New SWEC Report Proposes Novel Approach to Restoring Native Rio Grande Fishes

SWEC has released a report detailing a novel conceptual approach to restoring the native fishes of the Rio Grande.

The 46-page report is authored by Dr. David Propst, University of New Mexico and SWEC's executive director Kevin Bixby. Although specific to the Rio Grande in southern New Mexico and west Texas, the approach it describes could be applied to other highly modified river systems in the West.

The Rio Grande in southern New Mexico and west Texas has been heavily modified to meet human needs for irrigation and flood control, beginning with the completion of Elephant Butte Dam in 1916 as part of the federal Rio Grande Project. The ecological price of this development has been high. More than a century of dam building, channelization, and dewatering have taken a heavy toll on the river ecosystem. An estimated one-half to two-thirds of the original complement of native fish species has disappeared from this section of the river.

This paper proposes an approach to restoring native fish based on habitat enhancements that can potentially be undertaken without major changes to current river management. It focuses on finding and taking advantage of the “wet” spots in the system, where locations in the river channel, or off-channel in the irrigation system or floodplain, can be enhanced to create perennial aquatic habitats where certain fish species can survive during times of low river flows during the non-irrigation season (typically November through February). These sites would be physically connected to the river so that fish would be able to move back into the river channel during the irrigation season.

Longnose gar are one of several native fish species that have disappeared from this reach of the Rio Grande but could be reintroduced if sufficient habitat was restored.

A similar approach has been advocated for conserving fish in the middle Rio Grande of New Mexico (Cowley 2003). If there were enough of these refugial habitats, the small fish populations they supported could, in theory, collectively form a larger, self-sustaining metapopulation.

The report includes a literature review, identifies four potential project sites, and contains a list of potential stakeholders and funding sources for restoration efforts.

The study was funded by a grant from the U.S. Bureau of Reclamation, through the Paso del Norte Watershed Council and Texas A&M University.