Carrie Jensen’s first paper was accepted in Hydrological Processes this week. Her work is about characterizing the spatial and temporal dynamics of headwater stream wetting and drying. This manuscript documents patterns of stream network expansion, contraction, and disconnection in watersheds from New England, Appalachian Plateau, Valley and Ridge, and Blue Ridge physiographic regions. Her research has implications for how we define and describe streams and how that might translate into policy.
Jensen, C. K., McGuire, K. J., and Prince, P. S. (2017) Headwater stream length dynamics across four physiographic provinces of the Appalachian Highlands. Hydrological Processes, doi: 10.1002/hyp.11259.
Abstract: Understanding patterns of expansion, contraction, and disconnection of headwater stream length in diverse settings is invaluable for the effective management of water resources as well as for informing research in the hydrology, ecology, and biogeochemistry of temporary streams. More accurate mapping of the stream network and quantitative measures of flow duration in the vast headwater regions facilitate implementation of water quality regulation and other policies to protect waterways. We determined the length and connectivity of the wet stream and geomorphic channel network in three forested catchments (<75 ha) in each of four physiographic provinces of the Appalachian Highlands: the New England, Appalachian Plateau, Valley and Ridge, and Blue Ridge. We mapped wet stream length seven times at each catchment to characterize flow conditions between exceedance probabilities of <5% and >90% of the mean daily discharge. Stream network dynamics reflected geologic controls at both regional and local scales. Wet stream length was most variable at two Valley and Ridge catchments on a shale scarp slope and changed the least in the Blue Ridge. The density and source area of flow origins differed between the crystalline and sedimentary physiographic provinces, as the Appalachian Plateau and Valley and Ridge had fewer origins with much larger contributing areas than New England and the Blue Ridge. However, the length and surface connectivity of the wet stream depended on local lithology, geologic structure, and the distribution of surficial deposits such as boulders, glacially-derived material, and colluival debris or sediment valley fills. Several proxies indicate the magnitude of stream length dynamics, including bankfull channel width, network connectivity, the base flow index, and the ratio of geomorphic channel to wet stream length. Consideration of geologic characteristics at multiple spatial scales is imperative for future investigations of flow intermittency in headwaters.
We’re in the final throws of planning for the Gordon Research Conference on Catchment Science. The last day to apply is in one week (May 28). We have a great set of speakers, discussion leaders, and participants. This meeting promises to be stimulating and one that shouldn’t be missed! The schedule is posted here: https://www.grc.org/programs.aspx?id=12331.
The Gordon Research Conference (GRC) on Catchment Science unites ecologists, hydrologists, geochemists, pedologists, and other scientists who understand the need for interdisciplinary
research to advance catchment science. Catchment science, conceptually rooted in the physical boundaries that define a catchment or watershed, is inherently integrative in terms of processes operating in catchments and disciplines involved in the study of catchments. As such, an interdisciplinary and international conference that brings together established and developing experts to share and integrate the scientific diversity of catchment science is needed to advance the holistic understanding of catchment systems.
Kevin McGuire & Jakob Schelker
The GRC will be preceded by a two-day Gordon Research Seminar (GRS) that is organized by and designed for graduate students and post-doctoral researchers. The GRS provides opportunities
for the exchange of ideas among early career investigators and an occasion to build relationships with peers that will form the next generation of catchment scientists.
Robert Sabo & Inge Wiekenkamp
Great group of undergraduate students from this summer’s Hubbard Brook REU program. They liked to dig, dig, dig!
This Youtube video was recently posted from a field tour several of us gave during the 50th anniversary of the Hubbard Brook Ecosystem Study. There is good background on forested watershed studies, gaging streams, hydropedology, and local historical ecology at Hubbard Brook. Mark Green (USFS & Plymouth State), JP Gannon (Western Carolina University), Nick Grant (USFS), and Charlie Cogbill all make appearances.
A new student, David Lee, joined our lab this week. David completed his B.S. at the University of Florida in environmental engineering in 2015.
David was most recently working for the US Forest Service as a forestry technician/wilderness ranger and was stationed on the Eldorado National Forest in Pollock Pines, CA.
David will be working on a project based at the Hubbard Brook Experimental Forest in New Hampshire. Welcome to Blacksburg David!
Carrie Jensen was awarded a student seed grant through the Virginia Water Resources Research Center for her dissertation work on storm dynamics of expansion and contraction of temporary headwater streams. Andy Dolloff, with the US Forest Service Southern Research Station and the Department of Fish and Wildlife Conservation at Virginia Tech, is her Co-PI on the grant.
Carrie also contributed to a manuscript that was published online last week in Geophysical Research Letters. The study expanded on a geostatistical method described in McGuire et al. (2014), by developing a spatial stream network model of strontium isotopic composition of stream water in a large Alaska river basin. The model provided a means to quantify the influence of landscape versus in-stream processes on strontium isotopic composition of rivers.
2016), Dendritic network models: Improving isoscapes and quantifying influence of landscape and in-stream processes on strontium isotopes in rivers, Geophys. Res. Lett., 43, doi:10.1002/2016GL068904.
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Dr. Charley Kelly, a former lab member and now with the Division of Forestry and Natural Resources, West Virginia University, had a paper accepted in Geophysical Research Letters this week. The study re-examines several paired watershed studies from the Coweeta Hydrologic Lab, but focuses on high flows, low flows, and interactions with precipitation patterns.
Abstract: Increases in extreme precipitation events of floods and droughts are expected to occur worldwide. The increase in extreme events will result in changes in streamflow that are expected to affect water availability for human consumption and aquatic ecosystem function. We present an analysis that may greatly improve current streamflow models by quantifying the impact of the interaction between forest management and precipitation. We use daily long-term data from paired watersheds that have undergone forest harvest or species conversion. We find that interactive effects of climate change, represented by changes in observed precipitation trends, and forest management regime, significantly alters expected streamflow most often during extreme events, ranging from a decrease of 59% to an increase of 40% in streamflow, depending upon management. Our results suggest vegetation might be managed to compensate for hydrologic responses due to climate change to help mitigate effects of extreme changes in precipitation.
Kelly, C. N., K. J. McGuire, C. F. Miniat, and J. M. Vose (2016), Forest management changes streamflow response to increasing precipitation extremes, Geophysical Research Letters, 43, doi:10.1002/2016GL068058.
Congratulations to Carrie on being selected for a CUAHSI 2015 Pathfinder Fellowship. Carrie’s proposal titled, “Stream network expansion and contraction dynamics in headwater catchments throughout the Appalachian Highlands,” will be supported by CUAHSI (Consortium of Universities for the Advancement of Hydrologic Science, Inc.), which will provide her with an opportunity to enhance her dissertation project to include the Fernow Experimental Forest as field site. This summer she will spend several weeks at Fernow mapping stream channels allowing her to add the Allegheny Mountain section of the Appalachian Plateau physiographic province to field sites throughout the Appalachian Highlands. Carrie recently presented preliminary data from this project at the American Geophysical Union fall meeting in December.
Special Issue Tracer Advances Reviews
Tracer advances in catchment hydrology (pages 5135–5138) Kevin J. McGuire and Jeffrey J. McDonnell
Ecohydrological separation in wet, low energy northern environments? A preliminary assessment using different soil water extraction techniques (pages 5139–5152) Josie Geris, Doerthe Tetzlaff, Jeffrey McDonnell, James Anderson, Graeme Paton and Chris Soulsby
A preliminary assessment of water partitioning and ecohydrological coupling in northern headwaters using stable isotopes and conceptual runoff models (pages 5153–5173) Doerthe Tetzlaff, James Buttle, Sean K. Carey, Marjolein H. J. van Huijgevoort, Hjalmar Laudon, James P. McNamara, Carl P. J. Mitchell, Chris Spence, Rachel S. Gabor and Chris Soulsby
Established methods and new opportunities for pore water stable isotope analysis (pages 5174–5192) Matthias Sprenger, Barbara Herbstritt and Markus Weiler
Stable water isotopes suggest sub-canopy water recycling in a northern forested catchment (pages 5193–5202) Mark B. Green, Bethany K. Laursen, John L. Campbell, Kevin J. McGuire and Eric P. Kelsey
Tracking residence times in hydrological systems: forward and backward formulations (pages 5203–5213) Paolo Benettin, Andrea Rinaldo and Gianluca Botter
Velocities, celerities and the basin of attraction in catchment response (pages 5214–5226) Keith Beven and Jess Davies
Advancing tracer-aided rainfall–runoff modelling: a review of progress, problems and unrealised potential (pages 5227–5240) Christian Birkel and Chris Soulsby
Transit time distributions, legacy contamination and variability in biogeochemical 1/fα scaling: how are hydrological response dynamics linked to water quality at the catchment scale? (pages 5241–5256) Markus Hrachowitz, Ophelie Fovet, Laurent Ruiz and Hubert H. G. Savenije
Using concurrent DNA tracer injections to infer glacial flow pathways (pages 5257–5274) Helen E. Dahlke, Andrew G. Williamson, Christine Georgakakos, Selene Leung, Asha N. Sharma, Steve W. Lyon and M. Todd Walter
A tracer to bridge the scales: on the value of diatoms for tracing fast flow path connectivity from headwaters to meso-scale catchments (pages 5275–5289) Julian Klaus, Carlos E. Wetzel, Núria Martínez-Carreras, Luc Ector and Laurent Pfister
Application of isotope hydrograph separation to understand contributions of stormwater control measures to urban headwater streams (pages 5290–5306) Anne J. Jefferson, Colin D. Bell, Sandra M. Clinton and Sara K. McMillan
I have been going to Coweeta every one or two weeks for the past two months to monitor sprinkling events on the soil model. Although I am measuring only one thing, water, being precise is actually very difficult. There are 5 high-resolution tipping buckets on the hillslope to measure samples of input and one large tipping bucket at the bottom of the model to measure outflow.
I experimented with placement of PVC collectors that are designed to capture spatial variability of the input by expanding the collection areas and positions of each input tipping bucket. Then I experimented with acrylic collectors, which are longer and smoother. Finally, I put specimen cups out along a grid on the model to measure input by hand. It is a dependable low-tech, high-resolution solution.
On the last trip of this year I shut down and winterized the model. That means disconnecting the water supply to the irrigation system, shutting off the reverse osmosis pump, and draining the water from the lines and water tank, all in case of a hard freeze, which is uncommon but possible. My instruments, e.g., soil probes and tensiometers, are sitting in the shed, ready for installation in an upcoming trip.
The hillslope model with tipping buckets and data logger installed.
Calibrating the outflow tipping bucket (500 mL per tip).
Closeup of the outflow tipping bucket.
PVC collectors expand the area of water sampled, helping to capture spatial variability.
A grid of cups set out on the model give an accurate, high-resolution estimate of water input to the soil model.
Wiring soil moisture/temperature probes, tensiometers, and tipping bucket to the data logger in the dorm room.