Fort Collins Science Center

Aquatic Systems

The Aquatic Systems (AS) Branch is a team of scientists dedicated to advancing interdisciplinary science and providing science support to solve water-related environmental issues. The major research themes for this branch are: Riparian Ecology, Ecological Flows, Hydroscape Ecology, Aquatic Ecology and Contaminants, and Decision Support Systems. Natural resource managers have an increasing need for scientific information and stakeholders face enormous challenges of increasing and competing demands for water. The AS Branch employs and develops state-of-the-science approaches in field investigations, laboratory experiments, remote sensing, simulation and predictive modeling, and decision support tools. We use the aquatic experimental laboratory, the greenhouse, the botanical garden and other advanced facilities to conduct unique research. Our scientists pursue research on the ground, in the rivers, and in the skies, generating and testing hypotheses and collecting quantitative information to support planning and design in natural resource management and aquatic restoration. 

Filter Total Items: 18
Date published: August 30, 2017

Reconstructing Flow History From Riparian Tree Rings

Aquatic Systems Branch scientists analyze rings of riparian trees relating tree growth and establishment to historical flow. We then use the tree rings to reconstruct the flow in past centuries. Flow reconstructions discover the frequency and magnitude of past droughts and floods—information that is essential for management of rivers and water supplies. We also use downscaled climate...

Date published: February 2, 2017
Status: Active

Aquatic Experimental Laboratory (AXL)

Aquatic invertebrates are a key component of freshwater ecosystems, and an understanding of aquatic invertebrate taxonomy is central to freshwater science. The U.S. Geological Survey Aquatic Experimental Lab (AXL) at the Fort Collins Science Center has developed the North American Aquatic Macroinvertebrate Digital Reference Collection (NAAMDRC) to provide users with a graphic tool to aid in...

Contacts: David Walters, Ph.D., Robert E Zuellig, Ph.D., Boris Kondratieff
Date published: January 17, 2017

Ecological Drought in Riparian Ecosystems

Drought is killing riparian trees along many rivers in the western United States. The cause can be increasing temperature or decreasing precipitation, flow or water-table elevation. At multiple locations we are relating water availability to physiological measurements of tree survival and water stress, such as ring width, carbon stable isotope ratio and branch hydraulic conductivity. These...

Date published: December 3, 2016
Status: Active

Erosion and Invasive Saltcedar

Formation of arroyos in the late 1800s greatly increased erosion across the southwestern United States. Since the 1930s, however, this erosion has decreased, partly because of bank stabilization by introduced saltcedar. With Isleta Pueblo Indian Nation, the Aquatic Systems Branch developed a new sediment dating method using saltcedar tree rings. We applied the method in a landmark study of...

Date published: December 1, 2016
Status: Active

Riparian Ecology

Riparian ecologists in the AS Branch study interactions among flow, channel change, and vegetation along rivers across the western United States and worldwide. Our work focuses on issues relevant to the management of water and public lands, including dam operation, climate change, invasive species, and ecological restoration. Investigations take place on a range of scales. For example,...

Date published: November 29, 2016

Riparian Vegetation Response to Dam Removal

Dam removal is an approach to river restoration that is becoming increasingly common. In most cases, dam removal is driven by considerations other than river restoration like dam safety, but how dam removal affects aquatic and riparian systems is of great interest in many dam removals. My work in this area has had two areas of focus thus far: 1) studies of vegetation and geomorphic change...

Date published: November 29, 2016

Science to Inform Riparian Ecosystem Restoration and Management

Throughout the world, riparian habitats have been dramatically modified from their natural condition. Dams, non-native species and climate change are often principal drivers of these changes, via their alteration of water and sediment regimes that determine key resources for riparian plants.

Date published: November 29, 2016

Large-scale streamflow experiments

Because the underlying cause of riparian system alteration is often attributed to the effects of dams on flow regime, managing flow releases, particularly high flows, from dams is an often-advocated approach to river and riparian restoration. Our work has focused on understanding effects of managed high flow releases (a.k.a., pulse flows, controlled floods) from dams along rivers in the lower...

Date published: November 28, 2016
Status: Active

Biological Invasions of Riparian Ecosystems

Beginning in the early twentieth century, non-native trees and shrubs, including tamarisk (also commonly known as saltcedar) and Russian-olive, were introduced to the United States for use as ornamental plants and in erosion-control plantings. These plants spread extensively, becoming the third and fourth most frequently occurring woody riparian plants in the American West.


Date published: November 28, 2016

Streamflow-fluvial Geomorphology-riparian Vegetation Interactions

The foundation for applying science to river and riparian restoration contexts lies in a basic understanding of the factors that drive riparian vegetation dynamics. Much of our research is focused on clarifying relationships between streamflow, fluvial geomorphology, and riparian vegetation, including various feedbacks.

Date published: August 30, 2016

Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include...

Date published: August 29, 2016

Ecological Responses to Fish Reclamation Treatments

Piscicides have been used in Rocky Mountain stream and lakes to restore native fish populations. In the last two decades concerns over piscicide effects to non-target organisms, primarily aquatic invertebrates, has increased. Although piscicides have been used for more than 70 years the impact to invertebrate assemblages has not been well studied and is largely unknown. Given the importance a...