Data Related to our MATA 

Discussions on MLFF and Fis

Responses
0

2000400060008000

100001200014000

1989199019911992199319941995199619971998199920

Population size (N)

4+ Abundance AS4+ Abundance AS4+ Abundance AS4+ Abundance Jo

Latest Chub Population Estimates
Chub Recruitment Estimates

0

2000400060008000

100001200014000160001800020000

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

Year

Number of recruits

Age 2 Recruitment ASMR1Age 2 Recruitment ASMR2Age 2 Recruitment ASMR3

Hoopnet CPUE for Age 1 fish in the LCR (AGFD Data)

0

0.010.020.030.040.050.060.070.080.09

0.1

1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

CPUE (fish/hour
Rainbow Trout Estimates

Rainbow Trout CPE

(# fish per 10 Hrs Effort)

0

100200300400500600

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 

Grand Canyon Near LCR 

Grand CanyonGlen Canyon
Rainbow Trout Predicted vs. Observed under MLFF

250270290310330350370390410430450

1965 1970 1975 1980 1985 1990 1995 2000 2005

Mean vul fish length Model mean length (mm)

Survey Mean length

0

0.5

1

1.5

2

2.5

3

1965 1970 1975 1980 1985 1990 1995 2000 2005

Predicted angler CPUEObserved angler CPUE
Brown Trout & MLFF

Brown Trout Catch Per Effort (cpue)

0

0.20.40.60.8

1

1.2

1980 1985 1990 1995 2000

Year

Upstream/downstream cpue 

Average cpue,RM<80Average RM>130Average RM 80-13

0

(Bright Angel)
Data Related to our MATA 

Discussions on MLFF and Sa

Resource & Habitat Respons
C ∝ u*4Db-1

Engelund and Hansen (1967), Rubin and Topping (2001)

effect included in EIS
1

10

100

1,000

6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000 22,000

MARCH 6 - MARCH 12, 2003 5,000-20,000 cfs DAILY RANGEMAY 5 - MAY 11, 2003 7,500-13,500 cfs DAILY RANGEJULY 4 - JULY 8, 2003 10,500-18,500 cfs DAILY RANGE

SAND CONCENTRATION (mg/l)

WATER DISCHARGE (ft3/s)

y = 9.28e-16 * x^(4.08) R2= 0.966y = 9.96e-22 * x^(5.49) R2= 0.912y = 4.80e-20 * x^(5.07) R2= 0.930
• STEAD

SAND 60% OSAND 

• 5,000-2

OPTIOEXPOROF ROEXPOR

• 5,000-2

OPTIOEXPOROF ROEXPOR

0

5,000

10,00015,00020,00025,00030,000

SUNDAY

MONDAY

TUESDAY

WEDNESDAY

THURSDAY

FRIDAY

SATURDAY

Data 14

STEADY FLOWROD5,000-20,000 cfs non-ROD OPTION5,000-25,000 cfs non-ROD OPTION

WATER DISCHARGE (ft3/s)

J

RELEASE PATTERNS FOR AN 800,000 ACRE-FOOT MONTH
Known

• Effects of tributary floods on suspended

concentration and grain size in the ColoRiver

• Effects of high dam releases on suspen

sand concentration and grain size 

• Effects of BHBFs and power plant capa

releases conducted during sand-depleteperiods
Current sediment compon

of the experiment

• Can average or larger inputs of Paria R

sand, silt, and clay be managed (by sequences of dam releases) to offset thongoing erosion of fine-grained sedimenfrom Marble and Grand Canyons?...to increase turbidity over longer periods to benefit native fish?

• WE ARE STILL WAITING FOR NATUR

COOPERATE
Partially known

• Effect of daily range on sand 

concentration 

• Effects of ramping rates on sand 

concentration
Unknown

• Sand transfer between eddies and chan

during the various experimental flow op(though most eddies will lose sand durinlarger fluctuations, some key eddies maactually gain sand) 

• Maintenance of sandbars and backwate

the various experimental flow options

• Importance of seepage erosion as a fun

of down ramping rate

• Sandbar-terrestrial biological linkages u

the various experimental flow options (coupled to carbon and nutrient-budgets
The big question

If Paria River sediment inputs can b

managed to offset erosion...can hydropower constraints be relaxed fluctuating, “steady”, and BHBF flowseasonally sequenced (a.k.a. desigflows) to achieve multiple managemobjectives (sandbars, turbidity, etc.
1

10

100

1,000

10,000

5,000 10,000 15,000 20,000 

JAN 2003 WEEK 1JAN 2003 WEEK 2JAN 2003 WEEKS 3-4FEBRUARY 2003MARCH 2003

SAND CONCENTRATION (mg/l)

WATER DISCHARGE (ft 3 /s)

y =1.19e-04 * x^(1.55) R 2= 0.51

y = 1.54e-04 * x^(1.50) R 2= 0.31

y = 4.71e-07 * x^(2.06) R 2= 0.54

y = 6.42e-12 * x^(3.19) R 2= 0.69

y = 7.00e-15 * x^(3.86) R 2= 0.87
0

10,00020,00030,00040,00050,00060,000

1 2 3 4 5 6 7 8 9 10 11 12

MONTH

MEAN DISCHARGE (cfs) 1923-1965 1966-2003

Dam closure dramatically compressed flood frequencShifted high flows from spring to summer months – shighest annual monthly volumes now coincide with thseason, sand production period from July through Sep

Additionahigh-flow decreased The low-flwere reducthe mean dnearly dou

The net change was amplified by MLFF - optimizing FOR sAND against maintenance of sand bars!
The combined influences of compressed flood frequency 

elimination of about 93 percent of the sand supply, ensursand-transport relationships would shift dramatically in rTo short-term sequences of enrichment and winnowing osand supply on the bed. . . 

Evidence of called“Hysteresis” over short pduring our rfluctuating-fexperiments winter2003 . . . . 

Yet, we failed to grasp these transport dynamicsregulating export prior to completion of the EIS!

1

10

100

1,000

10,000

5,000 10,000 15,000 20,000 25,000

JAN 2003 WEEK 1JAN 2003 WEEK 2JAN 2003 WEEKS 3-4FEBRUARY 2003MARCH 2003

SAND CONCENTRATION (mg/l)

WATER DISCHARGE (ft 3 /s)

y =1.19e-04 * x^(1.55) R 2= 0.516

y = 1.54e-04 * x^(1.50) R 2= 0.310

y = 4.71e-07 * x^(2.06) R 2= 0.540 

y = 6.42e-12 * x^(3.19) R 2= 0.698 

y = 7.00e-15 * x^(3.86) R 2= 0.870
WHY DID WE MISS THIS NOW-OBVIOUS PHENOM

We now havabundant posuspended-setransport datto concentratgrain size . . combined wihistorical syn(Topping et 2000b) of hipre-dam data

From 1972 until 1999, we typically only sampled on-average once every 8 weeks (compared to 96times/day 

0

20,000

02004006008001,000

7-15-2003

7-17-2003

7-19-2003

7-21-2003

7-23-2003

7-25-2003

7-27-2003

7-29-2003

7-31-2003

8-2-2003

8-4-2003

8-6-2003

GRAND CANYON GAGE

DISCHARGE OF WATER

LISST 100LISST 25XEZQCABLEWAY

WATER DISCHARGE (ft PUMP

3

/s)

SAND CONCENTRATION (mg/l)
By Eliminating the Low Flows of the Pre-Dam 

and the of No-Action era . . .

We inadverteamplified the export of new erosion of exsand bars thapreviously bdocumented predicted by Laursen in hengineering the NPS. . . 

Laursen would have likely pointed this fact out, hadhe remain engaged in the EIS process, even in a review c

0

100002000030000400005000060000700008000090000

100000

49 53 58 62 67 72 76 81 85 90 95 99

Year

Flow (CFS) 

Daily Minimum Daily Maximum
New Sand Transport Rating Curves Suggest that

5,000 – 20,000 cfs Alternative Fluctuations

Increase transand vs. MLlower to modmonthly volureleases, but experimentamight transpsand in high months – PEWE SHOULTHIS PRED

Fluctuations from 5,000 – 25,000 cfs with relaxed rampinRange are always predicted to export more than MLFF.

Sand Transport at Grand Canyon

-100

0

100200300400

200 400 600 800 1000 1200

Monthl

y Volume from GCD 

(Ac-Ft * 1000)

% Change Relative to MLFFA5-20 5-25 Steady

Stable Flows are Best for Limiting Sand Transport!
RiverWare Simulations indicate that the probability of h

Volume release months (1,000,000 ac/ft) is low for the t

About half of projected morelease volumlikely be betw600,000 and ac/ft and woutherefore increxport under fluctuating flrelative to ML

Perhaps this impact is not critical if strategic BHBF’s are Result in sustainable sand-bar restoration under relaxed c

Projected GCD Monthly Volumes, 2004-2010

05

10152025303540

400 500 600 700 800 900 1000 1100

Monthly GCD Volume (Ac-Ft * 1000)

% of Months
Steve Wiele’s Preliminary Sand-Bar Simulations sugge

that some siteactually be abstore a little munder expandfluctuating flThis would sesupported by sand-bar and backwater dasuggesting wmore after No

However, without a sustainable bar strategy, the sand madata and transport relationships would predict ongoing er
Other Sand-Bar Simulations suggest. . .

that some siteactually be sostable under afluctuations, be subject to continual sanover time untby repeated, strategically tBHBF releas

If bars prove to be sustainable through relaxed implemenBHBF’s, then perhaps their erosion also manages for turb
Could “Sustainable” Sand-Bar Erosion Provide Benefit to 

Trade off assmight continuuseful in planexperimental sequences whstrategic “desflows turn resrestoration ansustainability opportunities multiple bene

We cannot explore the full range of options without takinand moving forward with experimentation to facilitate lea