U.S. Department of the Interior

U.S. Geological Survey

Sandbar Evolution: Extenthe Historical PerspectivGCDAMP TWG Meeting, PhoenixJune 22, 2009

Paul Grams and Ted Melis with confrom Joe Hazel (NAU) and Jack Sch
Why historical sandbar data? W

 Current monitoring extends back to 1990 This monitoring records the effects of the 

experimental post-dam high flows

 Including 1984 would allow comparison of 

following the largest and longest post-dam 

 This would provide stakeholders an expan

when considering present sandbar conditi

 1980s sandbar conditions has been evalua

based on bar area

 Aerial photographs taken in 1984 are high 

conducive to extracting volume informatio
Current sandbar monitoring 

 Sandbar monitoring data series 

 ~ 35+ sites 1990 – present (continuing every other year Measures sandbar area and volume

 Modern remote-sensing overflights (ex

orthorectified format)

 Systemwide 2002, 2004, 2005, 2009 (continuing every 4 y Measures sandbar area by semi-automated 

processing
Sandbar monitoring data ser

0

20,00040,00060,00080,000

100,000

Sand Bar Volume (m3)

Year

1990 1993 1996 1999 2002 2005 

1996 Beach/HabitatBuilding Flow

2004 HEF

High Elevation (>25,000 ft3/s)

Mid + High Elevation (>8,000 ft3/s)

Mid Elevation (8,000 - 25,000 ft3/s)

Provisional data: Nort
Sandbar monitoring data ser

0

20,00040,00060,00080,000

100,000

Sand Bar Volume (m3)

Year

1990 1993 1996 1999 2002 2005 

1996 Beach/HabitatBuilding Flow

2004 HEF

High Elevation (>25,000 ft3/s)

Mid + High Elevation (>8,000 ft3/s)

Mid Elevation (8,000 - 25,000 ft3/s)

Provisional data: Nort

???

???
Sandbar research providing inf

on pre-1990 sandbar condition Reach-based geomorphic mappin

 Several reaches 2 to 20 km in length Uses pre- and post-dam air photos Sandbar area only

 “Synthesis” reports for a few sele

where some pre-1990 survey data 

 Historical oblique photos

Mapping completed in several long reaches7-9 years compiled

1930s1950s1965197319841990s

~15,000 polygons in data base

Schmid

Reach-based Geomorphic Mapping
Ar

is thapreco

0

2000400060008000

10000

1930 1940 1950 1960 1970 1980 1990 2000

AREA, IN SQUARE METERS, LFTGPH

RW

BB

Schmid

Reach-based Geomorphic M
0

10002000300040005000

1985 1990 1995 2000

AREA, IN SQUARE METERS PHBB

RW

TG

LF

Marble Canyon 

average

NAU

(n=12)

NAU

(n=14)

A

Integration of sandbar data series with reachgeomorphic mapping for post-dam high flow 

Schm
Sandbar research providing inf

on pre-1990 sandbar condition Reach-based geomorphic mappin

 Several reaches 2 to 20 km in length Uses pre- and post-dam air photos Sandbar area only

 “Synthesis” reports for a few sele

where some pre-1990 survey data 

 Historical oblique photos
High-elevation bar volume at 8-

(Jackass) camp

Provisional data: Nort
High-elevation bar volume at 47

(Saddle) camp

Provisional data: Nort
Sandbar research providing inf

on pre-1990 sandbar condition Reach-based geomorphic mappin

 Several reaches 2 to 20 km in length Uses pre- and post-dam air photos Sandbar area only

 “Synthesis” reports for a few sele

where some pre-1990 survey data 

 Historical oblique photos
19 Mile Wash RM 19.41L: 

1985-2008 comparison

1100 March 30, 2008 (~7,700 ft3/s)

Provisional data
Eminence, RM 44.45L: 

1985-2008 comparison

1555 May 14, 2008 (~12,400 ft3/s)

1730 October 12, 1985 (~6,800 ft3/s)

Provisional data
Sandbar elevation at 8-mile (Ja

camp from interpretation of hisoblique photos

Rubin and others, 200
Summary: What do we know ab

historical sandbar conditions Average of 25% decrease in sand

between pre-dam period and 1990

 By area, some bars larger in 1984 

1990s to present, but not uniformsome cases, present bar area is cto early 1980s.

 Difference between pre-dam and 

greater than difference between 11990’s - present
What’s to be learned by extend

sandbar monitoring data series  Large changes in bar area may be associa

changes in volume or the reverse may be t

 May result in revised opinion of 1984 relativ

present

 Allow a determination of how much of the 

1984 was above vs. below the 45,000 cfs s

 If bar volume was larger in 1984, how much 

can be regained by a ~45,000 cfs high flow?

 Quantification of the relative role of sandb

change and vegetation change in affecting sandbar area from 1984 to present

 How much of the perceived larger bar area 

result of less vegetation covering those bar

If a pre-1990 reference is desiredinformed by including sandbar vo
Use of photogrammetry to dete

sandbar volume

 Pilot study 

completed in 2000

O’Brie
Use of photogrammetry to dete

sandbar volume Pilot study 

completed in 2000

 Used 1984 and 

1996 photos for sandbar monitoring site at Badger Rapid

O’Brie
Use of photogrammetry to dete

sandbar volume Pilot study 

completed in 2000

 Used 1984 and 

1996 photos for sandbar monitoring site at Badger Rapid

 Demonstrated 

that methods can be used to create topography with 30 cm or better uncertainty

O’Brie
Potential approach for photogr

project Establish agreement/contract with pho

professional to determine and documeusing GCMRC equipment and train GCpersonnel

 Expect that topographic surfaces could be 

least 2 to 3, possibly several more sites in f

 At end of first year, GCMRC would report o

estimated time and cost to complete generafor all sandbar monitoring sites

 Once generated, topographic surfaces wou

incorporated in sandbar data series

Estimated Cost: ~$85Not included in FY10
Conclusions

 Extending the sandbar monitorin

back to 1984 would provide valuaperspective on present sandbar crelative to condition following firslargest of the post-dam floods

 Implementing project requires co

assistance to develop methods a

 GCMRC has placed project on de

be implemented when funding is