The Design Did Not Build on History of Previous Work 

Though Useful as Starting Point, It Was Not Fully Adopt

“The Original Proposed Approach of 2002, with Five T

IMPLEMENT TREATMENT DO NOT IMPLEMENT TREATM

Increased

Fluctuations

In Daily Flows

(Jan – Mar)

Mechanical

Removal of Rainbow 

Trout in GC

(Jan-Mar, Jul - Dec)

Stable-Low

Flows in Fall

(Aug – Dec)

TCD

(Future)

Bea

Buil

WY2002-03 (JWY2003-04WY2004-05WY2005-06WY2006-07WY2007-08WY2008-09WY2009-10WY2010-11WY2011-12WY2012-13WY2013-14WY2014-15WY2015-16WY2016-17WY2017-18
Evolution in Design on Basis of Progress & Historical Perspectiv

The 2002 Revised Design with Two Controlled an

Randomized Treatments [May 2004]

IMPLEMENT TREATMENT DO NOT IMPLEMENT T

WY2018 Plus, Stable Fall Do Not Remove Fish Random ??? WY2017 Plus, Stable Fall Do Not Remove Fish Random ??? 

WY2016 MLFF + ExpFF Do Not Remove Fish Random ??? WY2015 MLFF + ExpFF Do Not Remove Fish Random ??? 

WY2014 Plus, Stable Fall Remove Fish Random ??? WY2013 Plus, Stable Fall Remove Fish Random ??? 

WY2012 MLFF + ExpFF Remove Fish Random ??? WY2011 MLFF + ExpFF Remove Fish Random ??? 

WY2010 Plus, Stable Fall Do Not Remove Fish Random ??? WY2009 Plus, Stable Fall Do Not Remove Fish Random ??? 

WY2008 MLFF + ExpFF Do Not Remove Fish Random ??? WY2007 MLFF + ExpFF Do Not Remove Fish Warming Event 

WY2006 Plus, Stable Fall Remove Fish Warming Event WY2005 Plus, Stable Fall Remove Fish Warming Event 

WY2004 MLFF + ExpFF Remove Fish Warming Event WY2003 MLFF + ExpFF Remove Fish Warming Event 

Naturally Warmed owing to 

Low Reservoir

Mechanical

Removal of Rainbow Trout in 

GC

(non-optimized)

MLFF + Designer 

Flow 

Treatments in 

Winter and 

Summer/Fall

Water Year
Update on Lake Powell

• Reservoir Level

– Current Elevation - 3602.0 ft (98 ft from full)

• low for 2005 – 3555.1 ft on 4/8/2005• lowest elevation since May 1969

– Current Live Storage 12.0 MAF (49%)– Projected Low (March 2006) – 3593.0 ft– Projected High (July 2006) – 3625.7 ft

• Warmer GCD Releases

– Maximum observed temperatures 

• 11/14/2003 – 13.2°C (56°F)• 10/5/2004 – 15.5°C (60°F)• 10/11/2005 – 15.8°C (61°F)• WY 2006 est. 12-13°C depending on hydrology
Historical Perspective on EX

• Let’s Step Back and Look

– MLFF+BHBF is the approved Management Action 

(baseline)

– EXP treatments include: reducing coldwater exotics, plus 

EXP trout suppression flows, and Fall BHBF test

– Nature decided to add thermal element– Managers decided to add LCR Translocation (conservation)

• Comparing Policies: Stable Shoreline 

Habitat vs. Warmer River

– “Fluctuating Flows” we decide???– “Temperature Control” nature’s own device?Warming was added to the MLFF operation after a 

decade of not being implemented!

Now What?
Status of Evolved Design on Basis of Historical Perspec

IMPLEMENT TREATMENT TREATMENT NOT IMPLEM

*WY2006, decision MLFF+Fall Testing Experimental Fish Removal ??? [?,?]

MLFF+EXP FF+Fall Experimental Fish Removal [++,++] Testing WY2005, [?,?]

WY2004, [?,0] MLFF+EXP FF Experimental Fish Removal [+,+] WY2003, [?,-] MLFF+EXP FF Experimental Fish Removal [+,+] 

WY2002, [?,-] MLFF only No Exotic Control [0,0] WY2001, [?,+] MLFF only No Exotic Control [0,0] 

WY2000, [+,+] MLFF+LSSF+HMF No Exotic Control [0,+] 

WY1999, [+,+] MLFF only No Exotic Control [0,0] 

WY1998, [+,+] MLFF+HMF No Exotic Control [0,0] 

WY1997, [0,+] MLFF only No Exotic Control [0,0] 

WY1996, [0,+] Interim+BHBF No Exotic Control [0,0] 

WY1995, [-,+] Interim only No Exotic Control [0,0] WY1994, [-,+] Interim only No Exotic Control [-,-] WY1993, [-,+] Interim only No Exotic Control [0,-] WY1992, [-,+] Interim only No Exotic Control [-,-] 

WY1991, [0,0] EXP Flows No Exotic Control [0,nd] 

(

R

Naturally Varied 

Temperature

(Relative to August Average 

at GCD, RM61)

[+, 0, -]

Mechanical

Removal of Rainbow Trout in 

GC

(with Progressive 

Optimization)

Dominant Dam 

Operation

(with Seasonal Variants 

Toward “Designer 

Flows,” but All Within 

ROD)

Water Year, w/

HBC & RBT 

Recruitment 

Success

[+ or -]
Considering Historical Perspective and Recent R

Forward Titration that Could Evolve to a Factorial Design In fact, we have 15 y

Forward Titration design already behind us with pretty solid data for both sedim

fisheries! The MLFF (and its precursor, Interim operation) was implemented frthrough 2001 with no Mechanical Removal or persistent thermal warming event

continued mostly MLFF operations and implemented MR along with Nature’s Oof the Selective Withdrawal Structure since 2002! Hence, after an 11-year long 

MLFF with cold water and unconstrained RBT recruitment, we are now headin

year of a block of MR coupled with a warm main-channel “event.” What to d

Selective Withdrawal Structure might be a handy tool to have in our 

experimental kit right now. Pursue Mechanical Removal of Warm & Cold fish MLFF Under the Range of Upper Basin Hydrologic Cycle If we continue monit

MLFF under the paired implementation of MR and warming, we have no way othat warming will continue. Perhaps we continue MR and let nature decide the 

warm event, or try to manage the system to prolong warming (while building the 

Managers might choose to enhance the probability of a HBC recruitm

by recommending stable Fall flows, but that could confound ability to discern Mfrom Habitat Stability? 

Remember, Carl said “...it ain’t just about learning . . . It’s about com

policies that managers are willing to commit to in order to benefit the resources!

Let’s Consider the Continued MLFF Options – Opti
Considering Historical Perspective and Recent Res

Evaluating Stable Flows vs. Mechanical Removal and WarmingWhat to do in the next 5-year phase (Phase V)?MLFF Under the Range of Upper Basin Hydrologic Cycle There is some chanc

Native Fishes response below GCD is dominated by Upper Basin Hydrology (cy

& dry/warm) once interactions with exotics are limited (through use of MR or olimiting their success). Perhaps flow stability should only be added to the Forw(our most costly treatment) after a sustained monitoring period under MLFF+MEvent? If no recruitment occurs by 2011, then a combination of stable flows, M(with operation of a SWS) could be the next step in the Forward Titration turne

We Should Recognize that In 5 More Years, Our Expwill be 20-years old!

What About Option #2 (add Stable Fall Flows)
SWS Could Allow Factorial Design w/ Decade Scale 

IMPLEMENT TREATMENT TREATMENT NOT IMPL

WY2013, [?,?] Amended MLFF? Perhaps Stop EXP MR? Action [++,++] WY2012, [?,?] Amended MLFF? Experimental Fish Removal Management [++,++] 

Experimental Fish Removal Through [++,++] 

*WY2011, decision MLFF ? Added) [?,?]

WY2010, [?,?] MLFF only Might be Experimental Fish Removal Extended [++,++] 

WY2009, [?,?] MLFF only Sand Bars Experimental Fish Removal Regime [++,++] 

WY2008, [?,?] MLFF only Tests for Experimental Fish Removal Warm Thermal [++,++] 

WY2007, [?,?] MLFF only (Ramping Experimental Fish Removal SWS Built? [++,++] 

??

*WY2006, decision MLFF+Fall Testing Experimental Fish Removal [++,++] [?,?]

[+

MLFF+EXP FF+Fall Experimental Fish Removal [++,++] Testing WY2005, [?,?]

WY2004, [?,0] MLFF+EXP FF Experimental Fish Removal [+,+] [-WY2003, [?,-] MLFF+EXP FF Experimental Fish Removal [+,+] [-

WY2002, [?,-] MLFF only No Exotic Control [0,0] [-WY2001, [?,+] MLFF only No Exotic Control [0,0] [+

WY2000, [+,+] MLFF+LSSF+HMF No Exotic Control [0,+] [-

WY1999, [+,+] MLFF only No Exotic Control [0,0] [+

WY1998, [+,+] MLFF+HMF No Exotic Control [0,0] [+

B

B

(Pa

Rela

Naturally Varied 

Temperature

(Relative to August Average 

at GCD, RM61)

[+, 0, -]

Mechanical

Removal of Rainbow Trout in 

GC

(with Progressive 

Optimization)

Dominant Dam 

Operation

(with Seasonal Variants 

Toward “Designer 

Flows,” but All Within 

ROD)

Water Year, w/

HBC & RBT 

Recruitment 

Success

[+ or -]
Other Options for Experimental Flows 2007-201

MINI EXPERIMENTS FOR CONSIDERATION

–

Ramping & Daily Range versus Beach Stability, etc.Alternative Operations for “Trout Suppression”Influence of Expanded Daily Variability on Food Base Associated Aquatic Resources, etc.All Options are Being Discussed/Considered in SPG aOngoing Conversations with SA’s and Cooperating S

What About Stakeholder Suggested Modifications of t

GCMRC’s Recommended Options (#1 or #2)

(add Relaxed Winter Fluctuating Flows, Stranding Flo

Altered Ramping Rates, etc.)