Home Back Next Print Exit
Introduction How Rivers Run Stories Value Of A River What We Can Do
Flow of a River - Hydrology
Factors of flow: Example (pg 8 of 11)

The new hydrologic regime, low temperatures and high water clarity hurt spawning of native fish, which evolved under the former conditions. The population of humpback chub, a native fish in the river once numbering in the millions, dropped to fewer than 2,000. New river conditions favored the rise of exotics, such as rainbow trout. Marsh plants and nonnative tamarisk trees invaded the riverbanks. Beaches eroded but no silt-laden floods replenished the beaches with sand from the riverbed.

To begin to rectify these imbalances, scientists engineered an eight-day flood of 45,000 cfs in the spring of 1996. The surge of water helped mimic some of the effects of the river's original hydrology but came up short in other ways. Several years later, scientists working with a 25-member consortium known as the Glen Canyon Dam Adaptive Management Work Group and the Department of the Interior have designed and studied new artificial peaks and lows meant to mimic the effects of the river's natural flow.

These modest attempts to mirror the natural flow are restoring some of the river's natural forces, to the benefit of natural conditions and native species.


Next Page

Introduction
Flow
Description
Water cycle
Watersheds
Stream order
Factors of flow
Consequences
Stories
Shape
Connections
Quality
Life
Summary
Home | References and Credits | Exit