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geomorphology

FYI: NCED Summer Institute on Earth-surface Dynamics

I basically recommend anything this NCED group puts together. The short courses on Mountain Rivers and Sand-bed Rivers that I took as late-stage PhD student were absolutely fantastic.

HOW DOES VEGETATION INFLUENCE LARGE-SCALE TOPOGRAPHIC FORM?
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In order to adequately describe the interactions among the physical, biological, geochemical, and anthropogenic processes that shape the Earth’s surface, we need to take a holistic, cross-disciplinary approach. Thus, the National Center for Earth-surface Dynamics (NCED) founded the Summer Institute on Earth-surface Dynamics (SIESD) as a forum to expose early-career scientists to laboratory experiments, fieldwork, and lectures on predictive Earth-surface science.

In 2010, the Summer Institute will focus on the science of rivers and vegetation. Participants will gain experience in: the basic physics of water-sediment-vegetation interaction; modeling the co-evolution of landscapes and their ecosystems; quantitative analysis of complex landscapes; LiDAR analysis of river topography and vegetation; and specifics of braided, meandering, and deltaic systems interacting with vegetation. In addition, students will gain hands-on experience with a suite of analytical tools including GeoNet (an automatic feature extraction tool for high resolution topography) and InVEST (a modeling environment to support environmental decision-making).The Institute will also expose students to broader-impacts research via the Science Museum of Minnesota and other NCED educational and diversity activities.

Eligibility: The Summer Institute is directed to graduate students in the final years of their PhD program, postdocs, or early-career scientists (three years from PhD). Applications from women, minorities, and individuals with disabilities are strongly encouraged.

Cost: NCED will make arrangements to cover local expenses related to participation in the Institute (enrollment, accommodations, breakfast, and lunch). However, students should remember they are responsible for the cost of transportation to/from Minnesota and all incidental expenses. Limited resources are available to cover travel expenses upon request.

Application Procedure: An online application is available at: http://www.nced.umn.edu/content/2010-summer-institute-earth-surface-dynamics-siesd-application.

Lecturers (subject to change): Chris Paola, Gary Parker, Brad Murray, Gordon Grant, Steve Polasky, and Efi Foufoula-Georgiou. Additional lecturers will be announced on the course website.

Deadline: The application and all supporting materials must be received by June 25, 2010.

For more information, please visit http://www.nced.umn.edu/content/summer-institute-earth-surface-dynamics.

Delta upon Delta

For some reason the last few days have seen me browsing the semi-frozen areas of the Earth and in my search for the perfect thermokarst landscape, I’ve run across some really nice deltas. I don’t know anything about the one below other than its location in far northwestern Saskatchewan, but it looks to me like this river had built a beautiful fan delta only to see the lake shoreline dramatically change (perhaps as a result of isostatic rebound?) triggering the building of not one, but two, new fan deltas like Mickey Mouse ears on the margins of the old one.

The image below is from Google Earth. Here’s the Flash Earth permanent link: http://www.flashearth.com/?lat=59.114818&lon=-109.354195&z=11.9&r…

Posted via web from Pathological Geomorphology

More tributes to Reds Wolman from all those who miss him

About two months ago, I noted with great sadness the passing of a legendary figure in fluvial geomorphology, M. Gordon “Reds” Wolman, long-time professor at The Johns Hopkins University and inspiration to hundreds, if not thousands, of geomorphologists, hydrologists, and environmental scientists around the world.

In the past two months, Wolman’s students and colleagues have done an outstanding job of paying tribute to our hero. On April 11th, generations of Wolman’s students gathered on the Hopkins campus for a memorial service, which included a eulogy from a childhood friend and reflections from Hopkins geomorphology colleague Peter Wilcock. The day before the memorial, many of the attendees conducted their own Reds’ style field trip to some of his favorite locations in Baltimore County and waved their arms and debated some of the same questions Reds had spent decades pondering. (Sadly, I could not attend the celebration, because I was leading my hydrogeology class on a field trip to Congaree National Park, but somehow I feel like Reds would understand.)

Among the lasting tributes to Wolman are a couple of JHU web pages, two wonderful videos (below), and perhaps my favorite memorial ever:

A permanent memorial tribute will be installed outside the classrooms in Ames Hall where Reds Wolman taught for more than a half century. Stones provided by students, colleagues and friends from around the world will be constructed into a path in a shape that mirrors a meandering river.

For those of you still wondering what all the fuss was about (and still reading this post), please take a few more minutes and listen to the preface of one of Wolman’s seminal works and some reflections from Wolman’s colleagues and students (including, if you listen carefully, me) and from Wolman himself.

[youtube=http://www.youtube.com/watch?v=-vCDJ8T5usY&hl=en_US&fs=1&]

[youtube=http://www.youtube.com/watch?v=iB2e0Ei04pg&hl=en_US&fs=1&]

Reds is deeply missed by all who knew him, but these wonderful tributes give us a small way to hang on to the man who influenced, encouraged, and inspired us.

Deltas into Rivers: Chippewa River into the Mississippi River, Wisconsin

The Chippewa River drains the glaciated terrains of north-central Wisconsin including major outwash plains from the margins of the Laurentide Ice Sheet.  The sand carried by the Chippewa is a major sediment source for the Upper Mississippi River for tens of miles downstream.  The Chippewa forms a beautiful delta into the Mississppi River, as seen below, creating the only natural lake on the Mississippi, in the form of Lake Pepin (birthplace of water-skiing, by the way).  I like this delta because we don’t often think of riverine deltas forming in the rivers, and their propogating upstream and downstream effects. Plus, it makes a pretty contrast to the dissected blufflands of the Driftless area.

Flash earth link: http://www.flashearth.com/?lat=44.418021&lon=-92.140805&z=11.6&r=0&src=msa If you zoom in on Flash Earth you can get some nice imagery of the sand bars and fluvial islands of the Chippewa as you move upstream, plus some nice long anastomosing reaches.

Posted via email from Pathological Geomorphology

The pathologically curvy Rio Grande Delta

I spent a summer in college staring at maps and aerial photographs of the Rio Grande delta in Texas and Mexico. Maybe now I can get some use out of it.  I was working with J.D.  Stanley at the Smithsonian’s NMNH and he pointed me to the apparently high sinuosity of deltaic channels on the Texas side of the Rio Grande delta.

According to my notes, the modern Rio Grande has a sinuosity of 2.075 in its delta, while Holocene channels have a sinuosity of 1.83, younger Pleistocene channels have a sinuosity of 1.81 and remnants of older Pleistocene channels have about 1.32. So our data suggests that the channels of the Rio Grande delta have gotten curvier over time. I also did a literature review of channel sinuosity in other deltas and found that the Rio Grande was indeed anomalously sinuous compared to many of the world’s major deltas.  In my review, only the Niger and Klangat Langat deltas were curvier. Unfortunately, we never came up with a good mechanism to explain why the Rio Grande was so curvaceous.

Indeed, if you look at the flash earth images (http://www.flashearth.com/?lat=26.07433&lon=-97.526349&z=10.4&r=0&src=msa)  below, you can see what caught our eye. One of the images is the majority of the delta (look for the anthropogenically straightened main outlet channel), one zooms in on the modern river mouth and area just to the north, one shows a portion of the southern, Mexico portion of the delta, and one shows the northern portion of the delta, which if I recall correctly has some of the oldest exposed deltaic deposits along with some eolian features (which can been seen in the image).

Posted via email from Pathological Geomorphology

Bombetoka Bay, Madagascar

Hunting for a Where on Google Earth location a while ago I ran across this wonderful tidally-influenced delta on the northwest coast of Madagascar. It is the mouth of the Betsiboka River and just north of the river mouth is the second largest port in Madagascar.

What struck me about the delta was not just the nice tug-of-war between riverine and tidal processes in shaping the islands, but the dramatic red color of the water in the Google Earth image (and others as well). This red color is symptomatic of the massive erosion resulting from rampant deforestation of the island.

The four photos are from Flash Earth, Google Earth, and the Gateway to Astronaut Photography, NASA Earth Observatory (ASTER satellite)

Flash earth permanent link: http://www.flashearth.com/?lat=-15.883853&lon=46.436067&z=10.8&r=0&src=msa

Astronaut Photograph: http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS005&roll=E&frame=9418

Earth Observatory ASTER image: http://earthobservatory.nasa.gov/IOTD/view.php?id=5245

Posted via email from Pathological Geomorphology

Is Anne a hydrologist? geomorphologist? hydrophillic geologist? or whathaveyou?

Cross-posted at Highly Allochthonous

The theme for the next edition of the geoblogosphere’s Accretionary Wedge carnival is along the lines of “what are you doing now?” Recently as I was whining to my Highly Allochthonous co-blogger about how busy my teaching was keeping me, and how I wouldn’t have time to write anything for the Wedge, Chris suggested that I exhume some navel-gazing writing I’d done a while ago and simply post that. And in slightly modified form, now I have.

So, what do I do? The major theme of my research is analyzing how geologic, topographic, and land use variability controls hydrologic response, climate sensitivity, and geomorphic evolution of watersheds, by partitioning water between surface and ground water. The goal of my research is to improve reach- to landscape-scale prediction of hydrologic and geomorphic response to human activities and climate change. My work includes contributions from field studies, stable isotope analyses, time series analyses, geographic information systems, and hydrological modeling. My process-based research projects allow me to investigate complex interactions between hydrology, geomorphology, geology, and biology that occur on real landscapes, to test conceptual models about catchment functioning, and to show whether predictive models are getting the right answers for the right reasons. My current and past research has allowed me to investigate landscapes as diverse as the Cascades Range volcanic arc, the Appalachian Mountains and Piedmont of the southeastern United States, the Canadian Arctic Archipelago, and the Upper Mississippi River watershed.

My on-going and developing research program focuses on three areas:

  1. Watershed influences on hydrologic response to climate variability and change;
  2. Controls on and effects of partitioning flowpaths between surface water and groundwater; and
  3. Influence of hydrologic regimes on landscape evolution and fluvial geomorphology

If you really want the long version of my research interests, venture onward. But don’t say I didn’t warn you.

Watershed influences on hydrologic response to climate variability and change

On-going climate change is predicted to have dramatic effects on the spatial distribution and timing of water resource availability. I use historical datasets, hydrologic modeling, and GIS analysis to examine how watershed characteristics can mediate hydrologic sensitivity to climate variability and change. Currently, I focus on climate sensitivity in watersheds with seasonal and transient snow and on down-scaling hydrologic impacts of climate change to smaller watersheds.

Watersheds with seasonal and transient snow: A long-held mantra is that watersheds with extensive groundwater are buffered from climate change effects, but in a pair of papers set in the Oregon Cascades, my collaborators and I showed the opposite to be true. Minimum streamflows in watersheds with abundant groundwater are more sensitive to loss of winter snowpack than in watersheds with little groundwater (Jefferson et al., 2008, Tague et al., 2008). Glaciers are another water reservoir often thought to buffer climate change impacts, and in a paper in review, we show that projected glacier loss from Mt. Hood will have significant impacts on water resources in the agricultural region downstream.

I have also been examining hydroclimate trends relative to hypsometry (elevation distribution) of watersheds in the maritime Pacific Northwest. Almost all work investigating hydrologic effects of climate change in the mountainous western United States focuses on areas with seasonal snowpacks, but in the maritime Northwest, most watersheds receive a mixture of winter rain and snow. My research investigates how much high-elevation watershed area is necessary for historical climate warming to be statistically detectable in streamflow records. Preliminary results were presented at the American Geophysical Union meeting in 2008, and I’m working on a paper with more complete results. Extending this work into the modeling domain, I am currently advising a graduate student using SnowModel to investigate the sensitivity of snowmelt production to projected warming in the Oregon Cascades, Colorado’s Fraser Experimental Forest, and Alaska’s North Slope, in collaboration with Glen Liston (Colorado State University).

Down-scaling climate impacts to watersheds and headwater streams: Most studies of hydrologic impacts of climate change have focused on regional scale projections or large watersheds. Relatively little work has been done to understand how hydrologic and geomorphic impacts will be felt in mesoscale catchments or headwater stream systems, yet most of the channel network (and aquatic habitat) exists in these small streams. In August 2009, I submitted a proposal to a Department of Energy early career program to investigate the effect of climate change on hydrology of the eastern seaboard of the US. This work proposed to contrast North Carolina’s South Fork Catawba River and New Hampshire’s Pemigewassett River and their headwater tributaries through a combination of modeling and field observations of the sensitivity of headwater stream networks to hydroclimatic variability. While the project was not funded, I am using the reviews to strengthen the proposal, and I plan to submit a revised proposal to NSF’s CAREER program in July. I have a graduate student already working on calibrating the RHESSys hydroecological model for the South Fork of the Catawba River.

Controls on flowpath partitioning between surface water and groundwater and the effects on stream hydrology, geomorphology and water quality

Many watershed models used in research and management applications make simplifying assumptions that partition water based on soil type and homogeneous porous bedrock. These assumptions are not reflective of reality in many parts of the world, including the fractured rocks of North Carolina’s Piedmont and Blue Ridge provinces. I am interested in understanding how water is partitioned between groundwater and surface water in heterogeneous environments, and what effect this partitioning has on stream hydrology, geomorphology, and water quality. My interest in the controls on flowpath partitioning began during my work in the Oregon Cascades Range, where I showed that lava flow geometry controlled groundwater flowpaths and the expression of springs (Jefferson et al., 2006). Currently, I am using fractured rock environments and urbanizing areas as places to explore the effects of heterogeneous permeability.

Fractured rock: The Piedmont and Blue Ridge provinces of the eastern United States are underlain by crystalline rocks, where groundwater is largely limited to discrete fractures. Groundwater-surface water interactions on fractured bedrock are largely unexplored, particularly at the scale of small headwater streams. I am interested in how groundwater upwelling from bedrock fractures and hyporheic flow influence the hydrology and water quality of headwater streams. A small grant facilitated data collection in three headwater streams which is forming the thesis for one of my graduate students, has precipitated a collaborative project with hydrogeologists from the North Carolina Division of Water Quality, and will serve as preliminary data for a proposal to NSF Hydrologic Sciences in June 2010.

Urban watersheds: Urbanization alters the partitioning of flowpaths between surface water and groundwater, by creating impervious surfaces that block recharge and installing leaky water and sewer lines that import water from beyond watershed boundaries. Also, the nature of the drainage network is transformed by the addition of stormwater sewers and detention basins. In September 2009, my collaborators and I submitted a proposal to NSF Environmental Engineering to look at how stormwater best management practices (BMPs) mitigate the effects of urbanization on headwater stream ecosystem services. While we weren’t funded, we were strongly encouraged to resubmit and did so in March 2010. We are also submitting a proposal to the National Center for Earth Surface Dynamics (NCED) visitor program to use the Outdoor Stream Lab at the University of Minnesota to investigate the interplay between stormwater releases and in-stream structures.

Influence of hydrologic regimes on landscape evolution and fluvial geomorphology

The movement of water on and through the landscape results in weathering, erosion, transport, and deposition of sediment. In turn, that sediment constrains the future routing of water. I am interested in how the hydrologic regime of a watershed affects the evolution of topography and fluvial geomorphology. My work in this area has examined million-year scales of landscape evolution in high permeability terrains, century-scale evolution of regulated rivers, and the form and function of headwater channels.

Evolution of high permeability terrains: The youngest portions of Oregon’s High Cascades have almost no surface water, because all water infiltrates into high permeability lava flows. Yet on older parts of the landscape, streams are abundant and have effectively eroded through the volcanic topography. In a paper in Earth Surface Processes and Landforms (Jefferson et al., 2010), I showed that this landscape evolution was accompanied and facilitated by a hydrologic evolution from geomorphically-ineffective stable, groundwater-fed hydrographs to flashy, runoff-dominated hydrographs. This coevolutionary sequence suggests that permeability may be an important control on the geomorphic character of a watershed.

Human and hydrologic influences on large river channels: Almost all large rivers in the developed world are profoundly affected by dams, which can alter the hydrologic regime by suppressing floods, supplementing low flows, and raising water levels in reservoirs. On the Upper Mississippi River, in the 70 years since dam construction, some parts of the river have lost islands, and with them habitat diversity, while in other areas new islands are emerging. In 2008-2009, I had a small grant that facilitated the examination of some islands with a unique, unpublished long-term topography dataset and its correlation with hydrologic patterns and human activities. This project became the thesis research of one of my graduate students, who will be defending his M.S. in May 2010.

Headwater channel form and function: Although headwater streams constitute 50-70% of stream length, the geomorphic processes that control their form and function are poorly understood. Most recent research on geomorphology of headwater streams has focused on streams in very steep landscapes, where debris flows and other mass wasting processes can have significant effects on channel geometry. In the Carolina Piedmont, gentle relief allows me to investigate the formation and function headwater channel networks, isolated from mass wasting processes. One of my graduate students has collected an extensive sediment size distribution dataset which shows that, at watershed areas <3 km2, downstream coarsening of sediment is more prevalent than the downstream fining widely observed in larger channels. Another graduate student is collecting data on channel head locations and flow recurrence and sediment transport in ephemeral channels in order to sort out the relative influences of topography, geology, and legacy land use effects on the uppermost reaches of headwater streams. Both of these projects have already resulted in presentations at GSA meetings.

Whew. So that’s what I do, between teaching some field-intensive courses and raising a preschooler. But, what am I? Hydrologist? Geomorphologist? Hydrophillic geologist? Or something else entirely?

Two tributes to Reds Wolman (1924-2010)

Cross-posted at Highly Allochthonous

M. Gordon “Reds” Wolman was a towering figure in 20th century fluvial geomorphology, fundamentally shaping our understanding of river forms and processes, profoundly influencing environmental education and river management, and educating scores of students that continue to push the boundaries of our scientific understanding of landscape and hydrologic processes.

But to say that Reds merely educated his students is an understatement, he touched our lives. Reds was my academic grandfather (my Ph.D. advisor’s Ph.D. advisor), he was my undergraduate geomorphology professor, and he was one of a small handful of people who have profoundly influenced my career.

I’ve included below a beautiful tribute to Reds Wolman, written by his friend and colleague Peter Wilcock. Below the fold, I’ve included some of my own memories of interacting with Prof. Wolman.

wolman.jpg

M. Gordon (Reds) Wolman

August 16, 1924 – February 24, 2010

Prof. Wolman’s career was defined by fundamental contributions to our understanding of rivers, supported by pioneering work in developing interdisciplinary environmental education and an extraordinary commitment to the application of research to river management and policy.

In his Ph.D. research at Harvard University and subsequent work with Luna Leopold at the U.S. Geological Survey, Prof. Wolman played a central role in defining rivers in a modern, quantitative and generalizable framework that still provides the standard against which new models and concepts are evaluated. The understanding and the methods developed in this work form the foundation of modern river geomorphology, engineering, and restoration. Building on this work, Prof. Wolman addressed a fundamental problem in river science: the magnitude and frequency of the processes that shape rivers and their ecosystems. Is it the rare and destructive storm that sets the size, shape and composition of river channels, or the small, persistent flows, or something in between? With his colleague John Miller, Prof. Wolman demonstrated that relatively common floods do the most work in shaping river channels and, further, that there is remarkable consistency in the frequency of these ‘effective’ floods. This result has guided interpretation of rivers and challenged river theory for the past 50 years, while also providing a key element of modern channel restoration and design. Prof. Wolman’s contribution extends to the pervasive impact of urbanization on rivers. With his colleague Asher Schick, he documented the impact of urbanization on stream channels, developing a characteristic sequence of events that defines the standard model against which impacts and remediation are evaluated.

Committed to the idea that environmental stewardship requires knowledge that is both deep and broad, Reds played a leading role–by personal example, by academic leadership at Johns Hopkins University, and by advising many academic and research programs–in defining the nature and scope of effective, rigorous, and interdisciplinary environmental education.

The link between science and society was not an abstract theme for Reds, but a path to action. Reds contributed sustained service and frequent chairmanship of National Academy Commissions, Boards, and Committees dealing with water management and policy. He also provided expert guidance to Resources for the Future, the World Health Organization, the International Scientific Committee on Problems of the Environment, the International Institute for Applied Systems Analysis, Oak Ridge National Laboratory, Savannah River Plant, and the State of Maryland among others. His indefatigable service, combined with his good-natured wisdom, influenced environmental decisions and decision-makers around the world.

For those who knew him, Reds’ professional accomplishments merely provide context for his greater personal contributions through his inspired combination of warmth, wit, and genuine affection for all he came into contact with.

The whole exceeded the sum of the parts. Reds was a distinguished scholar who played a central role in defining our modern understanding of rivers, a visionary academic who pioneered integrated environmental education, a devoted citizen who worked tirelessly to apply an understanding of rivers to their protection and wise use, and an extraordinary human being who inspired and delighted generations of students and colleagues, all friends.

Wolman was one of my scientific heroes and I am forever honored to have been his student. At age 17, already a budding geomorphology geek, and familiar with some of Wolman’s work, I learned that he was a professor at The Johns Hopkins University. His residence there, accompanied my chance to meet him as a prospective student, was a factor influencing my decision to apply to and attend the university. I couldn’t wait to take classes with him, and I did take both that he offered – probably rather earlier than was good for my intellectual maturity. His course “Water Resources Development: History and Principles” and his course on “Geomorphology” were and are amazinglly influential on my thinking about the world, my research interests, and my teaching style.

Wolman was amazing: unassuming, charming, friendly, funny, compassionate. He assigned his textbook,Fluvial Processes in Geomorphology, almost apologetically (it is the classic in the field), but he never asked us to read anything from it. Instead, he had a selected, but still daunting, list of papers for each topic and he asked us to read those that we thought would be most useful and relevant to us. He was probably my first professor to emphasize the primary literature of journal articles, and now I repay that favor to my Fluvial Processes students.

In one lab exercise, Wolman taught us how to pick up and measure 100 stones in a transect across the stream bed in order to quantify the sediment size distribution. It wasn’t until several years later, as an MS student, that I discovered that that method was the “Wolman Pebble Count” technique (that I will teach to my students next week). He smoked cigars in the field and then would chuck them into the stream. I remember when I made an aghast comment about it, and he said “What? It’ll biodegrade.” Those urban Baltimore streams had certainly seen far worse insults than the biodegradable litter of a man who knew more about them than anyone else.

I’ll never forget our first geomorphology field trip. It was January, only a few weeks into the term, clear and freezing cold and he drove us who knows where in Baltimore County, then had us pile out of the van someplace along a road, with a view down out over something (doesn’t really matter what). And then he said “Tell me the story of this place.” And he waited and waited for an answer. Actually, he did the same thing on every field trip, but after a while I got better at seeing and telling those stories. And now I do it to my students.

The term paper I wrote for his geomorphology class was on islands of the Upper Mississippi River, the very same island group that one of my MS students is finally doing a proper analysis of. I remember sitting in the library and being immensely frustrated with with my lit review for the paper because every paper I read had Wolman as an author or a major reference. His work with Luna Leopold on “River channel patterns: braided, meandering, or straight” seemed to be the pivotal paper on which my whole literature review depended. Finally, I thought “Forget it, I’m going to take a break and write the section about the history of human activities on the Upper Mississippi. Surely, Wolman didn’t have anything to do with that.” He didn’t, but his father Abel Wolman, sat on the Mississippi River Commission that oversaw management of the river and the Wolman name cropped up again.

Wolman liked my term paper, and I remember that his main question to me was whether I had accounted for the varying water level elevations in my analysis of the aerial photos and maps. I hadn’t, but I make sure every time I meet with my student to remind him that he needs to take that into account. This fall, when I had a chance to chat with Woman at the Gecological Society of America meeting, he asked me whether anything had come of that islands project. He remembered my term paper from 1999! I was so proud to tell him that it really, finally was being done properly and would eventually see the light of day in journal article form.

Wolman’s lectures were amazing. He was old school, with a lot of hand-scrawled notes and the occasional handout figure photocopied from a textbook or article. He’d joke about having multimedia presentations, by which he meant blackboard +/- overhead +/- slide projector +/- maps. I joke about that too on days I use the overhead projector, and my students laugh, but they don’t know the whole story. He had an incredible ability to weave literature and history and art and everything into his lectures. My very favorite example of this was when we were talking about aeolian processes and he discussed Ralph Bagnold’s treatise on The Physics of Blown Sand. Somehow he got onto a tangent and proceeded to tell us that Bagnold’s sister was Enid Bagnold, an author who wrote National Velvet, which was a movie that starred Elizabeth Taylor. In turn, that inspired a 15 minute discourse on the relative merits of various Elizabeth Taylor movies. Yet, somehow I never minded when he ran overtime in lecture (which he usually did) and I always chose to be late to my Calculus III lectures rather than tear myself away from Wolman’s stories.

Wolman wore bow ties every day, and he drove convertibles his whole life. When I was student, the convertible was a red Miata. One summer I was working in DC and taking the train back to Baltimore late on a Friday night. I was head down in a book and I heard a friendly voice ask if the seat next to me was taken. It was Reds, of course, fresh from being honored by the National Academies, if I recall properly. So that Friday night, we spent the hour long train ride talking about geomorphology and whether I should go to field camp or study abroad. He wouldn’t hear of me taking the bus from the train station to campus, so I got to ride in that red convertible.

Wolman gave me advice on choice of graduate school and he wrote my letters of recommendation. In the end, I chose to work with Gordon Grant, who earned his Ph.D. under Wolman. While Gordon is his own creative force, I especially treasure the moments when I hear Gordon channeling Reds Wolman in his discourse. I consider myself immensely lucky to have been taught by two such insightful, inspiring, and compassionate people and to trace my academic lineage back to a pivotal person in the history of my field. Better yet is that I got to know one of my scientific heroes and know that he was indeed an amazing person.

grant-jefferson-wolman.jpg
Gordon Grant, Anne Jefferson, and M. Gordon Wolman, October 2009.

Conference presentation: Effects of river management & sediment supply on island evolution in Pool 6 of the Upper Mississippi River, southeast Minnesota

Watershed Hydrogeology Lab graduate student Brock Freyer has spent the last two years learning deeply about the hydrology, geomorphology, and sedimentology of the Upper Mississippi River System, as well as learning to use some sophisticated GIS techniques for 3-D analysis of topographic data. This week he is presenting the results of his work: “Effects of river management & sediment supply on island evolution in Pool 6 of the Upper Mississippi River, southeast Minnesota” at the Upper Midwest Stream Restoration Symposium. Brock is speaking in a session on Large River Restoration. Brock will be defending his M.S. thesis sometime in late spring.

GSA Abstract: Hydrogeomorphic controls on the expression of stream water in less than 1 km2 Piedmont watersheds

The Watershed Hydrogeology lab abstract for the Northeastern/Southeastern Geological Society of America Meeting in Baltimore, March 14-16, 2010. I’ll be giving a talk at 8:45 am on Monday, March 15th in session T24. Hydrogeology of Wetlands and Watershed Processes. It’s also looking like all of the other co-authors will be attending the meeting as well, so if you come you can hear the inside scoop from the students doing the work.

Hydrogeomorphic controls on the expression of stream water in less than 1 km2 Piedmont watersheds

Jefferson, McGee, Moore, and Caveny-Cox
UNC Charlotte, Dept. of Geography and Earth Sciences

Rapid development of the North Carolina Piedmont is converting headwater watersheds from forested or agricultural to urbanized landscapes, affecting the hydrology and geomorphology of small streams. We examine the water sources and contributing areas to headwater streams in 12 small, forested watersheds near the Charlotte metropolitan area. These watersheds have experienced a history of timber harvest and agriculture typical of Piedmont landscapes. Stream networks are characterized by regolith-bedded ephemeral channels that contribute to mixed bedrock and gravel-bed perennial channels. Source areas for ephemeral channels are on the order of 1 ha, while perennial flow heads have contributing areas on the order of 10 ha. Surface flow in ephemeral reaches occurs during rain events exceeding 2.5 cm and ceases within hours of rainfall. Between rain events, channel head locations vary by 0-14 m and correspond to bedrock exposures or soil pipes. Streams show varying patterns of baseflow discharge versus watershed area, with some streams showing evidence of concentrated zones of groundwater upwelling. Upwelling zones, characterized by temperature and conductance perturbations, are found in both bedrock and alluvial reaches and are stationary across seasons. Down-welling is observed in sediment wedges upstream of fallen logs or debris jams, sometimes leading to complete dewatering of surface baseflow. There are no consistent longitudinal trends in sediment size, and there is partial mobility of bed sediments under moderately-frequent flows. While the study watersheds represent pre-urbanization hydrogeomorphology, legacy land-use effects may contribute to variations in channel network extent and incision in the study watersheds.