It has been a very interesting fall-winter season on the river. So far, winter has passed us by and it has been one of the mildest that I can remember. The high flow event came and went with little change on the river. The most notable occurrence was the extreme low flows before and after the high flow event for the entire month of November. This was the first time that we have seen flows this low in decades and if we have any say in the matter, it will be the last time. The low flows combined with warmer-than-normal river temperatures, thereby creating low oxygen levels from the dam releases. As a result, we saw a rapid decline in some fish condition and we lost some fish. There are areas of the river that were more impacted than others; while some areas saw no decline in fish health or population. We saw almost exactly the same thing in 2005. Lake Powell was considerably lower then and the water was even warmer than this year. The good news is that we had a very healthy trout population beforehand and we have a very good population today. We’re still seeing slightly warmer temperatures in the river which has happened a couple of times in years past when Lake Powell is low and receives a large runoff. Current river temperatures are running about 55 degrees which is about 7 degrees warmer than normal for this time of year … Optimal temperature for rainbow trout is 55 to 60 degrees so we are well within normal trout temperatures. The river temperatures should return to normal when Lake Powell “turns over,” which should happen any day now.
Recent fishing has been good and we expect the fish to begin spawning any day now. The spawn has begun later every year and while the peak spawn used to occur in early winter it now peaks in March.
There has been an ongoing aquatic food base study taken place over the past couple of years. The purpose of this study is multifaceted:
I believe that this is by far the most important study that has ever been conducted on this river. Previously, hundreds of millions of dollars has been spent studying sediment while ignoring the aquatic food base and resource. Common sense dictates that fish, birds, and animals do not live off of dirt or sand. The aquatic food base and habitat are the foundation for all that lives in the Colorado River. One of the long term goals of the food base study is to determine how to enhance the populations and production of aquatic insects in the river which will benefit native fish, trout, and migratory bird populations. This is a study and a goal that we can all embrace!
There is currently a 65% chance that there will be an El Nino event in 2015. Strong El Ninos almost always bring big snow packs to the Rockies which could help to fill both Lake Powell and Lake Mead.
Be sure to stop by the shop to see the flies that are currently working. The flies change on a daily basis and every day the LFA guides let everyone at the shop know the top producing flies and how to use them.
Note: This will be the last report from Dean. He’s retiring and in the near future you’ll likely run into him on a stream somewhere. From all of us here, best of luck Dean!
The fishing has been good with the higher flows. The first couple of days, scuds were really on fire. However, this week the clouds and fog have moved in and it has been difficult to get any sustained bite. You can catch a few and then have to move to new area. Streamers have been working the best with the cloud cover. It is predicted that next week will have some sunshine and everything should be working better. Midges, worms and scuds should be great choices. In the afternoons, a dry-dropper may be a good selection.
Not much info on the boulder field this week. With the higher flows, it has been difficult fishing in this area. Sunday is low water day and that is the time to fish in this area. Streamers would be best here.
From the big boulder down there are good numbers of fish. Nymph rigs with midges, San Juan worms or glo bugs will be working here with some sunlight. Streamers have been working well here. The more flash the better with streamers. Olive flash streamers have been working the best. Weekdays see almost no one fishing here, last weekend I counted four fishermen here
The area by the Paria confluence is very dangerous due to the high water event of November and flooding due to rains in Utah. This area has some very deep holes and the bank is very slippery. It is best if you fish just above the confluence and be very alert to deep water areas. Streamers are best in this area. At times, a dry-dropper can work in the afternoon.
I would rate the walk-in a 4.5 for this week.
With the higher flows, spin fishing has been working very well in the afternoon. The area from the big boulder to the Paria riffle has been doing really well on Kastmasters, Panther Martins and jigs. Gold is the color that really gets good numbers of grabs and larger fish at that.
For jigs, use 1/4-ounce in olive and black or just black or brown. Fishing spinners in the walk-in is the same technique as fishing streamers with a fly rod. Get a loop in your line for the streamer swing and move back toward you. Most strikes will happen as the jig moves quickly up and toward the shore. Also, remember that we recommend 4-pound test line with a 6- or 7-foot rod. You can also fish at Paria Beach area making long casts with very slow retrieves. Keep in mind that you need to get your offering deep in the water column to be effective, so slow retrieves are crucial to getting into the feeding zone faster.
I would rate the walk-in spin fishing as a 6.5 this week.
Fish Behavior 101. Some thoughts on why fish eat and why they don’t. “Any man who claims to understand fish is a fool.” T G
Fish are weird; there is just no getting around it. One day they are jumping in the boat, the next, they are nowhere to be found. Some people say that this is what keeps bringing us back to the stream, that this uncertainty we call “fishing” makes us more competitive. After all these years I do understand a little about fish and I would like to share some ideas on why fish are happy one day and not the next. First and foremost the fish have to be present in the area of water that you are fishing. Fish are not always going to be in the same spot. This is especially true at Lees Ferry where you have water that fluctuates on a daily and monthly basis. A spot that is stacked with fish at one flow may be a “fish desert” at another level. FOOD and SHELTER: the two things that determine the location of fish. If there is no food present there is no reason for a fish to be in a specific location. However, if you find the highest concentration of food, you will always find the highest concentration of fish, assuming that this concentration of food has been present long enough for the fish to locate it.
At Lees Ferry we have two different major feeding plots (each with hundreds of sub-plots). The first is PROLIFIC MIDGE HATCHES. Midges hatch throughout the year; however, by far the largest hatches occur in the spring. The lifecycle of a midge is very similar to a butterfly; the adult midge’s sole purpose is to make babies. In a nut shell, this is how it works…the adult midge mates with other midges in a swarm, then the female lands on the water to lay the fertilized eggs, she stays on the water for a second or so then flies off the water and then lands again to lay more eggs (this is a survival mechanism which helps protect her from being eaten by a fish). The eggs slowly sink and eventually hatch into a larvae (think of a tiny caterpillar) the midge lives as a larvae for a long time, living in the algae and mud. Then though some miracle of nature the midge larvae get a call to pupate in mass, (think of a butterfly chrysalis). As they pupate the midge, encased in a hard protective husk, slowly floats to the surface. The size and color of the midge pupae varies with the specie and with 50 different species of midges inhabiting Lees Ferry we have a large variety of sizes and colors of pupae. When the pupae reaches the surface, the midge hatches through the husk and the adult midge crawls out, dries his wings and flies off to repeat the entire process. Fish do feed on adult midges but mostly on the carcasses of dead midges that accumulate in back-eddies. The importance of a midge as a food source occurs in the emerging stage. When midges hatch they often do so in mass numbers and for long durations. The fish know this is happening and move into the riffles to feed on the emerging midges.
WHY DO FISH MOVE INTO RIFFLES TO FEED ON MIDGES? Midge pupae are small, anywhere from a size #18 to #30. It takes a lot of midges to sustain a Lees Ferry trout; however, if you were to measure the midges as a percentage of total biomass, they far exceed all other food sources combined. Riffles are areas of river where the water transitions from very shallow to slowly deeper water. Do not confuse “points” with riffles, they look similar, however, the water on “points” transitions from shallow to deep in a short area. Fish move into the shallowest part of the riffles to feed on the CONCENTRATED MIDGES. Imagine if you had a thousand midges in a column of water that was 3-feet deep versus 6-inches deep, the midges are going to be much more concentrated in the 6-inch deep water. This is why we often tell people that they are wading in areas that they should be fishing. The other kicker to midge hatches is water volume: as the water flow increase the midge hatches decrease. This is something that I do not understand but I know it to be true. So the best midge fishing is always in lower water flows. If I were to put a number to it I would say the best midge fishing is in water less than 14,000-cfs. This is why in the spring, (March, April, and May) some of our best fishing is on the weekends when the water is at the lowest level of the week. We often see good midge hatches in September and October, but not the mass swarms that happen in the spring.
The other situation that makes fish eat at Lees Ferry is HIGH WATER FLOWS. Anytime the water flows are high (above 16,000-cfs) food is dislodged, moved around, and transported by the current. Here we are talking about WORMS and SCUDS. High water flows normally occur 4 months each year, the 2 hottest months, July and August, and the 2 coldest months, December and January…this is all about electrical demand and high demand equals high flows. There are exceptions and high flows can occur at other times if there is a high lake level in Lake Powell and high runoff into the lake. This happened 1983-86 and a couple of other times in the 90’s. The best fishing periods at Lees Ferry has always been preceded by periods of higher than normal water flows. In high water the fish will concentrate in the rifles and the tail out of the riffles to feed on the drifting food. In addition to the riffles, feeding fish can be found though longs runs between riffles. This is the time of year that the most productive fishing is usually from a drifting boat as opposed to wading.
WEATHER. Any change in the weather can shut off fish feeding. I cannot explain why this happens, however I guarantee you that it is true. I was in Placentia, Belize last year fishing with noted guide Eworth Gartbutt. A cold front was pushing through (it dropped to a frigid 78 degrees) and Eworth said “Terry, you realize that permit fishing and a north wind do not go together.” I thought to myself how “fishing is fishing” no matter where you are in the world. Impending weather change make fish at Lees Ferry not want to eat. It might look like a normal day, the sun may be shining and not a breeze is blowing but a storm is on the way and the fish know it and for whatever reason they decide to take the day off from eating. I saw it this week when I was fishing with a customer that I have fished with for 2 decades and the weather that day was a classic cold front, it was windy, cold, and spitting rain. My client is a good stick and at the end of the day he had landed 2 fish and his companion had landed 3 fish and they were all smaller fish. The next day started cold but warmed quickly due to the cloudless day and bright sunshine. They landed more than 30-fish including a 19-in football and several fish that were in the 18-in range. If they would have only fished the one day that might have concluded that the fishing at Lees Ferry sucks or that we are “blowing smoke” or overrating how good the fishing is…that actually happened with one trip last month when a couple of guys had a similar experience fishing with me one day with a cold front pushing through. So poor weather makes for poor fishing most of the time, however, there are exceptions and I have seen some great fishing on days the wind is howling and the snow is flying. Often times the impending or approaching weather is worse on fishing that the bad weather itself. I can’t explain this but I can tell you that more often than not, a change in the weather will affect fishing in a negative way.
Glen Canyon Dam / Lake Powell
Current Status The unregulated inflow volume to Lake Powell in January was 348 thousand acre-feet (kaf) (96% of average). The release volume from Glen Canyon Dam in January was 862 kaf. The end of January elevation and storage of Lake Powell were 3,593.6 feet (106 feet from full pool) and 11.15 million acre-feet (maf) (46% of full capacity), respectively. The reservoir elevation is now declining and is expected to continue to decline until spring 2015.
Current Operations The operating tier for water year 2015 was established in August 2014 as the Upper Elevation Balancing Tier. In the Upper Elevation Balancing Tier the initial water year release volume is 8.23 maf; however, there is the possibility for an April adjustment to equalization or balancing operations to govern for the remainder of the water year. Under the minimum, most, and maximum probable inflow scenarios an April adjustment to balancing releases is projected to occur and Lake Powell is currently projected to release 9.0 maf in water year 2015. The minimum and maximum release projections, last updated in January, will be updated again in April. Reclamation will schedule operations at Glen Canyon Dam to achieve as practicably as possible the appropriate total annual release volume by September 30, 2015.
In February, the release volume will be approximately 600 kaf, with fluctuations anticipated between about 6,500 cfs in the nighttime to about 12,500 cfs in the daytime and consistent with the Glen Canyon Operating Criteria (Federal Register, Volume 62, No. 41, March 3, 1997). The anticipated release volume for March and April are 650 kaf and 600 kaf, respectively.
In addition to daily scheduled fluctuations for power generation, the instantaneous releases from Glen Canyon Dam may also fluctuate to provide 40 MW of system regulation. These instantaneous release adjustments stabilize the electrical generation and transmission system and translate to a range of about 1,200 cfs above or below the hourly scheduled release rate. Under system normal conditions, fluctuations for regulation are typically short lived and generally balance out over the hour with minimal or no noticeable impacts on downstream river flow conditions.
Releases from Glen Canyon Dam can also fluctuate beyond scheduled releases when called upon to respond to unscheduled power outages or power system emergencies. Depending on the severity of the system emergency, the response from Glen Canyon Dam can be significant, within the full range of the operating capacity of the power plant for as long as is necessary to maintain balance in the transmission system. Glen Canyon Dam typically maintains 27MW (approximately 800 cfs) of generation capacity in reserve in order to respond to a system emergency even when generation rates are already high. System emergencies occur fairly infrequently and typically require small responses from Glen Canyon Dam. However, these responses can have a noticeable impact on the river downstream of Glen Canyon Dam.
Inflow Forecasts and Model Projections The April to July 2015 water supply forecast for unregulated inflow to Lake Powell, issued on February 3, 2015, by the Colorado Basin River Forecast Center, projects that the most probable (median) unregulated inflow volume will be 5.2 maf (73% of average based on the period 19812010). The forecast decreased by 1.3 maf over the past month. At this early point in the season,
there is still significant uncertainty regarding this year’s water supply. The forecast ranges from a minimum probable of 3.4 maf (47% of average) to a maximum probable of 8.35 maf (117% of average). There is 10% chance that inflows could be higher than the maximum probable and a 10% chance they could be lower than the minimum probable.
As determined in the August 2014 24-Month Study, and documented in the 2015 Annual Operating Plan, Lake Powell’s operations in water year 2015 will be governed by the Upper Elevation Balancing Tier. In this tier, the initial water year release volume is 8.23 maf, however, there is the potential for an April adjustment to equalization or balancing releases in April 2015. If the April 2015 24-Month Study projects Lake Powell’s September 30, 2015, elevation to be greater than 3,649 feet, the Equalization Tier would govern Lake Powell’s operations for the remainder of water year 2015 and releases could be approximately 10.8 maf or greater. Based on analysis of a range of forecasted inflow scenarios, the current probability of realizing an inflow volume that would trigger equalization in 2015 is approximately 5 percent. If the April 2015 24Month Study projects Lake Powell’s September 30, 2015, elevation to be between 3,575 feet and 3,649 feet, and Lake Mead’s elevation to be less than 1,075 feet, Lake Powell’s annual release volume would be increased to balance the contents of Lake Mead and Lake Powell up to 9.0 maf. Based on analysis of a range of forecasted inflow scenarios, the current probability of realizing an inflow volume that would trigger balancing releases of up to 9.0 maf in 2015 is approximately 90 percent. The February 2015 24-Month Study projects that an April adjustment to balancing releases is likely to occur and Lake Powell is currently projected to release 9.0 maf in water year 2015.
Based on the current forecast, the February 24-Month Study projects Lake Powell elevation will end water year 2015 near 3,597 feet with approximately 11.47 maf in storage (47% capacity). Note that projections of elevation and storage have significant uncertainty at this early point in the season, primarily due to uncertainty regarding this season’s final snowpack and the resulting inflow to Lake Powell. Under the minimum probable inflow scenario, last updated in January, the projected end of water year elevation and storage are 3589 feet and 10.73 maf (44% capacity), respectively. Under the maximum probable inflow scenario, last updated in January, the projected end of water year elevation and storage are 3639 feet and 15.94 maf (66% capacity), respectively. The annual release volume from Lake Powell during water year 2015 is projected to be 9.0 maf under all three inflow scenarios. However, there is a 10% chance that inflows will be higher, potentially resulting in higher releases; and 10% chance that inflows will be lower, potentially resulting in lower releases. If inflows are less than the current forecasted minimum probable inflow, the water year 2015 annual release could be as low as 8.23 maf. If inflows are greater than the current forecasted maximum probable inflow, the annual release could be 10.8 maf or greater. Modeling of projected reservoir operations based on the minimum and maximum scenarios will be updated again in April.
Upper Colorado River Basin Hydrology The Upper Colorado River Basin regularly experiences significant year to year hydrologic variability. During the 15-year period 2000 to 2014, however, the unregulated inflow to Lake Powell, which is a good measure of hydrologic conditions in the Colorado River Basin, was above average in only 3 out of the past 15 years. The period 2000-2014 is the lowest 15-year period since the closure of Glen Canyon Dam in 1963, with an average unregulated inflow of 8.39 maf, or 78% of the 30-year average (1981-2010). (For comparison, the 1981-2010 total
water year average is 10.83 maf.) The unregulated inflow during the 2000-2014 period has ranged from a low of 2.64 maf (24% of average) in water year 2002 to a high of 15.97 maf (147% of average) in water year 2011. The water year 2014 unregulated inflow volume to Lake Powell was 10.381 maf (96% of average), which, though still below average, was significantly higher than inflows observed in 2012 and 2013 (45% and 47% of average, respectively). Under the current most probable forecast, total water year 2015 unregulated inflows to Lake Powell is projected to be 10.08 maf (93% of average).
At the beginning of water year 2015, total system storage in the Colorado River Basin was 30.0 maf (50% of 59.6 maf total system capacity). This is nearly the same as the total storage at the beginning of water year 2014 which began at 29.9 maf (50% of capacity). Since the beginning of water year 2000, total Colorado Basin storage has experienced year to year increases and decreases in response to wet and dry hydrology, ranging from a high of 94% of capacity at the beginning of 2000 to a low of 50% of capacity at the beginning of water year 2014. One wet year can significantly increase total system reservoir storage, just as persistent dry years can draw down the system storage. Based on current inflow forecasts, the current projected end of water year 2015 total Colorado Basin reservoir storage is approximately 28.7 maf (48% of capacity). The actual end of water year storage may vary from this projection, primarily due to uncertainty regarding next season’s snowpack and resulting runoff. Based on January minimum and maximum probable inflow forecasts and modeling the range is approximately 27.5 maf (46%) to 33.6 maf (56%), respectively.
Updated February 13, 2015 Katrina Grantz