April 2008 Grand Canyon Sedime

David Topping, Ron Griffiths, Tom Nick Voichick, Bob Tusso, Ted MPaul Grams, and many others at t
Large discharge-independent changes in susp

concentration and grain size over short (i.e., < 

0.1

1

10

100

1,000

10,000

100,000

100 1,000

PRE-DAM POST-DAM 

SUSPENDED-SAND

CONCENTRATION (mg/l)

INSTANTANEOUS DISCHARGE OF WATER (m

50 200 500 2,000 

IMMEDIATELY FOLLOWING 

FLOOD ON LCR

Three orders of magnitude range in sand concgiven water discharge.Implication...high resolution direct measuremeconcentration are required.

Preliminary results – su
Since 1999, we have been s

abnormal water years

• Knowing sand inputs is not enough to conduct f

levels of sand retention in key reaches must be 

• Only a 20% increase in downstream water deliv

a minimum factor of 2 increase in sand export (on monthly water distribution and grain size) 

• This return to a more “normal” flow scenario wil

the sand retention we have observed during “abmaf water years

• Demonstrable retention of tributary sand in the 

under “normal” water years is < 2 months (Topp

2000; Rubin et al., EOS, 2002; Wright et al., US

• Flows may be increasing above 8.23 maf this y

time since 1999! 
-2.0

-1.0

0.01.02.03.0

SEDIMENT-YEAR 2003 MASS-BALANCE SAND 

BETWEEN LEES FERRY AND THE GRAND CAN

JUL 2002

SEP 2002

NOV 2002

JAN 2003

MAR 2003

MAY 2003

MASS-BALANCE UNCERTAINTY ENVELOPEWATER DISCHARGE

SAND MASS IN REACH RELATIVE TO 

THAT ON JUL 1, 2002 (million metric tons)

LITTLE COLORADO RIVER FLOOD

ACCUMULATION

EROSION

Preliminary results – su
-2.0

-1.0

0.01.02.03.0

SEDIMENT-YEAR 2004 MASS-BALANCE SAND 

BETWEEN LEES FERRY AND THE GRAND CAN

JUL 2003

SEP 2003

NOV 2003

JAN 2004

MAR 2004

MAY 2004

MASS-BALANCE UNCERTAINTY ENVELOPEWATER DISCHARGE

SAND MASS IN REACH RELATIVE TO 

THAT ON JUL 1, 2003 (million metric tons)

PARIA RIVER FLOOD

ACCUMULATION

EROSION

Preliminary results – su
-2.0

0.02.04.06.08.0

SEDIMENT-YEAR 2005 MASS-BALANCE SAND 

BETWEEN LEES FERRY AND THE GRAND CAN

JUL 2004

SEP 2004

NOV 2004

JAN 2005

MAR 2005

MAY 2005

WATER DISCHAR

MASS-BALANCE UNCERTAINTY ENVELOPE

SAND MASS IN REACH RELATIVE TO 

THAT ON JUL 1, 2004 (million metric tons)

PARIA RIVER FLOOD

ACCUMULA

EROSIO

LARGE LCR FLOODS

Preliminary results – su
-1.0

-0.5

0.00.51.01.5

SEDIMENT-YEAR 2006 MASS-BALANCE SAND 

BETWEEN LEES FERRY AND THE GRAND CAN

JUL 2005

SEP 2005

NOV 2005

JAN 2006

MAR 2006

MAY 2006

WATER DISCHARGEMASS-BALANCE UNCERTAINTY ENVELOPE

SAND MASS IN REACH RELATIVE TO 

THAT ON JUL 1, 2005 (million metric tons)

PARIA RIVER FLOODS

ACCUMULA

EROSIO

Preliminary results – su
Antecedent reach-by-

sand-supply conditions 

the 2008 HFE

Preliminary results – su
0.0

0.51.01.52.02.53.03.54.0

OCT 2006

DEC 2006

FEB 2007

APR 2007

JUN 2007

AUG 2007

OCT 2007

TRIBUTARY SAND INPUT BETWEEN 

LEES FERRY AND GRAND CANYON 

OCTOBER 2006 - JANUARY 200

PARIA R. + LESSER MARBLE CANYON TRI(20% UNCERTAINTY)LITTLE COLORADO RIVER (30% UNCERTAINTY)

CUMULATIVE SAND INPUT SINCE OCT. 1, 2006

(million metric tons)

Preliminary results – su
-2.0

-1.0

0.01.02.03.04.05.06.0

OCT 2006 - JAN 2008 MASS-BALANCE SAND 

FOR UPPER MARBLE CANYON (river-miles 

OCT 2006

DEC 2006

FEB 2007

APR 2007

JUN 2007

AUG 2007

OCT 2007

MASS-BALANCE UNCERTAINTY ENVELOPE

WATER DISCHARGE

SAND MASS IN REACH RELATIVE TO 

THAT ON OCTOBER 1, 2006 (million metric tons)

ACCUMULATION

EROSION

TWO 5,000 cfs

PARIA RIVER

FLOODS

Demonstrable > 1 million metric tons sand acc

Preliminary results – su
-2.0

-1.0

0.01.02.03.04.05.06.0

OCT 2006 - JAN 2008 MASS-BALANCE SAND BU

FOR LOWER MARBLE CANYON (river-miles 30

OCT 2006

DEC 2006

FEB 2007

APR 2007

JUN 2007

AUG 2007

OCT 2007

DEC 2007

MASS-BALANCE UNCERTAINTY ENVELOPE

WATER DISCHARGE

SAND MASS IN REACH RELATIVE TO 

THAT ON OCTOBER 1, 2006 (million metric tons)

ACCUMULATION

EROSION

Demonstrable > 200,000 metric tons sand accumu

This reach was likely the major supplier of sand meadownstream at the Grand Canyon gage (RM 88) dur

Preliminary results – su
-2.0

-1.0

0.01.02.03.04.05.06.0

OCT 2006 - JAN 2008 MASS-BALANCE SAND 

FOR EASTERN GRAND CANYON (river-miles 

OCT 2006

DEC 2006

FEB 2007

APR 2007

JUN 2007

AUG 2007

OCT 2007

MASS-BALANCE UNCERTAINTY ENVELOPE

WATER DISCHARGE

SAND MASS IN REACH RELATIVE TO 

THAT ON OCTOBER 1, 2006 (million metric tons)

ACCUMULATION

EROSION

NO DEMONSTRABLE SAND ACCUMULAT

Preliminary results – su
ANY SAND ACCUMULATION FROM LOCAL TRIBUTA

THIS IS LIKELY <300,000 metric tons of s

-2.0-1.0

0.01.02.03.04.05.06.0

OCT 2006 - JAN 2008 MASS-BALANCE SAND BU

FOR CENTRAL & WESTERN GRAND CANYON (river-m

OCT 2006

DEC 2006

FEB 2007

APR 2007

JUN 2007

AUG 2007

OCT 2007

DEC 2007

MASS-BALANCE UNCERTAINTY ENVELOPE

WATER DISCHARGE

SAND MASS IN REACH RELATIVE TO 

THAT ON OCTOBER 1, 2006 (million metric tons)

ACCUMULATION

EROSION

NO DEMONSTRABLE SAND ACCUMULATION

Preliminary results – su
Data 48 3:14:09 PM 3/30/07

UPPER MARBLE CANYON (RM 1-30)LOWER MARBLE CANYON (RM 30-62)EASTERN GRAND CANYON (RM 62-88)CENTRAL & WESTERN GRAND CANYON (FAR WESTERN GRAND CANYON & LAKE M

On January 20, 2008, where was the saby tributaries since October 1, 2006?

Preliminary results – su