Cross sections illustrating the process of sediment

mobilization and redeposition for the controlled flood

release of 1996 from Glen Canyon Dam

Recent high flows on the Paria River and other Colorado River tributaries have provided an opportunity to test new techniques for managing the Lower Colorado River ecosystem. These recent flows have deposited large amounts of sediment in the main channel of the Colorado River. This high f low experiment, which is a controlled release from Glen Canyon Dam, is intended to move the sediment from the bottom of the main channel and rebuild sandbars, beaches, and backwater areas in the Grand Canyon. Since the closure of Glen Canyon Dam, sandbars have been eroded as a result of reduced sediment load in the river. Sandbars, beaches, and backwater areas are important parts of the Grand Canyon ecosystem and are important for wildlife and recreational use.

Sediment sampling on the Colorado River above Diamond Creek

Sediment sampling on the Paria River at Lees Ferry

Pre floodPre flood

Post floodPost flood

ControlledControlledfloodflood

Sand onchannel bed

Sandsuspended

Ri

Ri vveerr

Lees Ferry

LitLittletled

od

orara

Colo

Colo

Glen CanyonDam

GlenCanyon

DamGrandGrand

CanyonCanyonNationalNational

ParkPark

50 KILOMETERS

0 50 MILES

0

CCoolloorraaddoo

RRiivveerr

CCoolloorraaddoo

35˚Flagstaff

111˚114˚ UTAH

ARIZONAParia ver

LakePowell

LakeMead

113˚37˚ 36˚52’30’’

36˚50’

Base from U.S. Geological Survey,1:500,000, State base map

36˚

RiRivveerr

0938000009380000

0938200009382000

0940420009404200

PearceFerry

U.S.G.S. STREAMFLOW-GAGING STATION AND NUMBER

EXPLANATION

COLORADO RIVER HIGH FLOW EXPERIMENT

0938200009382000

0938310009383100

0940200009402000

0937991009379910

0940250009402500

Ri

DiC a

rkee

ondm

Page

112˚

Paria River

111˚37’30’’ 111˚35’

Lees Ferry

0938000009380000

CCoo ll

oorr

aaddoo RiRivveerr

1/2 MILE0

0 1/2 KILOMETER

0938200009382000

Real-time data of Paria River discharge retrieved from the U.S. Geological Survey Web homepage

Arizona URL: http://az.water.usgs.gov

Sand barsdeposited onriver banks

0940412009404120