Fossil Creek

Fossil Creek, Arizona is undergoing one of the largest river restoration projects undertaken in the southwest including a large dam decommissioning. Fossil Creek is a spring-fed perennial stream that has been dammed for nearly a century for hydropower production. The hydropower facility diverted the majority of Fossil Creek’s flow out of the watershed. In the last few decades exotic fish and crayfish have invaded Fossil Creek and have displaced native fish in the lower reaches. The restoration has two major components. First, in 2004 exotic fish were removed from a large section of the river using antimycin A, a chemical that targets fish. In June 2005 a large hydropower dam was decommissioned. Can we restore a river after a century of disturbance? Research in our laboratory is addressing the following questions:

How do native species respond to restoration? Employing a BACI design (Before After Control Impact), we will determine the relative importance of flow restoration versus exotic fish removal on the populations densities of native fish and invertebrates.
What are the effects of antimycin A on aquatic invertebrates? One of the unwanted side effects of chemical treatments to remove exotics is their propensity to kill other organisms. Aquatic insects are most at risk because they use gills to breathe (antimycin A targets gill breathing species) and have no escape route. We have conducted one of the most comprehensive field studies testing how antimycin A affects invertebrates. Does food web structure change with restoration. Using stable isotopes of carbon, nitrogen, and hydrogen we will determine food web structure before and after restoration. We have observed that in the presence of exotic fish, native fish feed lower on the food chain. Will native fish change their diet in areas of the stream where exotics have been removed? Stable isotopes will help us understand the timing and extent of food web changes induced by exotic fish removal.
Will exotic crayfish undermine restoration of Fossil Creek? The chemical used to kill exotic fish does not harm crayfish. Crayfish populations are increasing in Fossil Creek. Will removal of exotic bass, which prey on crayfish, inadvertently increase crayfish. Combining field surveys with manipulative experiments we are testing how crayfish densities change in the presence and absence of exotic fish.
How will travertine formation change with increased flow? Historic accounts of Fossil Creek describe a river with large travertine dams. Since the development of the hydropower facility in the early twentieth century, Fossil Creek has been starved of most of its calcium rich waters resulting in decreased travertine formation. In collaboration with Rod Parnell (Geology – Northern Arizona University) and Leonard Sklaar (Geology San Francisco State University) we are studying how travertine dams reform. (See Marks et al. 2005, Carter and Marks 2007).
How do ecosystem processes change with increased travertine formation? We are measuring a suite of large and small-scale ecosystem processes including decomposition, primary productivity, respiration, nutrient retention and leaf litter retention to determine how changes in geomorphology induced by increased travertine formation affect energy and nutrient flow in Fossil Creek.

We thank the following agencies who have provided financial support for this project: National Science Foundation, Arizona Game and Fish Heritage Fund, Nina Mason Pulliam Charitable Trust, United State Forest Service, Arizona Public Service, Merriam Powell Center for Environmental Research, Ecological Restoration Institute.

For an overview of dam decommissioning projects throughout the world please see our latest article in Scientific American – March 2007: Down Go the Dams. Our research was featured in a PBS documentary “ A River Reborn: The Restoration of Fossil Creek.” For more information on the documentary click here.

To view published, "in press" and accepted scientific research featuring Fossil Creek, scroll down For information about the Stakeholders Group and to view additional information about Fossil Creek, sroll down.

Fossil Creek Research

This section contains published and "in press" research conducted at Fossil Creek by current and past members of the Marks Lab. Research/monitoring conducted at Fossil Creek by government and state agencies, as well as unpublished research/monitoring conducted by NAU can be found in the Fossil Creek Stakeholders section of this page.

Fossil Creek Stakeholders Group

The Coconino National Forest and Northern Arizona University have convened the Fossil Creek Stakeholders Group. This group is composed of over 40 individuals representing 14 organizations/government entities. The purpose of the group is to assist the Forest Service in implementing on-the-ground actions to address pressing management issues, and locate funding to address these issues. Priorities include addressing immediate impacts to sensitive riparian and aquatic habitat (recreation, trash, human waste) as well as public education.

The Stakeholders Group has met to date in November 2007, May 2008, February 2009 and October 2009. A brief summary of the 2007 meeting as well as detailed notes from the 2008 and 2009 meetings are attached below.

Research, monitoring reports, and other information that provide information relevant to the management of Fossil Creek are listed below.

Fossil Creek

Research

Marks Lab Home

Restoring Fossil Creek

Fossil Creek Research

Fossil Creek Stakeholders Group