Jonathan Friedman is a hydrologist at the Fort Collins Science Center. Since joining the Fort Collins Science Center in 1993, he has devoted his career to studying interactions among riparian vegetation, river flow and channel change. Present research topics include use of riparian tree rings to reconstruct past river flow, quantification of federal reserved water rights, and determination of the effect of riparian vegetation on bank stability.
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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...
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...
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...
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,...
One of the biggest challenges facing resource managers today is not knowing exactly when, where, and how climate change effects will unfold. While models can be used to predict the types of impacts that climate change might have on a landscape, uncertainty remains surrounding factors such as how quickly changes will occur and how specific resources will respond. In order to plan for this...
In semi-arid regions, riparian and wetland ecosystems function as important migratory and breeding habitats and add significantly to local and regional biodiversity; however, these ecosystems are increasingly threatened by climate change and the potential synergistic effects of increasing demand for water and invasion by exotic species. As a continuation of our inaugural USGS National Climate...
This data release consists of sex ratio data from cottonwood trees at random points on the floodplain; tree core and tree ring data; floodplain and riparian cottonwood forest areas as shapefiles (SHP); and edges of water, channel centerline, valley bottom centerline, extent of valley bottom, and estimated bankfull channel data as shapefiles (SHP).
This study uses growth in vegetation during the monsoon season measured from LANDSAT imagery as a proxy for measured rainfall. NDVI values from 26 years of pre- and post-monsoon season Landsat imagery were derived across Yuma Proving Ground (YPG) in southwestern Arizona, USA.
A long-term study of the geomorphic history of the lower Rio Puerco arroyo in north-central New Mexico included the collection of high-precision (Real-time kinematic) GPS survey data (2002, 2007, 2010, and 2014), registration and rectification of historical aerial photographs (1935, 1950s, 1970s, and 1996), aerial LiDAR survey (2005) and post-flood (2006) satellite imagery.
We assessed the history of flow and riparian ecosystem change along the Wind River using cottonwood tree-ring data, streamgage records, historical temperature and precipitation data, drought indices, and local observations and Traditional Ecological Knowledge from elders of the Eastern Shoshone and Northern Arapaho Tribes of the Wind River...
McNeeley, Shannon M.; Friedman, Jonathan M.; Beeton, Tyler A.; Thaxton, Richard D.
Across the Upper Missouri River Basin, the recent drought of 2000 to 2010, known as the “turn-of-the-century drought,” was likely more severe than any in the instrumental record including the Dust Bowl drought. However, until now, adequate proxy records needed to better understand this event with regard to long-term variability have been lacking....
Martin, Justin; Pederson, Gregory T.; Woodhouse, Connie A.; Cook, Edward R.; McCabe, Gregory J.; Anchukaitis, Kevin J.; Wise, Erika K.; Erger, Patrick; Dolan, Larry S.; McGuire, Marketa; Gangopadhyay, Subhrendu; Chase, Katherine J.; Littell, Jeremy S.; Gray, Stephen; St. George, Scott; Friedman, Jonathan M.; Sauchyn, David J.; St. Jacques, Jeannine-Marie; King, John C. Long duration tree-ring records with annual precision allow for the reconstruction of past growing conditions. Investigations limited to the most common tree-ring proxy of ring width can be difficult to interpret, however, because radial growth is affected by multiple environmental processes. Furthermore, studies of living trees may miss important...
Schook, Derek M.; Friedman, Jonathan M.; Stricker, Craig A.; Csank, Adam Z.; Cooper, David J. Snake Creek flows east from the southern Snake Range in Nevada over complex lithology before leaving Great Basin National Park. The river travels over a section of karst limestone where some surface water naturally recharges the groundwater flow system. In 1961 a water diversion pipeline was constructed by downstream water users to transport...
Schook, Derek M.; Cooper, David J.; Friedman, Jonathan M.; Rice, Steven E.; Hoover, Jamie D.; Thaxton, Richard D. Paleohydrologic records can provide unique, long-term perspectives on streamflow variability and hydroclimate for use in water resource planning. Such long-term records can also play a key role in placing both present day events and projected future conditions into a broader context than that offered by instrumental observations. However,...
Martin, Justin; Pederson, Gregory T.; Woodhouse, Connie A.; Cook, Edward R; McCabe, Gregory J.; Wise, Erika K.; Erger, Patrick; Dolan, Larry; McGuire, Marketa; Gangopadhyay, Subhrendu; Chase, Katherine J.; Littell, Jeremy S.; Gray, Stephen; St. George, Scott; Friedman, Jonathan M.; Sauchyn, David J.; St. Jacques, Jannine; King, John W. The relict plains cottonwood (Populus deltoides subsp. monilifera) forest along the Missouri River between Lakes Sakakawea and Oahe includes trees as large as two meters in diameter. We cored 24 of these trees to determine their age and suitability for flow reconstruction. Because most of the trees were rotten in the center, we developed a method...
Friedman, Jonathan M.; Fisher R. Ankney; Marshall Wolf Stable carbon isotopes of riparian tree rings are enabling improved reconstruction of past climate variability, but this advance is limited by difficulty distinguishing the effects of tree age from those of climate. We investigated relative influence of age and climate trends in genus Populus, which dominates floodplain forests in Europe, Asia and...
Friedman, Jonathan M.; Stricker, Craig A.; Adam Z Csank; Honghua Zhou Plant leaf shape is highly variable. The beauty of leaves can be purely aesthetic, but also derives from the mystery of adaptive significance. This mystery is especially compelling for species with strongly varying leaf shape on a single tree. The desert poplar (Populus euphratica Oliv.) is an ancient and protected species, and forms riparian...
Dong, Quan; Friedman, Jonathan M.; Honghua Zhou Much of what we know about the functional ecology of aquatic and riparian ecosystems comes from work on regulated rivers (Johnson et al. 2012). What little we know about unregulated conditions on many of our larger rivers is often inferred from recollections of individuals, personal diaries, notes, maps, and collections from early scientific...
Scott, Michael L; Webb, Robert H.; Johnson, R. Roy; Turner, Raymond M.; Friedman, Jonathan M.; Fairley, Helen C. This report addresses the relation between flow of the Yampa River and occurrence of herbaceous and woody riparian vegetation in Dinosaur National Monument (DINO) with the goal of informing management decisions related to potential future water development. The Yampa River in DINO flows through diverse valley settings, from the relatively broad...
Scott, Michael L; Friedman, Jonathan M. The Upper Colorado River Endangered Fish Recovery Program has requested experimental flow releases from Flaming Gorge Dam for (1) elevated summer base flows to promote larval endangered Colorado pikeminnow, and (2) midsummer spike flows to disadvantage spawning invasive smallmouth bass. This white paper explores the effects of these proposed flow...
Friedman, Jonathan M. Understanding the complex influences of landscape and anthropogenic elements that shape the population genetic structure of invasive species provides insight into patterns of colonization and spread. The application of landscape genomics techniques to these questions may offer detailed, previously undocumented insights into factors influencing...
Lee, Soo-Rang; Jo, Yeong-Seok; Park, Chan-Ho; Friedman, Jonathan M.; Olson, Matthew S.