Allen C Gellis, Ph.D.

Allen's interests are in the broad area of fluvial geomorphology, with emphasis on understanding the erosion, transport, storage, delivery, and age of fluvial sediment. Much of Allen’s research is focused on developing approaches to understand the significant sources of fine-grained sediment using geochemical tracers or fingerprints at both small and regional watershed scales.

Biography

Education

Ph.D. in Geology - Dissertation Title: Suspended-Sediment Characteristics In Four Humid Tropical Watersheds Of Contrasting Land Use, Puerto Rico, Colorado State University

M.S. in Geology, Colorado State University

B.S. in Geology, State University of New York at Albany

 

Present Assignment: Fluvial Geomorphologist for the National Water Quality Assessments (NAWQA) Regional Stream Quality Assessment Team (RSQA)

The NAWQA-RSQA program has multiple objectives: (1) to access the status of ecological conditions in broad regions of the U.S., (2) to understand the relation of contaminants, nutrients, and sediment to ecologic condition and (3) to understand the role of human and natural factors in the occurrence of contaminants, nutrients, and sediment. We have conducted studies in 3 large ecosystems of the United States- the Midwest (MSQA), the Southeast (SESQA), and the Pacific Northwest (PNSQA) with 3 regions remaining. At all the RSQA sites, I develop the data collection for the physical habitat assessments and provide training and support for USGS NAWQA personnel.

My research with NAWQA includes: 1. Using radionuclides (7Be, 210Pbex, 137Cs) to determine the source(s) and age of fine-grained sediment (<0.063mm). 2. Developing appropriate metrics to understand the relation of sediment and channel morphologic stressors on the health of aquatic habitat. 3. Analyzing regional sediment loads and concentrations. My NAWQA research and its interpretations have enormous national implications that include understanding sediment sources at regional scales and determining the physical health of our Nations' rivers. With assistance from Laurel Woodruff, a major study objective of SESQA is to determine if the USGS Geochemical Soils Database (http://pubs.usgs.gov/of/2014/1082/) can be used as a source library for sediment fingerprinting. We are only 2 years into the analysis, and I have not yet published any significant research papers. I did present preliminary results of my sediment sourcing research using radionuclides at the 2014 AGU National Meeting. I am expected to publish several papers over the next year.

Present Assignment: Identifying Sediment Sources in the Sediment Total Maximum Daily Load Process (10 %)

The objective of this study is to bring the science of sediment sourcing to the practitioner level. This includes research on sediment budgets and sediment fingerprinting. The practitioners we are asked to assist include local and state agencies mandated to reduce sediment loads through the Sediment TMDL program. We are currently writing an EPA manual that highlights the methods and approaches used to identify sediment sources and develop sediment budgets.

Previous Assignment: Determining the sources of fine-grained sediment in small watersheds of the Chesapeake Bay

In the Chesapeake Bay, sediment and associated nutrients are having an adverse effect on the living resources and habitat of the Chesapeake Bay and its watershed.

As a team leader on sediment science for the Bay, a major focus of my research has been to develop tools and approaches to understand the erosion, transport, storage, and delivery of sediment at a range of spatial scales.

A major research initiative has been to develop the “sediment fingerprinting approach” under the general framework of sediment budgets in subbasins of the Chesapeake Bay. The sediment fingerprinting approach is based on characterizing each of the potential sediment sources within a watershed by a composite fingerprint, defined by a number of physical or geochemical properties of the source materials, and comparing the fingerprint of suspended sediment sampled at the watershed outlet with the fingerprints of the potential sources. This is an extremely complex problem that involves geomorphology, hydrology, geochemistry, and statistics. This is also an exciting area of research that will lead to scientific advances in fluvial geomorphology related to the erosion, transport, storage, and delivery of fine-grained sediment.

Sediment is one of the most common causes for the loss of stream-biologic integrity. These impaired water bodies are placed on the 303D list where a Sediment TMDL (total maximum daily load) is implemented. Identifying sediment sources is an important step in the U.S. Environmental Protection Agency’s (USEPA) Sediment TMDL process. Working with EPA, we are developing strategies to quantify sediment sources and develop sediment budgets that can become part of the Sediment TMDL framework.

Chesapeake Bay research has been presented at numerous scientific meetings and published in several outlets (Gellis et al., 2005a; Gellis and Landwehr 2006a; Devereux et al., 2010; Clune et al., 2010; Banks et al., 2010; Gellis and Walling, 2011; Merritts et al., 2011

Collaborators:

Universities: Dorothy Merritts, Bob Walters at Franklin and Marshall College; Scott Eaton and Steve Baedke at James Madison University; Rajith Mukundon at Hunter College, City University of New York; Arash Massoudieh at The Catholic University

USEPA – Ron Landy, Joseph Schubauer-Berigan, Paul Mayer

USGS – Milan Pavich, Cliff Hupp, Greg Noe, Faith Fitzpatrick, Katie Skalak; Edward Schenk; Ken Hyer, Joel Blomquist, John Brakebill

 

Past Research Assignment: Geomorphic Monitoring of the Kissimmee River Restoration, South-Central Florida

Assisted South Florida Water Management District in developing a geomorphic monitoring plan for the Kissimmee River Restoration Project (KRRP), which is among the largest ecosystem restoration projects in the world. The objective of this study was to establish a long-term geomorphic monitoring plan for the KRRP that will provide managers with data to manage the restoration.

A key question is whether the restored Kissimmee River channel will be stable under the new flow and sediment conditions.

The geomorphic plan we developed has three major components that are linked: (1) sediment transport (suspended and bedload), (2) channel morphologic analysis (plan-form and cross-sectional), and (3) flood-plain processes in restored and non-restored reaches in the Kissimmee River.

Key publications from the Kissimmee River study:

Gellis et al., 2010; Mossa et al., 2010; Schenk et al., 2011

Collaborators:

USGS – Cliff Hupp and Edward Schenk

University of Florida – Joann Mossa

USGS Florida Water Science Center

South Florida Water Management District

 

Past Research Assignment: Fingerprinting sources of fine-grained sediment in Laurel Hill Creek, PA

Laurel Hill Creek is a 324 km2 watershed in Somerset County, PA, tributary to the Youghiogheny River, which drains to the Ohio River. The Laurel Hill Creek watershed is 80% forested and 20% in agricultural. This watershed has great recreational value in that it has three state parks, including ski resorts and golf courses.

Competing interests of land development, maintaining an agricultural base, and sustaining environmental health are driving the interest to understand the significant sources of fine-grained sediment.

Study objectives in the Laurel Hill Creek watershed were to determine the sources of fine-grained sediment using the sediment fingerprinting approach.

The USGS publication on this study should be available in FY13.

Collaborator: Trout Unlimited, cooperator with the Pennsylvania WSC

 

Past Research Assignment: Sediment-source analysis of three tributaries to Lake Tahoe

Conducted a study with USDA-ARS to identify the significant sources of sediment in 3 watersheds draining to Lake Tahoe using the sediment fingerprinting approach.

Journal Publication on this study is expected out in 2013.

Collaborator: USDA-ARS - Andrew Simon

 

Past Research Assignment: Project Chief of the Rio Puerco study

My research on arroyo systems in the Southwest has focused on examining arroyo cut-and-fill cycles in the Late Quaternary, documenting arroyo channel changes in the historic record (last 100 years), and applying knowledge of arroyo dynamics and hillslope erosion to watershed rehabilitation strategies.

Interpretation made from my research suggests that over geologic time scales (~10,000 years) intrinsic processes may dictate when conditions are right for arroyo cutting.

Depending on the state of channel conditions (depth, width, channel slope, vegetation, etc.) the arroyo may not have the correct hydraulic conditions necessary for a climate change to trigger incision. This hypothesis that the state of the arroyo is important is further supported by my research on recent arroyo changes and climate changes in New Mexico.

Investigated geologic and modern rates of erosion in the Rio Puerco Basin using a variety of techniques.

  • The University of Vermont and the USGS collaborated to quantify denudation rates at the geologic scale (thousands of years) using Beryllium-10.
  • At the modern scale, field instruments were used to quantify the flux of sediment.

Results of the Rio Puerco study were presented at numerous scientific meetings and published in several outlets (Gellis et al., 2012; Elliott and others, 1999; Gellis and Elliott, 2001; Gellis and others, 2001).

During this period, I was also engaged in other studies including quantifying rates of channel change at the Chaco Culture National Historic Park (Gellis, 2002). A high point of my career during this period was working with Bill Emmett and Luna Leopold on semi-arid geomorphic processes in a watershed outside of Santa Fe, NM (Gellis and others, 2005b).

Collaborators:

USGS - Milan Pavich

New Mexico Bureau of Mines - Dave Love

Rio Puerco Management Committee

 

Past Research Assignment: Project Chief on a 3-year study in cooperation with the Zuni Indian Tribe, New Mexico to develop an approach to select a watershed for rehabilitation on the Reservation

Assisted the Zuni Indian Tribe in developing an approach to selection of a watershed for rehabilitation on the Reservation. The Zuni Conservation Project was one of the largest watershed restoration efforts in the Southwest.

We developed an approach to rank watersheds for restoration by using photogrammetric interpretations, erosion measurements, and channel surveys.

Results were presented at numerous scientific meetings and published in several outlets (Gellis et al., 1995, 1996, 1997; Gellis 1998a; Gellis et al., 2001a).

Collaborator: Zuni Indian Tribe

Past Research Assignment: Project Chief on a study examining sediment sources and their relation to reservoir sedimentation in San Juan’s main water-supply reservoir, Lago Loiza

Investigated suspended-sediment characteristics in humid-tropical watersheds in Puerto Rico.

The objectives of this research are to understand the significant hydrologic controls of suspended-sediment concentration and how previous events affect sediment concentrations.

I am also interested in how these controls on sediment characteristics will change in basins of differing land use (forest pasture, cropland, and urban).

Managed the sediment data collection program for the USGS Puerto Rico District. This included sediment collection at 21 streamflow stations, sediment records computation, and laboratory analysis of sediment.

Project Chief on a study examining sediment sources and their relation to reservoir sedimentation in San Juan’s main water-supply reservoir.

The study used a multi-disciplinary approach incorporating limnology, geomorphology, hydrology, GIS, aerial photographic interpretations, and sediment transport modeling.

Results were presented at numerous scientific meetings and published in several outlets (Gellis, 1993; Gellis and others, 1999; 2006). The data on suspended sediment I collected in Puerto Rico was used for my PhD dissertation (Gellis, 2003).

Collaborators:

USGS - Rick Webb

USDA-ARS - Sherwood McIntyre

Puerto Rican Aqueduct and Sewer Authority

 

Bibliography

Gellis, A.C., Elliott, J.G. and Pavich, M., 2017, Geomorphic processes responsible for decadal-scale arroyo changes, Rio Puerco, New Mexico: Geological Society of America Bulletin.

Gellis, A.C., Myers, M.K. Noe, G.B., Hupp, C.R. Schenk, E.R., and Myers, L., 2017, Storms, channel changes, and a sediment budget for an urban-suburban stream, Difficult Run, Virginia, USA: Geomorphology, v. 278, p.128–148.

Gellis, A., Fitzpatrick, F., and Schubauer-Berigan, J., 2016, A Manual to Identify Sources of Fluvial Sediment: EPA report, EPA/600/R-16/210, 106 p.  accessed at https://nepis.epa.gov/Exe/ZyPDF.cgi/P100QVM1.PDF?Dockey=P100QVM1.PDF

Collins, A.L., Pulley, S., Foster, I.D.L., Gellis., A., Porto, P., and Horowitz., A.J., 2017, Sediment source fingerprinting as an aid to catchment management: A review of the current state of knowledge and a methodological decision-tree for end-users, Journal of Environmental Management , http://dx.doi.org/10.1016/j.jenvman.2016.09.075.

Gellis, A.C., Fuller, C.C., Van Metre, P.C., 2017, Sources and ages of fine-grained sediment to streams using fallout radionuclides in the Midwestern United States: Journal of Environmental Management, v. 194, p. 73-85.  Available at https://authors.elsevier.com/a/1Uqbs14Z6tPRB1

Gellis, A.C., Fitzpatrick, F.A., Gorman-Sanisaca, Schunauer-Berigan, J. and Landy., R., 2015, Identifying Sediment Sources in the Sediment TMDL Process: 10th Federal Interagency Sedimentation Conference, Reno, NV, April 19-23, 2015, http://acwi.gov/sos/pubs/3rdJFIC/Contents/10A-Gellis.pdf

Gellis, A.C., Noe, G.B., Clune, J.W., Myers, M.K., Hupp, C.R., Schenk, E.R., and Schwarz, G.E., 2015, Sources of fine grained sediment in the Linganore Creek watershed, Frederick and Carroll Counties, Maryland, 2008–10: U.S. Geological Survey Scientific Investigations Report 2014–5147, 56 p. http://pubs.usgs.gov/sir/2014/5147/

Donovan, M., Miller, A., Baker., M., and Gellis., A., 2015, Sediment contributions from floodplains and legacy sediments to Piedmont streams of Baltimore County, Maryland Geomorphology, v. 235, p. 88-105.

Pizzuto, J., Schenk, E,R,, Hupp, C,R,, Gellis, A., Noe, G., Williamson, E., Karwan, D.L., O'Neal, M., Marquard, J., snf Aalto R., 2014, Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA: Water Resources Research, v. 50(2), p. 790-805.

Williamson, T. N., Christensen, V. G., Richardson, W. B., Frey, J. W., Gellis, A.C., Kieta, K. A., and Fitzpatrick, F. A., 2014, Stream Sediment Sources in Midwest Agricultural Basins with Land Retirement along Channel: Journal of Environmental Quality, v.43, p. 1624–1634.

Stewart, H.A., Massoudieh, A., and  Gellis, A., 2014, Sediment source apportionment in Laurel Hill Creek, PA, using Bayesian chemical mass balance and isotope fingerprinting Hydrological Processes, Published online in Wiley Online Library (wileyonlinelibrary.com) DOI:10.1002/hyp.10364, 15 p. This paper is based 100% on my data collection. 

Donovan, M., Miller, A., Baker., M., and Gellis., A., 2015, Sediment contributions from floodplains and legacy sediments to Piedmont streams of Baltimore County, Maryland Geomorphology, v. 235, p. 88-105

Gellis, A.C., Noe, G.B., Clune, J.W., Myers, M.K., Hupp, C.R., Schenk, E.R., and Schwarz, G.E., 2015, Sources of fine grained sediment in the Linganore Creek watershed, Frederick and Carroll Counties, Maryland, 2008–10: U.S. Geological Survey Scientific Investigations Report 2014–5147, 56 p.

Gellis, A.C., Fitzpatrick, F.A., Gorman-Sanisaca, Schubauer-Berigan, J. and Landy., R., 2015, Identifying Sediment Sources in the Sediment TMDL Process: 10th Federal Interagency Sedimentation Conference, Reno, NV, April 19-23, 2015, http://acwi.gov/sos/pubs/3rdJFIC/Contents/10A-Gellis.pdf

Gellis, A.C., 1988, Decreasing sediment and salt loads in the Colorado River basin--A response to arroyo evolution: Fort Collins, Colo., Colorado State University, unpublished M.S. thesis, 178 p.

Schumm, S.A., and Gellis, A.C., 1989, Sediment yield variations as a function of incised channel evolution, in Brush, L.M. et al., eds., Taming the Yellow River--Silt and floods: Kluwer Academic Publishers, p. 99-109.

Gellis, A.C., Hereford, R., and Schumm, S.A., 1989, Geomorphic and hydrologic control of sediment and salt loads in the Colorado River basin--Significance for conservation and land management: U.S. Geological Survey Open-File Report 89-121, 36 p.

Gellis, A.C., 1991, Construction effects on sediment for two basins, Puerto Rico: Proceedings of the Fifth Federal Interagency Sedimentation Conference, Las Vegas, Nev., chap. 4, p. 72-78.

Gellis, A.C., Hereford, R., Schumm, S.A., and Hayes, B.R., 1991, Channel evolution and hydrologic variations in the Colorado River basin--Factors influencing sediment and salt loads: Journal of Hydrology, v. 124, p. 317-344.

Gellis, A.C., 1992, Decreasing trends of suspended-sediment loads in selected streamflow stations in New Mexico: New Mexico Water Resources Research Institute Report No. 265, Proceedings of the 36th Annual New Mexico Water Conference, Las Cruces, N.Mex., p. 77-93.

Gellis, A.C., 1993, Results of investigation of erosion at the Petroglyph National Monument, New Mexico: U.S. Geological Survey Administrative Report, 27 p.

Gellis, A.C., 1993, The effects of Hurricane Hugo on suspended-sediment loads, Lago Loíza basin, Puerto Rico: Earth Surface Processes and Landforms, v.18, no. 5. p. 505-517.

Gellis, A.C., Cheama, A., Laahty, V., and Lalio, S., 1995, Assessment of gully-control structures in the Rio Nutria watershed, Zuni Reservation, New Mexico: Water Resources Bulletin, v. 31, no. 4, p. 633-636.

Gellis, A.C., 1995, Erosion assessment at the Petroglyph National Monument area, Albuquerque, New Mexico: U.S. Geological Survey Water-Resources Investigations Report 94-4205, 39 p.

Gellis, A.C., Andres, C., Lalio, S., and Enote, J., 1996, An approach to selecting a watershed for rehabilitation developed for the Zuni Reservation, New Mexico: Watershed 96 Proceedings, Baltimore, MD., June 8-12, 1996, p. 360-363.

Gellis, A.C., 1996, Gullying at the Petroglyph National Monument, New Mexico: Journal of Soil and Water Conservation, v.51, no.2, p.155-159.

Gellis, A.C., Andres, C., Lalio, S., and Enote, J., 1997, Selecting a watershed for rehabilitation at the Zuni Reservation. Watershed and Wet Weather Technical Bulletin, v.1, no. 1, p. 9-12.

Gellis, A.C., 1998a, Characterization and evaluation of channel and hillslope erosion on the Zuni Reservation, 1992-95: U.S. Geological Survey Water-Resources Investigations Report 97-4292, 51 p.

Gellis, A.C., 1998b, Surface-water and suspended-sediment inflow and outflow for Nutria Reservoir No. 3, Zuni Indian Reservation, New Mexico, March 1994 to September 1995: U.S. Geological Survey Water-Resources Investigations Report 98-4083, 22p.

Gellis, A.C., and Aby, S., 1998, Erosion yields in the Arroyo Chavez Basin, Rio Puerco, New Mexico: In Soil Water and Earthquakes around Socorro, New Mexico, Harrison, L.B.J., ed., Rocky Mountain Cell, Friends of the Pleistocene Field Trip Guidebook, September 10-13, 1998, 8 p.

Gellis, A.C., Webb, R.M.T., Wolfe, W.J., and McIntyre, S.C.I., 1999, Effects of land use on upland erosion, sediment transport, and reservoir sedimentation, Lago Loiza Basin, Puerto Rico: U.S. Geological Survey Water-Resources Investigations Report 99-4010, 60 p.

Elliott, J.G., Gellis, A.C., and Aby, S.B., 1999, Evolution of Arroyos--Incised Channels of the Southwestern United States: In Darby, S.E., and Simon, A., eds., Incised Channels--Processes, Forms, Engineering and Management, p. 153-185.

Gellis, A.C., Cheama, A., and Lalio, S.M., 2001a, Developing an approach for ranking watersheds for rehabilitation, Zuni Indian Reservation, New Mexico: Geomorphology, v. 37, p. 105-134.

Gellis, A.C., Pavich, M.J., and Ellwein, A., 2001b, Erosion and sediment yields in two subbasins of contrasting land use, Rio Puerco, New Mexico: Proceedings of the Seventh Federal Interagency Sedimentation Conference, Reno, Nevada, p. V83-V90.

Gellis, A.C, 2001, Factors controlling storm-generated suspended-sediment concentrations and loads in a humid-tropical basin, Quebrada Blanca, Puerto Rico: Proceedings of the Seventh Federal Interagency Sedimentation Conference, Reno, Nevada, p. V91-V98.

Love, D.W., and Gellis, A.C., 2001, What decision makers should know about arroyos in New Mexico: in Johnson, P.S., ed., Water, Watersheds, and Land Use in New Mexico, New Mexico Decision-Makers Field Guide no. 1, New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico, p. 81-83.

Gellis, A.C., and Elliott, J.G., 2001, Arroyo changes in selected watersheds of New Mexico, United States: In Harvey, M., and Anthony, D., eds., Applying Geomorphology to Environmental Management, A Special Publication Honoring Stanley A. Schumm, Water Resources Publications, LLC Press, p. 225-240.

Gellis, A., Pavich, M., Bierman, P., Ellwein, A., Aby, S., and Clapp, E., 2001, Comparison of geomorphic and isotopic measurements for erosion in the Rio Puerco, New Mexico, in Cole, J.C., ed., U. S. Geological Survey Middle Rio Grande basin study; proceedings Open-File Report - U. S. Geological Survey, U. S. Geological Survey, Reston, VA, p. 46-47.

Gellis, A.C., 2002, Twentieth Century Channel Changes in Chaco Culture National Historic Park: U.S. Geological Survey Water-Resources Investigations Report 01-4251, 42 p.

Gellis, A.C., 2003, Suspended-Sediment Characteristics in Four Humid Tropical Watersheds of Contrasting Land Use, Puerto Rico: Colorado State University, Unpublished PhD dissertation.

Gellis, A.C., Smith, S., and Stewart, S., 2003, Watershed sediment sources: in, A Summary Report of Sediment Processes in Chesapeake Bay and Watershed: edited by Michael Langland and Thomas Cronin, U.S. Geological Survey Water-Resources Investigations Report 03-4123, Chapter 3, p. 29-33.

Gellis, A.C., Pavich, M.J., Bierman, P., Ellwein, A., Aby, S., and Clapp, E., 2004, Modern sediment yield compared to geologic rates of sediment generation in a semiarid basin, New Mexico–Assessing the human impact: Earth Surface Processes and Landforms, v. 29, p.1359-1372.

Gellis, A.C., Banks, W.S.L., Langland, M.J., and Martucci, S., 2005a, Suspended-sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952-2002: Scientific Investigations Report 2004-5056, 59 p.

Gellis, A.C., Emmett, W.W., and Leopold, L.B., 2005b, Channel and hillslope processes revisited in the Arroyo de los Frijoles watershed near Santa Fe, New Mexico: U.S. Geological Survey Professional Paper 1704, 53 p.

Bierman, P.R., Reuter, J.M., Pavich, M., Gellis, A.C., Caffee, M.W., and Larsen, J., 2005, Using cosmogenic radionuclides to contrast rates of erosion and sediment yield in a semi-arid, arroyo-dominated landscape, Rio Puerco Basin, New Mexico: Earth Surfaces Processes and Landforms, v. 30, p. 935-953.

Gellis, A.C. and Landwehr, J.M., 2006a, Identifying sources of fine-grained suspended-sediment in the Pocomoke River, an Eastern Shore tributary to the Chesapeake Bay: Proceedings of the Joint Federal Interagency Conference 2006, 8th Federal Interagency Sedimentation Conference, April 2–6, 2006, Reno, NV, Paper 5C-1 in CD_ROM file ISBN 0-9779007-1-1, 9.

Gellis, A. C., Webb, R.M.T., Wolfe, W.J., and McIntyre, S.C.I., 2006b, Changes in Land use and Reservoir Sedimentation: A case study in the Lago Loiza basin, Puerto Rico: Physical Geography, v. 27, p. 39-69.

Gellis, A.C., Hupp, C.R., Pavich, M.J., Landwehr, J.M., Banks, W.S.L., Hubbard, B.E., Langland, M.J., Ritchie, J.C., and Reuter, J.M., 2009, Sources, Transport, and Storage of Sediment at Selected Sites in the Chesapeake Bay Watershed: Scientific Investigations Report 2008-5186, 95 p.

Mossa, J., Gellis, A.C., Hupp, C.R, Pearman, J.L., Garfield, U., Schenk, E., Rasmussen, J., Valdés, J., and Habermehl, P.,2010, Geomorphic Monitoring if the Kissimmee River Restoration-- 2006-2009: Final Report Submitted to the South Florida Water Management District Kissimmee River Division, West Palm Beach, FL, 195 p.

Devereux, O.H., Prestegaard, K.L., Needelman, B.A., Gellis, A.C., 2010, Suspended-sediment sources in an urban watershed, Northeast Branch Anacostia River, Maryland: Hydrological Processes, v. 24(11), p. 1391 – 1403.

Gellis., A.C., Pearman, Valdes, J.J., and Habermahl, P., 2010 Suspended-Sediment And Bedload Monitoring of the Kissimmee River Restoration, July 2007 Through September 2008: in Proceedings, 2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010, CD-ROM ISBN 978-0-0779007-3-2, 6D, 13p.

Clune, J.W., Gellis, A.C., and McKee, L.G., 2010, Agricultural Soil Erosion Rates for the Linganore Creek Watershed in the Piedmont Physiographic Province of the Chesapeake Bay Watershed: in Proceedings, 2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010, CD-ROM ISBN 978-0-0779007-3-2, 7A3, 8p.

Larsen, M.C., Gellis, A. C., Glysson, G.D., Gray, J.R., and Horowitz, A. J., 2010, Fluvial sediment in the environment: a national problem: in Proceedings, 2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010, 15 p.

Banks, W.S.L., Gellis, A.C., and Noe, G., 2010, Sources of Fine-Grained Suspended Sediment in Mill Stream Branch Watershed, Corsica River Basin, A Tributary to the Chesapeake Bay, Maryland, 2009, in Proceedings, 2nd Joint Federal Interagency, Las Vegas, NV, June 27 - July 1, 2010, CD-ROM ISBN 978-0-0779007-3-2, 6B, 12p.

Gellis, A.C., and Walling, D.E, 2011, Sediment-source fingerprinting (tracing) and sediment budgets as tools in targeting river and watershed restoration programs: Simon, A., Bennett, S.., Castro, J.M., eds., Stream Restoration in Dynamic Fluvial Systems: Scientific Approaches, Analyses, and Tools, American Geophysical Union Monograph Series 194, p. 263-291.

Merritts, D., Walter, R., Rahnis, M., Hartranft, J., Cox, S, Gellis, A., Potter, N., Hilgartner, W., Langland, M., Manion, L., Lippincott, C., Siddiqui, S., Rehman, Z., Scheid, C., Kratz, L., Shilling, A., Jenschke, M., Datin, K., Cranmer, E., Reed, A., Matuszewski, D., Voli, M., Ohlson, E., Neugebauer, A., Ahamed, A., Neal, C., Winter, A., and Becker, S., 2011, Anthropocene Streams and Base-level Controls from Historic Dams in the Unglaciated Mid-Atlantic Region, USA: Philosophical Transactions of the Royal Society A- Mathematical, Physical and Engineering Sciences, v. 369, p. 976-1009.

Schenk, E.R., Hupp, C.R., and Gellis, A.C., 2011, Sediment Dynamics in the Restored Reach of the Kissimmee River Basin, Florida-- A Vast Subtropical Riparian Wetland: River Research and Application, Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/rra.1577, 15 p.

Gellis, A.C., Pavich, M.J., Ellwein, A.L., Aby, S., Clark, I., Wieczorek, M.E., and Viger, R., 2012; Erosion, Storage, and Transport of Sediment in Two Subbasins of the Rio Puerco, New Mexico: Geological Society of America Bulletin, v. 124; no. 5/6; p. 817–841.

Schenk, E. R., Hupp, C. R., Gellis, A. and Noe, G. (2012), Developing a new stream metric for comparing stream function using a bank–floodplain sediment budget: a case study of three Piedmont streams. Earth Surf. Process. Landforms. doi: 10.1002/esp.3314

Massoudieh, A., Gellis., A.C., Banks, W.S., and Wieczorek, M.E., 2012, Suspended sediment source apportionment in Chesapeake Bay watershed using Bayesian chemical mass balance receptor modeling: Hydrological Processes, DOI: 10.1002/hyp.9429, published online: 6 JUL 2012.

Mukundan, R., Walling, D.E., Gellis, A.C., Slattery, M.C., and Radcliffe., D.R., 2012, Sediment Source Fingerprinting: Transforming from a Research Tool to a Management Tool: Journal of the American Water Resources Association, v. 48, no. 6, p. 1241–1257.

Sloto, R.A., Gellis, A.C., and Galeone, D.G., 2012, Total nitrogen and suspended-sediment loads and identification of suspended-sediment sources in the Laurel Hill Creek watershed, Somerset County, Pennsylvania, water years 2010–11: U.S. Geological Survey Scientific Investigations Report 2012–5250, 44 p.

Gellis, A.C., 2013, Factors influencing storm-generated suspended-sediment concentrations and loads in four basins of contrasting land use, humid-tropical Puerto Rico: CATENA, v. 104, p. 39-57.

Gellis, A.C., and Noe, G.B., 2013, Sediment source analysis in the Linganore Creek watershed, Maryland, USA, using the sediment fingerprinting approach: 2008 to 2010: In Mukundan, R., and Gellis, A.C., (eds.), Watershed Sediment Source Identification: Tools, Approaches, and Case Studies, Special issue of the Journal of Soils and Sediments, DOI 10.1007/s11368-013-0771-6, available online.

Gellis, A.C. and Mukundan, R., 2013, Watershed sediment source: identification: tools, approaches,and case studies: In Mukundan, R., and Gellis, A.C., (eds.), Watershed Sediment Source Identification: Tools, Approaches, and Case Studies, Special issue of the Journal of Soils and Sediments, DOI 10.1007/s11368-013-0778-z, available online.

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