WSP00684

• File Number: 8220.101.16
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 1/1/2000
• Author: Webb et al.
• Title: Sediment Delivery by Ungaged Tributaries of the Colorado River in Grand Canyon Arizona
• Water Supply Pro - Doc Type: Report/Study

Table 1, Geomorphic and sediment-yield reaches of the Colorado River In Grand Canyon (modified from Melis,
1997),

Averaga
Reach RIVER MILE Channel Width'
number Reach neme Starting Ending (m)
Geomorphic Reaches
0 Glen Canyon -15 0 137 (34)
1 Upper Wide I 0 8 108 (5)
2 Upper Narrow I 8 38 83 (2)
3 Upper Wide 11 38 77 133 (2)
4 Middle Narrow 11 77 170 69 (I)
4a IIAt 87 100 84 (3)
4b IIBt 117 128 93 (3)
5 Lower Wide III 170 213 126 (2)
6 Lower Narrow III 213 276 103 (5)~
Sediment-Yield Reaches
A Glen Canyon Dam - Paris River -15.5 0.9
B Paria - Little Colorado River 0.9 61.5
C Little Colorado - Bright Angel Creek 61.5 87.8
D Bright Angel - Kanab Creek 87.8 143.5
E Kanab - Havasu Creek 143.5 156.8
F Havasu - Diamond Creek 156.8 225.8
G Diamond - Grand Wash 225.8 276.0

. Width measured at approximately 8.000 ,pIs; standard deviation given in parentheses.
t Subreaches that widen over relatively short dislances.
t Based on measurements down to Diamond Creek~ the river is impounded by Lake Mead reservoir below river mile 240.

(09402500, mile 87,3), the Colorado River above
National Canyon (09404120, mile 166,0), and the
Colorado River above Diamond Creek (09404200,
mile 225,2); the primary tributary gaging stations
are Paria River at Lee's Ferry (09382000), the Little
Colorado River near Cameron (09402000), Kanab
Creek near Fredonia (09403780), and Havasu
Creek near Supai, Arizona (09404115). Several
other gaging stations on these tributaries have short
gaging records (Rote and others, 1997), A small
amount of sediment data has been collected for
Bright Angel Creek at Phantom Ranch, For this
report, we use seven sediment-yield reaches that
correspond to river segments between tributaries
with gaging records or other estimates of sediment
input (table I),

Drainage Areas of Ungaged Tributaries

We designated 768 geomorphically significant
tributaries between Glen Canyon Dam and the
Grand Wash Cliffs, updating the results of Melis

and others (1994; appendix I), The total drainage
area of these tributaries is 12,362 Jun2 (table 2);
most of these tributaries range from 1-5 km2 in area
(fig, 2a), and Reaches E and F have the largest area
of ungaged tributaries (fig. 2b). When 461 extra
areas that have an area of514 Jun2 are included, the
total area of ungaged tributaries yielding sediment
by streamflow is 12,876 Jun2. Of the 768 tributaries,
736 in Grand Canyon produce streamflow floods
and debris flows, whereas 32 tributaries between
Glen Canyon Dam and Lee's Ferry (miles -15 to
mile 0) produce only streamflow, Thus, the area of
ungaged tributaries contributing debris flows in
Grand Canyon is 12,072 Jun2,

CLIMATIC VARIABILITY IN THE
GRAND CANYON REGION

Geomorphic and sediment-transport processes
in Grand Canyon are related to climatic variability
(Graf and others, 1991; Hereford and Webb, 1992),

CLIMATIC VARIABILITV IN THE GRAND CANYON REGION 7