In
Iceland 2001
Frank
Magilligan
Professor
Geography Department
Dartmouth College
Contact:
Magilligan@dartmouth.edu
BACKGROUND:
I attended graduate school at the University of Wisconsin, Madison and received
a MS degree in Water Resources Management (1981), a MS in Geography (1983), and
a Ph.D. in Geography (1988). My research interests focus primarily on fluvial
geomorphology and surface water hydrology. In particular, my research addresses
stream channel and watershed response to environmental change -- whether the
change is generated by natural (e.g. climate change) or anthropogenic (e.g.
agriculture, grazing, or logging) causes.
My main research interests have been on the response and recovery of
stream channels to either large floods or watershed disturbance, and I have
recently become especially interested in the links between channel processes
and riparian ecology. In
particular, most of my research over the past few years has concentrated on the
hydro-ecological impacts of dams.
In collaboration with Carl
Renshaw from the Earth Sciences Department and Keith Nislow from the Forest
Service, we have been documenting the impacts of flow regulation on sediment
transport, embeddedness, and benthic macro-invertebrate community
structure. In our recent NSF
grant, we are exploring the downstream changes associated with flow regulation
relative to overall watershed structure, especially that associated with
tributary inputs of water and sediment.
In this work, we are using the fallout radionuclides 7Be and 210Pb
as tracers but also to age in-channel deposits (we have an outstanding Fallout
Radionuclide Lab with 6 Gamma Detectors). Lastly, I have been working in Downeast Maine evaluating the
long-term effects of logging on large woody debris (LWD) and salmonid habitat
in coastal Maine rivers.
I am currently involved in several other
projects, including some recent work with an archaeologist from UC-San Diego,
Paul Goldstein, working on El Nino floods in Peru and
their significance on Tiwanaku site abandonment (which was initially been
published in Geology). In this research, we are examining the
long-term evolution of El Nino’s and their role in cultural history in the
Moquegua River valley in Peru’s Atacama Desert. As part of this work, we are
now developing the broader Late Pleistocene to modern hydro-climatology of the
Atacama Desert.
TEACHING INTERESTS:
Geomorphology
Geohydrology
Water Resources Management & Policy
Human Impacts on the Environment
Environmental Studies
GRAD
PROGRAM:
Because of my affiliation with the Earth
Sciences Department at Dartmouth, I am able to supervise graduate
students. For information on their
graduate program, please check out their informational web
page. To find out what more
about our research group, please check out our web page that highlights our research
foci or scroll down to the bottom of the page to see a description of some
of my recent projects.
PUBLICATIONS:
HYDRO-ECOLOGICAL IMPACTS OF DAMS:
· Curtis, K.E, Renshaw, C.E., Magilligan, F.J, and Dade,
W.B., n.d.,Temporal and spatial scales of geomorphic
adjustments to reduced competency following flow regulation in bedload
dominated systems, Geomorphology, Submitted.
· Zimmerman,
J.K.H, Letcher, B.H., Nislow, K.H., Lutz, K.A., and Magilligan, F.J., n.d.,
Determining the effects of dams on subdaily variation in river flows at a
whole-basin scale, River Research and
Applications, In Press.
·
Svendsen, K.M., Renshaw,
C.E., Magilligan, F.J., Nislow, K.H., and Kaste, J.M., 2009, Altered flow and
sediment regimes at tributary junctions on flow regulated rivers: impact of hydrologic disruptions on
benthic macroinvertebrate communities, Hydrological
Processes, 23: 284-296. doi:
10.1002/hyp.7144
· Magilligan
F.J., Salant, N.L., Renshaw, C.E., Nislow, K.H., Heimsath, A., and Kaste, J.,
2006, Evaluating the impacts of impoundment on sediment transport using
short-lived fallout radionuclides, In:
Sediment Dynamics and the Hydromorphology
of Fluvial Systems (Ed. Rowan, J. and Werrity, A.), The International
Association of Hydrological Sciences (IAHS) Special Publication 306, IAHS
Press, Wallingford, UK, pp. 159 – 165.
· Nislow, K.H., Magilligan, F.J., Fassnacht, H.,
Bechtel, D. and Ruesink, A., 2002, Effects of hydrologic alteration on flood
regime of natural floodplain communities in the Upper Connecticut River, Journal American Water Resources Association,
38: 1533-1548.
LARGE WOODY DEBRIS
EVOLUTION
OF EL NINO’S AND HYDROCLIMATOLOGY OF THE ATACAMA DESERT
GEOMORPHIC
IMPACTS OF CATASTROPHIC FLOODS
· Smith, L.C.,
Sheng, Y., Magilligan, F.J., Smith, N.D., Gomez, B., Mertes, L.A.K., Krabill,
W.B., and Garvin, J.B., 2006, Geomorphic impact and recovery from the 1996
Skeidarársandur jökulhlaup, Iceland assessed with repeat-pass airborne lidar, Geomorphology 75: 65-75.
· Nislow, K.H., Magilligan, F.J., Folt, C.L., and
Kennedy, B.P., 2002, Within-basin variation in the immediate effects of a major
flood on stream fishes and invertebrates, Journal
of Freshwater Ecology 17: 305-18.
· Smith, L.C., Alsdorf, D.E, Magilligan, F.J., Gomez,
B., Mertes, L.A.K., Smith, N.D., and Garvin, J.B., 2000, Estimation of erosion
and deposition from SAR interferometry and net topographic change during the
1996 jökulhlaup, Skeidararsandur, Iceland, Water
Resources Research, 36:1583-94.
· Brakenridge, G.R., Knox, J.C., Paylor, N., and
Magilligan, F.J., 1994, Radar remote sensing aids study of the Great Flood of
1993. EOS ,
75: 521-527.
· Magilligan, F. J. 1992, Thresholds and the spatial
variability of flood power during extreme floods, Geomorphology, 5:373-390.
· Magilligan, F.J., 1992, Sedimentology of a
fine-grained aggrading floodplain. Geomorphology , 4:393-408.
· Magilligan, F.J., 1988, Variations in slope components
during large magnitude floods, Wisconsin, Annals
Association American Geographers., 78: 520-533.
HUMAN IMPACTS ON WATERSHEDS
· Magilligan, F.J. and McDowell, P.F., 1997, Stream
channel adjustments following the elimination of cattle grazing, Journal of the American Water Resources
Association, 33: 867-878.
· McDowell, P.F. and Magilligan, F.J. 1997, Response of
stream channels to removal of cattle grazing disturbance: overview of western
U.S. exclosure studies, In (eds.) S.S.Y. Wang, E.J.
Langendoen, and F.D. Shields, Management
of Landscapes Disturbed by Channel Incision, pp. 469-75, Oxford,
Mississippi.
· Magilligan, F.J. and Stamp, M.L., 1997, Historical
land-cover changes and hydrogeomorphic adjustment in a small Georgia watershed,
Annals Association of American Geographers,
87: 614-35.
· Magilligan, F.J., 1985, Historical floodplain
sedimentation in the Galena River basin, Wisconsin and Illinois, Annals Association American Geographers,
75: 583-594.
GRANTS:
2008 The Nature Conservancy, ($27,174), Linking riparian
dis-connectivity to hydrologic reductions following flow regulation in the
Connecticut River basin, PI, Magilligan
2007 National Science Foundation, The effects
of dams on watershed fragmentation and riparian dis-connectivity across
multiple scales ($315,000), PI: Magilligan, co-PIs: C. Renshaw, J. Kaste, and
B. Dade.
2007 Dartmouth College Rockefeller Center,
Climate change, El Niño, and hydrologic development in the Atacama Desert,
southern Peru ($7800), PI: Magilligan.
2007 National Science Foundation, Acquisition
of Intrinsic Ge Gamma Spectrometers ($97,000). PI: Renshaw; co-PIs: Magilligan, Kaste, and Dade.
2006 USDA Forest Service, Monitoring the
effects of large woody debris on the sediment budgets of small streams in the
Green Mountain National Forest ($25,000), PI: Magilligan.
2005 National Fish and Wildlife Foundation,
Assessing the role of large woody debris in Maine watersheds ($118,000), PIs:
F.J. Magilligan and K.H. Nislow.
2004 Dartmouth College: Rockefeller Center for the Social Sciences, Climate change and
floodplain development in an arid Andean environment, ($13,000), P.I.
Magilligan, F.J.
2003 USDA Forest Service, Pattern and process
in channel unit structure in New England streams: implications for stream
ecosystems and fish populations ($10,000), PI: Magilligan.
2003 National Science Foundation, The impacts of flow regulation by dams on the physical
and ecological characteristics of rivers, ($244,000), PI: Magilligan, F.,
co-PIs: Renshaw, Heimsath, and Nislow.
2002 Dartmouth College: Rockefeller
Center, The impacts of flow regulation by dams on the physical and
ecological characteristics of rivers, ($16,000), Magilligan, F., PI
1999 Dartmouth College: Rockefeller Center, A multi-scale analysis of geomorphic and
ecological influences on pool development, ($20,000), Magilligan, F., PI.
1998 NASA Land Surface Hydrology
Program, Real-time forecasting and rapid post-event assessment of erosional
and depositional flood damage, ($343,000 for three years) PI: Smith, L. (UCLA);
Co-PIs: Alsdorf, D., Garvin, J., Gomez, B., Izenberg, N., Jacobson, R.,
Magilligan, F., and Mertes, L.
1997 The Nature Conservancy,
Hydrologic Regimes in the Connecticut River Rapids Macrosite (CRRM): links to
landscape change and ecological integrity, ($43,000), Magilligan, PI.
1997 National Science Foundation,
Geomorphic impacts of the jokulhlaup flood on the Skeidararsandur, Iceland.
Gomez, Magilligan, Mertes, Smith, co-PIs ($48,000)
1996 Dartmouth College: Rockefeller
Center for Social Sciences, Riparian and stream channel morphologic
adjustments in New England streams, ($6,810).
1994 National
Science Foundation. Processes
and timing of geomorphic and hydraulic adjustments during stream channel
recovery. ($105,000). P. McDowell (University of
Oregon), co-PI.
1993 Whiting
Foundation. Hydropolitics in
the Middle East: hydrologic and social impacts of the Ataturk Dam (Turkey)
($5,800). Magilligan, PI
1993 Dartmouth College: Rockefeller
Program for Interdisciplinary Research. The hydrologic response to
historical land use change in a Maine watershed ($10,000). Magilligan and
Birnie, co-PIs.
1993 National
Science Foundation. Overbank
sedimentation during the Upper Mississippi River flood of 1993 between
Muscatine and Keokuk. ($22,000). Gomez, Magilligan,
Phillips and James, co-PIs.
1992 National
Science Foundation. Teaching
Enhancement Workshop in Hydrology. Co-sponsored by NSF-USGS. ($500).
1992 National
Science Foundation. Response and recovery of watersheds to environmental change ($100,000).
Magilligan, PI.
1992 National
Science Foundation. Research Experience for Undergraduates ($5,000). Magilligan,
PI.
1991 American
Chemical Society. Spatial and temporal patterns of sediment mobility during basin
de-stabilization. ($18,000). Magilligan, PI.
1986 National Science Foundation:
Doctoral Dissertation Improvement Grant. Slope and roughness
variation in small, meandering channels ($11,610). Magilligan, PI.
1986 Geological
Society of America. Penrose Dissertation Research Award. Slope
and roughness variation in small, meandering channels ($800).
Magilligan, PI.
A. Hydro-ecological Impacts of Dams
In this
project we are analyzing the impacts of flow regulation across the Upper
Connecticut River watershed.
Numerous dams exist along the mainstem Connecticut River with most
side-valley tributaries also dammed – mainly for flood control. With funding from NSF and The Nature
Conservancy, we have been doing detailed hydrologic and geomorphic analyses of
these structures with current research addressing the changes occurring
downstream of these dams, both within the channel and across the broader
riparian zone. In particular, we
are trying to understand the complex ways that tributaries ameliorate or
exacerbate the effects of flow regulation, on the discharge of both sediment
and water. Field sampling of
sediment, in conjunction with detailed lab analyses of fallout radionuclide
activities, indicates the increased embeddedness and long-term sequestration of
sediment downstream of these impoundments. HEC-RAS
flow modeling suggests that in most instances, the modern d50 along
the channel bed is immobile with even the largest releases not competent to
move even d25. Unlike
the impacts of dams in the western US where channel incision and bar erosion
predominate following impoundment, our results further suggest that in
situations typical of these geomorphic environments, where bed incision is
minimal and where sediment loads are low but bed caliber high, bar growth and
channel narrowing are significant adjustments at tributary junctions.
Therefore, the effects of dams on reduced competency may be more profound than
on reduced capacity, highlighting the importance of geologic and geomorphic
settings in understanding the fluvial response to impoundment.
B.
Large Woody Debris and Salmonid Habitat in Coastal Maine Watersheds.
In conjunction with Keith Nislow and the Gulf
of Maine Fish and Wildlife Service, we have been documenting the impacts of
logging in coastal Maine watershed.
With funding from the National Fish and Wildlife 
Foundation, we
conducted a cross-basin analysis in seven watersheds in coastal Maine,
documenting the size, frequency, volume, position, and orientation of LWD, as
well as the association between LWD, pool formation, and sediment storage. In conjunction with these LWD surveys,
we conducted extensive riparian vegetation surveys. We observed very low LWD frequencies and volumes across the
60 km of rivers surveyed. Frequency of LWD > 20 cm
diameter ranged from 15-50 pieces per km and wood volumes were commonly
< 10-20 m3 per km.
Moreover, most of this wood was located in the immediate low-flow
channel zone, was oriented parallel to flow, and failed to span the stream
channel. As a result, pool
formation associated with LWD is generally lacking and < 20% of the wood was
associated with sediment storage.
Low LWD volumes are consistent with the relatively young riparian stands
we observed, with the large majority of trees < 20 cm DBH. These results strongly reflect
the legacy of intensive timber harvest and land clearing and suggest that the
frequency and distribution of LWD may be considerably less than pre-settlement
and/or future desired conditions.
We further investigated the role of LWD in
sequestering sediment. In a study
along a 9 km stretch of the Ducktrap River of coastal Maine where sediment
inputs are well constrained, we are using a novel application of 7Be (half-life
~53 days) to calculate the storage times of fine-grain sediment sequestered by
in-channel obstructions (large woody debris and boulders). Using a constant initial activity (CIA)
sediment storage aging model, normalized for variations in sediment surface
areas, yields young (< 106 days) storage times in bars associated with
channel obstructions in the transport-dominated section, while those in the
transport-limited reach were found to be older (> 200 days) as evidenced by
the lack of detectable 7Be activity in the majority of samples. Estimates of sediment accumulation
rates also varied between reaches from 0.2 g/cm2 per day in the
transport-dominated reach to 0.7 g/cm2 per day in the
transport-limited reach. These
results underscore the importance of wood frequency and size in providing
longer-term sediment sequestration and further indicate that in disturbed
landscapes there may be a compounding effect on in-channel habitat where
increased sediment inputs lead to greater embeddedness due to decreased channel
margin storage times.
C.
El Niño Floods and the Hydroclimatology of the Atacama Desert
Using a combination of stratigraphic
evidence, geochronologic dating (14C and OSL), stable isotope
analyses, and water geochemistry along the Rio Moquegua in the northern fringes
of the Atacama Desert, we are assembling a paleoflood chronology for mainstem
and tributary sections for the past ca. 20 ka and ascertaining the variation in
ENSO frequency and magnitude.
Because of the inherent watershed structure and regional
hydroclimatology, mid-valley tributaries of the Rio Moquegua only flood during
El Niño episodes and thus provide an important proxy of extreme El Niños while
mainstem stratigraphy records both La Niña and El Niño episodes. El Niño floods appear to have been
pronounced during the late Pleistocene and up to at least the Younger Dryas
(~12,000 cal yr BP) while stratigraphic evidence of large El Niño floods is
lacking in tributary systems during the mid-Holocene. Flood stratigraphy in a ~ 2 ka 7 m high terrace along the
mainstem indicates an increased frequency and magnitude of large floods between
ca. 700 -1610 AD as compared to the period from ca. 160 BCE to 700 AD with
"mega-Niños" occurring ca. 1650 AD and ca. 1330 AD. Water geochemistry indicates that two
major aquifers exist, with wells in the mid-valley dating to 710 14C yr BP
suggesting that groundwater flow is not fossil water from a wetter Late
Pleistocene on the Altiplano nor exclusively recharged from local
precipitation. The 18O similarity
between groundwater in the mid-valley and the regional meteoric water line
(MWL) suggests a Pacific moisture source and the role of El Niño precipitation
events in recharging local aquifers. Thus El Niños and Pacific-sourced moisture
are an important component of the regional hydroclimatology and the variation
in ENSO frequency and intensity has significant social and hydrologic
repercussions in these hyperarid settings.