Restoring perennial flows on an arid land river. Case study: Pecos River, New Mexico

Authors: Stephen R. Davenport, James E. Brooks, Marilyn Myers, Christopher W. Hoagstrom

Year: 2010 (xlii)

Abstract

In 2006, the US Fish and Wildlife Service issued a Biological Opinion on proposed water operations of the Pecos River in New Mexico by the US Bureau of Reclamation. The Biological Opinion issued a reasonable and prudent measure that operations of the Pecos River could not result in surface flow intermittence, which had occurred for consecutive years during two periods in the last 20 years. These periods of surface flow intermittence resulted in declines in abundance of native pelagic spawning cyprinids. We present an historical overview of past efforts to restore perennial flows and the recent methods used to procure supplemental waters, restore habitat and develop flexibility in water management to meet this goal. To test the success of this effort we present the results of Pecos River fish community monitoring in the years that followed the last period of river drying. Native pelagic spawning cyprinids responded most favorably to continuous surface flows. Abundance of Pecos bluntnose shiner Notropis simus pecosensis, Rio Grande shiner Notropis jemezanus and speckled chub Macrhybopsis aestivalis increased dramatically since 2004 the last year of surface flow intermittence.